ewf_image/

image.rs

use std::collections::VecDeque;
use std::fs::File;
use std::io::{self, Read, Seek, SeekFrom};
use std::num::NonZeroUsize;
use std::path::{Path, PathBuf};
use std::sync::{
    Arc, Mutex,
    atomic::{AtomicBool, Ordering},
};

use lru::LruCache;
use md5::Digest as _;

use crate::codepage::decode_header_bytes;
use crate::decode::{
    ChunkEncoding, decode_chunk, raw_chunk_size_cap, validate_encoded_size,
    zlib_compressed_chunk_size_cap,
};
use crate::format::{ewf1, ewf2};
use crate::index::{LazyChunkIndex, TableRange, TableRangeKind};
use crate::metadata::{
    Ewf2Geometry, detect_ewf1_header_profile, detect_ewf1_header2_profile, parse_error2_data,
    parse_ewf2_case_data, parse_ewf2_device_info, parse_ewf2_device_info_values,
    parse_ewf2_error_table_data, parse_header_data, parse_header2_data, parse_session_data,
    parse_xhash_data, parse_xheader_data,
};
use crate::segment::discover_segments;
use crate::signature::{check_segment_files_corruption, check_segment_files_encryption};
use crate::single_files::parse_ewf2_single_files_data;
use crate::types::{
    AcquisitionError, CompressionLevel, CompressionMethod, CompressionValues, DataChunk,
    DataChunkEncoding, EncodedDataChunk, EwfMetadata, Format, FormatProfile, HeaderCodepage,
    HeaderDateFormat, ImageInfo, MediaFlags, MediaInfo, MediaType, MemoryExtent, OpenOptions,
    OpenStrictness, SectorRange, SegmentFileVersion, SingleFileEntry, SingleFilePermission,
    SingleFileSource, SingleFileSubject, SingleFilesAuxTables, SingleFilesInfo, StoredHashes,
};
use crate::{EwfError, Result};

const MAX_DECOMPRESSED_METADATA: u64 = 16 * 1024 * 1024;
const MAX_CHUNK_SIZE: u64 = 128 * 1024 * 1024;
const EWF1_HASH_SECTION_SIZE: u64 = 36;
const EWF1_DIGEST_SECTION_SIZE: u64 = 80;
const EWF1_LTREE_HEADER_SIZE: usize = 48;
const EWF2_HASH_SECTION_SIZE: u64 = 32;
const EWF2_TABLE_HEADER_V2_SIZE: u64 = 32;
const EWF2_TABLE_FOOTER_SIZE: u64 = 16;

/// Reader type accepted by [`Image::open_readers`].
///
/// Implemented automatically for any `Read + Seek + Send` type. Override
/// [`SegmentReader::segment_len`] when obtaining the length by seeking to the
/// end is not appropriate.
pub trait SegmentReader: Read + Seek + Send {
    /// Returns the total length of this segment in bytes.
    fn segment_len(&mut self) -> io::Result<u64> {
        let position = self.stream_position()?;
        let len = self.seek(SeekFrom::End(0))?;
        self.seek(SeekFrom::Start(position))?;
        Ok(len)
    }
}

impl<T> SegmentReader for T where T: Read + Seek + Send {}

type SegmentReaderHandle = Box<dyn SegmentReader>;

#[derive(Debug, Clone)]
/// Opened EWF image and logical media reader.
pub struct Image {
    inner: Arc<ImageInner>,
}

#[derive(Debug)]
struct ImageInner {
    info: ImageInfo,
    segments: Mutex<SegmentFilePool>,
    index: LazyChunkIndex,
    chunk_cache: Mutex<LruCache<u64, Arc<Vec<u8>>>>,
    checksum_errors: Mutex<Vec<SectorRange>>,
    read_zero_chunk_on_error: AtomicBool,
    abort_signaled: AtomicBool,
}

struct SegmentFilePool {
    files: Vec<Option<SegmentReaderHandle>>,
    open_order: VecDeque<usize>,
    maximum_open_handles: Option<usize>,
    mode: SegmentFilePoolMode,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum SegmentFilePoolMode {
    ReopenFromPath,
    SuppliedReaders,
}

impl std::fmt::Debug for SegmentFilePool {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("SegmentFilePool")
            .field("segment_count", &self.files.len())
            .field("open_count", &self.open_count())
            .field("open_order", &self.open_order)
            .field("maximum_open_handles", &self.maximum_open_handles)
            .field("mode", &self.mode)
            .finish()
    }
}

#[derive(Debug, Clone, Copy)]
struct Chunk {
    segment_index: usize,
    offset: u64,
    encoded_size: u64,
    logical_size: usize,
    encoding: ChunkEncoding,
    validate_checksum: bool,
}

#[derive(Clone, Copy)]
struct Ewf1DecodedEntry {
    compressed: bool,
    offset: u64,
}

#[derive(Debug, Clone)]
/// Seekable cursor over an [`Image`] logical media stream.
pub struct ImageCursor {
    image: Image,
    position: u64,
}

#[derive(Debug, Clone)]
/// Seekable cursor over one logical single-file catalog entry.
pub struct SingleFileCursor {
    image: Image,
    entry: SingleFileEntry,
    position: u64,
}

impl Image {
    /// Opens an EWF image from the first segment path.
    ///
    /// Adjacent segments are discovered automatically from the first path.
    ///
    /// # Errors
    ///
    /// Returns an error if no segment set can be discovered, a segment cannot
    /// be read, or the image is unsupported or malformed.
    pub fn open(path: impl AsRef<Path>) -> Result<Self> {
        Self::open_with_options(path, OpenOptions::default())
    }

    /// Opens an EWF image from the first segment path with explicit options.
    ///
    /// # Errors
    ///
    /// Returns an error if no segment set can be discovered, a segment cannot
    /// be read, or the image is unsupported or malformed.
    pub fn open_with_options(path: impl AsRef<Path>, options: OpenOptions) -> Result<Self> {
        let paths = discover_segments(path.as_ref())?;
        Self::open_segment_paths(paths, options)
    }

    /// Opens an EWF image from an explicit ordered segment path list.
    ///
    /// # Errors
    ///
    /// Returns an error if the list is empty, a segment cannot be read, or the
    /// image is unsupported or malformed.
    pub fn open_segments<P, I>(paths: I) -> Result<Self>
    where
        P: AsRef<Path>,
        I: IntoIterator<Item = P>,
    {
        Self::open_segments_with_options(paths, OpenOptions::default())
    }

    /// Opens an EWF image from explicit ordered segment paths with options.
    ///
    /// # Errors
    ///
    /// Returns an error if the list is empty, a segment cannot be read, or the
    /// image is unsupported or malformed.
    pub fn open_segments_with_options<P, I>(paths: I, options: OpenOptions) -> Result<Self>
    where
        P: AsRef<Path>,
        I: IntoIterator<Item = P>,
    {
        let paths = paths
            .into_iter()
            .map(|path| path.as_ref().to_path_buf())
            .collect();
        Self::open_segment_paths(paths, options)
    }

    /// Opens an EWF image from supplied readers and segment labels.
    ///
    /// Supplied readers are kept by the image and are not reopened from the
    /// filesystem. Labels are used anywhere this crate reports segment paths.
    ///
    /// # Errors
    ///
    /// Returns an error if the list is empty, a reader fails, or the image is
    /// unsupported or malformed.
    pub fn open_readers<N, R, I>(segments: I) -> Result<Self>
    where
        N: Into<PathBuf>,
        R: SegmentReader + 'static,
        I: IntoIterator<Item = (N, R)>,
    {
        Self::open_readers_with_options(segments, OpenOptions::default())
    }

    /// Opens an EWF image from supplied readers with explicit options.
    ///
    /// # Errors
    ///
    /// Returns an error if the list is empty, a reader fails, or the image is
    /// unsupported or malformed.
    pub fn open_readers_with_options<N, R, I>(segments: I, options: OpenOptions) -> Result<Self>
    where
        N: Into<PathBuf>,
        R: SegmentReader + 'static,
        I: IntoIterator<Item = (N, R)>,
    {
        let mut paths = Vec::new();
        let mut readers = Vec::new();
        for (name, reader) in segments {
            paths.push(name.into());
            readers.push(Box::new(reader) as SegmentReaderHandle);
        }
        Self::open_segment_readers(paths, readers, options)
    }

    fn open_segment_paths(paths: Vec<PathBuf>, options: OpenOptions) -> Result<Self> {
        if paths.is_empty() {
            return Err(EwfError::NoSegments("empty segment list".into()));
        }

        let segments = SegmentFilePool::new_path(paths.len(), options.maximum_open_handles)?;
        Self::open_segment_sources(paths, segments, options)
    }

    fn open_segment_readers(
        paths: Vec<PathBuf>,
        readers: Vec<SegmentReaderHandle>,
        options: OpenOptions,
    ) -> Result<Self> {
        if paths.is_empty() {
            return Err(EwfError::NoSegments("empty segment list".into()));
        }
        if paths.len() != readers.len() {
            return Err(EwfError::Malformed(
                "segment reader count does not match segment labels".into(),
            ));
        }

        let segments = SegmentFilePool::new_readers(readers, options.maximum_open_handles)?;
        Self::open_segment_sources(paths, segments, options)
    }

    fn open_segment_sources(
        paths: Vec<PathBuf>,
        mut segments: SegmentFilePool,
        options: OpenOptions,
    ) -> Result<Self> {
        let mut ranges = Vec::new();
        let mut metadata = EwfMetadata::default();
        let mut acquisition_errors = Vec::new();
        let mut memory_extents = Vec::new();
        let mut single_files = None;
        let mut ewf2_single_files_tables = SingleFilesAuxTables::default();
        let mut ewf2_increment_data = Vec::new();
        let mut ewf2_final_information = None;
        let mut ewf2_restart_data = None;
        let mut ewf2_analytical_data = None;
        let mut sessions = Vec::new();
        let mut tracks = Vec::new();
        let mut stored_hashes = StoredHashes::default();
        let mut media = MediaInfo::default();
        let mut chunk_size = 0;
        let mut logical_size = 0;
        let mut acquisition_complete = true;
        let mut format = None;
        let mut format_profile = None;
        let mut format_profile_hint_only = false;
        let mut next_ewf1_chunk = 0_u64;
        let mut discovered_table_chunks = 0_u64;
        let mut expected_set_identifier: Option<[u8; 16]> = None;
        let mut expected_ewf2_header_profile = None;
        let mut expected_ewf2_device_information = None;
        let mut expected_ewf2_case_data = None;

        for (segment_index, path) in paths.iter().enumerate() {
            let parsed = {
                let file = segments.file_mut(segment_index, path)?;
                parse_segment(
                    file.as_mut(),
                    path,
                    segment_index,
                    next_ewf1_chunk,
                    options.strictness,
                    options.header_codepage,
                )?
            };
            let expected_segment_number = u64::try_from(segment_index + 1)
                .map_err(|_| EwfError::Malformed("segment index overflow".into()))?;
            if parsed.segment_number != expected_segment_number {
                return Err(EwfError::Malformed(format!(
                    "segment {} declares segment number {}, expected {}",
                    segment_index + 1,
                    parsed.segment_number,
                    expected_segment_number
                )));
            }
            validate_set_identifier(&mut expected_set_identifier, parsed.set_identifier)?;
            validate_ewf2_header_profile(
                &mut expected_ewf2_header_profile,
                parsed.ewf2_header_profile,
            )?;
            if let Some(device_information) = parsed.ewf2_device_information.as_deref() {
                remember_ewf2_metadata_payload(
                    &mut expected_ewf2_device_information,
                    device_information,
                    "device information",
                )?;
            }
            if let Some(case_data) = parsed.ewf2_case_data.as_deref() {
                remember_ewf2_metadata_payload(
                    &mut expected_ewf2_case_data,
                    case_data,
                    "case data",
                )?;
            }
            if segment_index == 0 {
                chunk_size = parsed.chunk_size;
                logical_size = parsed.logical_size;
                acquisition_complete = parsed.acquisition_complete;
                media = parsed.media;
                metadata = parsed.metadata;
                acquisition_errors = parsed.acquisition_errors;
                memory_extents = parsed.memory_extents;
                single_files = parsed.single_files;
                ewf2_single_files_tables = parsed.ewf2_single_files_tables;
                ewf2_increment_data = parsed.ewf2_increment_data;
                ewf2_final_information = parsed.ewf2_final_information;
                ewf2_restart_data = parsed.ewf2_restart_data;
                ewf2_analytical_data = parsed.ewf2_analytical_data;
                sessions = parsed.sessions;
                tracks = parsed.tracks;
                format = Some(parsed.format);
                format_profile = Some(parsed.format_profile);
                format_profile_hint_only = parsed.format_profile_hint_only;
            } else {
                merge_segment_format_profile(
                    &mut format_profile,
                    &mut format_profile_hint_only,
                    parsed.format_profile,
                    parsed.format_profile_hint_only,
                )?;
                memory_extents.extend(parsed.memory_extents);
                merge_single_files(&mut single_files, parsed.single_files)?;
                merge_single_files_aux_tables(
                    &mut ewf2_single_files_tables,
                    parsed.ewf2_single_files_tables,
                )?;
                ewf2_increment_data.extend(parsed.ewf2_increment_data);
                merge_optional_ewf2_raw_section(
                    &mut ewf2_final_information,
                    parsed.ewf2_final_information,
                    "final information",
                )?;
                merge_optional_ewf2_string_section(
                    &mut ewf2_restart_data,
                    parsed.ewf2_restart_data,
                    "restart data",
                )?;
                merge_optional_ewf2_string_section(
                    &mut ewf2_analytical_data,
                    parsed.ewf2_analytical_data,
                    "analytical data",
                )?;
                sessions.extend(parsed.sessions);
                tracks.extend(parsed.tracks);
                acquisition_complete = parsed.acquisition_complete;
            }
            merge_hashes(&mut stored_hashes, &parsed.stored_hashes);
            if parsed.format == Format::Ewf1 {
                next_ewf1_chunk = next_ewf1_chunk
                    .checked_add(parsed.table_chunk_count)
                    .ok_or_else(|| EwfError::Malformed("EWF1 chunk count overflow".into()))?;
            }
            for range in &parsed.ranges {
                discovered_table_chunks = discovered_table_chunks.max(
                    range
                        .first_chunk
                        .checked_add(range.chunk_count)
                        .ok_or_else(|| {
                            EwfError::Malformed("table range chunk count overflow".into())
                        })?,
                );
            }
            ranges.extend(parsed.ranges);
        }

        let format = format.ok_or_else(|| EwfError::Malformed("image has no segments".into()))?;
        if format == Format::Ewf2
            && expected_ewf2_device_information.is_none()
            && expected_ewf2_case_data.is_none()
        {
            return Err(EwfError::Malformed(
                "missing EWF2 device information or case data section".into(),
            ));
        }

        if logical_size == 0 && chunk_size > 0 {
            logical_size = chunk_size
                .checked_mul(discovered_table_chunks)
                .ok_or_else(|| EwfError::Malformed("logical size overflow".into()))?;
        }
        if discovered_table_chunks > 0 {
            media.chunk_count = Some(discovered_table_chunks);
        }

        let info = ImageInfo {
            format,
            format_profile: format_profile.unwrap_or_default(),
            segment_count: paths.len(),
            segment_paths: paths,
            chunk_size,
            logical_size,
            acquisition_complete,
            header_codepage: options.header_codepage,
            header_values_date_format: options.header_values_date_format,
            media,
            metadata,
            stored_hashes,
            acquisition_errors,
            memory_extents,
            single_files,
            ewf2_single_files_tables,
            ewf2_increment_data,
            ewf2_final_information,
            ewf2_restart_data,
            ewf2_analytical_data,
            sessions,
            tracks,
        };
        let index = LazyChunkIndex::new(ranges, info.logical_size, info.chunk_size)?;
        let cache_size = NonZeroUsize::new(options.chunk_cache_size.max(1))
            .expect("chunk cache size is at least one");

        Ok(Self {
            inner: Arc::new(ImageInner {
                info,
                segments: Mutex::new(segments),
                index,
                chunk_cache: Mutex::new(LruCache::new(cache_size)),
                checksum_errors: Mutex::new(Vec::new()),
                read_zero_chunk_on_error: AtomicBool::new(options.read_zero_chunk_on_error),
                abort_signaled: AtomicBool::new(false),
            }),
        })
    }

    /// Returns parsed image metadata and geometry.
    pub fn info(&self) -> &ImageInfo {
        &self.inner.info
    }

