//! Implementation for C backends.
use std::cmp;
use std::fmt;
use std::marker;
use std::os::raw::{c_int, c_uint};
use std::ptr;
use super::*;
use crate::mem;
#[derive(Default)]
pub struct ErrorMessage(Option<&'static str>);
impl ErrorMessage {
pub fn get(&self) -> Option<&str> {
self.0
}
}
pub struct StreamWrapper {
// SAFETY: The field `inner` must always be accessed as a raw pointer,
// since it points to a cyclic structure, and it must never be copied
// by Rust.
pub inner: *mut mz_stream,
}
impl fmt::Debug for StreamWrapper {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(f, "StreamWrapper")
}
}
impl Default for StreamWrapper {
fn default() -> StreamWrapper {
// SAFETY: The field `state` will be initialized across the FFI to
// point to the opaque type `mz_internal_state`, which will contain a copy
// of `inner`. This cyclic structure breaks the uniqueness invariant of
// &mut mz_stream, so we must use a raw pointer instead of Box<mz_stream>.
StreamWrapper {
inner: Box::into_raw(Box::new(mz_stream {
next_in: ptr::null_mut(),
avail_in: 0,
total_in: 0,
next_out: ptr::null_mut(),
avail_out: 0,
total_out: 0,
msg: ptr::null_mut(),
adler: 0,
data_type: 0,
reserved: 0,
opaque: ptr::null_mut(),
state: ptr::null_mut(),
#[cfg(all(
feature = "any_zlib",
not(any(feature = "cloudflare-zlib-sys", feature = "libz-rs-sys"))
))]
zalloc: allocator::zalloc,
#[cfg(all(
feature = "any_zlib",
not(any(feature = "cloudflare-zlib-sys", feature = "libz-rs-sys"))
))]
zfree: allocator::zfree,
#[cfg(all(feature = "any_zlib", feature = "cloudflare-zlib-sys"))]
zalloc: Some(allocator::zalloc),
#[cfg(all(feature = "any_zlib", feature = "cloudflare-zlib-sys"))]
zfree: Some(allocator::zfree),
// for zlib-rs, it is most efficient to have it provide the allocator.
// The libz-rs-sys dependency is configured to use the rust system allocator
#[cfg(all(feature = "any_zlib", feature = "libz-rs-sys"))]
zalloc: None,
#[cfg(all(feature = "any_zlib", feature = "libz-rs-sys"))]
zfree: None,
})),
}
}
}
impl Drop for StreamWrapper {
fn drop(&mut self) {
// SAFETY: At this point, every other allocation for struct has been freed by
// `inflateEnd` or `deflateEnd`, and no copies of `inner` are retained by `C`,
// so it is safe to drop the struct as long as the user respects the invariant that
// `inner` must never be copied by Rust.
drop(unsafe { Box::from_raw(self.inner) });
}
}
#[cfg(all(feature = "any_zlib", not(feature = "libz-rs-sys")))]
mod allocator {
use super::*;
use std::alloc::{self, Layout};
use std::convert::TryFrom;
use std::os::raw::c_void;
const ALIGN: usize = std::mem::align_of::<usize>();
fn align_up(size: usize, align: usize) -> usize {
(size + align - 1) & !(align - 1)
}
pub extern "C" fn zalloc(_ptr: *mut c_void, items: uInt, item_size: uInt) -> *mut c_void {
// We need to multiply `items` and `item_size` to get the actual desired
// allocation size. Since `zfree` doesn't receive a size argument we
// also need to allocate space for a `usize` as a header so we can store
// how large the allocation is to deallocate later.
let size = match items
.checked_mul(item_size)
.and_then(|i| usize::try_from(i).ok())
.map(|size| align_up(size, ALIGN))
.and_then(|i| i.checked_add(std::mem::size_of::<usize>()))
{
Some(i) => i,
None => return ptr::null_mut(),
};
// Make sure the `size` isn't too big to fail `Layout`'s restrictions
let layout = match Layout::from_size_align(size, ALIGN) {
Ok(layout) => layout,
Err(_) => return ptr::null_mut(),
};
unsafe {
// Allocate the data, and if successful store the size we allocated
// at the beginning and then return an offset pointer.
let ptr = alloc::alloc(layout) as *mut usize;
if ptr.is_null() {
return ptr as *mut c_void;
}
*ptr = size;
ptr.add(1) as *mut c_void
}
}
pub extern "C" fn zfree(_ptr: *mut c_void, address: *mut c_void) {
unsafe {
// Move our address being freed back one pointer, read the size we
// stored in `zalloc`, and then free it using the standard Rust
// allocator.
let ptr = (address as *mut usize).offset(-1);
let size = *ptr;
let layout = Layout::from_size_align_unchecked(size, ALIGN);
alloc::dealloc(ptr as *mut u8, layout)
}
}
}
unsafe impl<D: Direction> Send for Stream<D> {}
unsafe impl<D: Direction> Sync for Stream<D> {}
/// Trait used to call the right destroy/end function on the inner
/// stream object on drop.
