Line data    Source code

       1             : /*
       2             :  * Copyright (c) 1997 - 2000 Kungliga Tekniska Högskolan
       3             :  * (Royal Institute of Technology, Stockholm, Sweden).
       4             :  * All rights reserved.
       5             :  *
       6             :  * Redistribution and use in source and binary forms, with or without
       7             :  * modification, are permitted provided that the following conditions
       8             :  * are met:
       9             :  *
      10             :  * 1. Redistributions of source code must retain the above copyright
      11             :  *    notice, this list of conditions and the following disclaimer.
      12             :  *
      13             :  * 2. Redistributions in binary form must reproduce the above copyright
      14             :  *    notice, this list of conditions and the following disclaimer in the
      15             :  *    documentation and/or other materials provided with the distribution.
      16             :  *
      17             :  * 3. Neither the name of the Institute nor the names of its contributors
      18             :  *    may be used to endorse or promote products derived from this software
      19             :  *    without specific prior written permission.
      20             :  *
      21             :  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
      22             :  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      23             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      24             :  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
      25             :  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      26             :  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
      27             :  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      28             :  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
      29             :  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
      30             :  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      31             :  * SUCH DAMAGE.
      32             :  */
      33             : 
      34             : #include "krb5_locl.h"
      35             : 
      36             : static u_long table[256];
      37             : 
      38             : #define CRC_GEN 0xEDB88320L
      39             : 
      40             : KRB5_LIB_FUNCTION void KRB5_LIB_CALL
      41           0 : _krb5_crc_init_table(void)
      42             : {
      43             :     static int flag = 0;
      44             :     unsigned long crc, poly;
      45             :     unsigned int i, j;
      46             : 
      47           0 :     if(flag) return;
      48           0 :     poly = CRC_GEN;
      49           0 :     for (i = 0; i < 256; i++) {
      50           0 :         crc = i;
      51           0 :         for (j = 8; j > 0; j--) {
      52           0 :             if (crc & 1) {
      53           0 :                 crc = (crc >> 1) ^ poly;
      54             :             } else {
      55           0 :                 crc >>= 1;
      56             :             }
      57             :         }
      58           0 :         table[i] = crc;
      59             :     }
      60           0 :     flag = 1;
      61             : }
      62             : 
      63             : KRB5_LIB_FUNCTION uint32_t KRB5_LIB_CALL
      64           0 : _krb5_crc_update (const char *p, size_t len, uint32_t res)
      65             : {
      66           0 :     while (len--)
      67           0 :         res = table[(res ^ *p++) & 0xFF] ^ (res >> 8);
      68           0 :     return res & 0xFFFFFFFF;
      69             : }