    /// Returns the first segment filename or supplied-reader label.
    pub fn filename(&self) -> &Path {
        self.inner.info.segment_paths[0].as_path()
    }

    /// Returns the number of segments in the opened image.
    pub fn number_of_segments(&self) -> usize {
        self.inner.info.segment_count
    }

    /// Returns the configured maximum number of open segment handles.
    ///
    /// # Errors
    ///
    /// Returns an error if the internal segment pool lock is poisoned.
    pub fn maximum_number_of_open_handles(&self) -> Result<Option<usize>> {
        Ok(self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?
            .maximum_open_handles())
    }

    /// Updates the maximum number of open segment handles.
    ///
    /// `None` allows all handles to remain open. Supplied-reader images cannot
    /// evict and reopen readers, so this value is validated against the reader
    /// set.
    ///
    /// # Errors
    ///
    /// Returns an error if the value is invalid for supplied readers or if the
    /// internal segment pool lock is poisoned.
    pub fn set_maximum_number_of_open_handles(
        &self,
        maximum_open_handles: Option<usize>,
    ) -> Result<()> {
        self.inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?
            .set_maximum_open_handles(maximum_open_handles)
    }

    /// Returns the current number of open segment handles.
    ///
    /// # Errors
    ///
    /// Returns an error if the internal segment pool lock is poisoned.
    pub fn number_of_open_segment_handles(&self) -> Result<usize> {
        Ok(self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?
            .open_count())
    }

    /// Returns all segment filenames or supplied-reader labels.
    pub fn segment_filenames(&self) -> &[PathBuf] {
        &self.inner.info.segment_paths
    }

    /// Returns one segment filename or supplied-reader label by index.
    pub fn segment_filename(&self, index: usize) -> Option<&Path> {
        self.inner
            .info
            .segment_paths
            .get(index)
            .map(PathBuf::as_path)
    }

    /// Returns the total byte size of all opened segment containers.
    ///
    /// For supplied readers, this uses [`SegmentReader::segment_len`].
    ///
    /// # Errors
    ///
    /// Returns an error if a segment length cannot be read, the internal segment
    /// pool lock is poisoned, or the total size overflows `u64`.
    pub fn segment_set_size(&self) -> Result<u64> {
        let paths = self.inner.info.segment_paths.clone();
        let mut segments = self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?;
        let mut size = 0_u64;
        for (segment_index, path) in paths.iter().enumerate() {
            size = size
                .checked_add(segments.file_mut(segment_index, path)?.segment_len()?)
                .ok_or_else(|| EwfError::Malformed("segment set size overflow".into()))?;
        }
        Ok(size)
    }

    /// Probes path-backed segment files for corruption-style structural errors.
    ///
    /// Images opened from supplied readers return `false` because there are no
    /// filesystem paths to reprobe.
    ///
    /// # Errors
    ///
    /// Returns an error if a path-backed probe fails unexpectedly.
    pub fn segment_files_corrupted(&self) -> Result<bool> {
        if self.has_supplied_segment_readers()? {
            return Ok(false);
        }
        check_segment_files_corruption(self.segment_filenames())
    }

    /// Probes path-backed segment files for EWF2 encryption markers.
    ///
    /// Images opened from supplied readers return `false` because there are no
    /// filesystem paths to reprobe.
    ///
    /// # Errors
    ///
    /// Returns an error if a path-backed probe fails unexpectedly.
    pub fn segment_files_encrypted(&self) -> Result<bool> {
        if self.has_supplied_segment_readers()? {
            return Ok(false);
        }
        check_segment_files_encryption(self.segment_filenames())
    }

    /// Returns the segment containing a logical chunk.
    ///
    /// # Errors
    ///
    /// Returns an error if `chunk_index` is outside the parsed chunk index or if
    /// the chunk index references a missing segment.
    pub fn segment_filename_for_chunk(&self, chunk_index: u64) -> Result<&Path> {
        let chunk = self.lookup_chunk(chunk_index)?;
        self.segment_filename(chunk.segment_index)
            .ok_or_else(|| EwfError::Malformed("chunk references missing segment".into()))
    }

    /// Returns the segment containing a logical byte offset.
    ///
    /// Offsets at or beyond the logical media size return `Ok(None)`.
    ///
    /// # Errors
    ///
    /// Returns an error if the chunk geometry is malformed.
    pub fn segment_filename_for_offset(&self, offset: u64) -> Result<Option<&Path>> {
        if offset >= self.inner.info.logical_size {
            return Ok(None);
        }
        let chunk_size = self.inner.info.chunk_size;
        if chunk_size == 0 {
            return Err(EwfError::Malformed("chunk size is zero".into()));
        }
        self.segment_filename_for_chunk(offset / chunk_size)
            .map(Some)
    }

    /// Returns the top-level EWF format generation.
    pub fn format(&self) -> Format {
        self.inner.info.format
    }

    /// Returns the inferred format profile.
    pub fn format_profile(&self) -> FormatProfile {
        self.inner.info.format_profile
    }

    /// Returns the logical chunk size in bytes.
    pub fn chunk_size(&self) -> u64 {
        self.inner.info.chunk_size
    }

    /// Returns the logical media size in bytes.
    pub fn media_size(&self) -> u64 {
        self.inner.info.logical_size
    }

    /// Returns the header codepage used for decoded EWF1 values.
    pub fn header_codepage(&self) -> HeaderCodepage {
        self.inner.info.header_codepage
    }

    /// Returns the date format applied to header date values.
    pub fn header_values_date_format(&self) -> HeaderDateFormat {
        self.inner.info.header_values_date_format
    }

    /// Returns sectors per chunk from media metadata.
    pub fn sectors_per_chunk(&self) -> Option<u64> {
        self.inner.info.media.sectors_per_chunk
    }

    /// Returns bytes per sector from media metadata.
    pub fn bytes_per_sector(&self) -> Option<u64> {
        self.inner.info.media.bytes_per_sector
    }

    /// Returns the logical sector count from media metadata.
    pub fn number_of_sectors(&self) -> Option<u64> {
        self.inner.info.media.sector_count
    }

    /// Returns the logical chunk count from media metadata.
    pub fn number_of_chunks(&self) -> Option<u64> {
        self.inner.info.media.chunk_count
    }

    /// Returns error granularity in sectors from media metadata.
    pub fn error_granularity(&self) -> Option<u64> {
        self.inner.info.media.error_granularity
    }

    /// Returns the segment set identifier.
    pub fn segment_file_set_identifier(&self) -> Option<[u8; 16]> {
        self.inner.info.media.set_identifier
    }

    /// Returns the EWF2 segment file version.
    pub fn segment_file_version(&self) -> Option<SegmentFileVersion> {
        self.inner.info.media.ewf2_segment_file_version
    }

    /// Returns the stored compression method metadata.
    pub fn compression_method(&self) -> Option<CompressionMethod> {
        self.inner.info.media.compression_method
    }

    /// Returns stored compression level and flags metadata.
    pub fn compression_values(&self) -> CompressionValues {
        self.inner.info.media.compression_values
    }

    /// Returns media type metadata.
    pub fn media_type(&self) -> Option<MediaType> {
        self.inner.info.media.media_type
    }

    /// Returns media flag metadata.
    pub fn media_flags(&self) -> MediaFlags {
        self.inner.info.media.media_flags
    }

    /// Returns memory acquisition extents.
    pub fn memory_extents(&self) -> &[MemoryExtent] {
        &self.inner.info.memory_extents
    }

    /// Returns the number of memory acquisition extents.
    pub fn number_of_memory_extents(&self) -> usize {
        self.inner.info.memory_extents.len()
    }

    /// Returns one memory acquisition extent by index.
    pub fn memory_extent(&self, index: usize) -> Option<&MemoryExtent> {
        self.inner.info.memory_extents.get(index)
    }

    /// Returns raw EWF2 increment data sections.
    pub fn ewf2_increment_data(&self) -> &[Vec<u8>] {
        &self.inner.info.ewf2_increment_data
    }

    /// Returns the number of EWF2 increment data sections.
    pub fn number_of_ewf2_increment_data_sections(&self) -> usize {
        self.inner.info.ewf2_increment_data.len()
    }

    /// Returns one raw EWF2 increment data section by index.
    pub fn ewf2_increment_data_section(&self, index: usize) -> Option<&[u8]> {
        self.inner
            .info
            .ewf2_increment_data
            .get(index)
            .map(Vec::as_slice)
    }

    /// Returns the raw EWF2 final information section.
    pub fn ewf2_final_information(&self) -> Option<&[u8]> {
        self.inner.info.ewf2_final_information.as_deref()
    }

    /// Returns EWF2 restart data text.
    pub fn ewf2_restart_data(&self) -> Option<&str> {
        self.inner.info.ewf2_restart_data.as_deref()
    }

    /// Returns EWF2 analytical data text.
    pub fn ewf2_analytical_data(&self) -> Option<&str> {
        self.inner.info.ewf2_analytical_data.as_deref()
    }

    /// Returns a header value by its EWF identifier.
    pub fn header_value(&self, identifier: &str) -> Option<std::borrow::Cow<'_, str>> {
        self.inner
            .info
            .metadata
            .header_value_with_date_format(identifier, self.inner.info.header_values_date_format)
    }

    /// Returns the number of available header values.
    pub fn number_of_header_values(&self) -> usize {
        self.inner.info.metadata.number_of_header_values()
    }

    /// Returns a header value identifier by enumeration index.
    pub fn header_value_identifier(&self, index: usize) -> Option<&str> {
        self.inner.info.metadata.header_value_identifier(index)
    }

    /// Returns a stored hash string by identifier.
    pub fn hash_value(&self, identifier: &str) -> Option<&str> {
        self.inner.info.stored_hashes.hash_value(identifier)
    }

    /// Returns the number of stored hash strings.
    pub fn number_of_hash_values(&self) -> usize {
        self.inner.info.stored_hashes.number_of_hash_values()
    }

    /// Returns a stored hash identifier by enumeration index.
    pub fn hash_value_identifier(&self, index: usize) -> Option<&str> {
        self.inner.info.stored_hashes.hash_value_identifier(index)
    }

    /// Returns a seekable cursor over the logical media stream.
    pub fn cursor(&self) -> ImageCursor {
        ImageCursor {
            image: self.clone(),
            position: 0,
        }
    }

    /// Reads logical media bytes at an absolute byte offset.
    ///
    /// Returns `Ok(0)` when `buf` is empty or `offset` is at or beyond the
    /// logical media size.
    ///
    /// # Errors
    ///
    /// Returns an error if chunk lookup, decoding, checksum validation, or
    /// segment I/O fails, or if [`Image::signal_abort`] has been called.
    pub fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize> {
        self.ensure_not_aborted()?;
        if buf.is_empty() || offset >= self.inner.info.logical_size {
            return Ok(0);
        }

        let chunk_size = self.inner.info.chunk_size;
        if chunk_size == 0 {
            return Err(EwfError::Malformed("chunk size is zero".into()));
        }

        let available = self.inner.info.logical_size - offset;
        let requested = u64::try_from(buf.len())
            .map_err(|_| EwfError::Malformed("read buffer length does not fit u64".into()))?;
        let to_read = available.min(requested);
        let mut copied = 0_usize;
        let mut current = offset;

        while u64::try_from(copied).expect("usize fits u64") < to_read {
            self.ensure_not_aborted()?;
            let chunk_id = current / chunk_size;
            let page_offset = usize::try_from(current % chunk_size)
                .map_err(|_| EwfError::Malformed("page offset does not fit usize".into()))?;
            let decoded = self.read_chunk(chunk_id)?;
            let remaining =
                usize::try_from(to_read - u64::try_from(copied).unwrap()).map_err(|_| {
                    EwfError::Malformed("remaining read size does not fit usize".into())
                })?;
            let page_available = decoded.len().saturating_sub(page_offset);
            let n = remaining.min(page_available);
            if n == 0 {
                break;
            }

            buf[copied..copied + n].copy_from_slice(&decoded[page_offset..page_offset + n]);
            copied += n;
            current += u64::try_from(n).expect("usize fits u64");
        }

        Ok(copied)
    }

    /// Alias for [`Image::read_at`].
    ///
    /// # Errors
    ///
    /// Returns the same errors as [`Image::read_at`].
    pub fn read_buffer_at_offset(&self, buf: &mut [u8], offset: u64) -> Result<usize> {
        self.read_at(buf, offset)
    }

    /// Reads bytes from a logical single-file catalog entry.
    ///
    /// Sparse extents read as zeroes. Duplicate-data entries read from their
    /// referenced media offset.
    ///
    /// # Errors
    ///
    /// Returns an error if the entry metadata is inconsistent, the requested
    /// file range is not covered by extents, underlying image reads fail, or
    /// [`Image::signal_abort`] has been called.
    pub fn read_single_file_at(
        &self,
        entry: &SingleFileEntry,
        buf: &mut [u8],
        offset: u64,
    ) -> Result<usize> {
        self.ensure_not_aborted()?;
        if buf.is_empty() {
            return Ok(0);
        }

        let file_size = single_file_size(entry)?;
        if offset >= file_size {
            return Ok(0);
        }

        let requested = u64::try_from(buf.len())
            .map_err(|_| EwfError::Malformed("read buffer length does not fit u64".into()))?;
        let to_read = requested.min(file_size - offset);
        let mut copied = 0_usize;
        let mut file_position = 0_u64;

        if entry.extents.is_empty()
            && let Some(duplicate_data_offset) = entry.duplicate_data_offset
            && duplicate_data_offset >= 0
        {
            let duplicate_data_offset = u64::try_from(duplicate_data_offset).map_err(|_| {
                EwfError::Malformed("single file duplicate data offset does not fit u64".into())
            })?;
            let image_offset = duplicate_data_offset.checked_add(offset).ok_or_else(|| {
                EwfError::Malformed("single file duplicate data offset overflow".into())
            })?;
            let read_size = usize::try_from(to_read).map_err(|_| {
                EwfError::Malformed("single file duplicate read size does not fit usize".into())
            })?;
            let out = &mut buf[..read_size];
            let read = self.read_at(out, image_offset)?;
            if read != read_size {
                return Err(EwfError::Malformed(
                    "single file duplicate data read was truncated".into(),
                ));
            }
            return Ok(read);
        }

        for extent in &entry.extents {
            let extent_start = file_position;
            let extent_end = extent_start
                .checked_add(extent.data_size)
                .ok_or_else(|| EwfError::Malformed("single file extent range overflow".into()))?;
            file_position = extent_end;

            let read_start = offset.max(extent_start);
            let read_end = (offset + to_read).min(extent_end);
            if read_start >= read_end {
                continue;
            }

            let extent_relative_offset = read_start
                .checked_sub(extent_start)
                .ok_or_else(|| EwfError::Malformed("single file extent offset underflow".into()))?;
            let output_offset = usize::try_from(read_start - offset).map_err(|_| {
                EwfError::Malformed("single file output offset does not fit usize".into())
            })?;
            let read_size = usize::try_from(read_end - read_start).map_err(|_| {
                EwfError::Malformed("single file read size does not fit usize".into())
            })?;
            let out = &mut buf[output_offset..output_offset + read_size];

            if extent.sparse {
                out.fill(0);
                copied += read_size;
                continue;
            }

            let image_offset = extent
                .data_offset
                .checked_add(extent_relative_offset)
                .ok_or_else(|| {
                    EwfError::Malformed("single file extent data offset overflow".into())
                })?;
            let read = self.read_at(out, image_offset)?;
            if read != read_size {
                return Err(EwfError::Malformed(
                    "single file extent read was truncated".into(),
                ));
            }
            copied += read_size;
        }

        if u64::try_from(copied).expect("usize fits u64") != to_read {
            return Err(EwfError::Malformed(
                "single file extents do not cover requested range".into(),
            ));
        }
        Ok(copied)
    }

    /// Alias for [`Image::read_single_file_at`].
    ///
    /// # Errors
    ///
    /// Returns the same errors as [`Image::read_single_file_at`].
    pub fn read_file_entry_at(
        &self,
        entry: &SingleFileEntry,
        buf: &mut [u8],
        offset: u64,
    ) -> Result<usize> {
        self.read_single_file_at(entry, buf, offset)
    }

    /// Returns the root logical single-file entry, if present.
    pub fn root_file_entry(&self) -> Option<&SingleFileEntry> {
        self.inner
            .info
            .single_files
            .as_ref()
            .map(|single_files| &single_files.root)
    }

