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use std::error::Error;
use std::fmt;
use std::io;
use std::slice;
use crate::ffi::{self, Backend, Deflate, DeflateBackend, ErrorMessage, Inflate, InflateBackend};
use crate::Compression;
/// Raw in-memory compression stream for blocks of data.
///
/// This type is the building block for the I/O streams in the rest of this
/// crate. It requires more management than the [`Read`]/[`Write`] API but is
/// maximally flexible in terms of accepting input from any source and being
/// able to produce output to any memory location.
///
/// It is recommended to use the I/O stream adaptors over this type as they're
/// easier to use.
///
#[derive(Debug)]
pub struct Compress {
inner: Deflate,
}
/// Raw in-memory decompression stream for blocks of data.
///
/// This type is the building block for the I/O streams in the rest of this
/// crate. It requires more management than the [`Read`]/[`Write`] API but is
/// maximally flexible in terms of accepting input from any source and being
/// able to produce output to any memory location.
///
/// It is recommended to use the I/O stream adaptors over this type as they're
/// easier to use.
///
#[derive(Debug)]
pub struct Decompress {
inner: Inflate,
}
/// Values which indicate the form of flushing to be used when compressing
/// in-memory data.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[non_exhaustive]
pub enum FlushCompress {
/// A typical parameter for passing to compression/decompression functions,
/// this indicates that the underlying stream to decide how much data to
/// accumulate before producing output in order to maximize compression.
None = ffi::MZ_NO_FLUSH as isize,
/// All pending output is flushed to the output buffer and the output is
/// aligned on a byte boundary so that the decompressor can get all input
/// data available so far.
///
/// Flushing may degrade compression for some compression algorithms and so
/// it should only be used when necessary. This will complete the current
/// deflate block and follow it with an empty stored block.
Sync = ffi::MZ_SYNC_FLUSH as isize,
/// All pending output is flushed to the output buffer, but the output is
/// not aligned to a byte boundary.
///
/// All of the input data so far will be available to the decompressor (as
/// with `Flush::Sync`. This completes the current deflate block and follows
/// it with an empty fixed codes block that is 10 bites long, and it assures
/// that enough bytes are output in order for the decompressor to finish the
/// block before the empty fixed code block.
Partial = ffi::MZ_PARTIAL_FLUSH as isize,
/// All output is flushed as with `Flush::Sync` and the compression state is
/// reset so decompression can restart from this point if previous
/// compressed data has been damaged or if random access is desired.
///
/// Using this option too often can seriously degrade compression.
Full = ffi::MZ_FULL_FLUSH as isize,
/// Pending input is processed and pending output is flushed.
///
/// The return value may indicate that the stream is not yet done and more
/// data has yet to be processed.
Finish = ffi::MZ_FINISH as isize,
}
/// Values which indicate the form of flushing to be used when
/// decompressing in-memory data.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[non_exhaustive]
pub enum FlushDecompress {
/// A typical parameter for passing to compression/decompression functions,
/// this indicates that the underlying stream to decide how much data to
/// accumulate before producing output in order to maximize compression.
None = ffi::MZ_NO_FLUSH as isize,
/// All pending output is flushed to the output buffer and the output is
/// aligned on a byte boundary so that the decompressor can get all input
/// data available so far.
///
/// Flushing may degrade compression for some compression algorithms and so
/// it should only be used when necessary. This will complete the current
/// deflate block and follow it with an empty stored block.
Sync = ffi::MZ_SYNC_FLUSH as isize,
/// Pending input is processed and pending output is flushed.
///
/// The return value may indicate that the stream is not yet done and more
/// data has yet to be processed.
Finish = ffi::MZ_FINISH as isize,
}
/// The inner state for an error when decompressing
#[derive(Debug)]
pub(crate) enum DecompressErrorInner {
General { msg: ErrorMessage },
NeedsDictionary(u32),
}
/// Error returned when a decompression object finds that the input stream of
/// bytes was not a valid input stream of bytes.
#[derive(Debug)]
pub struct DecompressError(pub(crate) DecompressErrorInner);
impl DecompressError {
/// Indicates whether decompression failed due to requiring a dictionary.
