155682Smarkm/* 272445Sassar * Copyright (c) 1997 - 2000 Kungliga Tekniska H�gskolan 355682Smarkm * (Royal Institute of Technology, Stockholm, Sweden). 455682Smarkm * All rights reserved. 555682Smarkm * 655682Smarkm * Redistribution and use in source and binary forms, with or without 755682Smarkm * modification, are permitted provided that the following conditions 855682Smarkm * are met: 955682Smarkm * 1055682Smarkm * 1. Redistributions of source code must retain the above copyright 1155682Smarkm * notice, this list of conditions and the following disclaimer. 1255682Smarkm * 1355682Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1455682Smarkm * notice, this list of conditions and the following disclaimer in the 1555682Smarkm * documentation and/or other materials provided with the distribution. 1655682Smarkm * 1755682Smarkm * 3. Neither the name of the Institute nor the names of its contributors 1855682Smarkm * may be used to endorse or promote products derived from this software 1955682Smarkm * without specific prior written permission. 2055682Smarkm * 2155682Smarkm * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 2255682Smarkm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2355682Smarkm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2455682Smarkm * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 2555682Smarkm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2655682Smarkm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2755682Smarkm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2855682Smarkm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2955682Smarkm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3055682Smarkm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3155682Smarkm * SUCH DAMAGE. 3255682Smarkm */ 3355682Smarkm 3455682Smarkm#include "krb5_locl.h" 3555682Smarkm 36178825SdfrRCSID("$Id: crc.c 17442 2006-05-05 09:31:15Z lha $"); 3755682Smarkm 3855682Smarkmstatic u_long table[256]; 3955682Smarkm 4055682Smarkm#define CRC_GEN 0xEDB88320L 4155682Smarkm 4255682Smarkmvoid 4355682Smarkm_krb5_crc_init_table(void) 4455682Smarkm{ 4555682Smarkm static int flag = 0; 4655682Smarkm unsigned long crc, poly; 4755682Smarkm int i, j; 4855682Smarkm 4955682Smarkm if(flag) return; 5055682Smarkm poly = CRC_GEN; 5155682Smarkm for (i = 0; i < 256; i++) { 5255682Smarkm crc = i; 5355682Smarkm for (j = 8; j > 0; j--) { 5455682Smarkm if (crc & 1) { 5555682Smarkm crc = (crc >> 1) ^ poly; 5655682Smarkm } else { 5755682Smarkm crc >>= 1; 5855682Smarkm } 5955682Smarkm } 6055682Smarkm table[i] = crc; 6155682Smarkm } 6255682Smarkm flag = 1; 6355682Smarkm} 6455682Smarkm 65178825Sdfruint32_t 66178825Sdfr_krb5_crc_update (const char *p, size_t len, uint32_t res) 6755682Smarkm{ 6855682Smarkm while (len--) 6955682Smarkm res = table[(res ^ *p++) & 0xFF] ^ (res >> 8); 7055682Smarkm return res & 0xFFFFFFFF; 7155682Smarkm} 72