    /// Returns a logical single-file entry by path.
    ///
    /// # Errors
    ///
    /// Returns an error if `path` contains an empty entry name.
    pub fn file_entry_by_path(&self, path: &str) -> Result<Option<&SingleFileEntry>> {
        self.inner
            .info
            .single_files
            .as_ref()
            .map_or(Ok(None), |single_files| single_files.entry_by_path(path))
    }

    /// Returns the source record associated with a logical single-file entry.
    pub fn source_for_file_entry(&self, entry: &SingleFileEntry) -> Option<&SingleFileSource> {
        self.inner
            .info
            .single_files
            .as_ref()?
            .source_for_entry(entry)
    }

    /// Returns the subject record associated with a logical single-file entry.
    pub fn subject_for_file_entry(&self, entry: &SingleFileEntry) -> Option<&SingleFileSubject> {
        self.inner
            .info
            .single_files
            .as_ref()?
            .subject_for_entry(entry)
    }

    /// Returns access-control entries associated with a logical single-file entry.
    pub fn access_control_entries_for_file_entry(
        &self,
        entry: &SingleFileEntry,
    ) -> &[SingleFilePermission] {
        self.inner
            .info
            .single_files
            .as_ref()
            .map_or(&[], |single_files| {
                single_files.access_control_entries_for_entry(entry)
            })
    }

    /// Returns the number of access-control entries for a logical single-file entry.
    pub fn number_of_access_control_entries_for_file_entry(
        &self,
        entry: &SingleFileEntry,
    ) -> usize {
        self.access_control_entries_for_file_entry(entry).len()
    }

    /// Returns one access-control entry for a logical single-file entry by index.
    pub fn access_control_entry_for_file_entry(
        &self,
        entry: &SingleFileEntry,
        index: usize,
    ) -> Option<&SingleFilePermission> {
        self.access_control_entries_for_file_entry(entry).get(index)
    }

    /// Returns the stored MD5 hash bytes.
    pub fn md5_hash(&self) -> Option<[u8; 16]> {
        self.inner.info.stored_hashes.md5
    }

    /// Returns the stored SHA1 hash bytes.
    pub fn sha1_hash(&self) -> Option<[u8; 20]> {
        self.inner.info.stored_hashes.sha1
    }

    /// Returns acquisition error ranges.
    pub fn acquisition_errors(&self) -> &[AcquisitionError] {
        &self.inner.info.acquisition_errors
    }

    /// Returns the number of acquisition error ranges.
    pub fn number_of_acquisition_errors(&self) -> usize {
        self.inner.info.acquisition_errors.len()
    }

    /// Returns one acquisition error range by index.
    pub fn acquisition_error(&self, index: usize) -> Option<&AcquisitionError> {
        self.inner.info.acquisition_errors.get(index)
    }

    /// Returns session sector ranges.
    pub fn sessions(&self) -> &[SectorRange] {
        &self.inner.info.sessions
    }

    /// Returns the number of session sector ranges.
    pub fn number_of_sessions(&self) -> usize {
        self.inner.info.sessions.len()
    }

    /// Returns one session sector range by index.
    pub fn session(&self, index: usize) -> Option<&SectorRange> {
        self.inner.info.sessions.get(index)
    }

    /// Returns track sector ranges.
    pub fn tracks(&self) -> &[SectorRange] {
        &self.inner.info.tracks
    }

    /// Returns the number of track sector ranges.
    pub fn number_of_tracks(&self) -> usize {
        self.inner.info.tracks.len()
    }

    /// Returns one track sector range by index.
    pub fn track(&self, index: usize) -> Option<&SectorRange> {
        self.inner.info.tracks.get(index)
    }

    /// Returns whether checksum-failed chunks are read as zero-filled data.
    pub fn read_zero_chunk_on_error(&self) -> bool {
        self.inner.read_zero_chunk_on_error.load(Ordering::Relaxed)
    }

    /// Sets whether checksum-failed chunks are read as zero-filled data.
    pub fn set_read_zero_chunk_on_error(&self, zero_on_error: bool) {
        self.inner
            .read_zero_chunk_on_error
            .store(zero_on_error, Ordering::Relaxed);
    }

    /// Signals future reads and verification to abort with [`EwfError::Aborted`].
    pub fn signal_abort(&self) {
        self.inner.abort_signaled.store(true, Ordering::Relaxed);
    }

    /// Returns checksum error ranges observed while reading.
    ///
    /// # Errors
    ///
    /// Returns an error if the internal checksum-error lock is poisoned.
    pub fn checksum_errors(&self) -> Result<Vec<SectorRange>> {
        Ok(self
            .inner
            .checksum_errors
            .lock()
            .map_err(|_| EwfError::Malformed("checksum errors lock poisoned".into()))?
            .clone())
    }

    /// Returns the number of checksum error ranges observed while reading.
    ///
    /// # Errors
    ///
    /// Returns an error if the internal checksum-error lock is poisoned.
    pub fn number_of_checksum_errors(&self) -> Result<usize> {
        Ok(self
            .inner
            .checksum_errors
            .lock()
            .map_err(|_| EwfError::Malformed("checksum errors lock poisoned".into()))?
            .len())
    }

    /// Returns one checksum error range observed while reading.
    ///
    /// # Errors
    ///
    /// Returns an error if the internal checksum-error lock is poisoned.
    pub fn checksum_error(&self, index: usize) -> Result<Option<SectorRange>> {
        Ok(self
            .inner
            .checksum_errors
            .lock()
            .map_err(|_| EwfError::Malformed("checksum errors lock poisoned".into()))?
            .get(index)
            .cloned())
    }

    /// Returns a seekable cursor over a logical single-file entry.
    pub fn single_file_cursor(&self, entry: &SingleFileEntry) -> SingleFileCursor {
        SingleFileCursor {
            image: self.clone(),
            entry: entry.clone(),
            position: 0,
        }
    }

    /// Returns a seekable cursor over a logical single-file entry by path.
    ///
    /// # Errors
    ///
    /// Returns an error if `path` contains an empty entry name.
    pub fn single_file_cursor_by_path(&self, path: &str) -> Result<Option<SingleFileCursor>> {
        self.file_entry_by_path(path)
            .map(|entry| entry.map(|entry| self.single_file_cursor(entry)))
    }

    /// Reads and decodes one logical data chunk.
    ///
    /// # Errors
    ///
    /// Returns an error if the chunk index is invalid, segment I/O fails,
    /// decoding fails, checksum validation fails under the current policy, or
    /// [`Image::signal_abort`] has been called.
    pub fn read_data_chunk(&self, chunk_index: u64) -> Result<DataChunk> {
        self.ensure_not_aborted()?;
        let chunk = self.lookup_chunk(chunk_index)?;
        let (data, corrupted) = self.decode_chunk_with_policy(chunk_index, chunk)?;
        let logical_offset = chunk_index
            .checked_mul(self.inner.info.chunk_size)
            .ok_or_else(|| EwfError::Malformed("data chunk logical offset overflow".into()))?;

        Ok(DataChunk {
            chunk_index,
            logical_offset,
            logical_size: chunk.logical_size,
            encoded_size: chunk.encoded_size,
            encoding: data_chunk_encoding(chunk.encoding),
            corrupted,
            data,
        })
    }

    /// Reads one encoded data chunk without decoding the payload.
    ///
    /// # Errors
    ///
    /// Returns an error if the chunk index is invalid, segment I/O fails, or
    /// [`Image::signal_abort`] has been called.
    pub fn read_encoded_data_chunk(&self, chunk_index: u64) -> Result<EncodedDataChunk> {
        self.ensure_not_aborted()?;
        let chunk = self.lookup_chunk(chunk_index)?;
        let data = self.read_encoded_chunk_bytes(chunk)?;
        let logical_offset = chunk_index
            .checked_mul(self.inner.info.chunk_size)
            .ok_or_else(|| EwfError::Malformed("data chunk logical offset overflow".into()))?;

        Ok(EncodedDataChunk {
            chunk_index,
            logical_offset,
            logical_size: chunk.logical_size,
            encoded_size: chunk.encoded_size,
            encoding: data_chunk_encoding(chunk.encoding),
            has_checksum: chunk.validate_checksum,
            data,
        })
    }

    fn read_chunk(&self, chunk_id: u64) -> Result<Arc<Vec<u8>>> {
        self.ensure_not_aborted()?;
        let cached = self
            .inner
            .chunk_cache
            .lock()
            .map_err(|_| EwfError::Malformed("chunk cache lock poisoned".into()))?
            .get(&chunk_id)
            .cloned();
        if let Some(cached) = cached {
            return Ok(cached);
        }

        let chunk = self.lookup_chunk(chunk_id)?;
        let (decoded, _) = self.decode_chunk_with_policy(chunk_id, chunk)?;
        let decoded = Arc::new(decoded);
        self.inner
            .chunk_cache
            .lock()
            .map_err(|_| EwfError::Malformed("chunk cache lock poisoned".into()))?
            .put(chunk_id, Arc::clone(&decoded));
        Ok(decoded)
    }

    fn lookup_chunk(&self, chunk_id: u64) -> Result<Chunk> {
        let (_, range) = self.inner.index.range_index_for(chunk_id)?;
        let local_index = chunk_id
            .checked_sub(range.first_chunk)
            .ok_or_else(|| EwfError::Malformed("chunk range underflow".into()))?;
        let logical_size = logical_chunk_size(
            self.inner.info.logical_size,
            self.inner.info.chunk_size,
            chunk_id,
        )?;

        match range.kind {
            TableRangeKind::Ewf1 => self.lookup_ewf1_chunk(range, local_index, logical_size),
            TableRangeKind::Ewf2 => self.lookup_ewf2_chunk(range, local_index, logical_size),
        }
    }

    fn lookup_ewf1_chunk(
        &self,
        range: &TableRange,
        local_index: u64,
        logical_size: usize,
    ) -> Result<Chunk> {
        let raw = self.read_u32_at(
            range.segment_index,
            table_entry_offset(range, local_index, 4)?,
        )?;
        let next_raw = if local_index + 1 < range.chunk_count {
            Some(self.read_u32_at(
                range.segment_index,
                table_entry_offset(range, local_index + 1, 4)?,
            )?)
        } else {
            None
        };
        let entry = decode_ewf1_entry(
            range,
            raw,
            self.inner.info.chunk_size,
            next_raw,
            local_index + 1 == range.chunk_count,
        )?;

        let next_offset = if let Some(next_raw) = next_raw {
            decode_ewf1_entry(
                range,
                next_raw,
                self.inner.info.chunk_size,
                None,
                local_index + 2 == range.chunk_count,
            )?
            .offset
        } else {
            range
                .data_end
                .ok_or_else(|| EwfError::Malformed("EWF1 table range has no data end".into()))?
        };

        if next_offset <= entry.offset {
            return Err(EwfError::Malformed(
                "EWF1 chunk offsets are not ordered".into(),
            ));
        }
        let encoded_size = next_offset - entry.offset;
        let encoding =
            ewf1_chunk_encoding(entry.compressed, encoded_size, self.inner.info.chunk_size)?;
        validate_ewf1_encoded_size(
            encoded_size,
            self.inner.info.chunk_size,
            encoding,
            range.ewf1_allow_large_compressed_chunks,
        )?;
        Ok(Chunk {
            segment_index: range.segment_index,
            offset: entry.offset,
            encoded_size,
            logical_size,
            encoding,
            validate_checksum: encoding == ChunkEncoding::Raw
                && u64::try_from(logical_size)
                    .ok()
                    .and_then(|size| size.checked_add(4))
                    == Some(encoded_size),
        })
    }

    fn lookup_ewf2_chunk(
        &self,
        range: &TableRange,
        local_index: u64,
        logical_size: usize,
    ) -> Result<Chunk> {
        let entry_offset = table_entry_offset(range, local_index, ewf2::TABLE_ENTRY_SIZE as u64)?;
        let entry_data = self.read_bytes_at(
            range.segment_index,
            entry_offset,
            ewf2::TABLE_ENTRY_SIZE as u64,
        )?;
        let compression_method = range
            .ewf2_compression_method
            .map(ewf2::CompressionMethod::from)
            .ok_or_else(|| EwfError::Malformed("EWF2 range has no compression method".into()))?;
        let entry = ewf2::TableEntry::parse(&entry_data, compression_method)?;
        let encoding = match entry.kind {
            ewf2::ChunkKind::Raw | ewf2::ChunkKind::Compressed(ewf2::CompressionMethod::None) => {
                ChunkEncoding::Raw
            }
            ewf2::ChunkKind::Compressed(ewf2::CompressionMethod::Zlib) => ChunkEncoding::Zlib,
            ewf2::ChunkKind::Compressed(ewf2::CompressionMethod::Bzip2) => ChunkEncoding::Bzip2,
            ewf2::ChunkKind::Compressed(ewf2::CompressionMethod::Unknown(method)) => {
                return Err(EwfError::Unsupported(format!(
                    "unknown EWF2 compression method {method}"
                )));
            }
            ewf2::ChunkKind::PatternFill => ChunkEncoding::PatternFill(entry.chunk_data_offset),
        };
        let validate_checksum = matches!(encoding, ChunkEncoding::Raw)
            && entry.flags & ewf2::CHUNK_FLAG_HAS_CHECKSUM != 0;
        validate_encoded_size(
            u64::from(entry.chunk_data_size),
            self.inner.info.chunk_size,
            encoding,
        )?;
        Ok(Chunk {
            segment_index: range.segment_index,
            offset: entry.chunk_data_offset,
            encoded_size: u64::from(entry.chunk_data_size),
            logical_size,
            encoding,
            validate_checksum,
        })
    }

    fn read_u32_at(&self, segment_index: usize, offset: u64) -> Result<u32> {
        let data = self.read_bytes_at(segment_index, offset, 4)?;
        Ok(u32::from_le_bytes(
            data[..4].try_into().expect("slice length checked"),
        ))
    }

    fn read_bytes_at(&self, segment_index: usize, offset: u64, size: u64) -> Result<Vec<u8>> {
        let path = self
            .inner
            .info
            .segment_paths
            .get(segment_index)
            .ok_or_else(|| EwfError::Malformed("table references missing segment".into()))?
            .clone();
        let mut segments = self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?;
        let file = segments.file_mut(segment_index, &path)?;
        read_exact_at(file.as_mut(), offset, size)
    }

    fn ensure_not_aborted(&self) -> Result<()> {
        if self.inner.abort_signaled.load(Ordering::Relaxed) {
            return Err(EwfError::Aborted);
        }
        Ok(())
    }

    fn has_supplied_segment_readers(&self) -> Result<bool> {
        Ok(self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?
            .has_supplied_readers())
    }

    fn read_encoded_chunk_bytes(&self, chunk: Chunk) -> Result<Vec<u8>> {
        self.ensure_not_aborted()?;
        if matches!(chunk.encoding, ChunkEncoding::PatternFill(_)) {
            return Ok(Vec::new());
        }

        let encoded_size = usize::try_from(chunk.encoded_size)
            .map_err(|_| EwfError::Malformed("encoded chunk size does not fit usize".into()))?;
        let path = self
            .inner
            .info
            .segment_paths
            .get(chunk.segment_index)
            .ok_or_else(|| EwfError::Malformed("chunk references missing segment".into()))?
            .clone();
        let mut segments = self
            .inner
            .segments
            .lock()
            .map_err(|_| EwfError::Malformed("segment file pool lock poisoned".into()))?;
        let file = segments.file_mut(chunk.segment_index, &path)?;
        let segment_size = file.segment_len()?;
        let end = chunk
            .offset
            .checked_add(chunk.encoded_size)
            .ok_or_else(|| EwfError::Malformed("chunk byte range overflow".into()))?;
        if end > segment_size {
            return Err(EwfError::Malformed(format!(
                "chunk byte range {}..{} exceeds segment size {}",
                chunk.offset, end, segment_size
            )));
        }

        let mut encoded = vec![0; encoded_size];
        file.seek(SeekFrom::Start(chunk.offset))?;
        file.read_exact(&mut encoded)?;
        Ok(encoded)
    }

    fn decode_chunk(&self, chunk: Chunk) -> Result<Vec<u8>> {
        let encoded = self.read_encoded_chunk_bytes(chunk)?;
        if chunk.validate_checksum {
            validate_raw_chunk_checksum(&encoded, chunk.logical_size)?;
        }
        decode_chunk(&encoded, chunk.encoding, chunk.logical_size)
    }

    fn decode_chunk_with_policy(&self, chunk_id: u64, chunk: Chunk) -> Result<(Vec<u8>, bool)> {
        match self.decode_chunk(chunk) {
            Ok(decoded) => Ok((decoded, false)),
            Err(EwfError::Malformed(_)) if self.read_zero_chunk_on_error() => {
                self.record_checksum_error(chunk_id, chunk.logical_size)?;
                Ok((vec![0; chunk.logical_size], true))
            }
            Err(err) => Err(err),
        }
    }

    fn record_checksum_error(&self, chunk_id: u64, logical_size: usize) -> Result<()> {
        let range = checksum_error_range(&self.inner.info, chunk_id, logical_size)?;
        let mut errors = self
            .inner
            .checksum_errors
            .lock()
            .map_err(|_| EwfError::Malformed("checksum errors lock poisoned".into()))?;
        if !errors.contains(&range) {
            errors.push(range);
        }
        Ok(())
    }
}

impl SegmentFilePool {
    fn new_path(segment_count: usize, maximum_open_handles: Option<usize>) -> Result<Self> {
        validate_maximum_open_handles(maximum_open_handles)?;
        Ok(Self {
            files: (0..segment_count).map(|_| None).collect(),
            open_order: VecDeque::new(),
            maximum_open_handles,
            mode: SegmentFilePoolMode::ReopenFromPath,
        })
    }

    fn new_readers(
        readers: Vec<SegmentReaderHandle>,
        maximum_open_handles: Option<usize>,
    ) -> Result<Self> {
        validate_maximum_open_handles(maximum_open_handles)?;
        let segment_count = readers.len();
        if maximum_open_handles.is_some_and(|maximum| maximum < segment_count) {
            return Err(EwfError::Unsupported(
                "maximum open handles cannot evict supplied segment readers".into(),
            ));
        }

