gecko-dev/mozglue/linker/SeekableZStream.cpp
Mike Hommey 813034fd1f Bug 847479 - Use raw zlib streams when compressing with szip. r=nfroyd
And keep compatibility to decompress old streams.
2013-03-06 07:29:41 +01:00

104 lines
2.9 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <algorithm>
#include "SeekableZStream.h"
#include "Logging.h"
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
#ifndef PAGE_MASK
#define PAGE_MASK (~ (PAGE_SIZE - 1))
#endif
bool
SeekableZStream::Init(const void *buf, size_t length)
{
const SeekableZStreamHeader *header = SeekableZStreamHeader::validate(buf);
if (!header) {
log("Not a seekable zstream");
return false;
}
buffer = reinterpret_cast<const unsigned char *>(buf);
totalSize = header->totalSize;
chunkSize = header->chunkSize;
lastChunkSize = header->lastChunkSize;
windowBits = header->windowBits;
offsetTable.Init(&header[1], header->nChunks);
/* Sanity check */
if ((chunkSize == 0) ||
(chunkSize % PAGE_SIZE) ||
(chunkSize > 8 * PAGE_SIZE) ||
(offsetTable.numElements() < 1) ||
(lastChunkSize == 0) ||
(lastChunkSize > chunkSize) ||
(length < totalSize)) {
log("Malformed or broken seekable zstream");
return false;
}
return true;
}
bool
SeekableZStream::Decompress(void *where, size_t chunk, size_t length)
{
while (length) {
size_t len = std::min(length, static_cast<size_t>(chunkSize));
if (!DecompressChunk(where, chunk, len))
return false;
where = reinterpret_cast<unsigned char *>(where) + len;
length -= len;
chunk++;
}
return true;
}
bool
SeekableZStream::DecompressChunk(void *where, size_t chunk, size_t length)
{
if (chunk >= offsetTable.numElements()) {
log("DecompressChunk: chunk #%" PRIdSize " out of range [0-%" PRIdSize ")",
chunk, offsetTable.numElements());
return false;
}
bool isLastChunk = (chunk == offsetTable.numElements() - 1);
size_t chunkLen = isLastChunk ? lastChunkSize : chunkSize;
if (length == 0 || length > chunkLen)
length = chunkLen;
debug("DecompressChunk #%" PRIdSize " @%p (%" PRIdSize "/% " PRIdSize ")",
chunk, where, length, chunkLen);
z_stream zStream;
memset(&zStream, 0, sizeof(zStream));
zStream.avail_in = (isLastChunk ? totalSize : uint32_t(offsetTable[chunk + 1]))
- uint32_t(offsetTable[chunk]);
zStream.next_in = const_cast<Bytef *>(buffer + uint32_t(offsetTable[chunk]));
zStream.avail_out = length;
zStream.next_out = reinterpret_cast<Bytef *>(where);
/* Decompress chunk */
if (inflateInit2(&zStream, windowBits) != Z_OK) {
log("inflateInit failed: %s", zStream.msg);
return false;
}
if (inflate(&zStream, (length == chunkLen) ? Z_FINISH : Z_SYNC_FLUSH)
!= (length == chunkLen) ? Z_STREAM_END : Z_OK) {
log("inflate failed: %s", zStream.msg);
return false;
}
if (inflateEnd(&zStream) != Z_OK) {
log("inflateEnd failed: %s", zStream.msg);
return false;
}
return true;
}