| 1 | /* zlib-adler32.js -- JavaScript implementation for the zlib crc32. |
| 2 | Version: 0.2.0 |
| 3 | LastModified: Apr 12 2012 |
| 4 | Copyright (C) 2012 Masanao Izumo <iz@onicos.co.jp> |
| 5 | |
| 6 | API documentation |
| 7 | ============================================================================== |
| 8 | Usage: crc = ZLIB.crc32(crc, buf, offset, len); |
| 9 | |
| 10 | Update a running CRC-32 with the bytes buf[offset..offset+len-1] and return the |
| 11 | updated CRC-32. If buf is null, this function returns the required |
| 12 | initial value for the for the crc. Pre- and post-conditioning (one's |
| 13 | complement) is performed within this function so it shouldn't be done by the |
| 14 | application. |
| 15 | |
| 16 | Usage example: |
| 17 | |
| 18 | var crc = ZLIB.crc32(0, null, 0, 0); |
| 19 | |
| 20 | while (read_buffer(buffer, length) != EOF) { |
| 21 | crc = ZLIB.crc32(crc, buffer, 0, length); |
| 22 | } |
| 23 | if (crc != original_crc) error(); |
| 24 | |
| 25 | ============================================================================== |
| 26 | Usage: crc = crc32_combine(crc1, crc2, len2); |
| 27 | |
| 28 | Combine two CRC-32 check values into one. For two sequences of bytes, |
| 29 | seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
| 30 | calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
| 31 | check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and |
| 32 | len2. |
| 33 | */ |
| 34 | |
| 35 | if( typeof ZLIB === 'undefined' ) { |
| 36 | alert('ZLIB is not defined. SRC zlib.js before zlib-crc32.js') |
| 37 | } |
| 38 | |
| 39 | (function() { |
| 40 | |
| 41 | /* crc32.c -- compute the CRC-32 of a data stream |
| 42 | * Copyright (C) 1995-2006, 2010, 2011 Mark Adler |
| 43 | * For conditions of distribution and use, see copyright notice in zlib.h |
| 44 | * |
| 45 | * Thanks to Rodney Brown <rbrown64@csc.com.au> for his contribution of faster |
| 46 | * CRC methods: exclusive-oring 32 bits of data at a time, and pre-computing |
| 47 | * tables for updating the shift register in one step with three exclusive-ors |
| 48 | * instead of four steps with four exclusive-ors. This results in about a |
| 49 | * factor of two increase in speed on a Power PC G4 (PPC7455) using gcc -O3. |
| 50 | */ |
| 51 | |
| 52 | var crc_table = [ |
| 53 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, |
| 54 | 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, |
| 55 | 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, |
| 56 | 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, |
| 57 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, |
| 58 | 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, |
| 59 | 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, |
| 60 | 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, |
| 61 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, |
| 62 | 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, |
| 63 | 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, |
| 64 | 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, |
| 65 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, |
| 66 | 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, |
| 67 | 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, |
| 68 | 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, |
| 69 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, |
| 70 | 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, |
| 71 | 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, |
| 72 | 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, |
| 73 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, |
| 74 | 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, |
| 75 | 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, |
| 76 | 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, |
| 77 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, |
| 78 | 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, |
| 79 | 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, |
| 80 | 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, |
| 81 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, |
| 82 | 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, |
| 83 | 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, |
| 84 | 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, |
| 85 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, |
| 86 | 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, |
| 87 | 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, |
| 88 | 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, |
| 89 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, |
| 90 | 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, |
| 91 | 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, |
| 92 | 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, |
| 93 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, |
| 94 | 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, |
| 95 | 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, |
| 96 | 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, |
| 97 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, |
| 98 | 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, |
| 99 | 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, |