        Ok(Self {
            files: readers.into_iter().map(Some).collect(),
            open_order: (0..segment_count).collect(),
            maximum_open_handles,
            mode: SegmentFilePoolMode::SuppliedReaders,
        })
    }

    fn maximum_open_handles(&self) -> Option<usize> {
        self.maximum_open_handles
    }

    fn set_maximum_open_handles(&mut self, maximum_open_handles: Option<usize>) -> Result<()> {
        validate_maximum_open_handles(maximum_open_handles)?;
        if !self.can_close_handles()
            && maximum_open_handles.is_some_and(|maximum| maximum < self.open_count())
        {
            return Err(EwfError::Unsupported(
                "maximum open handles cannot evict supplied segment readers".into(),
            ));
        }
        let previous_maximum_open_handles = self.maximum_open_handles;
        self.maximum_open_handles = maximum_open_handles;
        if let Err(err) = self.enforce_limit() {
            self.maximum_open_handles = previous_maximum_open_handles;
            return Err(err);
        }
        Ok(())
    }

    fn open_count(&self) -> usize {
        self.files.iter().filter(|file| file.is_some()).count()
    }

    fn reserve_handle(&mut self) -> Result<()> {
        if let Some(maximum_open_handles) = self.maximum_open_handles {
            if self.open_count() >= maximum_open_handles && !self.can_close_handles() {
                return Err(EwfError::Unsupported(
                    "maximum open handles cannot evict supplied segment readers".into(),
                ));
            }
            while self.open_count() >= maximum_open_handles {
                self.close_least_recently_used()?;
            }
        }
        Ok(())
    }

    fn file_mut(&mut self, segment_index: usize, path: &Path) -> Result<&mut SegmentReaderHandle> {
        let slot = self
            .files
            .get(segment_index)
            .ok_or_else(|| EwfError::Malformed("segment index out of range".into()))?;
        if slot.is_none() {
            self.reserve_handle()?;
            let file = match self.mode {
                SegmentFilePoolMode::ReopenFromPath => {
                    Some(Box::new(File::open(path)?) as SegmentReaderHandle)
                }
                SegmentFilePoolMode::SuppliedReaders => None,
            }
            .ok_or_else(|| {
                EwfError::Malformed("supplied segment reader was unexpectedly closed".into())
            })?;
            let slot = self
                .files
                .get_mut(segment_index)
                .ok_or_else(|| EwfError::Malformed("segment index out of range".into()))?;
            *slot = Some(file);
        }
        self.mark_used(segment_index);
        self.files[segment_index]
            .as_mut()
            .ok_or_else(|| EwfError::Malformed("segment file was not opened".into()))
    }

    fn can_close_handles(&self) -> bool {
        self.mode == SegmentFilePoolMode::ReopenFromPath
    }

    fn has_supplied_readers(&self) -> bool {
        self.mode == SegmentFilePoolMode::SuppliedReaders
    }

    fn mark_used(&mut self, segment_index: usize) {
        if let Some(position) = self
            .open_order
            .iter()
            .position(|open_segment_index| *open_segment_index == segment_index)
        {
            self.open_order.remove(position);
        }
        self.open_order.push_back(segment_index);
    }

    fn enforce_limit(&mut self) -> Result<()> {
        if let Some(maximum_open_handles) = self.maximum_open_handles {
            if self.open_count() > maximum_open_handles && !self.can_close_handles() {
                return Err(EwfError::Unsupported(
                    "maximum open handles cannot evict supplied segment readers".into(),
                ));
            }
            while self.open_count() > maximum_open_handles {
                self.close_least_recently_used()?;
            }
        }
        Ok(())
    }

    fn close_least_recently_used(&mut self) -> Result<()> {
        while let Some(segment_index) = self.open_order.pop_front() {
            if let Some(slot) = self.files.get_mut(segment_index)
                && slot.take().is_some()
            {
                return Ok(());
            }
        }
        Err(EwfError::Malformed(
            "segment file pool has no open handle to close".into(),
        ))
    }
}

fn validate_maximum_open_handles(maximum_open_handles: Option<usize>) -> Result<()> {
    if maximum_open_handles == Some(0) {
        return Err(EwfError::Unsupported(
            "maximum open handles must be at least one".into(),
        ));
    }
    Ok(())
}

fn data_chunk_encoding(encoding: ChunkEncoding) -> DataChunkEncoding {
    match encoding {
        ChunkEncoding::Raw => DataChunkEncoding::Raw,
        ChunkEncoding::Zlib => DataChunkEncoding::Zlib,
        ChunkEncoding::Bzip2 => DataChunkEncoding::Bzip2,
        ChunkEncoding::PatternFill(pattern) => DataChunkEncoding::PatternFill(pattern),
    }
}

impl ImageCursor {
    /// Returns the current logical media byte position.
    pub fn position(&self) -> u64 {
        self.position
    }

    /// Alias for [`ImageCursor::position`].
    pub fn offset(&self) -> u64 {
        self.position()
    }

    /// Reads logical media bytes at the current cursor position and advances.
    ///
    /// # Errors
    ///
    /// Returns an error if the underlying [`Image::read_at`] call fails or the
    /// cursor position would overflow.
    pub fn read_buffer(&mut self, buf: &mut [u8]) -> Result<usize> {
        let read = self.image.read_at(buf, self.position)?;
        self.position = self
            .position
            .checked_add(u64::try_from(read).expect("usize fits u64"))
            .ok_or_else(|| EwfError::Malformed("cursor position overflow".into()))?;
        Ok(read)
    }

    /// Seeks to `offset`, reads into `buf`, and advances by the bytes read.
    ///
    /// # Errors
    ///
    /// Returns the same errors as [`ImageCursor::read_buffer`].
    pub fn read_buffer_at_offset(&mut self, buf: &mut [u8], offset: u64) -> Result<usize> {
        self.position = offset;
        self.read_buffer(buf)
    }

    /// Seeks the cursor using [`SeekFrom`] and returns the new position.
    ///
    /// # Errors
    ///
    /// Returns an error if the seek would move before the start of the image or
    /// beyond `u64` addressable space.
    pub fn seek_offset(&mut self, pos: SeekFrom) -> Result<u64> {
        self.seek_position(pos).map_err(EwfError::from)
    }

    /// Returns the segment containing the current cursor position.
    ///
    /// Positions at or beyond the logical media size return `Ok(None)`.
    ///
    /// # Errors
    ///
    /// Returns an error if the image chunk geometry is malformed.
    pub fn segment_filename(&self) -> Result<Option<&Path>> {
        self.image.segment_filename_for_offset(self.position)
    }

    /// Reads the data chunk at the current cursor position and advances to the next chunk.
    ///
    /// Returns `Ok(None)` when the cursor is at or beyond the logical media end.
    ///
    /// # Errors
    ///
    /// Returns an error if reading the chunk fails or the cursor position would
    /// overflow.
    pub fn read_data_chunk(&mut self) -> Result<Option<DataChunk>> {
        let Some(chunk_index) = self.current_chunk_index()? else {
            return Ok(None);
        };
        let chunk = self.image.read_data_chunk(chunk_index)?;
        self.advance_to_chunk_end(chunk.logical_offset, chunk.logical_size)?;
        Ok(Some(chunk))
    }

    /// Reads the encoded data chunk at the current cursor position and advances.
    ///
    /// Returns `Ok(None)` when the cursor is at or beyond the logical media end.
    ///
    /// # Errors
    ///
    /// Returns an error if reading the chunk fails or the cursor position would
    /// overflow.
    pub fn read_encoded_data_chunk(&mut self) -> Result<Option<EncodedDataChunk>> {
        let Some(chunk_index) = self.current_chunk_index()? else {
            return Ok(None);
        };
        let chunk = self.image.read_encoded_data_chunk(chunk_index)?;
        self.advance_to_chunk_end(chunk.logical_offset, chunk.logical_size)?;
        Ok(Some(chunk))
    }

    fn current_chunk_index(&self) -> Result<Option<u64>> {
        if self.position >= self.image.info().logical_size {
            return Ok(None);
        }
        let chunk_size = self.image.info().chunk_size;
        if chunk_size == 0 {
            return Err(EwfError::Malformed("chunk size is zero".into()));
        }
        Ok(Some(self.position / chunk_size))
    }

    fn advance_to_chunk_end(&mut self, logical_offset: u64, logical_size: usize) -> Result<()> {
        let logical_size = u64::try_from(logical_size)
            .map_err(|_| EwfError::Malformed("chunk logical size does not fit u64".into()))?;
        self.position = logical_offset
            .checked_add(logical_size)
            .ok_or_else(|| EwfError::Malformed("cursor chunk end offset overflow".into()))?;
        Ok(())
    }

    fn seek_position(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
        let next = match pos {
            SeekFrom::Start(offset) => i128::from(offset),
            SeekFrom::End(offset) => {
                i128::from(self.image.info().logical_size) + i128::from(offset)
            }
            SeekFrom::Current(offset) => i128::from(self.position) + i128::from(offset),
        };
        if next < 0 {
            return Err(std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                "seek before start of image",
            ));
        }
        self.position = u64::try_from(next).map_err(|_| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                "seek position does not fit u64",
            )
        })?;
        Ok(self.position)
    }
}

impl Read for ImageCursor {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        self.read_buffer(buf).map_err(std::io::Error::other)
    }
}

impl Seek for ImageCursor {
    fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
        self.seek_position(pos)
    }
}

impl SingleFileCursor {
    /// Returns the current single-file byte position.
    pub fn position(&self) -> u64 {
        self.position
    }

    /// Alias for [`SingleFileCursor::position`].
    pub fn offset(&self) -> u64 {
        self.position()
    }

    /// Reads bytes at the current single-file position and advances.
    ///
    /// # Errors
    ///
    /// Returns an error if the underlying single-file read fails or the cursor
    /// position would overflow.
    pub fn read_buffer(&mut self, buf: &mut [u8]) -> Result<usize> {
        let read = self
            .image
            .read_single_file_at(&self.entry, buf, self.position)?;
        self.position = self
            .position
            .checked_add(u64::try_from(read).expect("usize fits u64"))
            .ok_or_else(|| EwfError::Malformed("single file cursor position overflow".into()))?;
        Ok(read)
    }

    /// Seeks to `offset`, reads into `buf`, and advances by the bytes read.
    ///
    /// # Errors
    ///
    /// Returns the same errors as [`SingleFileCursor::read_buffer`].
    pub fn read_buffer_at_offset(&mut self, buf: &mut [u8], offset: u64) -> Result<usize> {
        self.position = offset;
        self.read_buffer(buf)
    }

    /// Seeks the cursor using [`SeekFrom`] and returns the new position.
    ///
    /// # Errors
    ///
    /// Returns an error if the seek would move before the start of the file, the
    /// file size is unavailable, or the resulting position does not fit `u64`.
    pub fn seek_offset(&mut self, pos: SeekFrom) -> Result<u64> {
        self.seek_position(pos).map_err(EwfError::from)
    }

    fn seek_position(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
        let file_size = single_file_size(&self.entry).map_err(std::io::Error::other)?;
        let next = match pos {
            SeekFrom::Start(offset) => i128::from(offset),
            SeekFrom::End(offset) => i128::from(file_size) + i128::from(offset),
            SeekFrom::Current(offset) => i128::from(self.position) + i128::from(offset),
        };
        if next < 0 {
            return Err(std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                "cannot seek before start of single file",
            ));
        }
        self.position = u64::try_from(next).map_err(|_| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                "single file cursor position does not fit u64",
            )
        })?;
        Ok(self.position)
    }
}

impl Read for SingleFileCursor {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        self.read_buffer(buf).map_err(std::io::Error::other)
    }
}

impl Seek for SingleFileCursor {
    fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
        self.seek_position(pos)
    }

    fn stream_position(&mut self) -> std::io::Result<u64> {
        Ok(self.position)
    }
}

fn single_file_size(entry: &SingleFileEntry) -> Result<u64> {
    if let Some(size) = entry.size {
        return Ok(size);
    }

    entry.extents.iter().try_fold(0_u64, |total, extent| {
        total
            .checked_add(extent.data_size)
            .ok_or_else(|| EwfError::Malformed("single file size overflow".into()))
    })
}

struct ParsedSegment {
    format: Format,
    format_profile: FormatProfile,
    format_profile_hint_only: bool,
    segment_number: u64,
    set_identifier: Option<[u8; 16]>,
    ewf2_header_profile: Option<Ewf2HeaderProfile>,
    chunk_size: u64,
    logical_size: u64,
    acquisition_complete: bool,
    media: MediaInfo,
    ranges: Vec<TableRange>,
    table_chunk_count: u64,
    metadata: EwfMetadata,
    stored_hashes: StoredHashes,
    acquisition_errors: Vec<AcquisitionError>,
    memory_extents: Vec<MemoryExtent>,
    single_files: Option<SingleFilesInfo>,
    ewf2_single_files_tables: SingleFilesAuxTables,
    ewf2_increment_data: Vec<Vec<u8>>,
    ewf2_final_information: Option<Vec<u8>>,
    ewf2_restart_data: Option<String>,
    ewf2_analytical_data: Option<String>,
    sessions: Vec<SectorRange>,
    tracks: Vec<SectorRange>,
    ewf2_device_information: Option<Vec<u8>>,
    ewf2_case_data: Option<Vec<u8>>,
}

#[derive(Clone, Copy)]
struct Ewf2HeaderProfile {
    major_version: u8,
    minor_version: u8,
    compression_method: ewf2::CompressionMethod,
}

#[derive(Clone)]
struct Section {
    desc: ewf1::SectionDescriptor,
    data_offset: u64,
    data_size: u64,
}

#[derive(Clone, Copy)]
struct Ewf2Section {
    desc: ewf2::SectionDescriptor,
    data_offset: u64,
    data_size: u64,
    layout: Ewf2SectionLayout,
}

