diff options
Diffstat (limited to 'zlib/compress.c')
-rw-r--r-- | zlib/compress.c | 165 |
1 files changed, 86 insertions, 79 deletions
diff --git a/zlib/compress.c b/zlib/compress.c index 5a7eeee..e2db404 100644 --- a/zlib/compress.c +++ b/zlib/compress.c @@ -1,79 +1,86 @@ -/* compress.c -- compress a memory buffer
- * Copyright (C) 1995-2002 Jean-loup Gailly.
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
-
-/* @(#) $Id$ */
-
-#define ZLIB_INTERNAL
-#include "zlib.h"
-
-/* ===========================================================================
- Compresses the source buffer into the destination buffer. The level
- parameter has the same meaning as in deflateInit. sourceLen is the byte
- length of the source buffer. Upon entry, destLen is the total size of the
- destination buffer, which must be at least 0.1% larger than sourceLen plus
- 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
-
- compress2 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,
- Z_STREAM_ERROR if the level parameter is invalid.
-*/
-int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
- Bytef *dest;
- uLongf *destLen;
- const Bytef *source;
- uLong sourceLen;
- int level;
-{
- z_stream stream;
- int err;
-
- stream.next_in = (Bytef*)source;
- stream.avail_in = (uInt)sourceLen;
-#ifdef MAXSEG_64K
- /* Check for source > 64K on 16-bit machine: */
- if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
-#endif
- stream.next_out = dest;
- stream.avail_out = (uInt)*destLen;
- if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
-
- stream.zalloc = (alloc_func)0;
- stream.zfree = (free_func)0;
- stream.opaque = (voidpf)0;
-
- err = deflateInit(&stream, level);
- if (err != Z_OK) return err;
-
- err = deflate(&stream, Z_FINISH);
- if (err != Z_STREAM_END) {
- deflateEnd(&stream);
- return err == Z_OK ? Z_BUF_ERROR : err;
- }
- *destLen = stream.total_out;
-
- err = deflateEnd(&stream);
- return err;
-}
-
-/* ===========================================================================
- */
-int ZEXPORT compress (dest, destLen, source, sourceLen)
- Bytef *dest;
- uLongf *destLen;
- const Bytef *source;
- uLong sourceLen;
-{
- return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
-}
-
-/* ===========================================================================
- If the default memLevel or windowBits for deflateInit() is changed, then
- this function needs to be updated.
- */
-uLong ZEXPORT compressBound (sourceLen)
- uLong sourceLen;
-{
- return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11;
-}
+/* compress.c -- compress a memory buffer + * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +/* @(#) $Id$ */ + +#define ZLIB_INTERNAL +#include "zlib.h" + +/* =========================================================================== + Compresses the source buffer into the destination buffer. The level + parameter has the same meaning as in deflateInit. sourceLen is the byte + length of the source buffer. Upon entry, destLen is the total size of the + destination buffer, which must be at least 0.1% larger than sourceLen plus + 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. + + compress2 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, + Z_STREAM_ERROR if the level parameter is invalid. +*/ +int ZEXPORT compress2 (dest, destLen, source, sourceLen, level) + Bytef *dest; + uLongf *destLen; + const Bytef *source; + uLong sourceLen; + int level; +{ + z_stream stream; + int err; + const uInt max = (uInt)-1; + uLong left; + + left = *destLen; + *destLen = 0; + + stream.zalloc = (alloc_func)0; + stream.zfree = (free_func)0; + stream.opaque = (voidpf)0; + + err = deflateInit(&stream, level); + if (err != Z_OK) return err; + + stream.next_out = dest; + stream.avail_out = 0; + stream.next_in = (z_const Bytef *)source; + stream.avail_in = 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 = sourceLen > (uLong)max ? max : (uInt)sourceLen; + sourceLen -= stream.avail_in; + } + err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH); + } while (err == Z_OK); + + *destLen = stream.total_out; + deflateEnd(&stream); + return err == Z_STREAM_END ? Z_OK : err; +} + +/* =========================================================================== + */ +int ZEXPORT compress (dest, destLen, source, sourceLen) + Bytef *dest; + uLongf *destLen; + const Bytef *source; + uLong sourceLen; +{ + return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); +} + +/* =========================================================================== + If the default memLevel or windowBits for deflateInit() is changed, then + this function needs to be updated. + */ +uLong ZEXPORT compressBound (sourceLen) + uLong sourceLen; +{ + return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + + (sourceLen >> 25) + 13; +} |