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extern crate alloc;
#[cfg(feature = "serde")]
use serde::Deserialize;
use core::fmt;
use core::ops::Not;
use crate::raw::{RawRecord, RawRecordArena, RawRecordsIter};
#[cfg(feature = "serde")]
use crate::{deserialize, error};
use crate::{Headers, Position};
pub struct ByteRecordArena {
pub(crate) inner: RawRecordArena,
pub(crate) start_pos: Option<Position>,
pub(crate) headers_inner: Option<Headers>,
pub(crate) bytes_init: usize,
}
pub struct ByteRecordsIter<'a>(RawRecordsIter<'a>);
impl ByteRecordArena {
pub fn new() -> ByteRecordArena {
ByteRecordArena {
inner: RawRecordArena::new(),
start_pos: None,
headers_inner: None,
bytes_init: 0,
}
}
pub fn with_headers(headers: Headers) -> ByteRecordArena {
ByteRecordArena {
inner: RawRecordArena::new(),
start_pos: None,
headers_inner: Some(headers),
bytes_init: 0,
}
}
/// Returns the amount of full records. A possible partial record isn't included in the count.
pub fn record_count(&self) -> u64 {
self.inner.record_ends.len() as u64
}
/// Tells if ByteRecordArea contains a partial record.
/// If either of field_data or field_ends contains items that isn't contained in a full
/// record indicated by record_ends, the arena is considered to contain a partial record.
pub fn is_partial(&self) -> bool {
self.inner.is_partial()
}
/// Tells if ByteRecordArena is empty
/// i.e. it doesn't contain any input information. This includes:
/// 1) doesn't contain any header information
/// 2) doesn't contain any records
/// However, it doesn't mean that the arena is in a "freshly initialized" state;
/// it might contain a non-zero starting position or headers.
pub fn is_empty(&self) -> bool {
self.record_count() == 0 && self.is_partial().not()
}
// TODO: do we need this? Maybe delete it.
/// Tells if ByteRecordArena is in the "freshly initialized" state
/// i.e. it hasn't got any input information. This includes:
/// 1) doesn't contain any header information
/// 2) doesn't contain any records
/// 3) doesn't contain partial records
/// 4) doesn't have starting position other than 0.
/// However, it doesn't take into account some purely internal properties that have only
/// diminishingly small performance effects. These properties include the internal capacity
/// of the storage fields and the info whether they have been zeroed or contain undefined bytes.
pub fn is_pristine(&self) -> bool {
self.is_empty() && self.headers().is_none() && self.start_pos.is_none()
}
/// Migrates the partial data over another arena.
/// All data, including the partial record, on the `other` arena is deleted.
/// Returns partial data length and partial field count.
pub fn migrate_partial(&mut self, other: &mut ByteRecordArena) -> (usize, usize) {
other.start_pos = None; // TODO: Is it correct to reset this?
self.inner.migrate_partial(&mut other.inner)
}
/// Deletes all records except the partial record.
/// The user is expected to continue reading the partial record.
/// Sets the start position anew, to be set again by Reader.
pub fn flush(&mut self) -> (usize, usize) {
self.start_pos = None;
self.inner.flush()
}
/// Deletes all records including the partial record.
/// TODO: decide what to do with headers and start up position
pub fn clear(&mut self) {
self.start_pos = None;
self.inner.clear();
}
pub fn headers(&self) -> Option<&Headers> {
if let Some(headers) = &self.headers_inner {
Some(headers)
} else {
None
}
}
pub fn start_pos(&self) -> Option<&Position> {
self.start_pos.as_ref()
}
pub fn expose_data(&mut self) -> &mut [u8] {
let cap = self.inner.field_data.capacity();
let old_len = self.inner.field_data.len();
if self.bytes_init < cap {
self.inner.field_data.resize(cap, 0);
self.bytes_init = cap;
} else {
// Optimization: we don't need to initialize data
// if it's done earlier, as indicated by `self.bytes_init`
unsafe { self.inner.field_data.set_len(cap) };
}
&mut self.inner.field_data[old_len..]
}
pub fn terminate_field(&mut self, field_size: usize) {
let &(last_record_end_field_data, last_record_end_field_end) =
self.inner.record_ends.last().unwrap_or(&(0, 0));
let field_ends = &self.inner.field_ends[last_record_end_field_end..];
let last_field_end = *field_ends.last().unwrap_or(&0);
// "Original" means that we reconstruct self.inner.field_data.len()
// as it was before calling `expose_data` that extended it to the full capacity.
let original_data_len = last_record_end_field_data + last_field_end;
let new_data_len = original_data_len + field_size;
assert!(new_data_len <= self.bytes_init);
self.inner.field_data.truncate(new_data_len);
let new_field_end = last_field_end + field_size;
self.inner.field_ends.push(new_field_end);
}
pub fn terminate_record(&mut self) {
self.inner
.record_ends
.push((self.inner.field_data.len(), self.inner.field_ends.len()));
}
pub fn reserve_space(&mut self, data: usize) {
let old_len = self.inner.field_data.len();
// Not only reserve, but also ensure that the buffer is initialized
self.inner.field_data.resize(data, 0);
self.bytes_init = self.inner.field_data.len();
self.inner.field_data.truncate(old_len);
}
pub fn iter(&self) -> ByteRecordsIter<'_> {
ByteRecordsIter(self.inner.iter())
}
#[cfg(feature = "serde")]
pub fn deserialize<'de, D: Deserialize<'de>>(
&'de self,
output: &mut Vec<D>,
) -> Result<usize, error::Error> {
deserialize::deserialize_byte_record_arena(&self.inner, None, output)
}
pub fn complete_partial(&mut self) {
self.inner.complete_partial()
}
}
impl<'a> Iterator for ByteRecordsIter<'a> {
type Item = RawRecord<'a>;
fn next(&mut self) -> Option<Self::Item> {
self.0.next()
}
}
impl fmt::Debug for ByteRecordArena {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
fmt::Debug::fmt(&self.inner, f)
}
}