///
/// The resulting integer is the Adler-32 checksum of the dictionary
/// required.
pub fn needs_dictionary(&self) -> Option<u32> {
match self.0 {
DecompressErrorInner::NeedsDictionary(adler) => Some(adler),
_ => None,
}
}
}
#[inline]
pub(crate) fn decompress_failed<T>(msg: ErrorMessage) -> Result<T, DecompressError> {
Err(DecompressError(DecompressErrorInner::General { msg }))
}
#[inline]
pub(crate) fn decompress_need_dict<T>(adler: u32) -> Result<T, DecompressError> {
Err(DecompressError(DecompressErrorInner::NeedsDictionary(
adler,
)))
}
/// Error returned when a compression object is used incorrectly or otherwise
/// generates an error.
#[derive(Debug)]
pub struct CompressError {
pub(crate) msg: ErrorMessage,
}
#[inline]
pub(crate) fn compress_failed<T>(msg: ErrorMessage) -> Result<T, CompressError> {
Err(CompressError { msg })
}
/// Possible status results of compressing some data or successfully
/// decompressing a block of data.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Status {
/// Indicates success.
///
/// Means that more input may be needed but isn't available
/// and/or there's more output to be written but the output buffer is full.
Ok,
/// Indicates that forward progress is not possible due to input or output
/// buffers being empty.
///
/// For compression it means the input buffer needs some more data or the
/// output buffer needs to be freed up before trying again.
///
/// For decompression this means that more input is needed to continue or
/// the output buffer isn't large enough to contain the result. The function
/// can be called again after fixing both.
BufError,
/// Indicates that all input has been consumed and all output bytes have
/// been written. Decompression/compression should not be called again.
///
/// For decompression with zlib streams the adler-32 of the decompressed
/// data has also been verified.
StreamEnd,
}
impl Compress {
/// Creates a new object ready for compressing data that it's given.
///
/// The `level` argument here indicates what level of compression is going
/// to be performed, and the `zlib_header` argument indicates whether the
/// output data should have a zlib header or not.
pub fn new(level: Compression, zlib_header: bool) -> Compress {
Compress {
inner: Deflate::make(level, zlib_header, ffi::MZ_DEFAULT_WINDOW_BITS as u8),
}
}
/// Creates a new object ready for compressing data that it's given.
///
/// The `level` argument here indicates what level of compression is going
/// to be performed, and the `zlib_header` argument indicates whether the
/// output data should have a zlib header or not. The `window_bits` parameter
/// indicates the base-2 logarithm of the sliding window size and must be
/// between 9 and 15.
///
/// # Panics
///
/// If `window_bits` does not fall into the range 9 ..= 15,
/// `new_with_window_bits` will panic.
#[cfg(feature = "any_zlib")]
pub fn new_with_window_bits(
level: Compression,
zlib_header: bool,
window_bits: u8,
) -> Compress {
assert!(
window_bits > 8 && window_bits < 16,
"window_bits must be within 9 ..= 15"
);
Compress {
inner: Deflate::make(level, zlib_header, window_bits),
}
}
/// Creates a new object ready for compressing data that it's given.
///
/// The `level` argument here indicates what level of compression is going
/// to be performed.
///
/// The Compress object produced by this constructor outputs gzip headers
/// for the compressed data.
///
/// # Panics
///
/// If `window_bits` does not fall into the range 9 ..= 15,
/// `new_with_window_bits` will panic.
#[cfg(feature = "any_zlib")]
pub fn new_gzip(level: Compression, window_bits: u8) -> Compress {
assert!(
window_bits > 8 && window_bits < 16,
"window_bits must be within 9 ..= 15"
);
Compress {
inner: Deflate::make(level, true, window_bits + 16),
}
}
/// Returns the total number of input bytes which have been processed by
/// this compression object.
pub fn total_in(&self) -> u64 {
self.inner.total_in()
}
/// Returns the total number of output bytes which have been produced by
/// this compression object.
pub fn total_out(&self) -> u64 {
self.inner.total_out()
}
/// Specifies the compression dictionary to use.
///
/// Returns the Adler-32 checksum of the dictionary.
