1 /* 7zCrcOpt.c -- CRC32 calculation
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2 2015-03-01 : Igor Pavlov : Public domain */
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10 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
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12 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
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14 const Byte *p = (const Byte *)data;
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15 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
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16 v = CRC_UPDATE_BYTE_2(v, *p);
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17 for (; size >= 4; size -= 4, p += 4)
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19 v ^= *(const UInt32 *)p;
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21 table[0x300 + ((v ) & 0xFF)]
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22 ^ table[0x200 + ((v >> 8) & 0xFF)]
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23 ^ table[0x100 + ((v >> 16) & 0xFF)]
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24 ^ table[0x000 + ((v >> 24))];
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26 for (; size > 0; size--, p++)
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27 v = CRC_UPDATE_BYTE_2(v, *p);
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31 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
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33 const Byte *p = (const Byte *)data;
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34 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
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35 v = CRC_UPDATE_BYTE_2(v, *p);
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36 for (; size >= 8; size -= 8, p += 8)
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39 v ^= *(const UInt32 *)p;
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41 table[0x700 + ((v ) & 0xFF)]
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42 ^ table[0x600 + ((v >> 8) & 0xFF)]
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43 ^ table[0x500 + ((v >> 16) & 0xFF)]
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44 ^ table[0x400 + ((v >> 24))];
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45 d = *((const UInt32 *)p + 1);
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47 table[0x300 + ((d ) & 0xFF)]
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48 ^ table[0x200 + ((d >> 8) & 0xFF)]
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49 ^ table[0x100 + ((d >> 16) & 0xFF)]
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50 ^ table[0x000 + ((d >> 24))];
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52 for (; size > 0; size--, p++)
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53 v = CRC_UPDATE_BYTE_2(v, *p);
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62 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
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64 #define CRC_UPDATE_BYTE_2_BE(crc, b) (table[(((crc) >> 24) ^ (b))] ^ ((crc) << 8))
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66 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
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68 const Byte *p = (const Byte *)data;
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70 v = CRC_UINT32_SWAP(v);
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71 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
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72 v = CRC_UPDATE_BYTE_2_BE(v, *p);
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73 for (; size >= 4; size -= 4, p += 4)
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75 v ^= *(const UInt32 *)p;
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77 table[0x000 + ((v ) & 0xFF)]
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78 ^ table[0x100 + ((v >> 8) & 0xFF)]
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79 ^ table[0x200 + ((v >> 16) & 0xFF)]
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80 ^ table[0x300 + ((v >> 24))];
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82 for (; size > 0; size--, p++)
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83 v = CRC_UPDATE_BYTE_2_BE(v, *p);
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84 return CRC_UINT32_SWAP(v);
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87 UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
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89 const Byte *p = (const Byte *)data;
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91 v = CRC_UINT32_SWAP(v);
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92 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
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93 v = CRC_UPDATE_BYTE_2_BE(v, *p);
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94 for (; size >= 8; size -= 8, p += 8)
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97 v ^= *(const UInt32 *)p;
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99 table[0x400 + ((v ) & 0xFF)]
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100 ^ table[0x500 + ((v >> 8) & 0xFF)]
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101 ^ table[0x600 + ((v >> 16) & 0xFF)]
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102 ^ table[0x700 + ((v >> 24))];
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103 d = *((const UInt32 *)p + 1);
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105 table[0x000 + ((d ) & 0xFF)]
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106 ^ table[0x100 + ((d >> 8) & 0xFF)]
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107 ^ table[0x200 + ((d >> 16) & 0xFF)]
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108 ^ table[0x300 + ((d >> 24))];
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110 for (; size > 0; size--, p++)
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111 v = CRC_UPDATE_BYTE_2_BE(v, *p);
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112 return CRC_UINT32_SWAP(v);
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