compress.c revision 21673
1/* compress.c -- compress a memory buffer 2 * Copyright (C) 1995-1996 Jean-loup Gailly. 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6/* $FreeBSD: head/lib/libz/compress.c 21673 1997-01-14 07:20:47Z jkh $ */ 7 8#include "zlib.h" 9 10/* =========================================================================== 11 Compresses the source buffer into the destination buffer. sourceLen is 12 the byte length of the source buffer. Upon entry, destLen is the total 13 size of the destination buffer, which must be at least 0.1% larger than 14 sourceLen plus 8 bytes. Upon exit, destLen is the actual size of the 15 compressed buffer. 16 This function can be used to compress a whole file at once if the 17 input file is mmap'ed. 18 compress returns Z_OK if success, Z_MEM_ERROR if there was not 19 enough memory, Z_BUF_ERROR if there was not enough room in the output 20 buffer. 21*/ 22int compress (dest, destLen, source, sourceLen) 23 Bytef *dest; 24 uLongf *destLen; 25 const Bytef *source; 26 uLong sourceLen; 27{ 28 z_stream stream; 29 int err; 30 31 stream.next_in = (Bytef*)source; 32 stream.avail_in = (uInt)sourceLen; 33#ifdef MAXSEG_64K 34 /* Check for source > 64K on 16-bit machine: */ 35 if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR; 36#endif 37 stream.next_out = dest; 38 stream.avail_out = (uInt)*destLen; 39 if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR; 40 41 stream.zalloc = (alloc_func)0; 42 stream.zfree = (free_func)0; 43 stream.opaque = (voidpf)0; 44 45 err = deflateInit(&stream, Z_DEFAULT_COMPRESSION); 46 if (err != Z_OK) return err; 47 48 err = deflate(&stream, Z_FINISH); 49 if (err != Z_STREAM_END) { 50 deflateEnd(&stream); 51 return err == Z_OK ? Z_BUF_ERROR : err; 52 } 53 *destLen = stream.total_out; 54 55 err = deflateEnd(&stream); 56 return err; 57} 58