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use std::error::Error;
use std::fmt;
use std::io;
use std::marker;
use std::slice;
use libc::{c_int, c_uint};
use Compression;
use ffi;
/// 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.
///
/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
#[derive(Debug)]
pub struct Compress {
inner: Stream<DirCompress>,
}
/// 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.
///
/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
/// [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
#[derive(Debug)]
pub struct Decompress {
inner: Stream<DirDecompress>,
}
#[derive(Debug)]
struct Stream<D: Direction> {
stream_wrapper: ffi::StreamWrapper,
total_in: u64,
total_out: u64,
_marker: marker::PhantomData<D>,
}
unsafe impl<D: Direction> Send for Stream<D> {}
unsafe impl<D: Direction> Sync for Stream<D> {}
trait Direction {
unsafe fn destroy(stream: *mut ffi::mz_stream) -> c_int;
}
#[derive(Debug)]
enum DirCompress {}
#[derive(Debug)]
enum DirDecompress {}
/// Values which indicate the form of flushing to be used when compressing or
/// decompressing in-memory data.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Flush {
/// 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 decompessor to finish the
/// block before the empty fixed code block.
Partial = ffi::MZ_PARTIAL_FLUSH as isize,
/// A deflate block is completed and emitted, as for `Flush::Sync`, but the
/// output is not aligned on a byte boundary and up to seven vits of the
/// current block are held to be written as the next byte after the next
/// deflate block is completed.
///
/// In this case the decompressor may not be provided enough bits at this
/// point in order to complete decompression of the data provided so far to
/// the compressor, it may need to wait for the next block to be emitted.
/// This is for advanced applications that need to control the emission of
/// deflate blocks.
Block = ffi::MZ_BLOCK 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,
}
/// 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 DataError(());
/// 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' smore 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 {
unsafe {
let mut state = ffi::StreamWrapper::default();
let ret = ffi::mz_deflateInit2(&mut *state,
level as c_int,
ffi::MZ_DEFLATED,
if zlib_header {
ffi::MZ_DEFAULT_WINDOW_BITS
} else {
-ffi::MZ_DEFAULT_WINDOW_BITS
},
9,
ffi::MZ_DEFAULT_STRATEGY);
debug_assert_eq!(ret, 0);
Compress {
inner: Stream {
stream_wrapper: state,
total_in: 0,
total_out: 0,
_marker: marker::PhantomData,
},
}
}
}
/// 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
}
/// 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) {
let rc = unsafe { ffi::mz_deflateReset(&mut *self.inner.stream_wrapper) };
assert_eq!(rc, ffi::MZ_OK);
self.inner.total_in = 0;
self.inner.total_out = 0;
}
/// 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 flushing 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: Flush)
-> Status {
let raw = &mut *self.inner.stream_wrapper;
raw.next_in = input.as_ptr() as *mut _;
raw.avail_in = input.len() as c_uint;
raw.next_out = output.as_mut_ptr();
raw.avail_out = output.len() as c_uint;
let rc = unsafe { ffi::mz_deflate(raw, flush as c_int) };
// Unfortunately the total counters provided by zlib might be only
// 32 bits wide and overflow while processing large amounts of data.
self.inner.total_in += (raw.next_in as usize -
input.as_ptr() as usize) as u64;
self.inner.total_out += (raw.next_out as usize -
output.as_ptr() as usize) as u64;
match rc {
ffi::MZ_OK => Status::Ok,
ffi::MZ_BUF_ERROR => Status::BufError,
ffi::MZ_STREAM_END => Status::StreamEnd,
c => panic!("unknown return code: {}", c),
}
}
/// 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: Flush)
-> Status {
let cap = output.capacity();
let len = output.len();
unsafe {
let before = self.total_out();
let ret = {
let ptr = output.as_mut_ptr().offset(len as isize);
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);
return 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 {
unsafe {
let mut state = ffi::StreamWrapper::default();
let ret = ffi::mz_inflateInit2(&mut *state,
if zlib_header {
ffi::MZ_DEFAULT_WINDOW_BITS
} else {
-ffi::MZ_DEFAULT_WINDOW_BITS
});
debug_assert_eq!(ret, 0);
Decompress {
inner: Stream {
stream_wrapper: state,
total_in: 0,
total_out: 0,
_marker: marker::PhantomData,
},
}
}
}
/// 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 provided can either be `Flush::None`, `Flush::Sync`,
/// or `Flush::Finish`. If the first call passes `Flush::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 `Flush::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
/// `DataError` to indicate that the stream of input bytes is corrupted.
