compress.c File Reference

#include "zlib.h"

Macros
#define	ZLIB_INTERNAL

Functions
int ZEXPORT	compress2 (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level)
int ZEXPORT	compress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
uLong ZEXPORT	compressBound (uLong sourceLen)

Macro Definition Documentation

ZLIB_INTERNAL

#define ZLIB_INTERNAL

Function Documentation

compress2()

int ZEXPORT compress2	(	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;
}

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compress()

int ZEXPORT compress	(	Bytef *	dest,
		uLongf *	destLen,
		const Bytef *	source,
		uLong	sourceLen
	)

{
    return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
}

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compressBound()

uLong ZEXPORT compressBound

(

uLong

sourceLen

)

{
    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
           (sourceLen >> 25) + 13;
}