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