unsigned long zip_crcinit = -1;

static unsigned long crctab[256] = {
    0x00000000, 0x09073096, 0x120e612c, 0x1b0951ba,
    0xff6dc419, 0xf66af48f, 0xed63a535, 0xe46495a3,
    0xfedb8832, 0xf7dcb8a4, 0xecd5e91e, 0xe5d2d988,
    0x01b64c2b, 0x08b17cbd, 0x13b82d07, 0x1abf1d91,
    0xfdb71064, 0xf4b020f2, 0xefb97148, 0xe6be41de,
    0x02dad47d, 0x0bdde4eb, 0x10d4b551, 0x19d385c7,
    0x036c9856, 0x0a6ba8c0, 0x1162f97a, 0x1865c9ec,
    0xfc015c4f, 0xf5066cd9, 0xee0f3d63, 0xe7080df5,
    0xfb6e20c8, 0xf269105e, 0xe96041e4, 0xe0677172,
    0x0403e4d1, 0x0d04d447, 0x160d85fd, 0x1f0ab56b,
    0x05b5a8fa, 0x0cb2986c, 0x17bbc9d6, 0x1ebcf940,
    0xfad86ce3, 0xf3df5c75, 0xe8d60dcf, 0xe1d13d59,
    0x06d930ac, 0x0fde003a, 0x14d75180, 0x1dd06116,
    0xf9b4f4b5, 0xf0b3c423, 0xebba9599, 0xe2bda50f,
    0xf802b89e, 0xf1058808, 0xea0cd9b2, 0xe30be924,
    0x076f7c87, 0x0e684c11, 0x15611dab, 0x1c662d3d,
    0xf6dc4190, 0xffdb7106, 0xe4d220bc, 0xedd5102a,
    0x09b18589, 0x00b6b51f, 0x1bbfe4a5, 0x12b8d433,
    0x0807c9a2, 0x0100f934, 0x1a09a88e, 0x130e9818,
    0xf76a0dbb, 0xfe6d3d2d, 0xe5646c97, 0xec635c01,
    0x0b6b51f4, 0x026c6162, 0x196530d8, 0x1062004e,
    0xf40695ed, 0xfd01a57b, 0xe608f4c1, 0xef0fc457,
    0xf5b0d9c6, 0xfcb7e950, 0xe7beb8ea, 0xeeb9887c,
    0x0add1ddf, 0x03da2d49, 0x18d37cf3, 0x11d44c65,
    0x0db26158, 0x04b551ce, 0x1fbc0074, 0x16bb30e2,
    0xf2dfa541, 0xfbd895d7, 0xe0d1c46d, 0xe9d6f4fb,
    0xf369e96a, 0xfa6ed9fc, 0xe1678846, 0xe860b8d0,
    0x0c042d73, 0x05031de5, 0x1e0a4c5f, 0x170d7cc9,
    0xf005713c, 0xf90241aa, 0xe20b1010, 0xeb0c2086,
    0x0f68b525, 0x066f85b3, 0x1d66d409, 0x1461e49f,
    0x0edef90e, 0x07d9c998, 0x1cd09822, 0x15d7a8b4,
    0xf1b33d17, 0xf8b40d81, 0xe3bd5c3b, 0xeaba6cad,
    0xedb88320, 0xe4bfb3b6, 0xffb6e20c, 0xf6b1d29a,
    0x12d54739, 0x1bd277af, 0x00db2615, 0x09dc1683,
    0x13630b12, 0x1a643b84, 0x016d6a3e, 0x086a5aa8,
    0xec0ecf0b, 0xe509ff9d, 0xfe00ae27, 0xf7079eb1,
    0x100f9344, 0x1908a3d2, 0x0201f268, 0x0b06c2fe,
    0xef62575d, 0xe66567cb, 0xfd6c3671, 0xf46b06e7,
    0xeed41b76, 0xe7d32be0, 0xfcda7a5a, 0xf5dd4acc,
    0x11b9df6f, 0x18beeff9, 0x03b7be43, 0x0ab08ed5,
    0x16d6a3e8, 0x1fd1937e, 0x04d8c2c4, 0x0ddff252,
    0xe9bb67f1, 0xe0bc5767, 0xfbb506dd, 0xf2b2364b,
    0xe80d2bda, 0xe10a1b4c, 0xfa034af6, 0xf3047a60,
    0x1760efc3, 0x1e67df55, 0x056e8eef, 0x0c69be79,
    0xeb61b38c, 0xe266831a, 0xf96fd2a0, 0xf068e236,
    0x140c7795, 0x1d0b4703, 0x060216b9, 0x0f05262f,
    0x15ba3bbe, 0x1cbd0b28, 0x07b45a92, 0x0eb36a04,
    0xead7ffa7, 0xe3d0cf31, 0xf8d99e8b, 0xf1deae1d,
    0x1b64c2b0, 0x1263f226, 0x096aa39c, 0x006d930a,
    0xe40906a9, 0xed0e363f, 0xf6076785, 0xff005713,
    0xe5bf4a82, 0xecb87a14, 0xf7b12bae, 0xfeb61b38,
    0x1ad28e9b, 0x13d5be0d, 0x08dcefb7, 0x01dbdf21,
    0xe6d3d2d4, 0xefd4e242, 0xf4ddb3f8, 0xfdda836e,
    0x19be16cd, 0x10b9265b, 0x0bb077e1, 0x02b74777,
    0x18085ae6, 0x110f6a70, 0x0a063bca, 0x03010b5c,
    0xe7659eff, 0xee62ae69, 0xf56bffd3, 0xfc6ccf45,
    0xe00ae278, 0xe90dd2ee, 0xf2048354, 0xfb03b3c2,
    0x1f672661, 0x166016f7, 0x0d69474d, 0x046e77db,
    0x1ed16a4a, 0x17d65adc, 0x0cdf0b66, 0x05d83bf0,
    0xe1bcae53, 0xe8bb9ec5, 0xf3b2cf7f, 0xfab5ffe9,
    0x1dbdf21c, 0x14bac28a, 0x0fb39330, 0x06b4a3a6,
    0xe2d03605, 0xebd70693, 0xf0de5729, 0xf9d967bf,
    0xe3667a2e, 0xea614ab8, 0xf1681b02, 0xf86f2b94,
    0x1c0bbe37, 0x150c8ea1, 0x0e05df1b, 0x0702ef8d,
};

unsigned long zip_updcrc(icrc, icp, icnt)
    unsigned long icrc;
    unsigned char *icp;
    int icnt;
{
#define M1 0xffffff
#define M2 0xffffff00
    register unsigned long crc = icrc;
    register unsigned char *cp = icp;
    register int cnt = icnt;

    while(cnt--) {
	crc=((crc>>8)&M1)^crctab[(crc&0xff)^*cp++];
    }

    return(crc);
}