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[reactos.git] / 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 "config.h"
23 #include "wine/port.h"
24
25 #include <stdio.h>
26
27 #include "dbghelp_private.h"
28
29 /* Copyright (C) 1986 Gary S. Brown. Modified by Robert Shearman. You may use
30 the following calc_crc32 code or tables extracted from it, as desired without
31 restriction. */
32
33 /**********************************************************************\
34 |* Demonstration program to compute the 32-bit CRC used as the frame *|
35 |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71 *|
36 |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level *|
37 |* protocol). The 32-bit FCS was added via the Federal Register, *|
38 |* 1 June 1982, p.23798. I presume but don't know for certain that *|
39 |* this polynomial is or will be included in CCITT V.41, which *|
40 |* defines the 16-bit CRC (often called CRC-CCITT) polynomial. FIPS *|
41 |* PUB 78 says that the 32-bit FCS reduces otherwise undetected *|
42 |* errors by a factor of 10^-5 over 16-bit FCS. *|
43 \**********************************************************************/
44
45 /* First, the polynomial itself and its table of feedback terms. The */
46 /* polynomial is */
47 /* 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 */
48 /* Note that we take it "backwards" and put the highest-order term in */
49 /* the lowest-order bit. The X^32 term is "implied"; the LSB is the */
50 /* X^31 term, etc. The X^0 term (usually shown as "+1") results in */
51 /* the MSB being 1. */
52
53 /* Note that the usual hardware shift register implementation, which */
54 /* is what we're using (we're merely optimizing it by doing eight-bit */
55 /* chunks at a time) shifts bits into the lowest-order term. In our */
56 /* implementation, that means shifting towards the right. Why do we */
57 /* do it this way? Because the calculated CRC must be transmitted in */
58 /* order from highest-order term to lowest-order term. UARTs transmit */
59 /* characters in order from LSB to MSB. By storing the CRC this way, */
60 /* we hand it to the UART in the order low-byte to high-byte; the UART */
61 /* sends each low-bit to hight-bit; and the result is transmission bit */
62 /* by bit from highest- to lowest-order term without requiring any bit */
63 /* shuffling on our part. Reception works similarly. */
64
65 /* The feedback terms table consists of 256, 32-bit entries. Notes: */
66 /* */
67 /* 1. The table can be generated at runtime if desired; code to do so */
68 /* is shown later. It might not be obvious, but the feedback */
69 /* terms simply represent the results of eight shift/xor opera- */
70 /* tions for all combinations of data and CRC register values. */
71 /* */
72 /* 2. The CRC accumulation logic is the same for all CRC polynomials, */
73 /* be they sixteen or thirty-two bits wide. You simply choose the */
74 /* appropriate table. Alternatively, because the table can be */
75 /* generated at runtime, you can start by generating the table for */
76 /* the polynomial in question and use exactly the same "updcrc", */
77 /* if your application needn't simultaneously handle two CRC */
78 /* polynomials. (Note, however, that XMODEM is strange.) */
79 /* */
80 /* 3. For 16-bit CRCs, the table entries need be only 16 bits wide; */
81 /* of course, 32-bit entries work OK if the high 16 bits are zero. */
82 /* */
83 /* 4. The values must be right-shifted by eight bits by the "updcrc" */
84 /* logic; the shift must be unsigned (bring in zeroes). On some */
85 /* hardware you could probably optimize the shift in assembler by */
86 /* using byte-swap instructions. */
87
88
89 DWORD calc_crc32(int fd)
90 {
91 #define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
92 static const DWORD crc_32_tab[] =
93 { /* CRC polynomial 0xedb88320 */
94 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
95 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
96 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
97 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
98 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
99 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
100 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
101 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
102 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
103 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
104 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
105 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
106 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
107 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
108 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
109 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
110 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
111 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
112 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
113 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
114 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
115 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
116 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
117 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
118 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
119 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
120 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
121 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
122 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
123 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
124 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
125 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
126 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
127 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
128 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
129 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
130 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
131 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
132 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
133 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
134 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
135 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
136 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
137 };
138 int i, r;
139 unsigned char buffer[8192];
140 DWORD crc = ~0;
141
142 _lseek(fd, 0, SEEK_SET);
143 while ((r = _read(fd, buffer, sizeof(buffer))) > 0)
144 {
145 for (i = 0; i < r; i++) crc = UPDC32(buffer[i], crc);
146 }
147 return ~crc;
148 #undef UPDC32
149 }