#[derive(Clone, Copy, PartialEq, Eq)]
enum Ewf2SectionLayout {
    LeadingDescriptor,
    TrailingDescriptor,
}

fn parse_ewf1_segment(
    file: &mut dyn SegmentReader,
    segment_index: usize,
    first_chunk: u64,
    profile_hint: FormatProfile,
    header_codepage: HeaderCodepage,
) -> Result<ParsedSegment> {
    let mut header = [0; ewf1::FILE_HEADER_SIZE];
    file.seek(SeekFrom::Start(0))?;
    file.read_exact(&mut header)?;
    let file_header = ewf1::FileHeader::parse(&header)?;

    let sections = scan_ewf1_sections(file)?;
    let acquisition_complete = ewf1_acquisition_complete(&sections);
    let volume = sections
        .iter()
        .find(|section| {
            matches!(
                section.desc.section_type.as_str(),
                "volume" | "disk" | "data"
            )
        })
        .ok_or_else(|| EwfError::Malformed("missing EWF1 media section".into()))
        .and_then(|section| {
            let data = read_exact_at(file, section.data_offset, section.data_size)?;
            validate_present_ewf1_media_checksum(&data, &section.desc.section_type)?;
            ewf1::Volume::parse(&data)
        })?;
    let chunk_size = volume.chunk_size()?;
    validate_chunk_size(chunk_size)?;
    let declared_logical_size = volume.logical_size()?;
    let logical_size = if declared_logical_size > 0 {
        declared_logical_size
    } else {
        chunk_size
            .checked_mul(u64::from(volume.chunk_count))
            .ok_or_else(|| EwfError::Malformed("EWF1 logical size overflow".into()))?
    };
    let smart_profile = !file_header.logical && volume.smart;
    let media = MediaInfo {
        sectors_per_chunk: Some(u64::from(volume.sectors_per_chunk)),
        bytes_per_sector: Some(u64::from(volume.bytes_per_sector)),
        sector_count: Some(volume.sector_count),
        chunk_count: Some(u64::from(volume.chunk_count)),
        error_granularity: volume.error_granularity.map(u64::from),
        set_identifier: volume.set_identifier,
        ewf2_segment_file_version: None,
        compression_method: Some(CompressionMethod::Zlib),
        compression_values: CompressionValues {
            level: volume
                .compression_level
                .map(|value| CompressionLevel::from_i8(value as i8))
                .unwrap_or_default(),
            ..CompressionValues::default()
        },
        media_type: volume
            .media_type
            .map(ewf1_media_type)
            .or_else(|| smart_profile.then_some(MediaType::Removable)),
        media_flags: ewf1_media_flags(volume.media_flags, file_header.logical || smart_profile),
    };

    let mut metadata = EwfMetadata::default();
    let mut stored_hashes = StoredHashes::default();
    let mut acquisition_errors = Vec::new();
    let memory_extents = Vec::new();
    let mut single_files = None;
    let mut format_profile = if file_header.logical {
        FormatProfile::LogicalEnCase5
    } else if smart_profile {
        FormatProfile::Smart
    } else if profile_hint != FormatProfile::Unknown {
        profile_hint
    } else {
        FormatProfile::EnCase5
    };
    let mut format_profile_hint_only = !file_header.logical && !smart_profile;
    let mut format_profile_detected_from_header2 = false;
    let mut sessions = Vec::new();
    let mut tracks = Vec::new();
    for section in &sections {
        match section.desc.section_type.as_str() {
            "header" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let payload = ewf1_metadata_payload(&data);
                let text = decode_header_bytes(&payload, header_codepage);
                if !format_profile_detected_from_header2
                    && apply_detected_ewf1_format_profile(
                        &mut format_profile,
                        detect_ewf1_header_profile(&text, 1),
                    )
                {
                    format_profile_hint_only = false;
                }
                parse_header_data(&payload, header_codepage, &mut metadata);
            }
            "header2" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let payload = ewf1_metadata_payload(&data);
                if apply_detected_ewf1_format_profile(
                    &mut format_profile,
                    detect_ewf1_header2_profile(&payload),
                ) {
                    format_profile_hint_only = false;
                    format_profile_detected_from_header2 = true;
                }
                parse_header2_data(&payload, &mut metadata);
            }
            "xheader" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let payload = ewf1_metadata_payload(&data);
                parse_xheader_data(&payload, &mut metadata);
            }
            "error2" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                acquisition_errors.extend(parse_error2_data(&data)?);
            }
            "session" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let parsed_sessions = parse_session_data(&data, 1, volume.sector_count)?;
                sessions.extend(parsed_sessions.sessions);
                tracks.extend(parsed_sessions.tracks);
            }
            "hash" => {
                validate_hash_section_size(section.data_size, EWF1_HASH_SECTION_SIZE, "EWF1 MD5")?;
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                validate_adler32_checksum(&data, 32, 32, "EWF1 MD5 hash")?;
                if stored_hashes.md5.is_none()
                    && let Some(hash) = parse_nonzero_hash(&data)
                {
                    stored_hashes.md5 = Some(hash);
                    insert_hash_value(&mut stored_hashes, "MD5", &hash);
                }
            }
            "digest" => {
                validate_hash_section_size(
                    section.data_size,
                    EWF1_DIGEST_SECTION_SIZE,
                    "EWF1 digest",
                )?;
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                validate_adler32_checksum(&data, 76, 76, "EWF1 digest")?;
                if stored_hashes.md5.is_none()
                    && let Some(hash) = parse_nonzero_hash(&data[..16])
                {
                    stored_hashes.md5 = Some(hash);
                    insert_hash_value(&mut stored_hashes, "MD5", &hash);
                }
                if stored_hashes.sha1.is_none()
                    && let Some(hash) = parse_nonzero_hash(&data[16..36])
                {
                    stored_hashes.sha1 = Some(hash);
                    insert_hash_value(&mut stored_hashes, "SHA1", &hash);
                }
            }
            "xhash" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let payload = ewf1_metadata_payload(&data);
                parse_xhash_data(&payload, &mut stored_hashes);
            }
            "ltree" => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_single_files(&mut single_files, Some(parse_ewf1_ltree_data(&data)?))?;
            }
            _ => {}
        }
    }

    let ranges = parse_ewf1_ranges(
        file,
        &sections,
        segment_index,
        first_chunk,
        logical_size,
        volume.smart,
    )?;
    let table_chunk_count = ranges.iter().try_fold(0_u64, |count, range| {
        count
            .checked_add(range.chunk_count)
            .ok_or_else(|| EwfError::Malformed("EWF1 table chunk count overflow".into()))
    })?;
    Ok(ParsedSegment {
        format: Format::Ewf1,
        format_profile,
        format_profile_hint_only,
        segment_number: u64::from(file_header.segment_number),
        set_identifier: volume.set_identifier,
        ewf2_header_profile: None,
        chunk_size,
        logical_size,
        acquisition_complete,
        media,
        ranges,
        table_chunk_count,
        metadata,
        stored_hashes,
        acquisition_errors,
        memory_extents,
        single_files,
        ewf2_single_files_tables: SingleFilesAuxTables::default(),
        ewf2_increment_data: Vec::new(),
        ewf2_final_information: None,
        ewf2_restart_data: None,
        ewf2_analytical_data: None,
        sessions,
        tracks,
        ewf2_device_information: None,
        ewf2_case_data: None,
    })
}

fn ewf1_media_type(value: u8) -> MediaType {
    match value {
        0x00 => MediaType::Removable,
        0x01 => MediaType::Fixed,
        0x03 => MediaType::Optical,
        0x0e => MediaType::SingleFiles,
        0x10 => MediaType::Memory,
        value => MediaType::Unknown(value),
    }
}

fn ewf1_media_flags(value: Option<u8>, logical_file_header: bool) -> MediaFlags {
    value.map_or(
        MediaFlags {
            physical: !logical_file_header,
            fastbloc: false,
            tableau: false,
        },
        |value| MediaFlags {
            physical: value & 0x02 != 0,
            fastbloc: value & 0x04 != 0,
            tableau: value & 0x08 != 0,
        },
    )
}

fn ewf1_format_profile_hint_from_path(path: &Path) -> FormatProfile {
    match path.extension().and_then(|extension| extension.to_str()) {
        Some(extension) if extension.starts_with('e') => FormatProfile::Ewf,
        Some(extension) if extension.starts_with('E') => FormatProfile::EnCase2,
        Some(extension) if extension.starts_with('L') => FormatProfile::LogicalEnCase5,
        Some(extension) if extension.starts_with('s') || extension.starts_with('S') => {
            FormatProfile::Smart
        }
        _ => FormatProfile::Unknown,
    }
}

fn parse_segment(
    file: &mut dyn SegmentReader,
    path: &Path,
    segment_index: usize,
    first_ewf1_chunk: u64,
    strictness: OpenStrictness,
    header_codepage: HeaderCodepage,
) -> Result<ParsedSegment> {
    let mut signature = [0; 8];
    file.seek(SeekFrom::Start(0))?;
    file.read_exact(&mut signature)?;
    if signature == ewf1::EVF_SIGNATURE || signature == ewf1::LVF_SIGNATURE {
        parse_ewf1_segment(
            file,
            segment_index,
            first_ewf1_chunk,
            ewf1_format_profile_hint_from_path(path),
            header_codepage,
        )
    } else if signature == ewf2::EX01_SIGNATURE || signature == ewf2::LEF2_SIGNATURE {
        parse_ewf2_segment(file, segment_index, strictness)
    } else {
        Err(EwfError::InvalidSignature)
    }
}

fn parse_ewf2_segment(
    file: &mut dyn SegmentReader,
    segment_index: usize,
    strictness: OpenStrictness,
) -> Result<ParsedSegment> {
    let mut header = [0; ewf2::FILE_HEADER_SIZE];
    file.seek(SeekFrom::Start(0))?;
    file.read_exact(&mut header)?;
    let header = ewf2::FileHeader::parse(&header)?;
    let sections = scan_ewf2_sections(file, strictness)?;
    let acquisition_complete = ewf2_acquisition_complete(&sections);

    let mut chunk_size = 0;
    let mut logical_size = 0;
    let mut metadata = EwfMetadata::default();
    let mut stored_hashes = StoredHashes::default();
    let mut acquisition_errors = Vec::new();
    let mut memory_extents = Vec::new();
    let mut single_files = None;
    let mut ewf2_single_files_tables = SingleFilesAuxTables::default();
    let mut ewf2_increment_data = Vec::new();
    let mut ewf2_final_information = None;
    let mut ewf2_restart_data = None;
    let mut ewf2_analytical_data = None;
    let mut session_table_data = Vec::new();
    let mut sessions = Vec::new();
    let mut tracks = Vec::new();
    let mut media = MediaInfo {
        sectors_per_chunk: None,
        bytes_per_sector: None,
        sector_count: None,
        chunk_count: None,
        error_granularity: None,
        set_identifier: Some(header.set_identifier),
        ewf2_segment_file_version: Some(SegmentFileVersion {
            major: header.major_version,
            minor: header.minor_version,
        }),
        compression_method: Some(public_compression_method(header.compression_method)),
        compression_values: CompressionValues::default(),
        media_type: None,
        media_flags: MediaFlags {
            physical: !header.logical,
            fastbloc: false,
            tableau: false,
        },
    };
    let mut device_information = None;
    let mut case_data = None;
    for section in &sections {
        match section.desc.section_type {
            ewf2::SectionType::DeviceInformation => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let data = ewf2_metadata_payload(&data, header.compression_method)?;
                remember_ewf2_metadata_payload(
                    &mut device_information,
                    &data,
                    "device information",
                )?;
                parse_ewf2_device_info_values(&data, &mut metadata);
                let geometry = parse_ewf2_device_info(&data)?;
                if let Some(size) = geometry.chunk_size {
                    chunk_size = size;
                }
                if let Some(size) = geometry.logical_size {
                    logical_size = size;
                }
                apply_ewf2_geometry(&mut media, geometry);
            }
            ewf2::SectionType::CaseData => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                let data = ewf2_metadata_payload(&data, header.compression_method)?;
                remember_ewf2_metadata_payload(&mut case_data, &data, "case data")?;
                parse_ewf2_case_data(&data, &mut metadata);
                let geometry = parse_ewf2_device_info(&data)?;
                if chunk_size == 0
                    && let Some(size) = geometry.chunk_size
                {
                    chunk_size = size;
                }
                if logical_size == 0
                    && let Some(size) = geometry.logical_size
                {
                    logical_size = size;
                }
                apply_ewf2_geometry_if_missing(&mut media, geometry);
            }
            ewf2::SectionType::Md5Hash => {
                validate_hash_section_size(section.data_size, EWF2_HASH_SECTION_SIZE, "EWF2 MD5")?;
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                validate_adler32_checksum(&data, 16, 16, "EWF2 MD5 hash")?;
                if stored_hashes.md5.is_none()
                    && let Some(hash) = parse_nonzero_hash(&data)
                {
                    stored_hashes.md5 = Some(hash);
                    insert_hash_value(&mut stored_hashes, "MD5", &hash);
                }
            }
            ewf2::SectionType::Sha1Hash => {
                validate_hash_section_size(section.data_size, EWF2_HASH_SECTION_SIZE, "EWF2 SHA1")?;
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                validate_adler32_checksum(&data, 20, 20, "EWF2 SHA1 hash")?;
                if stored_hashes.sha1.is_none()
                    && let Some(hash) = parse_nonzero_hash(&data)
                {
                    stored_hashes.sha1 = Some(hash);
                    insert_hash_value(&mut stored_hashes, "SHA1", &hash);
                }
            }
            ewf2::SectionType::ErrorTable => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                acquisition_errors.extend(parse_ewf2_error_table_data(&data)?);
            }
            ewf2::SectionType::MemoryExtentsTable => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                memory_extents.extend(parse_ewf2_memory_extents_table(&data)?);
            }
            ewf2::SectionType::SingleFilesData => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_single_files(
                    &mut single_files,
                    Some(parse_ewf2_single_files_data(&data)?),
                )?;
            }
            ewf2::SectionType::SingleFilesTable => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_single_files_aux_u64_table(
                    &mut ewf2_single_files_tables.table_0x21_entries,
                    parse_ewf2_single_files_aux_u64_table(&data, "EWF2 single files 0x21 table")?,
                    "0x21",
                )?;
            }
            ewf2::SectionType::SingleFilesMd5HashTable => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_single_files_aux_md5_table(
                    &mut ewf2_single_files_tables.md5_hashes,
                    parse_ewf2_single_files_md5_hash_table(&data)?,
                )?;
            }
            ewf2::SectionType::SingleFilesUnknownTable => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_single_files_aux_u64_table(
                    &mut ewf2_single_files_tables.table_0x23_entries,
                    parse_ewf2_single_files_aux_u64_table(&data, "EWF2 single files 0x23 table")?,
                    "0x23",
                )?;
            }
            ewf2::SectionType::IncrementData => {
                ewf2_increment_data.push(read_exact_at(
                    file,
                    section.data_offset,
                    section.data_size,
                )?);
            }
            ewf2::SectionType::FinalInformation => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                merge_optional_ewf2_raw_section(
                    &mut ewf2_final_information,
                    Some(data),
                    "final information",
                )?;
            }
            ewf2::SectionType::RestartData => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                ewf2_restart_data = Some(decode_ewf2_string_section(
                    &data,
                    header.compression_method,
                    "restart data",
                )?);
            }
            ewf2::SectionType::AnalyticalData => {
                let data = read_exact_at(file, section.data_offset, section.data_size)?;
                ewf2_analytical_data = Some(decode_ewf2_string_section(
                    &data,
                    header.compression_method,
                    "analytical data",
                )?);
            }
            ewf2::SectionType::SessionTable => {
                session_table_data.push(read_exact_at(
                    file,
                    section.data_offset,
                    section.data_size,
                )?);
            }
            _ => {}
        }
    }

    let media_sector_count = media.sector_count.unwrap_or(0);
    for data in session_table_data {
        let parsed_sessions = parse_session_data(&data, 2, media_sector_count)?;
        sessions.extend(parsed_sessions.sessions);
        tracks.extend(parsed_sessions.tracks);
    }

    if chunk_size == 0 {
        chunk_size = 32_768;
    }
    validate_chunk_size(chunk_size)?;
    let ranges = parse_ewf2_ranges(
        file,
        &sections,
        segment_index,
        logical_size,
        header.compression_method,
    )?;
    if logical_size == 0 {
        let discovered_chunks = ranges.iter().try_fold(0_u64, |max, range| {
            let end = range
                .first_chunk
                .checked_add(range.chunk_count)
                .ok_or_else(|| EwfError::Malformed("EWF2 table chunk count overflow".into()))?;
            Ok::<u64, EwfError>(max.max(end))
        })?;
        logical_size = chunk_size
            .checked_mul(discovered_chunks)
            .ok_or_else(|| EwfError::Malformed("EWF2 logical size overflow".into()))?;
    }
    let table_chunk_count = ranges.iter().try_fold(0_u64, |count, range| {
        count
            .checked_add(range.chunk_count)
            .ok_or_else(|| EwfError::Malformed("EWF2 table chunk count overflow".into()))
    })?;

