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//! This module contains functionality for decompression.
#[cfg(feature = "with-alloc")]
use crate::alloc::{boxed::Box, vec, vec::Vec};
use ::core::usize;
#[cfg(all(feature = "std", feature = "with-alloc"))]
use std::error::Error;
pub mod core;
mod output_buffer;
pub mod stream;
use self::core::*;
const TINFL_STATUS_FAILED_CANNOT_MAKE_PROGRESS: i32 = -4;
const TINFL_STATUS_BAD_PARAM: i32 = -3;
const TINFL_STATUS_ADLER32_MISMATCH: i32 = -2;
const TINFL_STATUS_FAILED: i32 = -1;
const TINFL_STATUS_DONE: i32 = 0;
const TINFL_STATUS_NEEDS_MORE_INPUT: i32 = 1;
const TINFL_STATUS_HAS_MORE_OUTPUT: i32 = 2;
/// Return status codes.
#[repr(i8)]
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum TINFLStatus {
/// More input data was expected, but the caller indicated that there was no more data, so the
/// input stream is likely truncated.
///
/// This can't happen if you have provided the
/// [`TINFL_FLAG_HAS_MORE_INPUT`][core::inflate_flags::TINFL_FLAG_HAS_MORE_INPUT] flag to the
/// decompression. By setting that flag, you indicate more input exists but is not provided,
/// and so reaching the end of the input data without finding the end of the compressed stream
/// would instead return a [`NeedsMoreInput`][Self::NeedsMoreInput] status.
FailedCannotMakeProgress = TINFL_STATUS_FAILED_CANNOT_MAKE_PROGRESS as i8,
/// The output buffer is an invalid size; consider the `flags` parameter.
BadParam = TINFL_STATUS_BAD_PARAM as i8,
/// The decompression went fine, but the adler32 checksum did not match the one
/// provided in the header.
Adler32Mismatch = TINFL_STATUS_ADLER32_MISMATCH as i8,
/// Failed to decompress due to invalid data.
Failed = TINFL_STATUS_FAILED as i8,
/// Finished decompression without issues.
///
/// This indicates the end of the compressed stream has been reached.
Done = TINFL_STATUS_DONE as i8,
/// The decompressor needs more input data to continue decompressing.
///
/// This occurs when there's no more consumable input, but the end of the stream hasn't been
/// reached, and you have supplied the
/// [`TINFL_FLAG_HAS_MORE_INPUT`][core::inflate_flags::TINFL_FLAG_HAS_MORE_INPUT] flag to the
/// decompressor. Had you not supplied that flag (which would mean you were asserting that you
/// believed all the data was available) you would have gotten a
/// [`FailedCannotMakeProcess`][Self::FailedCannotMakeProgress] instead.
NeedsMoreInput = TINFL_STATUS_NEEDS_MORE_INPUT as i8,
/// There is still pending data that didn't fit in the output buffer.
HasMoreOutput = TINFL_STATUS_HAS_MORE_OUTPUT as i8,
}
impl TINFLStatus {
pub fn from_i32(value: i32) -> Option<TINFLStatus> {
use self::TINFLStatus::*;
match value {
TINFL_STATUS_FAILED_CANNOT_MAKE_PROGRESS => Some(FailedCannotMakeProgress),
TINFL_STATUS_BAD_PARAM => Some(BadParam),
TINFL_STATUS_ADLER32_MISMATCH => Some(Adler32Mismatch),
TINFL_STATUS_FAILED => Some(Failed),
TINFL_STATUS_DONE => Some(Done),
TINFL_STATUS_NEEDS_MORE_INPUT => Some(NeedsMoreInput),
TINFL_STATUS_HAS_MORE_OUTPUT => Some(HasMoreOutput),
_ => None,
}
}
}
/// Struct return when decompress_to_vec functions fail.
#[cfg(feature = "with-alloc")]
#[derive(Debug)]
pub struct DecompressError {
/// Decompressor status on failure. See [TINFLStatus] for details.
pub status: TINFLStatus,
/// The currently decompressed data if any.
pub output: Vec<u8>,
}
#[cfg(feature = "with-alloc")]
impl alloc::fmt::Display for DecompressError {
fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
f.write_str(match self.status {
TINFLStatus::FailedCannotMakeProgress => "Truncated input stream",
TINFLStatus::BadParam => "Invalid output buffer size",
TINFLStatus::Adler32Mismatch => "Adler32 checksum mismatch",
TINFLStatus::Failed => "Invalid input data",
TINFLStatus::Done => unreachable!(),
TINFLStatus::NeedsMoreInput => "Truncated input stream",
TINFLStatus::HasMoreOutput => "Output size exceeded the specified limit",
})
}
}
/// Implement Error trait only if std feature is requested as it requires std.
