3d99b69296c7e4504126b175a58176581ff57f08
[openwrt/openwrt.git] / tools / mkimage / src / crc32.c
1 /*
2 * This file is derived from crc32.c from the zlib-1.1.3 distribution
3 * by Jean-loup Gailly and Mark Adler.
4 */
5
6 /* crc32.c -- compute the CRC-32 of a data stream
7 * Copyright (C) 1995-1998 Mark Adler
8 * For conditions of distribution and use, see copyright notice in zlib.h
9 */
10
11 #ifndef USE_HOSTCC /* Shut down "ANSI does not permit..." warnings */
12 #include <common.h> /* to get command definitions like CFG_CMD_JFFS2 */
13 #endif
14
15 #include "zlib.h"
16
17 #define local static
18 #define ZEXPORT /* empty */
19 unsigned long crc32 (unsigned long, const unsigned char *, unsigned int);
20
21 #ifdef DYNAMIC_CRC_TABLE
22
23 local int crc_table_empty = 1;
24 local uLongf crc_table[256];
25 local void make_crc_table OF((void));
26
27 /*
28 Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
29 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.
30
31 Polynomials over GF(2) are represented in binary, one bit per coefficient,
32 with the lowest powers in the most significant bit. Then adding polynomials
33 is just exclusive-or, and multiplying a polynomial by x is a right shift by
34 one. If we call the above polynomial p, and represent a byte as the
35 polynomial q, also with the lowest power in the most significant bit (so the
36 byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
37 where a mod b means the remainder after dividing a by b.
38
39 This calculation is done using the shift-register method of multiplying and
40 taking the remainder. The register is initialized to zero, and for each
41 incoming bit, x^32 is added mod p to the register if the bit is a one (where
42 x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
43 x (which is shifting right by one and adding x^32 mod p if the bit shifted
44 out is a one). We start with the highest power (least significant bit) of
45 q and repeat for all eight bits of q.
46
47 The table is simply the CRC of all possible eight bit values. This is all
48 the information needed to generate CRC's on data a byte at a time for all
49 combinations of CRC register values and incoming bytes.
50 */
51 local void make_crc_table()
52 {
53 uLong c;
54 int n, k;
55 uLong poly; /* polynomial exclusive-or pattern */
56 /* terms of polynomial defining this crc (except x^32): */
57 static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
58
59 /* make exclusive-or pattern from polynomial (0xedb88320L) */
60 poly = 0L;
61 for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
62 poly |= 1L << (31 - p[n]);
63
64 for (n = 0; n < 256; n++)
65 {
66 c = (uLong)n;
67 for (k = 0; k < 8; k++)
68 c = c & 1 ? poly ^ (c >> 1) : c >> 1;
69 crc_table[n] = c;
70 }
71 crc_table_empty = 0;
72 }
73 #else
74 /* ========================================================================
75 * Table of CRC-32's of all single-byte values (made by make_crc_table)
76 */
77 local const uLongf crc_table[256] = {
78 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
79 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
80 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
81 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
82 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
83 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
84 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
85 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
86 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
87 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
88 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
89 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
90 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
91 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
92 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
93 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
94 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
95 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
96 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
97 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
98 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
99 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
100 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
101 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
102 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
103 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
104 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
105 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
106 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
107 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
108 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
109 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
110 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
111 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
112 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
113 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
114 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
115 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
116 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
117 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
118 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
119 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
120 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
121 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
122 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
123 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
124 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
125 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
126 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
127 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
128 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
129 0x2d02ef8dL
130 };
131 #endif
132
133 #if 0
134 /* =========================================================================
135 * This function can be used by asm versions of crc32()
136 */
137 const uLongf * ZEXPORT get_crc_table()
138 {
139 #ifdef DYNAMIC_CRC_TABLE
140 if (crc_table_empty) make_crc_table();
141 #endif
142 return (const uLongf *)crc_table;
143 }
144 #endif
145
146 /* ========================================================================= */
147 #define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
148 #define DO2(buf) DO1(buf); DO1(buf);
149 #define DO4(buf) DO2(buf); DO2(buf);
150 #define DO8(buf) DO4(buf); DO4(buf);
151
152 /* ========================================================================= */
153 uLong ZEXPORT crc32(crc, buf, len)
154 uLong crc;
155 const Bytef *buf;
156 uInt len;
157 {
158 #ifdef DYNAMIC_CRC_TABLE
159 if (crc_table_empty)
160 make_crc_table();
161 #endif
162 crc = crc ^ 0xffffffffL;
163 while (len >= 8)
164 {
165 DO8(buf);
166 len -= 8;
167 }
168 if (len) do {
169 DO1(buf);
170 } while (--len);
171 return crc ^ 0xffffffffL;
172 }
173
174 #if (CONFIG_COMMANDS & CFG_CMD_JFFS2) || \
175 ((CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY))
176
177 /* No ones complement version. JFFS2 (and other things ?)
178 * don't use ones compliment in their CRC calculations.
179 */
180 uLong ZEXPORT crc32_no_comp(uLong crc, const Bytef *buf, uInt len)
181 {
182 #ifdef DYNAMIC_CRC_TABLE
183 if (crc_table_empty)
184 make_crc_table();
185 #endif
186 while (len >= 8)
187 {
188 DO8(buf);
189 len -= 8;
190 }
191 if (len) do {
192 DO1(buf);
193 } while (--len);
194
195 return crc;
196 }
197
198 #endif /* CFG_CMD_JFFS2 */