    Ok(ParsedSegment {
        format: Format::Ewf2,
        format_profile: if header.logical {
            FormatProfile::Ewf2LogicalEnCase7
        } else {
            FormatProfile::Ewf2EnCase7
        },
        format_profile_hint_only: false,
        segment_number: u64::from(header.segment_number),
        set_identifier: Some(header.set_identifier),
        ewf2_header_profile: Some(Ewf2HeaderProfile {
            major_version: header.major_version,
            minor_version: header.minor_version,
            compression_method: header.compression_method,
        }),
        chunk_size,
        logical_size,
        acquisition_complete,
        media,
        ranges,
        table_chunk_count,
        metadata,
        stored_hashes,
        acquisition_errors,
        memory_extents,
        single_files,
        ewf2_single_files_tables,
        ewf2_increment_data,
        ewf2_final_information,
        ewf2_restart_data,
        ewf2_analytical_data,
        sessions,
        tracks,
        ewf2_device_information: device_information,
        ewf2_case_data: case_data,
    })
}

fn scan_ewf1_sections(file: &mut dyn SegmentReader) -> Result<Vec<Section>> {
    let file_len = file.segment_len()?;
    let mut sections = Vec::new();
    let mut offset = ewf1::FILE_HEADER_SIZE as u64;
    for _ in 0..4096 {
        let descriptor_end = offset
            .checked_add(ewf1::SECTION_DESCRIPTOR_SIZE as u64)
            .ok_or_else(|| EwfError::Malformed("EWF1 section descriptor overflow".into()))?;
        if descriptor_end > file_len {
            return Err(EwfError::Malformed(
                "EWF1 section descriptor exceeds file".into(),
            ));
        }
        let mut buf = [0; ewf1::SECTION_DESCRIPTOR_SIZE];
        file.seek(SeekFrom::Start(offset))?;
        file.read_exact(&mut buf)?;
        validate_present_adler32_checksum(&buf, 72, 72, "EWF1 section descriptor")?;
        let desc = ewf1::SectionDescriptor::parse(&buf, offset)?;
        let data_size = desc.data_size()?;
        let data_offset = descriptor_end;
        if data_offset
            .checked_add(data_size)
            .is_none_or(|end| end > file_len)
        {
            return Err(EwfError::Malformed("EWF1 section data exceeds file".into()));
        }
        let section_type = desc.section_type.clone();
        let next = desc.next;
        sections.push(Section {
            desc,
            data_offset,
            data_size,
        });
        if matches!(section_type.as_str(), "done" | "next") || next == 0 {
            return Ok(sections);
        }
        if next <= offset {
            return Err(EwfError::Malformed(
                "EWF1 section chain does not advance".into(),
            ));
        }
        offset = next;
    }
    Err(EwfError::Malformed("EWF1 section chain is too long".into()))
}

fn ewf1_acquisition_complete(sections: &[Section]) -> bool {
    sections
        .last()
        .is_none_or(|section| section.desc.section_type != "next")
}

fn scan_ewf2_sections(
    file: &mut dyn SegmentReader,
    strictness: OpenStrictness,
) -> Result<Vec<Ewf2Section>> {
    let file_len = file.segment_len()?;
    if file_len < ewf2::FILE_HEADER_SIZE as u64 + ewf2::SECTION_DESCRIPTOR_SIZE as u64 {
        return Err(EwfError::Malformed("EWF2 file is too short".into()));
    }

    if let Some(sections) = scan_ewf2_leading_sections(file, file_len, strictness)? {
        return Ok(sections);
    }
    scan_ewf2_trailing_sections(file, file_len, strictness)
}

fn scan_ewf2_leading_sections(
    file: &mut dyn SegmentReader,
    file_len: u64,
    strictness: OpenStrictness,
) -> Result<Option<Vec<Ewf2Section>>> {
    let mut sections = Vec::new();
    let mut offset = ewf2::FILE_HEADER_SIZE as u64;

    loop {
        if offset
            .checked_add(ewf2::SECTION_DESCRIPTOR_SIZE as u64)
            .is_none_or(|end| end > file_len)
        {
            if sections.is_empty() {
                return Ok(None);
            }
            return Err(EwfError::Malformed(
                "EWF2 leading section descriptor exceeds file".into(),
            ));
        }

        let mut buf = [0; ewf2::SECTION_DESCRIPTOR_SIZE];
        file.seek(SeekFrom::Start(offset))?;
        file.read_exact(&mut buf)?;
        let Ok(desc) = ewf2::SectionDescriptor::parse(&buf, offset) else {
            return if sections.is_empty() {
                Ok(None)
            } else {
                Err(EwfError::Malformed(
                    "EWF2 leading section descriptor is invalid".into(),
                ))
            };
        };
        if !is_valid_ewf2_leading_descriptor(desc, strictness) {
            return if sections.is_empty() {
                Ok(None)
            } else {
                Err(EwfError::Malformed(
                    "EWF2 leading section descriptor is invalid".into(),
                ))
            };
        }
        validate_present_adler32_checksum(&buf, 60, 60, "EWF2 section descriptor")?;

        let data_offset = offset
            .checked_add(u64::from(desc.descriptor_size))
            .ok_or_else(|| EwfError::Malformed("EWF2 section data offset overflow".into()))?;
        let data_end = data_offset
            .checked_add(desc.data_size)
            .ok_or_else(|| EwfError::Malformed("EWF2 section advance overflow".into()))?;
        if data_end > file_len {
            return if sections.is_empty() {
                Ok(None)
            } else {
                Err(EwfError::Malformed("EWF2 section data exceeds file".into()))
            };
        }
        let padding_size = ewf2_section_padding_size(desc)?;
        let next_offset = data_end
            .checked_add(padding_size)
            .ok_or_else(|| EwfError::Malformed("EWF2 section padding overflow".into()))?;
        if next_offset > file_len {
            return Err(EwfError::Malformed(
                "EWF2 section padding exceeds file".into(),
            ));
        }
        reject_encrypted_ewf2_section(desc)?;
        validate_ewf2_section_integrity_hash(file, desc, data_offset)?;
        let section_type = desc.section_type;
        sections.push(Ewf2Section {
            desc,
            data_offset,
            data_size: desc.data_size,
            layout: Ewf2SectionLayout::LeadingDescriptor,
        });
        if is_terminal_ewf2_section(section_type) {
            return Ok(Some(sections));
        }
        if next_offset <= offset {
            return Err(EwfError::Malformed(
                "EWF2 leading section chain does not advance".into(),
            ));
        }
        offset = next_offset;
    }
}

fn scan_ewf2_trailing_sections(
    file: &mut dyn SegmentReader,
    file_len: u64,
    strictness: OpenStrictness,
) -> Result<Vec<Ewf2Section>> {
    let mut sections = Vec::new();
    let header_size = ewf2::FILE_HEADER_SIZE as u64;
    let descriptor_size = ewf2::SECTION_DESCRIPTOR_SIZE as u64;
    let mut offset = file_len
        .checked_sub(descriptor_size)
        .ok_or_else(|| EwfError::Malformed("EWF2 file is too short".into()))?;
    let max_sections = ((file_len - header_size) / descriptor_size).saturating_add(1);

    for _ in 0..max_sections {
        let mut buf = [0; ewf2::SECTION_DESCRIPTOR_SIZE];
        file.seek(SeekFrom::Start(offset))?;
        file.read_exact(&mut buf)?;
        let desc = ewf2::SectionDescriptor::parse(&buf, offset)?;
        if !is_valid_ewf2_descriptor(desc, strictness) {
            return Err(EwfError::Malformed(
                "EWF2 trailing section descriptor is invalid".into(),
            ));
        }
        validate_present_adler32_checksum(&buf, 60, 60, "EWF2 section descriptor")?;
        ewf2_section_padding_size(desc)?;
        let data_offset = if desc.previous_offset == 0 {
            header_size
        } else {
            desc.previous_offset
                .checked_add(descriptor_size)
                .ok_or_else(|| {
                    EwfError::Malformed("EWF2 previous section offset overflow".into())
                })?
        };
        if data_offset < header_size {
            return Err(EwfError::Malformed(
                "EWF2 trailing section data precedes file header".into(),
            ));
        }
        let data_end = data_offset
            .checked_add(desc.data_size)
            .ok_or_else(|| EwfError::Malformed("EWF2 trailing section data overflow".into()))?;
        if data_end > offset {
            return Err(EwfError::Malformed(
                "EWF2 trailing section data exceeds descriptor".into(),
            ));
        }
        if desc.previous_offset != 0 {
            if desc.previous_offset >= desc.offset {
                return Err(EwfError::Malformed(
                    "EWF2 previous section offset is not before current section".into(),
                ));
            }
            let previous_end = desc
                .previous_offset
                .checked_add(descriptor_size)
                .ok_or_else(|| {
                    EwfError::Malformed("EWF2 previous section offset overflow".into())
                })?;
            if previous_end > offset {
                return Err(EwfError::Malformed(
                    "EWF2 previous section overlaps current section descriptor".into(),
                ));
            }
        }

        reject_encrypted_ewf2_section(desc)?;
        validate_ewf2_section_integrity_hash(file, desc, data_offset)?;
        let previous_offset = desc.previous_offset;
        sections.push(Ewf2Section {
            desc,
            data_offset,
            data_size: desc.data_size,
            layout: Ewf2SectionLayout::TrailingDescriptor,
        });
        if previous_offset == 0 {
            sections.reverse();
            return Ok(sections);
        }
        offset = previous_offset;
    }

    Err(EwfError::Malformed(
        "EWF2 trailing section descriptor chain is too long".into(),
    ))
}

fn is_valid_ewf2_descriptor(desc: ewf2::SectionDescriptor, strictness: OpenStrictness) -> bool {
    desc.descriptor_size == ewf2::SECTION_DESCRIPTOR_SIZE as u32
        && (strictness == OpenStrictness::Lenient
            || !matches!(desc.section_type, ewf2::SectionType::Unknown(_)))
}

fn is_valid_ewf2_leading_descriptor(
    desc: ewf2::SectionDescriptor,
    strictness: OpenStrictness,
) -> bool {
    is_valid_ewf2_descriptor(desc, strictness)
}

fn ewf2_section_padding_size(desc: ewf2::SectionDescriptor) -> Result<u64> {
    let padding_size = u64::from(desc.padding_size);
    if padding_size > desc.data_size {
        return Err(EwfError::Malformed(
            "EWF2 section padding size exceeds data size".into(),
        ));
    }
    Ok(padding_size)
}

fn reject_encrypted_ewf2_section(desc: ewf2::SectionDescriptor) -> Result<()> {
    if desc.section_type == ewf2::SectionType::EncryptionKeys {
        return Err(EwfError::Unsupported(
            "encrypted EWF2 image with encryption keys section".into(),
        ));
    }
    if desc.encrypted {
        return Err(EwfError::Unsupported(format!(
            "encrypted EWF2 {:?} section",
            desc.section_type
        )));
    }
    Ok(())
}

fn validate_ewf2_section_integrity_hash(
    file: &mut dyn SegmentReader,
    desc: ewf2::SectionDescriptor,
    data_offset: u64,
) -> Result<()> {
    if !desc.has_integrity_hash {
        return Ok(());
    }

    let mut hasher = md5::Md5::new();
    let mut remaining = desc.data_size;
    let mut buffer = [0; 8192];
    file.seek(SeekFrom::Start(data_offset))?;
    while remaining > 0 {
        let take = usize::try_from(remaining.min(buffer.len() as u64))
            .expect("section hash read is bounded by buffer length");
        file.read_exact(&mut buffer[..take])?;
        md5::Digest::update(&mut hasher, &buffer[..take]);
        remaining -= u64::try_from(take).expect("usize fits u64");
    }

    let calculated: [u8; 16] = hasher.finalize().into();
    if calculated != desc.data_integrity_hash {
        return Err(EwfError::Malformed(
            "EWF2 section data integrity hash mismatch".into(),
        ));
    }

    Ok(())
}

fn remember_ewf2_metadata_payload(
    target: &mut Option<Vec<u8>>,
    data: &[u8],
    label: &str,
) -> Result<()> {
    if let Some(existing) = target {
        if existing.as_slice() != data {
            return Err(EwfError::Malformed(format!("EWF2 {label} does not match")));
        }
    } else {
        *target = Some(data.to_vec());
    }
    Ok(())
}

fn is_terminal_ewf2_section(section_type: ewf2::SectionType) -> bool {
    matches!(
        section_type,
        ewf2::SectionType::Done | ewf2::SectionType::Next
    )
}

fn ewf2_acquisition_complete(sections: &[Ewf2Section]) -> bool {
    sections
        .last()
        .is_none_or(|section| section.desc.section_type != ewf2::SectionType::Next)
}

fn parse_ewf2_memory_extents_table(data: &[u8]) -> Result<Vec<MemoryExtent>> {
    const ENTRY_SIZE: usize = 16;

    if !data.len().is_multiple_of(ENTRY_SIZE) {
        return Err(EwfError::Malformed(
            "EWF2 memory extents table has partial entry".into(),
        ));
    }

    Ok(data
        .chunks_exact(ENTRY_SIZE)
        .map(|entry| MemoryExtent {
            start_page: u64::from_le_bytes(entry[0..8].try_into().expect("slice length checked")),
            page_count: u64::from_le_bytes(entry[8..16].try_into().expect("slice length checked")),
        })
        .collect())
}

fn parse_ewf1_ltree_data(data: &[u8]) -> Result<SingleFilesInfo> {
    if data.len() < EWF1_LTREE_HEADER_SIZE {
        return Err(EwfError::Malformed(
            "EWF1 ltree section is too short".into(),
        ));
    }

    let single_files_data_size =
        u64::from_le_bytes(data[16..24].try_into().expect("ltree header size checked"));
    let single_files_data_size = usize::try_from(single_files_data_size)
        .map_err(|_| EwfError::Malformed("EWF1 ltree data size does not fit usize".into()))?;
    let single_files_data_end = EWF1_LTREE_HEADER_SIZE
        .checked_add(single_files_data_size)
        .ok_or_else(|| EwfError::Malformed("EWF1 ltree data size overflow".into()))?;
    if single_files_data_end > data.len() {
        return Err(EwfError::Malformed(
            "EWF1 ltree data size exceeds section".into(),
        ));
    }

    let stored = u32::from_le_bytes(data[24..28].try_into().expect("ltree header size checked"));
    let mut header = data[..EWF1_LTREE_HEADER_SIZE].to_vec();
    header[24..28].fill(0);
    validate_adler32_checksum_value(stored, &header, "EWF1 ltree header")?;

    parse_ewf2_single_files_data(&data[EWF1_LTREE_HEADER_SIZE..single_files_data_end])
}

fn parse_ewf2_single_files_aux_u64_table(data: &[u8], label: &str) -> Result<Vec<u64>> {
    parse_ewf2_single_files_aux_table(data, 8, label, |entry| {
        u64::from_le_bytes(entry.try_into().expect("entry size checked"))
    })
}

fn parse_ewf2_single_files_md5_hash_table(data: &[u8]) -> Result<Vec<[u8; 16]>> {
    parse_ewf2_single_files_aux_table(data, 16, "EWF2 single files MD5 hash table", |entry| {
        entry.try_into().expect("entry size checked")
    })
}

fn parse_ewf2_single_files_aux_table<T>(
    data: &[u8],
    entry_size: usize,
    label: &str,
    parse_entry: impl Fn(&[u8]) -> T,
) -> Result<Vec<T>> {
    const PADDED_HEADER_SIZE: usize = 32;
    const FOOTER_SIZE: usize = 4;

    if data.len() < PADDED_HEADER_SIZE + FOOTER_SIZE {
        return Err(EwfError::Malformed(format!("{label} is too short")));
    }

    validate_present_adler32_checksum(data, 16, 16, &format!("{label} header"))?;
    let entry_count = u32::from_le_bytes(data[0..4].try_into().expect("slice length checked"));
    let entry_bytes = usize::try_from(entry_count)
        .map_err(|_| EwfError::Malformed(format!("{label} entry count does not fit usize")))?
        .checked_mul(entry_size)
        .ok_or_else(|| EwfError::Malformed(format!("{label} entry bytes overflow")))?;
    let entries_offset = PADDED_HEADER_SIZE;
    let entries_end = entries_offset
        .checked_add(entry_bytes)
        .ok_or_else(|| EwfError::Malformed(format!("{label} entry range overflow")))?;
    let footer_end = entries_end
        .checked_add(FOOTER_SIZE)
        .ok_or_else(|| EwfError::Malformed(format!("{label} footer range overflow")))?;
    if footer_end > data.len() {
        return Err(EwfError::Malformed(format!(
            "{label} entries exceed section"
        )));
    }