#[cfg(all(feature = "std", feature = "with-alloc"))]
impl Error for DecompressError {}
#[cfg(feature = "with-alloc")]
fn decompress_error(status: TINFLStatus, output: Vec<u8>) -> Result<Vec<u8>, DecompressError> {
Err(DecompressError { status, output })
}
/// Decompress the deflate-encoded data in `input` to a vector.
///
/// NOTE: This function will not bound the output, so if the output is large enough it can result in an out of memory error.
/// It is therefore suggested to not use this for anything other than test programs, use the functions with a specified limit, or
/// ideally streaming decompression via the [flate2](https://github.com/alexcrichton/flate2-rs) library instead.
///
/// Returns a [`Result`] containing the [`Vec`] of decompressed data on success, and a [struct][DecompressError] containing the status and so far decompressed data if any on failure.
#[inline]
#[cfg(feature = "with-alloc")]
pub fn decompress_to_vec(input: &[u8]) -> Result<Vec<u8>, DecompressError> {
decompress_to_vec_inner(input, 0, usize::max_value())
}
/// Decompress the deflate-encoded data (with a zlib wrapper) in `input` to a vector.
///
/// NOTE: This function will not bound the output, so if the output is large enough it can result in an out of memory error.
/// It is therefore suggested to not use this for anything other than test programs, use the functions with a specified limit, or
/// ideally streaming decompression via the [flate2](https://github.com/alexcrichton/flate2-rs) library instead.
///
/// Returns a [`Result`] containing the [`Vec`] of decompressed data on success, and a [struct][DecompressError] containing the status and so far decompressed data if any on failure.
#[inline]
#[cfg(feature = "with-alloc")]
pub fn decompress_to_vec_zlib(input: &[u8]) -> Result<Vec<u8>, DecompressError> {
decompress_to_vec_inner(
input,
inflate_flags::TINFL_FLAG_PARSE_ZLIB_HEADER,
usize::max_value(),
)
}
/// Decompress the deflate-encoded data in `input` to a vector.
///
/// The vector is grown to at most `max_size` bytes; if the data does not fit in that size,
/// the error [struct][DecompressError] will contain the status [`TINFLStatus::HasMoreOutput`] and the data that was decompressed on failure.
///
/// As this function tries to decompress everything in one go, it's not ideal for general use outside of tests or where the output size is expected to be small.
/// It is suggested to use streaming decompression via the [flate2](https://github.com/alexcrichton/flate2-rs) library instead.
///
/// Returns a [`Result`] containing the [`Vec`] of decompressed data on success, and a [struct][DecompressError] on failure.
#[inline]
#[cfg(feature = "with-alloc")]
pub fn decompress_to_vec_with_limit(
input: &[u8],
max_size: usize,
) -> Result<Vec<u8>, DecompressError> {
decompress_to_vec_inner(input, 0, max_size)
}
/// Decompress the deflate-encoded data (with a zlib wrapper) in `input` to a vector.
/// The vector is grown to at most `max_size` bytes; if the data does not fit in that size,
/// the error [struct][DecompressError] will contain the status [`TINFLStatus::HasMoreOutput`] and the data that was decompressed on failure.
///
/// As this function tries to decompress everything in one go, it's not ideal for general use outside of tests or where the output size is expected to be small.
/// It is suggested to use streaming decompression via the [flate2](https://github.com/alexcrichton/flate2-rs) library instead.
///
/// Returns a [`Result`] containing the [`Vec`] of decompressed data on success, and a [struct][DecompressError] on failure.
#[inline]
#[cfg(feature = "with-alloc")]
pub fn decompress_to_vec_zlib_with_limit(
input: &[u8],
max_size: usize,
) -> Result<Vec<u8>, DecompressError> {
decompress_to_vec_inner(input, inflate_flags::TINFL_FLAG_PARSE_ZLIB_HEADER, max_size)
}
/// Backend of various to-[`Vec`] decompressions.
///
/// Returns [`Vec`] of decompressed data on success and the [error struct][DecompressError] with details on failure.
