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Add uncompress2() function, which returns the input size used.

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This commit is contained in:
Mark Adler
2016-11-15 20:45:01 -07:00
parent 001300d0d9
commit 37281ac222
2 changed files with 39 additions and 18 deletions
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47
uncompr.c
View File

@@ -1,5 +1,5 @@
/* uncompr.c -- decompress a memory buffer /* uncompr.c -- decompress a memory buffer
* Copyright (C) 1995-2003, 2010, 2014 Jean-loup Gailly, Mark Adler * Copyright (C) 1995-2003, 2010, 2014, 2016 Jean-loup Gailly, Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h * For conditions of distribution and use, see copyright notice in zlib.h
*/ */
@@ -9,31 +9,34 @@
#include "zlib.h" #include "zlib.h"
/* =========================================================================== /* ===========================================================================
Decompresses the source buffer into the destination buffer. sourceLen is Decompresses the source buffer into the destination buffer. *sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total the byte length of the source buffer. Upon entry, *destLen is the total size
size of the destination buffer, which must be large enough to hold the of the destination buffer, which must be large enough to hold the entire
entire uncompressed data. (The size of the uncompressed data must have uncompressed data. (The size of the uncompressed data must have been saved
been saved previously by the compressor and transmitted to the decompressor previously by the compressor and transmitted to the decompressor by some
by some mechanism outside the scope of this compression library.) mechanism outside the scope of this compression library.) Upon exit,
Upon exit, destLen is the actual size of the compressed buffer. *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 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not enough
enough memory, Z_BUF_ERROR if there was not enough room in the output memory, Z_BUF_ERROR if there was not enough room in the output buffer, or
buffer, or Z_DATA_ERROR if the input data was corrupted, including if the Z_DATA_ERROR if the input data was corrupted, including if the input data is
input data is an incomplete zlib stream. an incomplete zlib stream.
*/ */
int ZEXPORT uncompress (dest, destLen, source, sourceLen) int ZEXPORT uncompress2 (dest, destLen, source, sourceLen)
Bytef *dest; Bytef *dest;
uLongf *destLen; uLongf *destLen;
const Bytef *source; const Bytef *source;
uLong sourceLen; uLong *sourceLen;
{ {
z_stream stream; z_stream stream;
int err; int err;
const uInt max = (uInt)0 - 1; const uInt max = (uInt)0 - 1;
uLong left; uLong len, left;
Byte buf[1]; /* for detection of incomplete stream when *destLen == 0 */ Byte buf[1]; /* for detection of incomplete stream when *destLen == 0 */
len = *sourceLen;
if (*destLen) { if (*destLen) {
left = *destLen; left = *destLen;
*destLen = 0; *destLen = 0;
@@ -61,12 +64,13 @@ int ZEXPORT uncompress (dest, destLen, source, sourceLen)
left -= stream.avail_out; left -= stream.avail_out;
} }
if (stream.avail_in == 0) { if (stream.avail_in == 0) {
stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen; stream.avail_in = len > (uLong)max ? max : (uInt)len;
sourceLen -= stream.avail_in; len -= stream.avail_in;
} }
err = inflate(&stream, Z_NO_FLUSH); err = inflate(&stream, Z_NO_FLUSH);
} while (err == Z_OK); } while (err == Z_OK);
*sourceLen -= len + stream.avail_in;
if (dest != buf) if (dest != buf)
*destLen = stream.total_out; *destLen = stream.total_out;
else if (stream.total_out && err == Z_BUF_ERROR) else if (stream.total_out && err == Z_BUF_ERROR)
@@ -78,3 +82,12 @@ int ZEXPORT uncompress (dest, destLen, source, sourceLen)
err == Z_BUF_ERROR && left + stream.avail_out ? Z_DATA_ERROR : err == Z_BUF_ERROR && left + stream.avail_out ? Z_DATA_ERROR :
err; err;
} }
int ZEXPORT uncompress (dest, destLen, source, sourceLen)
Bytef *dest;
uLongf *destLen;
const Bytef *source;
uLong sourceLen;
{
return uncompress2(dest, destLen, source, &sourceLen);
}

10
zlib.h
View File

@@ -1246,7 +1246,7 @@ ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
uncompressed data. (The size of the uncompressed data must have been saved uncompressed data. (The size of the uncompressed data must have been saved
previously by the compressor and transmitted to the decompressor by some previously by the compressor and transmitted to the decompressor by some
mechanism outside the scope of this compression library.) Upon exit, destLen mechanism outside the scope of this compression library.) Upon exit, destLen
is the actual size of the uncompressed buffer. is the actual size of the uncompressed data.
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 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 enough memory, Z_BUF_ERROR if there was not enough room in the output
@@ -1255,6 +1255,14 @@ ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
buffer with the uncompressed data up to that point. buffer with the uncompressed data up to that point.
*/ */
ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen,
const Bytef *source, uLong *sourceLen));
/*
Same as uncompress, except that sourceLen is a pointer, where the
length of the source is *sourceLen. On return, *sourceLen is the number of
source bytes consumed.
*/
/* gzip file access functions */ /* gzip file access functions */
/* /*