    let stored = u32::from_le_bytes(
        data[entries_end..entries_end + FOOTER_SIZE]
            .try_into()
            .expect("footer range checked"),
    );
    if stored != 0 {
        validate_adler32_checksum_value(stored, &data[entries_offset..entries_end], label)?;
    }
    Ok(data[entries_offset..entries_end]
        .chunks_exact(entry_size)
        .map(parse_entry)
        .collect())
}

fn parse_ewf1_ranges(
    file: &mut dyn SegmentReader,
    sections: &[Section],
    segment_index: usize,
    first_chunk: u64,
    logical_size: u64,
    allow_large_compressed_chunks: bool,
) -> Result<Vec<TableRange>> {
    let mut ranges = Vec::new();
    let mut next_chunk = first_chunk;
    let mut previous_table: Option<(bool, u32, u64)> = None;
    for section in sections
        .iter()
        .filter(|section| matches!(section.desc.section_type.as_str(), "table" | "table2"))
    {
        if section.data_size < 24 {
            return Err(EwfError::Malformed(
                "EWF1 table section is too short".into(),
            ));
        }
        let data = read_exact_at(file, section.data_offset, 24)?;
        validate_present_adler32_checksum(&data, 20, 20, "EWF1 table header")?;
        let entry_count = u32::from_le_bytes(data[0..4].try_into().expect("slice length checked"));
        let base_offset = u64::from_le_bytes(data[8..16].try_into().expect("slice length checked"));
        if entry_count == 0 {
            continue;
        }
        if section.desc.section_type == "table2"
            && previous_table.is_some_and(|(previous_was_table, previous_count, previous_base)| {
                previous_was_table && previous_count == entry_count && previous_base == base_offset
            })
        {
            continue;
        }

        let entry_bytes = u64::from(entry_count)
            .checked_mul(4)
            .ok_or_else(|| EwfError::Malformed("EWF1 table entry bytes overflow".into()))?;
        let entries_offset = section
            .data_offset
            .checked_add(24)
            .ok_or_else(|| EwfError::Malformed("EWF1 table entry offset overflow".into()))?;
        let entries_end = entries_offset
            .checked_add(entry_bytes)
            .ok_or_else(|| EwfError::Malformed("EWF1 table entry range overflow".into()))?;
        let section_end = section
            .data_offset
            .checked_add(section.data_size)
            .ok_or_else(|| EwfError::Malformed("EWF1 table section range overflow".into()))?;
        if entries_end > section_end {
            return Err(EwfError::Malformed(
                "EWF1 table entries exceed section".into(),
            ));
        }
        let first_entry_offset = if base_offset == 0 {
            let raw = read_exact_at(file, entries_offset, 4)?;
            Some(u64::from(
                u32::from_le_bytes(raw.try_into().expect("first table entry read size checked"))
                    & 0x7fff_ffff,
            ))
        } else {
            None
        };
        let table_resident_without_entries_checksum =
            first_entry_offset.is_some_and(|offset| offset == entries_end);
        if entries_end
            .checked_add(4)
            .is_some_and(|footer_end| footer_end <= section_end)
            && !table_resident_without_entries_checksum
        {
            validate_present_table_entries_checksum(
                file,
                entries_offset,
                entry_bytes,
                entries_end,
                "EWF1 table entries",
            )?;
        }

        let (data_base, data_end) = if let Some(sectors) =
            matching_sectors_section(sections, base_offset).or_else(|| {
                first_entry_offset
                    .and_then(|offset| sectors_section_containing_offset(sections, offset))
            }) {
            let data_end = sectors
                .data_offset
                .checked_add(sectors.data_size)
                .ok_or_else(|| EwfError::Malformed("EWF1 sectors range overflow".into()))?;
            (base_offset, data_end)
        } else {
            let resident_data_start = if table_resident_without_entries_checksum {
                entries_end
            } else {
                entries_end.checked_add(4).ok_or_else(|| {
                    EwfError::Malformed("EWF1 table-resident data offset overflow".into())
                })?
            };
            if resident_data_start > section_end {
                return Err(EwfError::Malformed(
                    "EWF1 table-resident data starts beyond table section".into(),
                ));
            }
            (0, section_end)
        };

        ranges.push(TableRange {
            kind: TableRangeKind::Ewf1,
            segment_index,
            first_chunk: next_chunk,
            chunk_count: u64::from(entry_count),
            entries_offset,
            base_offset: data_base,
            data_end: Some(data_end),
            ewf1_allow_large_compressed_chunks: allow_large_compressed_chunks,
            ewf2_compression_method: None,
        });
        next_chunk = next_chunk
            .checked_add(u64::from(entry_count))
            .ok_or_else(|| EwfError::Malformed("EWF1 table chunk count overflow".into()))?;
        previous_table = Some((
            section.desc.section_type == "table",
            entry_count,
            base_offset,
        ));
    }

    if ranges.is_empty() && logical_size > 0 {
        return Err(EwfError::Malformed("EWF1 table coverage is missing".into()));
    }
    Ok(ranges)
}

fn matching_sectors_section(sections: &[Section], base_offset: u64) -> Option<&Section> {
    sections
        .iter()
        .filter(|section| section.desc.section_type == "sectors")
        .find(|section| {
            base_offset == section.desc.offset
                || sectors_section_contains_offset(section, base_offset)
        })
}

fn sectors_section_containing_offset(sections: &[Section], offset: u64) -> Option<&Section> {
    sections
        .iter()
        .filter(|section| section.desc.section_type == "sectors")
        .find(|section| sectors_section_contains_offset(section, offset))
}

fn sectors_section_contains_offset(section: &Section, offset: u64) -> bool {
    section
        .data_offset
        .checked_add(section.data_size)
        .is_some_and(|data_end| offset >= section.data_offset && offset <= data_end)
}

fn parse_ewf2_ranges(
    file: &mut dyn SegmentReader,
    sections: &[Ewf2Section],
    segment_index: usize,
    logical_size: u64,
    compression_method: ewf2::CompressionMethod,
) -> Result<Vec<TableRange>> {
    let mut ranges = Vec::new();
    for section in sections
        .iter()
        .filter(|section| section.desc.section_type == ewf2::SectionType::SectorTable)
    {
        let minimum_table_header_size = match section.layout {
            Ewf2SectionLayout::LeadingDescriptor => ewf2::TABLE_HEADER_SIZE as u64,
            Ewf2SectionLayout::TrailingDescriptor => EWF2_TABLE_HEADER_V2_SIZE,
        };
        if section.data_size < minimum_table_header_size {
            return Err(EwfError::Malformed("EWF2 sector table is too short".into()));
        }
        let header_read_size = if section.data_size >= EWF2_TABLE_HEADER_V2_SIZE {
            EWF2_TABLE_HEADER_V2_SIZE
        } else {
            minimum_table_header_size
        };
        let data = read_exact_at(file, section.data_offset, header_read_size)?;
        validate_present_adler32_checksum(&data, 16, 16, "EWF2 table header")?;
        let header = ewf2::TableHeader::parse(&data[..ewf2::TABLE_HEADER_SIZE])?;
        let entry_count = u64::from(header.entry_count);
        if entry_count == 0 {
            continue;
        }
        let entries_bytes = entry_count
            .checked_mul(ewf2::TABLE_ENTRY_SIZE as u64)
            .ok_or_else(|| EwfError::Malformed("EWF2 table entry bytes overflow".into()))?;
        let table_header_and_padding_size = match section.layout {
            Ewf2SectionLayout::TrailingDescriptor => EWF2_TABLE_HEADER_V2_SIZE,
            Ewf2SectionLayout::LeadingDescriptor => {
                let full_header_entries_size = EWF2_TABLE_HEADER_V2_SIZE
                    .checked_add(entries_bytes)
                    .ok_or_else(|| EwfError::Malformed("EWF2 table size overflow".into()))?;
                if section.data_size >= full_header_entries_size {
                    EWF2_TABLE_HEADER_V2_SIZE
                } else {
                    ewf2::TABLE_HEADER_SIZE as u64
                }
            }
        };
        let entries_offset = section
            .data_offset
            .checked_add(table_header_and_padding_size)
            .ok_or_else(|| EwfError::Malformed("EWF2 table entry offset overflow".into()))?;
        let entries_end = entries_offset
            .checked_add(entries_bytes)
            .ok_or_else(|| EwfError::Malformed("EWF2 table entry range overflow".into()))?;
        let section_end = section
            .data_offset
            .checked_add(section.data_size)
            .ok_or_else(|| EwfError::Malformed("EWF2 table section range overflow".into()))?;
        if entries_end > section_end {
            return Err(EwfError::Malformed(
                "EWF2 table entries exceed section".into(),
            ));
        }
        if entries_end
            .checked_add(EWF2_TABLE_FOOTER_SIZE)
            .is_some_and(|footer_end| footer_end <= section_end)
        {
            validate_present_table_entries_checksum(
                file,
                entries_offset,
                entries_bytes,
                entries_end,
                "EWF2 table entries",
            )?;
        }

        ranges.push(TableRange {
            kind: TableRangeKind::Ewf2,
            segment_index,
            first_chunk: header.first_chunk,
            chunk_count: entry_count,
            entries_offset,
            base_offset: 0,
            data_end: None,
            ewf1_allow_large_compressed_chunks: false,
            ewf2_compression_method: Some(compression_method_code(compression_method)),
        });
    }

    if ranges.is_empty() && logical_size > 0 {
        return Err(EwfError::Malformed("EWF2 image has no sector table".into()));
    }
    Ok(ranges)
}

fn read_exact_at(file: &mut dyn SegmentReader, offset: u64, size: u64) -> Result<Vec<u8>> {
    let mut data = vec![
        0;
        usize::try_from(size).map_err(|_| {
            EwfError::Malformed("read size does not fit usize".into())
        })?
    ];
    file.seek(SeekFrom::Start(offset))?;
    file.read_exact(&mut data)?;
    Ok(data)
}

fn table_entry_offset(range: &TableRange, local_index: u64, entry_size: u64) -> Result<u64> {
    range
        .entries_offset
        .checked_add(
            local_index
                .checked_mul(entry_size)
                .ok_or_else(|| EwfError::Malformed("table entry offset overflow".into()))?,
        )
        .ok_or_else(|| EwfError::Malformed("table entry offset overflow".into()))
}

fn validate_ewf1_encoded_size(
    encoded_size: u64,
    chunk_size: u64,
    encoding: ChunkEncoding,
    allow_large_compressed_chunks: bool,
) -> Result<()> {
    if encoding == ChunkEncoding::Zlib {
        let standard_maximum = zlib_compressed_chunk_size_cap(chunk_size)?;
        if !allow_large_compressed_chunks && encoded_size <= standard_maximum {
            return validate_encoded_size(encoded_size, chunk_size, encoding);
        }
        if encoded_size == 0 {
            return Err(EwfError::Malformed("chunk data size is zero".into()));
        }
        let maximum = chunk_size
            .checked_mul(2)
            .ok_or_else(|| EwfError::Malformed("EWF1 chunk size cap overflow".into()))?;
        if encoded_size > maximum {
            return Err(EwfError::Malformed(format!(
                "EWF1 compressed chunk size {encoded_size} exceeds maximum {maximum}"
            )));
        }
        Ok(())
    } else {
        validate_encoded_size(encoded_size, chunk_size, encoding)
    }
}

fn ewf1_chunk_encoding(
    entry_compressed: bool,
    encoded_size: u64,
    chunk_size: u64,
) -> Result<ChunkEncoding> {
    if entry_compressed {
        return Ok(ChunkEncoding::Zlib);
    }
    if encoded_size > raw_chunk_size_cap(chunk_size)?
        && encoded_size <= zlib_compressed_chunk_size_cap(chunk_size)?
    {
        return Ok(ChunkEncoding::Zlib);
    }
    Ok(ChunkEncoding::Raw)
}

fn decode_ewf1_entry(
    range: &TableRange,
    raw: u32,
    chunk_size: u64,
    next_raw: Option<u32>,
    is_final: bool,
) -> Result<Ewf1DecodedEntry> {
    let entry = ewf1::TableEntry::parse(&raw.to_le_bytes())?;
    let masked_offset = range
        .base_offset
        .checked_add(entry.offset)
        .ok_or_else(|| EwfError::Malformed("EWF1 chunk offset overflow".into()))?;

    if should_use_full_width_ewf1_offset(range, raw, masked_offset, chunk_size, next_raw, is_final)?
    {
        return Ok(Ewf1DecodedEntry {
            compressed: false,
            offset: range
                .base_offset
                .checked_add(u64::from(raw))
                .ok_or_else(|| EwfError::Malformed("EWF1 chunk offset overflow".into()))?,
        });
    }

    Ok(Ewf1DecodedEntry {
        compressed: entry.compressed,
        offset: masked_offset,
    })
}

fn should_use_full_width_ewf1_offset(
    range: &TableRange,
    raw: u32,
    masked_offset: u64,
    chunk_size: u64,
    next_raw: Option<u32>,
    is_final: bool,
) -> Result<bool> {
    if range.base_offset == 0 || raw & 0x8000_0000 == 0 {
        return Ok(false);
    }
    let Some(data_end) = range.data_end else {
        return Ok(false);
    };
    let data_len = data_end
        .checked_sub(range.base_offset)
        .ok_or_else(|| EwfError::Malformed("EWF1 data region precedes base offset".into()))?;
    if data_len <= 0x8000_0000 {
        return Ok(false);
    }

    let full_offset = range
        .base_offset
        .checked_add(u64::from(raw))
        .ok_or_else(|| EwfError::Malformed("EWF1 chunk offset overflow".into()))?;
    if full_offset >= data_end {
        return Ok(false);
    }

    if let Some(next_raw) = next_raw {
        let next_masked = range
            .base_offset
            .checked_add(u64::from(next_raw & 0x7fff_ffff))
            .ok_or_else(|| EwfError::Malformed("EWF1 next chunk offset overflow".into()))?;
        let masked_is_valid = next_masked > masked_offset
            && next_masked - masked_offset <= zlib_compressed_chunk_size_cap(chunk_size)?;
        if masked_is_valid {
            return Ok(false);
        }

        let next_full = if next_raw & 0x8000_0000 != 0 {
            range
                .base_offset
                .checked_add(u64::from(next_raw))
                .ok_or_else(|| EwfError::Malformed("EWF1 next chunk offset overflow".into()))?
        } else {
            next_masked
        };
        return Ok(
            next_full > full_offset && next_full - full_offset <= raw_chunk_size_cap(chunk_size)?
        );
    }

    if is_final {
        let masked_size = data_end.saturating_sub(masked_offset);
        let full_size = data_end - full_offset;
        return Ok(masked_size > zlib_compressed_chunk_size_cap(chunk_size)?
            && full_size <= raw_chunk_size_cap(chunk_size)?);
    }

    Ok(false)
}

fn logical_chunk_size(logical_size: u64, chunk_size: u64, chunk_id: u64) -> Result<usize> {
    let logical_offset = chunk_id
        .checked_mul(chunk_size)
        .ok_or_else(|| EwfError::Malformed("logical chunk offset overflow".into()))?;
    let size = logical_size.saturating_sub(logical_offset).min(chunk_size);
    usize::try_from(size)
        .map_err(|_| EwfError::Malformed("logical chunk size does not fit usize".into()))
}

fn checksum_error_range(
    info: &ImageInfo,
    chunk_id: u64,
    logical_size: usize,
) -> Result<SectorRange> {
    let logical_offset = chunk_id
        .checked_mul(info.chunk_size)
        .ok_or_else(|| EwfError::Malformed("checksum error logical offset overflow".into()))?;
    let logical_size = u64::try_from(logical_size)
        .map_err(|_| EwfError::Malformed("checksum error size does not fit u64".into()))?;
    let Some(bytes_per_sector) = info.media.bytes_per_sector.filter(|value| *value != 0) else {
        return Ok(SectorRange {
            first_sector: logical_offset,
            sector_count: logical_size.max(1),
        });
    };

