dll/win32/dbghelp/crc32.c

   1 /*
   2  * File crc32.c - calculate CRC32 checksum of a file
   3  *
   4  * Copyright (C) 1996, Eric Youngdale.
   5  *               1999-2007 Eric Pouech
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  20  */
  21
  22 #include "dbghelp_private.h"
  23
  24 /* Copyright (C) 1986 Gary S. Brown
  25  * Modified by Robert Shearman. You may use the following calc_crc32 code or
  26  * tables extracted from it, as desired without restriction. */
  27
  28 /**********************************************************************\
  29 |* Demonstration program to compute the 32-bit CRC used as the frame  *|
  30 |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71     *|
  31 |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level     *|
  32 |* protocol).  The 32-bit FCS was added via the Federal Register,     *|
  33 |* 1 June 1982, p.23798.  I presume but don't know for certain that   *|
  34 |* this polynomial is or will be included in CCITT V.41, which        *|
  35 |* defines the 16-bit CRC (often called CRC-CCITT) polynomial.  FIPS  *|
  36 |* PUB 78 says that the 32-bit FCS reduces otherwise undetected       *|
  37 |* errors by a factor of 10^-5 over 16-bit FCS.                       *|
  38 \**********************************************************************/
  39
  40 /* First, the polynomial itself and its table of feedback terms.  The  */
  41 /* polynomial is                                                       */
  42 /* 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 */
  43 /* Note that we take it "backwards" and put the highest-order term in  */
  44 /* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
  45 /* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
  46 /* the MSB being 1.                                                    */
  47
  48 /* Note that the usual hardware shift register implementation, which   */
  49 /* is what we're using (we're merely optimizing it by doing eight-bit  */
  50 /* chunks at a time) shifts bits into the lowest-order term.  In our   */
  51 /* implementation, that means shifting towards the right.  Why do we   */
  52 /* do it this way?  Because the calculated CRC must be transmitted in  */
  53 /* order from highest-order term to lowest-order term.  UARTs transmit */
  54 /* characters in order from LSB to MSB.  By storing the CRC this way,  */
  55 /* we hand it to the UART in the order low-byte to high-byte; the UART */
  56 /* sends each low-bit to hight-bit; and the result is transmission bit */
  57 /* by bit from highest- to lowest-order term without requiring any bit */
  58 /* shuffling on our part.  Reception works similarly.                  */
  59
  60 /* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
  61 /*                                                                     */
  62 /*  1. The table can be generated at runtime if desired; code to do so */
  63 /*     is shown later.  It might not be obvious, but the feedback      */
  64 /*     terms simply represent the results of eight shift/xor opera-    */
  65 /*     tions for all combinations of data and CRC register values.     */
  66 /*                                                                     */
  67 /*  2. The CRC accumulation logic is the same for all CRC polynomials, */
  68 /*     be they sixteen or thirty-two bits wide.  You simply choose the */
  69 /*     appropriate table.  Alternatively, because the table can be     */
  70 /*     generated at runtime, you can start by generating the table for */
  71 /*     the polynomial in question and use exactly the same "updcrc",   */
  72 /*     if your application needn't simultaneously handle two CRC       */
  73 /*     polynomials.  (Note, however, that XMODEM is strange.)          */
  74 /*                                                                     */
  75 /*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
  76 /*     of course, 32-bit entries work OK if the high 16 bits are zero. */
  77 /*                                                                     */
  78 /*  4. The values must be right-shifted by eight bits by the "updcrc"  */
  79 /*     logic; the shift must be unsigned (bring in zeroes).  On some   */
  80 /*     hardware you could probably optimize the shift in assembler by  */
  81 /*     using byte-swap instructions.                                   */
  82
  83
  84 DWORD calc_crc32(int fd)
  85 {
  86 #define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
  87     static const DWORD crc_32_tab[] =
  88     { /* CRC polynomial 0xedb88320 */
  89         0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
  90         0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
  91         0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
  92         0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  93         0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
  94         0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
  95         0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
  96         0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  97         0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
  98         0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  99         0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
 100         0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
 101         0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
 102         0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
 103         0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
 104         0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
 105         0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
 106         0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
 107         0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
 108         0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
 109         0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
 110         0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
 111         0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
 112         0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
 113         0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
 114         0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
 115         0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
 116         0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
 117         0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
 118         0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
 119         0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
 120         0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
 121         0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
 122         0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
 123         0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
 124         0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
 125         0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
 126         0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
 127         0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
 128         0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
 129         0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
 130         0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
 131         0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
 132     };
 133     int                 i, r;
 134     unsigned char       buffer[8192];
 135     DWORD               crc = ~0;
 136
 137     lseek(fd, 0, SEEK_SET);
 138     while ((r = read(fd, buffer, sizeof(buffer))) > 0)
 139     {
 140         for (i = 0; i < r; i++) crc = UPDC32(buffer[i], crc);
 141     }
 142     return ~crc;
 143 #undef UPDC32
 144 }