pub trait Direction {
unsafe fn destroy(stream: *mut mz_stream) -> c_int;
}
#[derive(Debug)]
pub enum DirCompress {}
#[derive(Debug)]
pub enum DirDecompress {}
#[derive(Debug)]
pub struct Stream<D: Direction> {
pub stream_wrapper: StreamWrapper,
pub total_in: u64,
pub total_out: u64,
pub _marker: marker::PhantomData<D>,
}
impl<D: Direction> Stream<D> {
pub fn msg(&self) -> ErrorMessage {
// SAFETY: The field `inner` must always be accessed as a raw pointer,
// since it points to a cyclic structure. No copies of `inner` can be
// retained for longer than the lifetime of `self`.
let msg = unsafe { (*self.stream_wrapper.inner).msg };
ErrorMessage(if msg.is_null() {
None
} else {
let s = unsafe { std::ffi::CStr::from_ptr(msg) };
std::str::from_utf8(s.to_bytes()).ok()
})
}
}
impl<D: Direction> Drop for Stream<D> {
fn drop(&mut self) {
unsafe {
let _ = D::destroy(self.stream_wrapper.inner);
}
}
}
impl Direction for DirCompress {
unsafe fn destroy(stream: *mut mz_stream) -> c_int {
mz_deflateEnd(stream)
}
}
impl Direction for DirDecompress {
unsafe fn destroy(stream: *mut mz_stream) -> c_int {
mz_inflateEnd(stream)
}
}
#[derive(Debug)]
pub struct Inflate {
pub inner: Stream<DirDecompress>,
}
impl InflateBackend for Inflate {
fn make(zlib_header: bool, window_bits: u8) -> Self {
unsafe {
let state = StreamWrapper::default();
let ret = mz_inflateInit2(
state.inner,
if zlib_header {
window_bits as c_int
} else {
-(window_bits as c_int)
},
);
assert_eq!(ret, 0);
Inflate {
inner: Stream {
stream_wrapper: state,
total_in: 0,
total_out: 0,
_marker: marker::PhantomData,
},
}
}
}
fn decompress(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushDecompress,
) -> Result<Status, DecompressError> {
let raw = self.inner.stream_wrapper.inner;
// SAFETY: The field `inner` must always be accessed as a raw pointer,
// since it points to a cyclic structure. No copies of `inner` can be
// retained for longer than the lifetime of `self`.
unsafe {
(*raw).msg = ptr::null_mut();
(*raw).next_in = input.as_ptr() as *mut u8;
(*raw).avail_in = cmp::min(input.len(), c_uint::MAX as usize) as c_uint;
(*raw).next_out = output.as_mut_ptr();
(*raw).avail_out = cmp::min(output.len(), c_uint::MAX as usize) as c_uint;
let rc = 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;
// reset these pointers so we don't accidentally read them later
(*raw).next_in = ptr::null_mut();
(*raw).avail_in = 0;
(*raw).next_out = ptr::null_mut();
(*raw).avail_out = 0;
match rc {
MZ_DATA_ERROR | MZ_STREAM_ERROR | MZ_MEM_ERROR => {
mem::decompress_failed(self.inner.msg())
}
MZ_OK => Ok(Status::Ok),
MZ_BUF_ERROR => Ok(Status::BufError),
MZ_STREAM_END => Ok(Status::StreamEnd),
MZ_NEED_DICT => mem::decompress_need_dict((*raw).adler as u32),
c => panic!("unknown return code: {}", c),
}
}
}
fn reset(&mut self, zlib_header: bool) {
let bits = if zlib_header {
MZ_DEFAULT_WINDOW_BITS
} else {
-MZ_DEFAULT_WINDOW_BITS
};
unsafe {
inflateReset2(self.inner.stream_wrapper.inner, bits);
}
self.inner.total_out = 0;
self.inner.total_in = 0;
}
}
impl Backend for Inflate {
#[inline]
fn total_in(&self) -> u64 {
self.inner.total_in
}
#[inline]
fn total_out(&self) -> u64 {
self.inner.total_out
}
}
#[derive(Debug)]
pub struct Deflate {
pub inner: Stream<DirCompress>,
}
impl DeflateBackend for Deflate {
fn make(level: Compression, zlib_header: bool, window_bits: u8) -> Self {
unsafe {
let state = StreamWrapper::default();
let ret = mz_deflateInit2(
state.inner,
level.0 as c_int,
MZ_DEFLATED,
if zlib_header {
window_bits as c_int
} else {
-(window_bits as c_int)
},
8,
MZ_DEFAULT_STRATEGY,
);
assert_eq!(ret, 0);
Deflate {
inner: Stream {
stream_wrapper: state,
total_in: 0,
total_out: 0,
_marker: marker::PhantomData,
},
}
}
}
fn compress(
&mut self,
input: &[u8],
output: &mut [u8],
flush: FlushCompress,
) -> Result<Status, CompressError> {
let raw = self.inner.stream_wrapper.inner;
// SAFETY: The field `inner` must always be accessed as a raw pointer,
// since it points to a cyclic structure. No copies of `inner` can be
// retained for longer than the lifetime of `self`.
