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/*
* Copyright © 2021 Valve Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifdef HAVE_COMPRESSION
#include <assert.h>
/* Ensure that zlib uses 'const' in 'z_const' declarations. */
#ifndef ZLIB_CONST
#define ZLIB_CONST
#endif
#ifdef HAVE_ZLIB
#include "zlib.h"
#endif
#ifdef HAVE_ZSTD
#include "zstd.h"
#endif
#include "util/compress.h"
#include "macros.h"
/* 3 is the recomended level, with 22 as the absolute maximum */
#define ZSTD_COMPRESSION_LEVEL 3
size_t
util_compress_max_compressed_len(size_t in_data_size)
{
#ifdef HAVE_ZSTD
/* from the zstd docs (https://facebook.github.io/zstd/zstd_manual.html):
* compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
*/
return ZSTD_compressBound(in_data_size);
#elif defined(HAVE_ZLIB)
/* From https://zlib.net/zlib_tech.html:
*
* "In the worst possible case, where the other block types would expand
* the data, deflation falls back to stored (uncompressed) blocks. Thus
* for the default settings used by deflateInit(), compress(), and
* compress2(), the only expansion is an overhead of five bytes per 16 KB
* block (about 0.03%), plus a one-time overhead of six bytes for the
* entire stream."
*/
size_t num_blocks = (in_data_size + 16383) / 16384; /* round up blocks */
return in_data_size + 6 + (num_blocks * 5);
#else
STATIC_ASSERT(false);
#endif
}
/* Compress data and return the size of the compressed data */
size_t
util_compress_deflate(const uint8_t *in_data, size_t in_data_size,
uint8_t *out_data, size_t out_buff_size)
{
#ifdef HAVE_ZSTD
size_t ret = ZSTD_compress(out_data, out_buff_size, in_data, in_data_size,
ZSTD_COMPRESSION_LEVEL);
if (ZSTD_isError(ret))
return 0;
return ret;
#elif defined(HAVE_ZLIB)
size_t compressed_size = 0;
/* allocate deflate state */
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.next_in = in_data;
strm.next_out = out_data;
strm.avail_in = in_data_size;
strm.avail_out = out_buff_size;
int ret = deflateInit(&strm, Z_BEST_COMPRESSION);
if (ret != Z_OK) {
(void) deflateEnd(&strm);
return 0;
}
/* compress until end of in_data */
ret = deflate(&strm, Z_FINISH);
/* stream should be complete */
assert(ret == Z_STREAM_END);
if (ret == Z_STREAM_END) {
compressed_size = strm.total_out;
}
/* clean up and return */
(void) deflateEnd(&strm);
return compressed_size;
#else
STATIC_ASSERT(false);
# endif
}
/**
* Decompresses data, returns true if successful.
*/
bool
util_compress_inflate(const uint8_t *in_data, size_t in_data_size,
uint8_t *out_data, size_t out_data_size)
{
#ifdef HAVE_ZSTD
size_t ret = ZSTD_decompress(out_data, out_data_size, in_data, in_data_size);
return !ZSTD_isError(ret);
#elif defined(HAVE_ZLIB)
z_stream strm;
/* allocate inflate state */
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.next_in = in_data;
strm.avail_in = in_data_size;
strm.next_out = out_data;
strm.avail_out = out_data_size;
int ret = inflateInit(&strm);
if (ret != Z_OK)
return false;
ret = inflate(&strm, Z_NO_FLUSH);
assert(ret != Z_STREAM_ERROR); /* state not clobbered */
/* Unless there was an error we should have decompressed everything in one
* go as we know the uncompressed file size.
*/
if (ret != Z_STREAM_END) {
(void)inflateEnd(&strm);
return false;
}
assert(strm.avail_out == 0);
/* clean up and return */
(void)inflateEnd(&strm);
return true;
#else
STATIC_ASSERT(false);
#endif
}
#endif
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