Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include <flate.h>
#include "zlib.h"

int
deflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize, int level, int debug)
{
        ulong adler;
        int n;

        if(dsize < 6)
                return FlateOutputFail;

        n = deflateblock(dst + 2, dsize - 6, src, ssize, level, debug);
        if(n < 0)
                return n;

        dst[0] = ZlibDeflate | ZlibWin32k;

        /* bogus zlib encoding of compression level */
        dst[1] = ((level > 2) + (level > 5) + (level > 8)) << 6;

        /* header check field */
        dst[1] |= 31 - ((dst[0] << 8) | dst[1]) % 31;

        adler = adler32(1, src, ssize);
        dst[n + 2] = adler >> 24;
        dst[n + 3] = adler >> 16;
        dst[n + 4] = adler >> 8;
        dst[n + 5] = adler;

        return n + 6;
}