unsafe {
(*raw).msg = ptr::null_mut();
(*raw).next_in = input.as_ptr() as *mut _;
(*raw).avail_in = cmp::min(input.len(), c_uint::MAX as usize) as c_uint;
(*raw).next_out = output.as_mut_ptr();
(*raw).avail_out = cmp::min(output.len(), c_uint::MAX as usize) as c_uint;
let rc = 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;
// reset these pointers so we don't accidentally read them later
(*raw).next_in = ptr::null_mut();
(*raw).avail_in = 0;
(*raw).next_out = ptr::null_mut();
(*raw).avail_out = 0;
match rc {
MZ_OK => Ok(Status::Ok),
MZ_BUF_ERROR => Ok(Status::BufError),
MZ_STREAM_END => Ok(Status::StreamEnd),
MZ_STREAM_ERROR => mem::compress_failed(self.inner.msg()),
c => panic!("unknown return code: {}", c),
}
}
}
fn reset(&mut self) {
self.inner.total_in = 0;
self.inner.total_out = 0;
let rc = unsafe { mz_deflateReset(self.inner.stream_wrapper.inner) };
assert_eq!(rc, MZ_OK);
}
}
impl Backend for Deflate {
#[inline]
fn total_in(&self) -> u64 {
self.inner.total_in
}
#[inline]
fn total_out(&self) -> u64 {
self.inner.total_out
}
}
pub use self::c_backend::*;
/// For backwards compatibility, we provide symbols as `mz_` to mimic the miniz API
#[allow(bad_style)]
#[allow(unused_imports)]
mod c_backend {
use std::mem;
use std::os::raw::{c_char, c_int};
#[cfg(feature = "zlib-ng")]
use libz_ng_sys as libz;
#[cfg(all(not(feature = "zlib-ng"), feature = "zlib-rs"))]
use libz_rs_sys as libz;
#[cfg(all(not(feature = "zlib-ng"), feature = "cloudflare_zlib"))]
use cloudflare_zlib_sys as libz;
#[cfg(all(
not(feature = "cloudflare_zlib"),
not(feature = "zlib-ng"),
not(feature = "zlib-rs")
))]
use libz_sys as libz;
pub use libz::deflate as mz_deflate;
pub use libz::deflateEnd as mz_deflateEnd;
pub use libz::deflateReset as mz_deflateReset;
pub use libz::inflate as mz_inflate;
pub use libz::inflateEnd as mz_inflateEnd;
pub use libz::z_stream as mz_stream;
pub use libz::*;
pub use libz::Z_BLOCK as MZ_BLOCK;
pub use libz::Z_BUF_ERROR as MZ_BUF_ERROR;
pub use libz::Z_DATA_ERROR as MZ_DATA_ERROR;
pub use libz::Z_DEFAULT_STRATEGY as MZ_DEFAULT_STRATEGY;
pub use libz::Z_DEFLATED as MZ_DEFLATED;
pub use libz::Z_FINISH as MZ_FINISH;
pub use libz::Z_FULL_FLUSH as MZ_FULL_FLUSH;
pub use libz::Z_MEM_ERROR as MZ_MEM_ERROR;
pub use libz::Z_NEED_DICT as MZ_NEED_DICT;
pub use libz::Z_NO_FLUSH as MZ_NO_FLUSH;
pub use libz::Z_OK as MZ_OK;
pub use libz::Z_PARTIAL_FLUSH as MZ_PARTIAL_FLUSH;
pub use libz::Z_STREAM_END as MZ_STREAM_END;
pub use libz::Z_STREAM_ERROR as MZ_STREAM_ERROR;
pub use libz::Z_SYNC_FLUSH as MZ_SYNC_FLUSH;
pub const MZ_DEFAULT_WINDOW_BITS: c_int = 15;
#[cfg(feature = "zlib-ng")]
const ZLIB_VERSION: &'static str = "2.1.0.devel\0";
#[cfg(all(not(feature = "zlib-ng"), feature = "zlib-rs"))]
const ZLIB_VERSION: &'static str = "0.1.0\0";
#[cfg(not(any(feature = "zlib-ng", feature = "zlib-rs")))]
const ZLIB_VERSION: &'static str = "1.2.8\0";
pub unsafe extern "C" fn mz_deflateInit2(
stream: *mut mz_stream,
level: c_int,
method: c_int,
window_bits: c_int,
mem_level: c_int,
strategy: c_int,
) -> c_int {
libz::deflateInit2_(
stream,
level,
method,
window_bits,
mem_level,
strategy,
ZLIB_VERSION.as_ptr() as *const c_char,
mem::size_of::<mz_stream>() as c_int,
)
}
pub unsafe extern "C" fn mz_inflateInit2(stream: *mut mz_stream, window_bits: c_int) -> c_int {
libz::inflateInit2_(
stream,
window_bits,
ZLIB_VERSION.as_ptr() as *const c_char,
mem::size_of::<mz_stream>() as c_int,
)
}
}
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