Struct delharc::decode::LhaDecodeReader

pub struct LhaDecodeReader<R> { /* private fields */ }

LhaDecodeReader provides a convenient way to parse and decode LHA/LZH files.

To read the current archived file’s content use the std::io::Read trait methods on the instance of this type. After reading the whole file (until EOF), the calculated checksum should be verified using LhaDecodeReader::crc_check.

To parse and decode the next archive file, invoke LhaDecodeReader::next_file.

After parsing the LHA header, a decompressed content of a file can be simply read from the LhaDecodeReader<R>, which decompresses it using a proper decoder, designated in the header, while reading data from the underlying stream.

If the compression method is not supported by the decoder, but otherwise the header has been parsed successfully, invoke LhaDecodeReader::is_decoder_supported to ensure you can actually read the file. Otherwise, trying to read from an unsupported decoder will result in an error.

no_std

Without the std feature in the absence of std::io the crate’s Read trait methods should be used instead to read the content of the decompressed files.

Implementations

impl<R: Read> LhaDecodeReader<R>

where R::Error: Debug,

pub fn new(rd: R) -> Result<LhaDecodeReader<R>, LhaDecodeError<R>>

Return a new instance of LhaDecodeReader<R> after reading and parsing the first header from source.

Provide a stream reader as rd.

Errors

Return an error if the header could not be read or parsed.

pub fn begin_new(&mut self, rd: R) -> Result<bool, LhaDecodeError<R>>

Attempt to read the first file header from a new source stream and initialize a decoder returning Ok(true) on success. Return Ok(false) if there are no more headers in the stream.

Provide a stream reader as rd.

When Ok is returned, regardles of the retuned boolean value, the inner reader is being always replaced with the given rd.

When Ok(false) has been returned, trying to read from the decoder will result in an error.

Errors

Returns an error if the header could not be read or parsed. In this instance the inner stream reader is not being replaced by a new one and the provided source stream can be retrieved from the returned error.

pub fn begin_with_header_and_decoder( &mut self, header: LhaHeader, decoder: DecoderAny<Take<R>> )

Assign externally parsed header and decoder to this instance of LhaDecodeReader<R>.

It is up to the caller to make sure the decoder and the header are matching each other.

The decoder should be initialized with the reader limited by the Take wrapper with its limit set to the LhaHeader::compressed_size number of bytes.

This method assumes the file will be read and decoded from its beginning.

pub fn next_file(&mut self) -> Result<bool, LhaDecodeError<R>>

Attempt to parse the next file’s header.

The remaining content of the previous file is being skipped if the current file’s content has not been read entirely.

On success returns Ok(true) if the next header has been read and parsed successfully. If there are no more headers, returns Ok(false).

Errors

Returns an error if the header could not be read or parsed. In this instance the underlying stream source will be taken and returned with the error.

Panic

Panics if called when the underlying stream reader has been already taken.

no_std

To skip the remaining file’s content this function uses 8 KB stack-allocated buffer when using with std feature enabled. Without std the buffer size is 512 bytes. See also LhaDecodeReader::next_file_with_sink.

pub fn next_file_with_sink<const BUF: usize>( &mut self ) -> Result<bool, LhaDecodeError<R>>

Attempt to parse the next file’s header.

Exactly like LhaDecodeReader::next_file but allows to specify the sink buffer size as BUF.

Panics

Panics when BUF = 0.

pub fn header(&self) -> &LhaHeader

Return a reference to the last parsed file’s LhaHeader.

pub fn into_inner(self) -> R

Unwrap the underlying stream reader and return it.

Panics

Panics if the reader has been already taken.

pub fn take_inner(&mut self) -> Option<R>

Take the inner stream reader value out of the decoder, leaving a none in its place.

After this call, reading from this instance will result in a panic.

pub fn len(&self) -> u64

Return the number of remaining bytes of the currently decompressed file to be read.

pub fn is_empty(&self) -> bool

Return whether the current file has been finished reading or if the file was empty.

pub fn is_present(&self) -> bool

Return whether an underlying stream reader is present in the decoder.

pub fn is_absent(&self) -> bool

Return whether an underlying stream reader is absent from the decoder.

An attempt to read file’s content in this state will result in a panic.

pub fn crc_is_ok(&self) -> bool

Return whether the computed CRC-16 matches the checksum in the header.

This should be called after the whole file has been read.

pub fn crc_check(&self) -> LhaResult<u16, R>

Return CRC-16 checksum if the computed checksum matches the one in the header. Otherwise return an LhaError::Checksum error.

This should be called after the whole file has been read.

pub fn is_decoder_supported(&self) -> bool

Return whether the current file’s compression method is supported.

If this method returns false, trying to read from the decoder will result in an error. In this instance it is still ok to skip to the next file.

Note

If the variant of compression is CompressionMethod::Lhd this method will return false. In this instance check the result from header’s LhaHeader::is_directory to determine what steps should be taken next.

Trait Implementations

impl<R: Debug> Debug for LhaDecodeReader<R>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<R: Read> Default for LhaDecodeReader<R>

A default implementation creates an instance of LhaDecodeReader<R> with no reader present and with a phony header.

fn default() -> Self

Returns the “default value” for a type.

impl<R: Read<Error = Error>> Read for LhaDecodeReader<R>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Read the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.