#[cfg(feature = "any_zlib")]
pub fn set_dictionary(&mut self, dictionary: &[u8]) -> Result<u32, CompressError> {
let stream = &mut *self.inner.inner.stream_wrapper;
stream.msg = std::ptr::null_mut();
let rc = unsafe {
assert!(dictionary.len() < ffi::uInt::MAX as usize);
ffi::deflateSetDictionary(stream, dictionary.as_ptr(), dictionary.len() as ffi::uInt)
};
match rc {
ffi::MZ_STREAM_ERROR => compress_failed(self.inner.inner.msg()),
ffi::MZ_OK => Ok(stream.adler as u32),
c => panic!("unknown return code: {}", c),
}
}
/// Quickly resets this compressor without having to reallocate anything.
///
/// This is equivalent to dropping this object and then creating a new one.
pub fn reset(&mut self) {
self.inner.reset();
}
/// Dynamically updates the compression level.
///
/// This can be used to switch between compression levels for different
/// kinds of data, or it can be used in conjunction with a call to reset
/// to reuse the compressor.
///
/// This may return an error if there wasn't enough output space to complete
/// the compression of the available input data before changing the
/// compression level. Flushing the stream before calling this method
/// ensures that the function will succeed on the first call.
#[cfg(feature = "any_zlib")]
pub fn set_level(&mut self, level: Compression) -> Result<(), CompressError> {
use std::os::raw::c_int;
let stream = &mut *self.inner.inner.stream_wrapper;
stream.msg = std::ptr::null_mut();
let rc = unsafe { ffi::deflateParams(stream, level.0 as c_int, ffi::MZ_DEFAULT_STRATEGY) };
match rc {
ffi::MZ_OK => Ok(()),
ffi::MZ_BUF_ERROR => compress_failed(self.inner.inner.msg()),
c => panic!("unknown return code: {}", c),
}
}
/// Compresses the input data into the output, consuming only as much
/// input as needed and writing as much output as possible.
///
/// The flush option can be any of the available `FlushCompress` parameters.
///
/// To learn how much data was consumed or how much output was produced, use
/// the `total_in` and `total_out` functions before/after this is called.
pub fn compress(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushCompress,
) -> Result<Status, CompressError> {
self.inner.compress(input, output, flush)
}
/// Compresses the input data into the extra space of the output, consuming
/// only as much input as needed and writing as much output as possible.
///
/// This function has the same semantics as `compress`, except that the
/// length of `vec` is managed by this function. This will not reallocate
/// the vector provided or attempt to grow it, so space for the output must
/// be reserved in the output vector by the caller before calling this
/// function.
pub fn compress_vec(
&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: FlushCompress,
) -> Result<Status, CompressError> {
let cap = output.capacity();
let len = output.len();
unsafe {
let before = self.total_out();
let ret = {
let ptr = output.as_mut_ptr().add(len);
let out = slice::from_raw_parts_mut(ptr, cap - len);
self.compress(input, out, flush)
};
output.set_len((self.total_out() - before) as usize + len);
ret
}
}
}
impl Decompress {
/// Creates a new object ready for decompressing data that it's given.
///
/// The `zlib_header` argument indicates whether the input data is expected
/// to have a zlib header or not.
pub fn new(zlib_header: bool) -> Decompress {
Decompress {
inner: Inflate::make(zlib_header, ffi::MZ_DEFAULT_WINDOW_BITS as u8),
}
}
/// Creates a new object ready for decompressing data that it's given.
///
/// The `zlib_header` argument indicates whether the input data is expected
/// to have a zlib header or not. The `window_bits` parameter indicates the
/// base-2 logarithm of the sliding window size and must be between 9 and 15.
///
/// # Panics
///
/// If `window_bits` does not fall into the range 9 ..= 15,
/// `new_with_window_bits` will panic.
#[cfg(feature = "any_zlib")]
pub fn new_with_window_bits(zlib_header: bool, window_bits: u8) -> Decompress {
assert!(
window_bits > 8 && window_bits < 16,
"window_bits must be within 9 ..= 15"
);
Decompress {
inner: Inflate::make(zlib_header, window_bits),
}
}
/// Creates a new object ready for decompressing data that it's given.