| 100 | 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, |
| 101 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, |
| 102 | 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, |
| 103 | 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, |
| 104 | 0x2d02ef8d ]; |
| 105 | |
| 106 | /* ========================================================================= */ |
| 107 | function crc32_string(crc, buf, offset, len) |
| 108 | { |
| 109 | if (buf == null) return 0; |
| 110 | |
| 111 | crc = crc ^ 0xffffffff; |
| 112 | while (len >= 8) { |
| 113 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 114 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 115 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 116 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 117 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 118 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 119 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 120 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 121 | len -= 8; |
| 122 | } |
| 123 | if (len) do { |
| 124 | crc = crc_table[(crc ^ buf.charCodeAt(offset++)) & 0xff] ^ (crc >>> 8) |
| 125 | } while (--len); |
| 126 | return crc ^ 0xffffffff; |
| 127 | } |
| 128 | |
| 129 | /* ========================================================================= */ |
| 130 | function crc32_array(crc, buf, offset, len) |
| 131 | { |
| 132 | if (buf == null) return 0; |
| 133 | |
| 134 | crc = crc ^ 0xffffffff; |
| 135 | while (len >= 8) { |
| 136 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 137 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 138 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 139 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 140 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 141 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 142 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 143 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 144 | len -= 8; |
| 145 | } |
| 146 | if (len) do { |
| 147 | crc = crc_table[(crc ^ buf[offset++]) & 0xff] ^ (crc >>> 8) |
| 148 | } while (--len); |
| 149 | return crc ^ 0xffffffff; |
| 150 | } |
| 151 | |
| 152 | /* ========================================================================= */ |
| 153 | ZLIB.crc32 = function(crc, buf, offset, len) |
| 154 | { |
| 155 | if(typeof buf === 'string') { |
| 156 | return crc32_string(crc, buf, offset, len); |
| 157 | } else { |
| 158 | return crc32_array(crc, buf, offset, len); |
| 159 | } |
| 160 | }; |
| 161 | |
| 162 | /* ========================================================================= */ |
| 163 | var GF2_DIM = 32; /* dimension of GF(2) vectors (length of CRC) */ |
| 164 | |
| 165 | /* ========================================================================= */ |
| 166 | function gf2_matrix_times(mat, vec) |
| 167 | { |
| 168 | var sum; |
| 169 | var mat_i = 0; |
| 170 | |
| 171 | sum = 0; |
| 172 | while (vec) { |
| 173 | if (vec & 1) |
| 174 | sum ^= mat[mat_i]; |
| 175 | vec >>= 1; |
| 176 | mat_i++; |
| 177 | } |
| 178 | return sum; |
| 179 | } |
| 180 | |
| 181 | /* ========================================================================= */ |
| 182 | function gf2_matrix_square(square, mat) |
| 183 | { |
| 184 | var n; |
| 185 | |
| 186 | for (n = 0; n < GF2_DIM; n++) |
| 187 | square[n] = gf2_matrix_times(mat, mat[n]); |
| 188 | } |
| 189 | |
| 190 | /* ========================================================================= */ |
| 191 | ZLIB.crc32_combine = function(crc1, crc2, len2) |
| 192 | { |
| 193 | var n; |
| 194 | var row; |
| 195 | var even; /* even-power-of-two zeros operator */ |
| 196 | var odd; /* odd-power-of-two zeros operator */ |
| 197 | |
| 198 | /* degenerate case (also disallow negative lengths) */ |
| 199 | if (len2 <= 0) |
| 200 | return crc1; |
| 201 | |
| 202 | even = new Array(GF2_DIM); |
| 203 | odd = new Array(GF2_DIM); |
| 204 | |
| 205 | /* put operator for one zero bit in odd */ |
| 206 | odd[0] = 0xedb88320; /* CRC-32 polynomial */ |
| 207 | row = 1; |
| 208 | for (n = 1; n < GF2_DIM; n++) { |
| 209 | odd[n] = row; |
| 210 | row <<= 1; |
| 211 | } |
| 212 | |
| 213 | /* put operator for two zero bits in even */ |
| 214 | gf2_matrix_square(even, odd); |
| 215 | |
| 216 | /* put operator for four zero bits in odd */ |
| 217 | gf2_matrix_square(odd, even); |
| 218 | |
| 219 | /* apply len2 zeros to crc1 (first square will put the operator for one |
| 220 | zero byte, eight zero bits, in even) */ |
| 221 | do { |
| 222 | /* apply zeros operator for this bit of len2 */ |
| 223 | gf2_matrix_square(even, odd); |
| 224 | if (len2 & 1) |
| 225 | crc1 = gf2_matrix_times(even, crc1); |
| 226 | len2 >>= 1; |
| 227 | |
| 228 | /* if no more bits set, then done */ |
| 229 | if (len2 == 0) |
| 230 | break; |
| 231 | |
| 232 | /* another iteration of the loop with odd and even swapped */ |
| 233 | gf2_matrix_square(odd, even); |
| 234 | if (len2 & 1) |
| 235 | crc1 = gf2_matrix_times(odd, crc1); |
| 236 | len2 >>= 1; |
| 237 | |
| 238 | /* if no more bits set, then done */ |
| 239 | } while (len2 != 0); |
| 240 | |
| 241 | /* return combined crc */ |
| 242 | crc1 ^= crc2; |
| 243 | return crc1; |
| 244 | }; |
| 245 | |
| 246 | }()); |