]> andersk Git - openssh.git/blobdiff - crc32.c
- djm@cvs.openbsd.org 2010/01/30 02:54:53
[openssh.git] / crc32.c
diff --git a/crc32.c b/crc32.c
index 1d69496ab3dc51f61404c25ba800c12e40af826c..c192eb4d66da889ea2c83836d0327671d30f6b7a 100644 (file)
--- a/crc32.c
+++ b/crc32.c
-/* The implementation here was originally done by Gary S. Brown.  I have
-   borrowed the tables directly, and made some minor changes to the
-   crc32-function (including changing the interface). //ylo */
+/* $OpenBSD: crc32.c,v 1.11 2006/04/22 18:29:33 stevesk Exp $ */
 
+/*
+ * Copyright (c) 2003 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
 #include "includes.h"
-RCSID("$Id$");
-
 #include "crc32.h"
 
-  /* ============================================================= */
-  /*  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or       */
-  /*  code or tables extracted from it, as desired without restriction.     */
-  /*                                                                        */
-  /*  First, the polynomial itself and its table of feedback terms.  The    */
-  /*  polynomial is                                                         */
-  /*  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0   */
-  /*                                                                        */
-  /*  Note that we take it "backwards" and put the highest-order term in    */
-  /*  the lowest-order bit.  The X^32 term is "implied"; the LSB is the     */
-  /*  X^31 term, etc.  The X^0 term (usually shown as "+1") results in      */
-  /*  the MSB being 1.                                                      */
-  /*                                                                        */
-  /*  Note that the usual hardware shift register implementation, which     */
-  /*  is what we're using (we're merely optimizing it by doing eight-bit    */
-  /*  chunks at a time) shifts bits into the lowest-order term.  In our     */
-  /*  implementation, that means shifting towards the right.  Why do we     */
-  /*  do it this way?  Because the calculated CRC must be transmitted in    */
-  /*  order from highest-order term to lowest-order term.  UARTs transmit   */
-  /*  characters in order from LSB to MSB.  By storing the CRC this way,    */
-  /*  we hand it to the UART in the order low-byte to high-byte; the UART   */
-  /*  sends each low-bit to hight-bit; and the result is transmission bit   */
-  /*  by bit from highest- to lowest-order term without requiring any bit   */
-  /*  shuffling on our part.  Reception works similarly.                    */
-  /*                                                                        */
-  /*  The feedback terms table consists of 256, 32-bit entries.  Notes:     */
-  /*                                                                        */
-  /*      The table can be generated at runtime if desired; code to do so   */
-  /*      is shown later.  It might not be obvious, but the feedback        */
-  /*      terms simply represent the results of eight shift/xor opera-      */
-  /*      tions for all combinations of data and CRC register values.       */
-  /*                                                                        */
-  /*      The values must be right-shifted by eight bits by the "updcrc"    */
-  /*      logic; the shift must be unsigned (bring in zeroes).  On some     */
-  /*      hardware you could probably optimize the shift in assembler by    */
-  /*      using byte-swap instructions.                                     */
-  /*      polynomial $edb88320                                              */
-  /*                                                                        */
-  /*  --------------------------------------------------------------------  */
-
-static unsigned int crc32_tab[] = {
-      0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
-      0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
-      0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
-      0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
-      0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
-      0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
-      0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
-      0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
-      0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
-      0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
-      0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
-      0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
-      0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
-      0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
-      0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
-      0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
-      0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
-      0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
-      0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
-      0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
-      0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
-      0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
-      0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
-      0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
-      0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
-      0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
-      0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
-      0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
-      0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
-      0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
-      0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
-      0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
-      0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
-      0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
-      0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
-      0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
-      0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
-      0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
-      0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
-      0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
-      0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
-      0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
-      0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
-      0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
-      0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
-      0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
-      0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
-      0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
-      0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
-      0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
-      0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
-      0x2d02ef8dL
-   };
+static const u_int32_t crc32tab[] = {
+       0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL,
+       0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
+       0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L,
+       0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
+       0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
+       0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
+       0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
+       0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
+       0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L,
+       0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
+       0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L,
+       0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
+       0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L,
+       0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
+       0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
+       0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
+       0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
+       0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
+       0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 0xe10e9818L,
+       0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
+       0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL,
+       0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
+       0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL,
+       0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L,
+       0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
+       0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL,
+       0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
+       0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L,
+       0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L,
+       0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
+       0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L,
+       0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
+       0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL,
+       0xead54739L, 0x9dd277afL, 0x04db2615L, 0x73dc1683L,
+       0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
+       0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L,
+       0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
+       0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L,
+       0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL,
+       0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
+       0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L,
+       0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
+       0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L,
+       0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L,
+       0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
+       0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL,
+       0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
+       0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL,
+       0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 0x026d930aL,
+       0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
+       0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L,
+       0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
+       0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL,
+       0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L,
+       0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
+       0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L,
+       0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
+       0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL,
+       0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L,
+       0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
+       0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L,
+       0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
+       0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L,
+       0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL
+};
 
-/* Return a 32-bit CRC of the contents of the buffer. */
-
-unsigned int crc32(const unsigned char *s, unsigned int len)
+u_int32_t
+ssh_crc32(const u_char *buf, u_int32_t size)
 {
-  unsigned int i;
-  unsigned int crc32val;
-  
-  crc32val = 0;
-  for (i = 0;  i < len;  i ++)
-    {
-      crc32val =
-       crc32_tab[(crc32val ^ s[i]) & 0xff] ^
-         (crc32val >> 8);
-    }
-  return crc32val;
+       u_int32_t i, crc;
+
+       crc = 0;
+       for (i = 0; i < size; i++)
+               crc = crc32tab[(crc ^ buf[i]) & 0xff] ^ (crc >> 8);
+       return crc;
 }
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