    Ok(SectorRange {
        first_sector: logical_offset / bytes_per_sector,
        sector_count: logical_size.div_ceil(bytes_per_sector).max(1),
    })
}

fn validate_chunk_size(chunk_size: u64) -> Result<()> {
    if chunk_size == 0 {
        return Err(EwfError::Malformed("chunk size is zero".into()));
    }
    if chunk_size > MAX_CHUNK_SIZE {
        return Err(EwfError::Malformed(format!(
            "chunk size {chunk_size} exceeds maximum {MAX_CHUNK_SIZE}"
        )));
    }
    Ok(())
}

fn apply_ewf2_geometry(media: &mut MediaInfo, geometry: Ewf2Geometry) {
    if let Some(value) = geometry.sectors_per_chunk {
        media.sectors_per_chunk = Some(value);
    }
    if let Some(value) = geometry.bytes_per_sector {
        media.bytes_per_sector = Some(value);
    }
    if let Some(value) = geometry.sector_count {
        media.sector_count = Some(value);
    }
    if let Some(value) = geometry.chunk_count {
        media.chunk_count = Some(value);
    }
    if let Some(value) = geometry.error_granularity {
        media.error_granularity = Some(value);
    }
    if let Some(value) = geometry.media_type {
        media.media_type = Some(value);
    }
    if let Some(value) = geometry.physical {
        media.media_flags.physical = value;
    }
    media.media_flags.fastbloc |= geometry.fastbloc;
    media.media_flags.tableau |= geometry.tableau;
}

fn apply_ewf2_geometry_if_missing(media: &mut MediaInfo, geometry: Ewf2Geometry) {
    if media.sectors_per_chunk.is_none() {
        media.sectors_per_chunk = geometry.sectors_per_chunk;
    }
    if media.bytes_per_sector.is_none() {
        media.bytes_per_sector = geometry.bytes_per_sector;
    }
    if media.sector_count.is_none() {
        media.sector_count = geometry.sector_count;
    }
    if media.chunk_count.is_none() {
        media.chunk_count = geometry.chunk_count;
    }
    if media.error_granularity.is_none() {
        media.error_granularity = geometry.error_granularity;
    }
    if media.media_type.is_none() {
        media.media_type = geometry.media_type;
    }
    if let Some(value) = geometry.physical {
        media.media_flags.physical = value;
    }
    media.media_flags.fastbloc |= geometry.fastbloc;
    media.media_flags.tableau |= geometry.tableau;
}

fn public_compression_method(method: ewf2::CompressionMethod) -> CompressionMethod {
    match method {
        ewf2::CompressionMethod::None => CompressionMethod::None,
        ewf2::CompressionMethod::Zlib => CompressionMethod::Zlib,
        ewf2::CompressionMethod::Bzip2 => CompressionMethod::Bzip2,
        ewf2::CompressionMethod::Unknown(method) => CompressionMethod::Unknown(method),
    }
}

fn compression_method_code(method: ewf2::CompressionMethod) -> u16 {
    match method {
        ewf2::CompressionMethod::None => 0,
        ewf2::CompressionMethod::Zlib => 1,
        ewf2::CompressionMethod::Bzip2 => 2,
        ewf2::CompressionMethod::Unknown(method) => method,
    }
}

fn merge_hashes(target: &mut StoredHashes, source: &StoredHashes) {
    if target.md5.is_none() {
        target.md5 = source.md5;
    }
    if target.sha1.is_none() {
        target.sha1 = source.sha1;
    }
    for (identifier, value) in &source.hash_values {
        target
            .hash_values
            .entry(identifier.clone())
            .or_insert_with(|| value.clone());
    }
}

fn merge_segment_format_profile(
    target: &mut Option<FormatProfile>,
    target_hint_only: &mut bool,
    source: FormatProfile,
    source_hint_only: bool,
) -> Result<()> {
    if source == FormatProfile::Unknown {
        return Ok(());
    }
    match target {
        Some(existing) if *existing == FormatProfile::Unknown => {
            *existing = source;
            *target_hint_only = source_hint_only;
        }
        Some(existing) if *existing == source => {
            if !source_hint_only {
                *target_hint_only = false;
            }
        }
        Some(existing)
            if *target_hint_only
                && !source_hint_only
                && ewf1_profile_hint_matches_detected_profile(*existing, source) =>
        {
            *existing = source;
            *target_hint_only = false;
        }
        Some(existing)
            if !*target_hint_only
                && source_hint_only
                && ewf1_profile_hint_matches_detected_profile(source, *existing) => {}
        Some(existing) if *existing != source => {
            return Err(EwfError::Malformed(format!(
                "segment format profiles do not match ({existing:?} != {source:?})",
            )));
        }
        Some(_) => {}
        None => {
            *target = Some(source);
            *target_hint_only = source_hint_only;
        }
    }
    Ok(())
}

fn ewf1_profile_hint_matches_detected_profile(
    hint: FormatProfile,
    detected: FormatProfile,
) -> bool {
    matches!(
        hint,
        FormatProfile::EnCase2 | FormatProfile::EnCase5 | FormatProfile::Ewf
    ) && matches!(
        detected,
        FormatProfile::EnCase1
            | FormatProfile::EnCase2
            | FormatProfile::EnCase3
            | FormatProfile::EnCase4
            | FormatProfile::EnCase5
            | FormatProfile::EnCase6
            | FormatProfile::EnCase7
            | FormatProfile::FtkImager
            | FormatProfile::Linen5
            | FormatProfile::Linen6
            | FormatProfile::Linen7
    )
}

fn apply_detected_ewf1_format_profile(
    target: &mut FormatProfile,
    detected: Option<FormatProfile>,
) -> bool {
    let Some(detected) = detected.filter(|profile| *profile != FormatProfile::Unknown) else {
        return false;
    };
    if *target == FormatProfile::Smart && detected == FormatProfile::FtkImager {
        *target = detected;
        return true;
    }
    if matches!(
        target,
        FormatProfile::Smart
            | FormatProfile::LogicalEnCase5
            | FormatProfile::LogicalEnCase6
            | FormatProfile::LogicalEnCase7
    ) {
        return false;
    }
    *target = detected;
    true
}

fn merge_single_files(
    target: &mut Option<SingleFilesInfo>,
    source: Option<SingleFilesInfo>,
) -> Result<()> {
    if let Some(source) = source {
        if target.is_some() {
            return Err(EwfError::Malformed(
                "EWF2 image has duplicate single files data sections".into(),
            ));
        }
        *target = Some(source);
    }
    Ok(())
}

fn merge_single_files_aux_tables(
    target: &mut SingleFilesAuxTables,
    source: SingleFilesAuxTables,
) -> Result<()> {
    merge_single_files_aux_u64_table(
        &mut target.table_0x21_entries,
        source.table_0x21_entries,
        "0x21",
    )?;
    merge_single_files_aux_md5_table(&mut target.md5_hashes, source.md5_hashes)?;
    merge_single_files_aux_u64_table(
        &mut target.table_0x23_entries,
        source.table_0x23_entries,
        "0x23",
    )
}

fn merge_single_files_aux_u64_table(
    target: &mut Vec<u64>,
    source: Vec<u64>,
    table_name: &str,
) -> Result<()> {
    if source.is_empty() {
        return Ok(());
    }
    if !target.is_empty() {
        return Err(EwfError::Malformed(format!(
            "EWF2 image has duplicate single files {table_name} table sections"
        )));
    }
    *target = source;
    Ok(())
}

fn merge_single_files_aux_md5_table(
    target: &mut Vec<[u8; 16]>,
    source: Vec<[u8; 16]>,
) -> Result<()> {
    if source.is_empty() {
        return Ok(());
    }
    if !target.is_empty() {
        return Err(EwfError::Malformed(
            "EWF2 image has duplicate single files MD5 hash table sections".into(),
        ));
    }
    *target = source;
    Ok(())
}

fn merge_optional_ewf2_string_section(
    target: &mut Option<String>,
    source: Option<String>,
    label: &str,
) -> Result<()> {
    let Some(source) = source else {
        return Ok(());
    };
    if target.is_some() {
        return Err(EwfError::Malformed(format!(
            "EWF2 image has duplicate {label} sections"
        )));
    }
    *target = Some(source);
    Ok(())
}

fn merge_optional_ewf2_raw_section(
    target: &mut Option<Vec<u8>>,
    source: Option<Vec<u8>>,
    label: &str,
) -> Result<()> {
    let Some(source) = source else {
        return Ok(());
    };
    if target.is_some() {
        return Err(EwfError::Malformed(format!(
            "EWF2 image has duplicate {label} sections"
        )));
    }
    *target = Some(source);
    Ok(())
}

fn parse_nonzero_hash<const N: usize>(data: &[u8]) -> Option<[u8; N]> {
    let value = data.get(..N)?;
    let mut hash = [0; N];
    hash.copy_from_slice(value);
    hash.iter().any(|byte| *byte != 0).then_some(hash)
}

fn validate_adler32_checksum(
    data: &[u8],
    checksum_offset: usize,
    checksum_data_size: usize,
    label: &str,
) -> Result<()> {
    let stored = u32::from_le_bytes(
        data[checksum_offset..checksum_offset + 4]
            .try_into()
            .expect("hash section size checked"),
    );
    validate_adler32_checksum_value(stored, &data[..checksum_data_size], label)
}

fn validate_present_adler32_checksum(
    data: &[u8],
    checksum_offset: usize,
    checksum_data_size: usize,
    label: &str,
) -> Result<()> {
    let stored = u32::from_le_bytes(
        data[checksum_offset..checksum_offset + 4]
            .try_into()
            .expect("checksum offset checked"),
    );
    if stored == 0 {
        return Ok(());
    }
    validate_adler32_checksum_value(stored, &data[..checksum_data_size], label)
}

fn validate_present_table_entries_checksum(
    file: &mut dyn SegmentReader,
    entries_offset: u64,
    entry_bytes: u64,
    checksum_offset: u64,
    label: &str,
) -> Result<()> {
    let checksum = read_exact_at(file, checksum_offset, 4)?;
    let stored = u32::from_le_bytes(
        checksum
            .as_slice()
            .try_into()
            .expect("checksum size checked"),
    );
    if stored == 0 {
        return Ok(());
    }
    let entries = read_exact_at(file, entries_offset, entry_bytes)?;
    validate_adler32_checksum_value(stored, &entries, label)
}

fn validate_present_ewf1_media_checksum(data: &[u8], section_type: &str) -> Result<()> {
    let Some(checksum_offset) = data.len().checked_sub(4) else {
        return Ok(());
    };
    validate_present_adler32_checksum(
        data,
        checksum_offset,
        checksum_offset,
        &format!("EWF1 {section_type}"),
    )
}

fn validate_adler32_checksum_value(stored: u32, checksum_data: &[u8], label: &str) -> Result<()> {
    let calculated = adler32(checksum_data);
    if stored != calculated {
        return Err(EwfError::Malformed(format!("{label} checksum mismatch")));
    }
    Ok(())
}

fn validate_raw_chunk_checksum(encoded: &[u8], logical_size: usize) -> Result<()> {
    let checksum_offset = logical_size;
    if encoded.len() < checksum_offset + 4 {
        return Err(EwfError::Malformed(
            "raw chunk checksum trailer is missing".into(),
        ));
    }
    validate_adler32_checksum(encoded, checksum_offset, logical_size, "raw chunk checksum")
}

fn adler32(data: &[u8]) -> u32 {
    const MOD_ADLER: u32 = 65_521;
    let mut a = 1_u32;
    let mut b = 0_u32;
    for byte in data {
        a = (a + u32::from(*byte)) % MOD_ADLER;
        b = (b + a) % MOD_ADLER;
    }
    (b << 16) | a
}

fn insert_hash_value(stored_hashes: &mut StoredHashes, identifier: &str, hash: &[u8]) {
    stored_hashes
        .hash_values
        .entry(identifier.to_string())
        .or_insert_with(|| hex_string(hash));
}

fn hex_string(bytes: &[u8]) -> String {
    const HEX: &[u8; 16] = b"0123456789abcdef";
    let mut out = String::with_capacity(bytes.len() * 2);
    for byte in bytes {
        out.push(char::from(HEX[(byte >> 4) as usize]));
        out.push(char::from(HEX[(byte & 0x0f) as usize]));
    }
    out
}

fn validate_hash_section_size(observed: u64, expected: u64, label: &str) -> Result<()> {
    if observed != expected {
        return Err(EwfError::Malformed(format!(
            "{label} hash section has size {observed}, expected {expected}"
        )));
    }
    Ok(())
}

fn validate_set_identifier(
    expected: &mut Option<[u8; 16]>,
    observed: Option<[u8; 16]>,
) -> Result<()> {
    let Some(observed) = observed else {
        return Ok(());
    };
    if let Some(expected) = expected {
        if *expected != observed {
            return Err(EwfError::Malformed(
                "segment set identifier mismatch".into(),
            ));
        }
    } else {
        *expected = Some(observed);
    }
    Ok(())
}

fn validate_ewf2_header_profile(
    expected: &mut Option<Ewf2HeaderProfile>,
    observed: Option<Ewf2HeaderProfile>,
) -> Result<()> {
    let Some(observed) = observed else {
        return Ok(());
    };
    if let Some(expected) = expected {
        if expected.major_version != observed.major_version
            || expected.minor_version != observed.minor_version
        {
            return Err(EwfError::Malformed(
                "EWF2 segment file format version mismatch".into(),
            ));
        }
        if expected.compression_method != observed.compression_method {
            return Err(EwfError::Malformed(
                "EWF2 segment file compression method mismatch".into(),
            ));
        }
    } else {
        *expected = Some(observed);
    }
    Ok(())
}

fn ewf1_metadata_payload(data: &[u8]) -> Vec<u8> {
    let mut decompressed = Vec::new();
    let result = flate2::read::ZlibDecoder::new(data)
        .take(MAX_DECOMPRESSED_METADATA + 1)
        .read_to_end(&mut decompressed);
    if result.is_ok() && decompressed.len() <= MAX_DECOMPRESSED_METADATA as usize {
        decompressed
    } else {
        data.to_vec()
    }
}

fn ewf2_metadata_payload(
    data: &[u8],
    _compression_method: ewf2::CompressionMethod,
) -> Result<Vec<u8>> {
    if data.first() == Some(&0x78) {
        return decompress_ewf2_metadata(flate2::read::ZlibDecoder::new(data));
    }
    if data.starts_with(b"BZh") {
        return decompress_ewf2_metadata(bzip2::read::BzDecoder::new(data));
    }
    Ok(data.to_vec())
}

fn decode_ewf2_string_section(
    data: &[u8],
    compression_method: ewf2::CompressionMethod,
    label: &str,
) -> Result<String> {
    let payload = ewf2_metadata_payload(data, compression_method)?;
    if payload.len() % 2 != 0 {
        return Err(EwfError::Malformed(format!(
            "EWF2 {label} section has odd UTF-16 size"
        )));
    }

    let units: Vec<u16> = payload
        .chunks_exact(2)
        .map(|chunk| u16::from_le_bytes(chunk.try_into().expect("slice length checked")))
        .collect();
    let text = String::from_utf16(&units)
        .map_err(|_| EwfError::Malformed(format!("EWF2 {label} section is not valid UTF-16LE")))?;
    Ok(text.strip_prefix('\u{feff}').unwrap_or(&text).to_owned())
}

fn decompress_ewf2_metadata(reader: impl Read) -> Result<Vec<u8>> {
    let mut decompressed = Vec::new();
    reader
        .take(MAX_DECOMPRESSED_METADATA + 1)
        .read_to_end(&mut decompressed)
        .map_err(|err| EwfError::Malformed(format!("EWF2 metadata decompression failed: {err}")))?;
    if decompressed.len() > MAX_DECOMPRESSED_METADATA as usize {
        return Err(EwfError::Malformed(
            "EWF2 metadata exceeds decompressed size limit".into(),
        ));
    }
    Ok(decompressed)
}

#[cfg(test)]
mod tests {
    use std::io::Write;

    use flate2::write::ZlibEncoder;

    use super::*;

    #[test]
    fn ewf1_metadata_payload_decompresses_zlib_data() {
        let mut encoder = ZlibEncoder::new(Vec::new(), flate2::Compression::default());
        encoder.write_all(b"metadata").unwrap();
        let compressed = encoder.finish().unwrap();

        assert_eq!(ewf1_metadata_payload(&compressed), b"metadata");
    }

    #[test]
    fn ewf1_metadata_payload_keeps_plain_data() {
        assert_eq!(ewf1_metadata_payload(b"plain metadata"), b"plain metadata");
    }

    #[test]
    fn ewf2_metadata_payload_decompresses_zlib_data() {
        let mut encoder = ZlibEncoder::new(Vec::new(), flate2::Compression::default());
        encoder.write_all(b"metadata").unwrap();
        let compressed = encoder.finish().unwrap();

        assert_eq!(
            ewf2_metadata_payload(&compressed, ewf2::CompressionMethod::Zlib).unwrap(),
            b"metadata"
        );
    }
}