cosmopolitan/third_party/zlib/uncompr.c

92 lines
3.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=4 sts=4 sw=4 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 1995-2003,2010,2014,2016 Jean-loup Gailly and Mark Adler │
│ Use of this source code is governed by the BSD-style licenses that can │
│ be found in the third_party/zlib/LICENSE file. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "third_party/zlib/zlib.h"
asm(".ident\t\"\\n\\n\
zlib (zlib License)\\n\
Copyright 1995-2017 Jean-loup Gailly and Mark Adler\"");
asm(".include \"libc/disclaimer.inc\"");
/**
* Decompresses the source buffer into the destination buffer. *sourceLen is
* the byte length of the source buffer. Upon entry, *destLen is the total size
* of the destination buffer, which must be large enough to hold the entire
* uncompressed data. (The size of the uncompressed data must have been saved
* previously by the compressor and transmitted to the decompressor by some
* mechanism outside the scope of this compression library.) Upon exit,
* *destLen is the size of the decompressed data and *sourceLen is the number
* of source bytes consumed. Upon return, source + *sourceLen points to the
* first unused input byte.
*
* uncompress returns Z_OK if success, Z_MEM_ERROR if there was not enough
* memory, Z_BUF_ERROR if there was not enough room in the output buffer, or
* Z_DATA_ERROR if the input data was corrupted, including if the input data is
* an incomplete zlib stream.
*/
int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
uLong *sourceLen) {
z_stream stream;
int err;
const uInt max = (uInt)-1;
uLong len, left;
Byte buf[1]; /* for detection of incomplete stream when *destLen == 0 */
len = *sourceLen;
if (*destLen) {
left = *destLen;
*destLen = 0;
} else {
left = 1;
dest = buf;
}
stream.next_in = (const Bytef *)source;
stream.avail_in = 0;
stream.zalloc = (alloc_func)0;
stream.zfree = (free_func)0;
stream.opaque = (voidpf)0;
err = inflateInit(&stream);
if (err != Z_OK) return err;
stream.next_out = dest;
stream.avail_out = 0;
do {
if (stream.avail_out == 0) {
stream.avail_out = left > (uLong)max ? max : (uInt)left;
left -= stream.avail_out;
}
if (stream.avail_in == 0) {
stream.avail_in = len > (uLong)max ? max : (uInt)len;
len -= stream.avail_in;
}
err = inflate(&stream, Z_NO_FLUSH);
} while (err == Z_OK);
*sourceLen -= len + stream.avail_in;
if (dest != buf)
*destLen = stream.total_out;
else if (stream.total_out && err == Z_BUF_ERROR)
left = 1;
inflateEnd(&stream);
return err == Z_STREAM_END
? Z_OK
: err == Z_NEED_DICT
? Z_DATA_ERROR
: err == Z_BUF_ERROR && left + stream.avail_out
? Z_DATA_ERROR
: err;
}
int uncompress(Bytef *dest, uLongf *destLen, const Bytef *source,
uLong sourceLen) {
return uncompress2(dest, destLen, source, &sourceLen);
}