Function loopi

source/src/main.cpp:292–313

    z.avail_out = sizeof(buf);

    loopi(ih)
    {
        uchar filter = 0;
        loopj(2)
        {
            z.next_in = j ? (Bytef *)data + i*pitch : (Bytef *)&filter;
            z.avail_in = j ? iw*3 : 1;
            while(z.avail_in > 0)
            {
                if(deflate(&z, Z_NO_FLUSH) != Z_OK) goto cleanuperror;
                #define FLUSHZ do { \
                    int flush = sizeof(buf) - z.avail_out; \
                    crc = crc32(crc, buf, flush); \
                    len += flush; \
                    f->write(buf, flush); \
                    z.next_out = (Bytef *)buf; \
                    z.avail_out = sizeof(buf); \
                } while(0)
                FLUSHZ;
            }
        }
    }

    for(;;)
    {