pub fn decompress(&mut self,
input: &[u8],
output: &mut [u8],
flush: Flush)
-> Result<Status, DataError> {
let raw = &mut *self.inner.stream_wrapper;
raw.next_in = input.as_ptr() as *mut u8;
raw.avail_in = input.len() as c_uint;
raw.next_out = output.as_mut_ptr();
raw.avail_out = output.len() as c_uint;
let rc = unsafe { ffi::mz_inflate(raw, flush as c_int) };
// Unfortunately the total counters provided by zlib might be only
// 32 bits wide and overflow while processing large amounts of data.
self.inner.total_in += (raw.next_in as usize -
input.as_ptr() as usize) as u64;
self.inner.total_out += (raw.next_out as usize -
output.as_ptr() as usize) as u64;
match rc {
ffi::MZ_DATA_ERROR |
ffi::MZ_STREAM_ERROR => Err(DataError(())),
ffi::MZ_OK => Ok(Status::Ok),
ffi::MZ_BUF_ERROR => Ok(Status::BufError),
ffi::MZ_STREAM_END => Ok(Status::StreamEnd),
c => panic!("unknown return code: {}", c),
}
}
/// 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
/// `DataError` to indicate that the stream of input bytes is corrupted.
pub fn decompress_vec(&mut self,
input: &[u8],
output: &mut Vec<u8>,
flush: Flush)
-> Result<Status, DataError> {
let cap = output.capacity();
let len = output.len();
unsafe {
let before = self.total_out();
let ret = {
let ptr = output.as_mut_ptr().offset(len as isize);
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);
return ret
}
}
/// 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._reset(zlib_header);
}
#[cfg(feature = "zlib")]
fn _reset(&mut self, zlib_header: bool) {
let bits = if zlib_header {
ffi::MZ_DEFAULT_WINDOW_BITS
} else {
-ffi::MZ_DEFAULT_WINDOW_BITS
};
unsafe {
ffi::inflateReset2(&mut *self.inner.stream_wrapper, bits);
}
self.inner.total_out = 0;
self.inner.total_in = 0;
}
#[cfg(not(feature = "zlib"))]
fn _reset(&mut self, zlib_header: bool) {
*self = Decompress::new(zlib_header);
}
}
impl Error for DataError {
fn description(&self) -> &str { "deflate data error" }
}
impl From<DataError> for io::Error {
fn from(data: DataError) -> io::Error {
io::Error::new(io::ErrorKind::Other, data)
}
}
impl fmt::Display for DataError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.description().fmt(f)
}
}
impl Direction for DirCompress {
unsafe fn destroy(stream: *mut ffi::mz_stream) -> c_int {
ffi::mz_deflateEnd(stream)
}
}
impl Direction for DirDecompress {
unsafe fn destroy(stream: *mut ffi::mz_stream) -> c_int {
ffi::mz_inflateEnd(stream)
}
}
impl<D: Direction> Drop for Stream<D> {
fn drop(&mut self) {
unsafe {
let _ = D::destroy(&mut *self.stream_wrapper);
}
}
}
#[cfg(test)]
mod tests {
use std::io::Write;
use write;
use {Compression, Decompress, Flush};
#[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, Flush::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, Flush::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, Flush::Finish).unwrap();
assert_eq!(decoder.total_out(), string.len() as u64);
assert!(dst.starts_with(string));
decoder.reset(false);
decoder.decompress(&deflate, &mut dst, Flush::Finish).unwrap();
assert_eq!(decoder.total_out(), string.len() as u64);
assert!(dst.starts_with(string));
}
}