blob: 17d1351bdc8e9d988638899570feee09ea3a71d1 [file] [log] [blame] [edit]
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "bin/gzip.h"
#include "platform/allocation.h"
#include "platform/assert.h"
#include "platform/globals.h"
#include "zlib/zlib.h"
namespace dart {
namespace bin {
void Decompress(const uint8_t* input,
intptr_t input_len,
uint8_t** output,
intptr_t* output_length) {
ASSERT(input != nullptr);
ASSERT(input_len > 0);
ASSERT(output != nullptr);
ASSERT(output_length != nullptr);
const intptr_t kChunkSize = 256 * 1024;
// Initialize output.
intptr_t output_capacity = input_len * 2;
if (output_capacity < kChunkSize) {
output_capacity = kChunkSize;
}
*output = reinterpret_cast<uint8_t*>(malloc(output_capacity));
uint8_t* chunk_out = reinterpret_cast<uint8_t*>(malloc(kChunkSize));
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
int ret = inflateInit2(&strm, 32 + MAX_WBITS);
ASSERT(ret == Z_OK);
intptr_t input_cursor = 0;
intptr_t output_cursor = 0;
do {
// Setup input.
intptr_t size_in = input_len - input_cursor;
if (size_in > kChunkSize) {
size_in = kChunkSize;
}
strm.avail_in = size_in;
strm.next_in = const_cast<uint8_t*>(&input[input_cursor]);
// Inflate until we've exhausted the current input chunk.
do {
// Setup output.
strm.avail_out = kChunkSize;
strm.next_out = &chunk_out[0];
// Inflate.
ret = inflate(&strm, Z_SYNC_FLUSH);
// We either hit the end of the stream or made forward progress.
ASSERT((ret == Z_STREAM_END) || (ret == Z_OK));
// Grow output buffer size.
intptr_t size_out = kChunkSize - strm.avail_out;
if (size_out > (output_capacity - output_cursor)) {
output_capacity *= 2;
ASSERT(size_out <= (output_capacity - output_cursor));
*output = reinterpret_cast<uint8_t*>(realloc(*output, output_capacity));
}
// Copy output.
memmove(&((*output)[output_cursor]), &chunk_out[0], size_out);
output_cursor += size_out;
} while (strm.avail_out == 0);
// We've processed size_in bytes.
input_cursor += size_in;
// We're finished decompressing when zlib tells us.
} while (ret != Z_STREAM_END);
inflateEnd(&strm);
*output_length = output_cursor;
free(chunk_out);
}
} // namespace bin
} // namespace dart