///
/// The Decompress object produced by this constructor expects gzip headers
/// for the compressed data.
///
/// # Panics
///
/// If `window_bits` does not fall into the range 9 ..= 15,
/// `new_with_window_bits` will panic.
#[cfg(feature = "any_zlib")]
pub fn new_gzip(window_bits: u8) -> Decompress {
assert!(
window_bits > 8 && window_bits < 16,
"window_bits must be within 9 ..= 15"
);
Decompress {
inner: Inflate::make(true, window_bits + 16),
}
}
/// Returns the total number of input bytes which have been processed by
/// this decompression object.
pub fn total_in(&self) -> u64 {
self.inner.total_in()
}
/// Returns the total number of output bytes which have been produced by
/// this decompression object.
pub fn total_out(&self) -> u64 {
self.inner.total_out()
}
/// Decompresses the input data into the output, consuming only as much
/// input as needed and writing as much output as possible.
///
/// The flush option can be any of the available `FlushDecompress` parameters.
///
/// If the first call passes `FlushDecompress::Finish` it is assumed that
/// the input and output buffers are both sized large enough to decompress
/// the entire stream in a single call.
///
/// A flush value of `FlushDecompress::Finish` indicates that there are no
/// more source bytes available beside what's already in the input buffer,
/// and the output buffer is large enough to hold the rest of the
/// decompressed data.
///
/// To learn how much data was consumed or how much output was produced, use
/// the `total_in` and `total_out` functions before/after this is called.
///
/// # Errors
///
/// If the input data to this instance of `Decompress` is not a valid
/// zlib/deflate stream then this function may return an instance of
/// `DecompressError` to indicate that the stream of input bytes is corrupted.
pub fn decompress(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushDecompress,
) -> Result<Status, DecompressError> {
self.inner.decompress(input, output, flush)
}
/// Decompresses the input data into the extra space in the output vector
/// specified by `output`.
///
/// This function has the same semantics as `decompress`, except that the
/// length of `vec` is managed by this function. This will not reallocate
/// the vector provided or attempt to grow it, so space for the output must
/// be reserved in the output vector by the caller before calling this
/// function.
///
/// # Errors
///
/// If the input data to this instance of `Decompress` is not a valid
/// zlib/deflate stream then this function may return an instance of
/// `DecompressError` to indicate that the stream of input bytes is corrupted.
pub fn decompress_vec(
&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: FlushDecompress,
) -> Result<Status, DecompressError> {
let cap = output.capacity();
let len = output.len();
unsafe {
let before = self.total_out();
let ret = {
let ptr = output.as_mut_ptr().add(len);
let out = slice::from_raw_parts_mut(ptr, cap - len);
self.decompress(input, out, flush)
};
output.set_len((self.total_out() - before) as usize + len);
ret
}
}
/// Specifies the decompression dictionary to use.
#[cfg(feature = "any_zlib")]
pub fn set_dictionary(&mut self, dictionary: &[u8]) -> Result<u32, DecompressError> {
let stream = &mut *self.inner.inner.stream_wrapper;
stream.msg = std::ptr::null_mut();
let rc = unsafe {
assert!(dictionary.len() < ffi::uInt::MAX as usize);
ffi::inflateSetDictionary(stream, dictionary.as_ptr(), dictionary.len() as ffi::uInt)
};
match rc {
ffi::MZ_STREAM_ERROR => decompress_failed(self.inner.inner.msg()),
ffi::MZ_DATA_ERROR => decompress_need_dict(stream.adler as u32),
ffi::MZ_OK => Ok(stream.adler as u32),
c => panic!("unknown return code: {}", c),
}
}
/// Performs the equivalent of replacing this decompression state with a
/// freshly allocated copy.
///
/// This function may not allocate memory, though, and attempts to reuse any
/// previously existing resources.
