/* compress.c -- compress a memory buffer
- * Copyright (C) 1995-1996 Jean-loup Gailly.
- * For conditions of distribution and use, see copyright notice in zlib.h
+ * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
*/
-/* $Id: compress.c,v 1.6 1995/05/03 17:27:08 jloup Exp $ */
+/* @(#) $Id$ */
+#define ZLIB_INTERNAL
#include "zlib.h"
/* ===========================================================================
- Compresses 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 at least 0.1% larger than
- sourceLen plus 8 bytes. Upon exit, destLen is the actual size of the
- compressed buffer.
- This function can be used to compress a whole file at once if the
- input file is mmap'ed.
- compress 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.
+ 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 compress (dest, destLen, source, sourceLen)
+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;
- stream.next_in = (Bytef*)source;
- stream.avail_in = (uInt)sourceLen;
- /* Check for source > 64K on 16-bit machine: */
- if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
-
- stream.next_out = dest;
- stream.avail_out = (uInt)*destLen;
- if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
+ left = *destLen;
+ *destLen = 0;
stream.zalloc = (alloc_func)0;
stream.zfree = (free_func)0;
stream.opaque = (voidpf)0;
- err = deflateInit(&stream, Z_DEFAULT_COMPRESSION);
+ 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;
- }
+ 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);
+}
- err = deflateEnd(&stream);
- return err;
+/* ===========================================================================
+ 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;
}