#[cfg(feature = "with-alloc")]
fn decompress_to_vec_inner(
input: &[u8],
flags: u32,
max_output_size: usize,
) -> Result<Vec<u8>, DecompressError> {
let flags = flags | inflate_flags::TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF;
let mut ret: Vec<u8> = vec![0; input.len().saturating_mul(2).min(max_output_size)];
let mut decomp = Box::<DecompressorOxide>::default();
let mut in_pos = 0;
let mut out_pos = 0;
loop {
// Wrap the whole output slice so we know we have enough of the
// decompressed data for matches.
let (status, in_consumed, out_consumed) =
decompress(&mut decomp, &input[in_pos..], &mut ret, out_pos, flags);
in_pos += in_consumed;
out_pos += out_consumed;
match status {
TINFLStatus::Done => {
ret.truncate(out_pos);
return Ok(ret);
}
TINFLStatus::HasMoreOutput => {
// if the buffer has already reached the size limit, return an error
if ret.len() >= max_output_size {
return decompress_error(TINFLStatus::HasMoreOutput, ret);
}
// calculate the new length, capped at `max_output_size`
let new_len = ret.len().saturating_mul(2).min(max_output_size);
ret.resize(new_len, 0);
}
_ => return decompress_error(status, ret),
}
}
}
/// Decompress one or more source slices from an iterator into the output slice.
///
/// * On success, returns the number of bytes that were written.
/// * On failure, returns the failure status code.
///
/// This will fail if the output buffer is not large enough, but in that case
/// the output buffer will still contain the partial decompression.
///
/// * `out` the output buffer.
/// * `it` the iterator of input slices.
/// * `zlib_header` if the first slice out of the iterator is expected to have a
/// Zlib header. Otherwise the slices are assumed to be the deflate data only.
/// * `ignore_adler32` if the adler32 checksum should be calculated or not.
pub fn decompress_slice_iter_to_slice<'out, 'inp>(
out: &'out mut [u8],
it: impl Iterator<Item = &'inp [u8]>,
zlib_header: bool,
ignore_adler32: bool,
) -> Result<usize, TINFLStatus> {
use self::core::inflate_flags::*;
let mut it = it.peekable();
let r = &mut DecompressorOxide::new();
let mut out_pos = 0;
while let Some(in_buf) = it.next() {
let has_more = it.peek().is_some();
let flags = {
let mut f = TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF;
if zlib_header {
f |= TINFL_FLAG_PARSE_ZLIB_HEADER;
}
if ignore_adler32 {
f |= TINFL_FLAG_IGNORE_ADLER32;
}
if has_more {
f |= TINFL_FLAG_HAS_MORE_INPUT;
}
f
};
let (status, _input_read, bytes_written) = decompress(r, in_buf, out, out_pos, flags);
out_pos += bytes_written;
match status {
TINFLStatus::NeedsMoreInput => continue,
TINFLStatus::Done => return Ok(out_pos),
e => return Err(e),
}
}
// If we ran out of source slices without getting a `Done` from the
// decompression we can call it a failure.
Err(TINFLStatus::FailedCannotMakeProgress)
}
#[cfg(test)]
mod test {
use super::{
decompress_slice_iter_to_slice, decompress_to_vec_zlib, decompress_to_vec_zlib_with_limit,
DecompressError, TINFLStatus,
};
const ENCODED: [u8; 20] = [
120, 156, 243, 72, 205, 201, 201, 215, 81, 168, 202, 201, 76, 82, 4, 0, 27, 101, 4, 19,
];
#[test]
fn decompress_vec() {
let res = decompress_to_vec_zlib(&ENCODED[..]).unwrap();
assert_eq!(res.as_slice(), &b"Hello, zlib!"[..]);
}
#[test]
fn decompress_vec_with_high_limit() {
let res = decompress_to_vec_zlib_with_limit(&ENCODED[..], 100_000).unwrap();
assert_eq!(res.as_slice(), &b"Hello, zlib!"[..]);
}
#[test]
fn fail_to_decompress_with_limit() {
let res = decompress_to_vec_zlib_with_limit(&ENCODED[..], 8);
match res {
Err(DecompressError {
status: TINFLStatus::HasMoreOutput,
..
}) => (), // expected result
_ => panic!("Decompression output size limit was not enforced"),
}
}
#[test]
fn test_decompress_slice_iter_to_slice() {
// one slice
let mut out = [0_u8; 12_usize];
let r =
decompress_slice_iter_to_slice(&mut out, Some(&ENCODED[..]).into_iter(), true, false);
assert_eq!(r, Ok(12));
assert_eq!(&out[..12], &b"Hello, zlib!"[..]);
// some chunks at a time
for chunk_size in 1..13 {
// out buffer needs to have +1 byte available when the chunk size cuts
// the adler32 data off from the last actual data.
let mut out = [0_u8; 12_usize + 1];
let r =
decompress_slice_iter_to_slice(&mut out, ENCODED.chunks(chunk_size), true, false);
assert_eq!(r, Ok(12));
assert_eq!(&out[..12], &b"Hello, zlib!"[..]);
}
// output buffer too small
let mut out = [0_u8; 3_usize];
let r = decompress_slice_iter_to_slice(&mut out, ENCODED.chunks(7), true, false);
assert!(r.is_err());
}
}