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/*
* Copyright 2009, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
//
// GzDecompressor decompresses a gzip compressed byte stream
// calling the client's ProcessBytes() method with the uncompressed stream
//
#include "import/cross/gz_decompressor.h"
#include <assert.h>
#include "import/cross/memory_stream.h"
const size_t kChunkSize = 16384;
namespace o3d {
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GzDecompressor::GzDecompressor(StreamProcessor *callback_client)
: callback_client_(callback_client) {
// Initialize inflate state
strm_.zalloc = Z_NULL;
strm_.zfree = Z_NULL;
strm_.opaque = Z_NULL;
strm_.avail_in = 0;
strm_.next_in = Z_NULL;
// Store this, so we can later check if it's OK to start processing
init_result_ = inflateInit2(&strm_, 31);
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GzDecompressor::~GzDecompressor() {
inflateEnd(&strm_);
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
int GzDecompressor::ProcessBytes(MemoryReadStream *stream,
size_t bytes_to_process) {
// Don't even bother trying if we didn't get initialized properly
if (init_result_ != Z_OK) return init_result_;
uint8 out[kChunkSize];
int result;
size_t have;
// Don't try to read more than our stream has
size_t remaining = stream->GetRemainingByteCount();
if (bytes_to_process > remaining) {
return Z_STREAM_ERROR; // could have our own error code, but good enough...
}
// Use direct memory access on the MemoryStream object
strm_.avail_in = bytes_to_process;
strm_.next_in = const_cast<uint8*>(stream->GetDirectMemoryPointer());
stream->Skip(bytes_to_process);
// Run inflate() on input until output buffer not full
do {
strm_.avail_out = kChunkSize;
strm_.next_out = out;
result = inflate(&strm_, Z_NO_FLUSH);
// error check here - return error codes if necessary
assert(result != Z_STREAM_ERROR); /* state not clobbered */
switch (result) {
case Z_NEED_DICT:
result = Z_DATA_ERROR; /* and fall through */
case Z_DATA_ERROR:
case Z_MEM_ERROR:
return result;
}
have = kChunkSize - strm_.avail_out;
// Callback with the decompressed byte stream
MemoryReadStream decompressed_stream(out, have);
if (callback_client_) {
int client_result =
callback_client_->ProcessBytes(&decompressed_stream, have);
if (client_result != 0) {
return client_result; // propagate callback errors
}
}
} while (strm_.avail_out == 0);
return result;
}
} // namespace o3d
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