///
/// The argument provided here indicates whether the reset state will
/// attempt to decode a zlib header first or not.
pub fn reset(&mut self, zlib_header: bool) {
self.inner.reset(zlib_header);
}
}
impl Error for DecompressError {}
impl DecompressError {
/// Retrieve the implementation's message about why the operation failed, if one exists.
pub fn message(&self) -> Option<&str> {
match &self.0 {
DecompressErrorInner::General { msg } => msg.get(),
_ => None,
}
}
}
impl From<DecompressError> for io::Error {
fn from(data: DecompressError) -> io::Error {
io::Error::new(io::ErrorKind::Other, data)
}
}
impl fmt::Display for DecompressError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let msg = match &self.0 {
DecompressErrorInner::General { msg } => msg.get(),
DecompressErrorInner::NeedsDictionary { .. } => Some("requires a dictionary"),
};
match msg {
Some(msg) => write!(f, "deflate decompression error: {}", msg),
None => write!(f, "deflate decompression error"),
}
}
}
impl Error for CompressError {}
impl CompressError {
/// Retrieve the implementation's message about why the operation failed, if one exists.
pub fn message(&self) -> Option<&str> {
self.msg.get()
}
}
impl From<CompressError> for io::Error {
fn from(data: CompressError) -> io::Error {
io::Error::new(io::ErrorKind::Other, data)
}
}
impl fmt::Display for CompressError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.msg.get() {
Some(msg) => write!(f, "deflate compression error: {}", msg),
None => write!(f, "deflate compression error"),
}
}
}
#[cfg(test)]
mod tests {
use std::io::Write;
use crate::write;
use crate::{Compression, Decompress, FlushDecompress};
#[cfg(feature = "any_zlib")]
use crate::{Compress, FlushCompress};
#[test]
fn issue51() {
let data = vec![
0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0xb3, 0xc9, 0x28, 0xc9,
0xcd, 0xb1, 0xe3, 0xe5, 0xb2, 0xc9, 0x48, 0x4d, 0x4c, 0xb1, 0xb3, 0x29, 0xc9, 0x2c,
0xc9, 0x49, 0xb5, 0x33, 0x31, 0x30, 0x51, 0xf0, 0xcb, 0x2f, 0x51, 0x70, 0xcb, 0x2f,
0xcd, 0x4b, 0xb1, 0xd1, 0x87, 0x08, 0xda, 0xe8, 0x83, 0x95, 0x00, 0x95, 0x26, 0xe5,
0xa7, 0x54, 0x2a, 0x24, 0xa5, 0x27, 0xe7, 0xe7, 0xe4, 0x17, 0xd9, 0x2a, 0x95, 0x67,
0x64, 0x96, 0xa4, 0x2a, 0x81, 0x8c, 0x48, 0x4e, 0xcd, 0x2b, 0x49, 0x2d, 0xb2, 0xb3,
0xc9, 0x30, 0x44, 0x37, 0x01, 0x28, 0x62, 0xa3, 0x0f, 0x95, 0x06, 0xd9, 0x05, 0x54,
0x04, 0xe5, 0xe5, 0xa5, 0x67, 0xe6, 0x55, 0xe8, 0x1b, 0xea, 0x99, 0xe9, 0x19, 0x21,
0xab, 0xd0, 0x07, 0xd9, 0x01, 0x32, 0x53, 0x1f, 0xea, 0x3e, 0x00, 0x94, 0x85, 0xeb,
0xe4, 0xa8, 0x00, 0x00, 0x00,
];
let mut decoded = Vec::with_capacity(data.len() * 2);
let mut d = Decompress::new(false);
// decompressed whole deflate stream
assert!(d
.decompress_vec(&data[10..], &mut decoded, FlushDecompress::Finish)
.is_ok());
// decompress data that has nothing to do with the deflate stream (this
// used to panic)
drop(d.decompress_vec(&[0], &mut decoded, FlushDecompress::None));
}
#[test]
fn reset() {
let string = "hello world".as_bytes();
let mut zlib = Vec::new();
let mut deflate = Vec::new();
let comp = Compression::default();
write::ZlibEncoder::new(&mut zlib, comp)
.write_all(string)
.unwrap();
write::DeflateEncoder::new(&mut deflate, comp)
.write_all(string)
.unwrap();
let mut dst = [0; 1024];
let mut decoder = Decompress::new(true);
decoder
.decompress(&zlib, &mut dst, FlushDecompress::Finish)
.unwrap();
assert_eq!(decoder.total_out(), string.len() as u64);
assert!(dst.starts_with(string));
