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Diffstat (limited to 'compat/zlib/compress.c')
| -rw-r--r-- | compat/zlib/compress.c | 86 | 
1 files changed, 86 insertions, 0 deletions
| diff --git a/compat/zlib/compress.c b/compat/zlib/compress.c new file mode 100644 index 0000000..e2db404 --- /dev/null +++ b/compat/zlib/compress.c @@ -0,0 +1,86 @@ +/* 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; +} | 
