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-rw-r--r--zlib/compress.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/zlib/compress.c b/zlib/compress.c
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+/* 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;
+}