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