decoder.reset(false);
decoder
.decompress(&deflate, &mut dst, FlushDecompress::Finish)
.unwrap();
assert_eq!(decoder.total_out(), string.len() as u64);
assert!(dst.starts_with(string));
}
#[cfg(feature = "any_zlib")]
#[test]
fn set_dictionary_with_zlib_header() {
let string = "hello, hello!".as_bytes();
let dictionary = "hello".as_bytes();
let mut encoded = Vec::with_capacity(1024);
let mut encoder = Compress::new(Compression::default(), true);
let dictionary_adler = encoder.set_dictionary(&dictionary).unwrap();
encoder
.compress_vec(string, &mut encoded, FlushCompress::Finish)
.unwrap();
assert_eq!(encoder.total_in(), string.len() as u64);
assert_eq!(encoder.total_out(), encoded.len() as u64);
let mut decoder = Decompress::new(true);
let mut decoded = [0; 1024];
let decompress_error = decoder
.decompress(&encoded, &mut decoded, FlushDecompress::Finish)
.expect_err("decompression should fail due to requiring a dictionary");
let required_adler = decompress_error.needs_dictionary()
.expect("the first call to decompress should indicate a dictionary is required along with the required Adler-32 checksum");
assert_eq!(required_adler, dictionary_adler,
"the Adler-32 checksum should match the value when the dictionary was set on the compressor");
let actual_adler = decoder.set_dictionary(&dictionary).unwrap();
assert_eq!(required_adler, actual_adler);
// Decompress the rest of the input to the remainder of the output buffer
let total_in = decoder.total_in();
let total_out = decoder.total_out();
let decompress_result = decoder.decompress(
&encoded[total_in as usize..],
&mut decoded[total_out as usize..],
FlushDecompress::Finish,
);
assert!(decompress_result.is_ok());
assert_eq!(&decoded[..decoder.total_out() as usize], string);
}
#[cfg(feature = "any_zlib")]
#[test]
fn set_dictionary_raw() {
let string = "hello, hello!".as_bytes();
let dictionary = "hello".as_bytes();
let mut encoded = Vec::with_capacity(1024);
let mut encoder = Compress::new(Compression::default(), false);
encoder.set_dictionary(&dictionary).unwrap();
encoder
.compress_vec(string, &mut encoded, FlushCompress::Finish)
.unwrap();
assert_eq!(encoder.total_in(), string.len() as u64);
assert_eq!(encoder.total_out(), encoded.len() as u64);
let mut decoder = Decompress::new(false);
decoder.set_dictionary(&dictionary).unwrap();
let mut decoded = [0; 1024];
let decompress_result = decoder.decompress(&encoded, &mut decoded, FlushDecompress::Finish);
assert!(decompress_result.is_ok());
assert_eq!(&decoded[..decoder.total_out() as usize], string);
}
#[cfg(feature = "any_zlib")]
#[test]
fn test_gzip_flate() {
let string = "hello, hello!".as_bytes();
let mut encoded = Vec::with_capacity(1024);
let mut encoder = Compress::new_gzip(Compression::default(), 9);
encoder
.compress_vec(string, &mut encoded, FlushCompress::Finish)
.unwrap();
assert_eq!(encoder.total_in(), string.len() as u64);
assert_eq!(encoder.total_out(), encoded.len() as u64);
let mut decoder = Decompress::new_gzip(9);
let mut decoded = [0; 1024];
decoder
.decompress(&encoded, &mut decoded, FlushDecompress::Finish)
.unwrap();
assert_eq!(&decoded[..decoder.total_out() as usize], string);
}
#[cfg(feature = "any_zlib")]
#[test]
fn test_error_message() {
let mut decoder = Decompress::new(false);
let mut decoded = [0; 128];
let garbage = b"xbvxzi";
let err = decoder
.decompress(&*garbage, &mut decoded, FlushDecompress::Finish)
.unwrap_err();
assert_eq!(err.message(), Some("invalid stored block lengths"));
}
}