1 | #ifndef HASH_HPP |
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2 | #define HASH_HPP |
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3 | |
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4 | /*============================================================================= |
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5 | hash.hpp - Hash Utilities. |
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6 | Created on: 18-December-2011 |
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7 | Author: Ken Herdy |
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8 | =============================================================================*/ |
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9 | |
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10 | // #define HASH_HPP_DEBUG |
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11 | |
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12 | //#define NDEBUG // if NDEBUG then disable assertions |
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13 | |
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14 | #include "bitblock.hpp" |
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15 | #include <cassert> |
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16 | #include <stdint.h> |
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17 | #include <iostream> |
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18 | |
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19 | /////////////////////////////////////////////////////////////////////////////// |
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20 | // |
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21 | // WARNING: Pad or Perish |
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22 | // |
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23 | // 'bit_slice' and 'byte_slice' slice forward via a static cast to the |
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24 | // uint64_t type at the position of the base address + bit_idx |
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25 | // and require up to sizeof(uint64_t) bytes of additional padding. |
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26 | // |
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27 | /////////////////////////////////////////////////////////////////////////////// |
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28 | |
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29 | static int32_t bytes2bits(int32_t bytes) { return bytes * 8; } |
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30 | static int32_t bits2bytes(int32_t bits) /*{ return (bits + 8) / (8); } */ { return (((bits & (8-1)) != 0) ? (bits + 8) / (8) : (bits/8)); } |
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31 | static IDISA_ALWAYS_INLINE uint64_t gen_mask(const uint32_t mask_bits); |
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32 | |
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33 | //static IDISA_ALWAYS_INLINE uint64_t byte_slice(const uint8_t * base, const int32_t byte_idx, const uint32_t slice_bytes); |
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34 | //static IDISA_ALWAYS_INLINE uint64_t byte_compress_hash(const uint8_t * h0, const uint8_t * h1, const int32_t byte_idx, const uint32_t slice_bytes, const uint32_t hash_bytes); |
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35 | |
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36 | static IDISA_ALWAYS_INLINE uint64_t bit_slice(const uint8_t * base, const int32_t bit_idx, const uint32_t slice_bits); |
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37 | static IDISA_ALWAYS_INLINE uint64_t bit_compress_hash(const uint8_t * h0, const uint8_t * h1, const int32_t bit_idx, const uint32_t slice_bits, const uint32_t hash_bits); |
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38 | |
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39 | /////////////////////////////////////////////////////////////////////////////// |
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40 | |
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41 | static IDISA_ALWAYS_INLINE uint64_t gen_mask(const uint32_t mask_bits) { |
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42 | assert(mask_bits >= 0); |
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43 | |
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44 | const uint64_t ONE = 1; |
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45 | uint64_t mask = (ONE << mask_bits) - ONE; |
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46 | #ifdef HASH_HPP_DEBUG |
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47 | print_register<uint64_t>("mask", mask); |
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48 | #endif |
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49 | return mask; |
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50 | } |
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51 | |
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52 | //static IDISA_ALWAYS_INLINE uint64_t byte_slice(const uint8_t * base, const int32_t byte_idx, const uint32_t slice_bytes) { |
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53 | // assert(slice_bytes >= 0 && slice_bytes <= sizeof(uint64_t)); |
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54 | // assert(byte_idx >= 0); |
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55 | |
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56 | // uint64_t shift = *((uint64_t *)(base + byte_idx)); |
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57 | // uint64_t mask = gen_mask(bytes2bits(slice_bytes)); |
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58 | // uint64_t r = shift & mask; |
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59 | |
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60 | //#ifdef HASH_HPP_DEBUG |
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61 | // print_register<BitBlock>("base", *(BitBlock *)base); |
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62 | // std::cout << "byte index:" << byte_idx << std::endl; |
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63 | // print_register<BitBlock>("shift", *(BitBlock *)&shift); |
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64 | // print_register<uint64_t>("mask", mask); |
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65 | // print_register<uint64_t>("r", r); |
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66 | //#endif |
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67 | |
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68 | // return r; |
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69 | //} |
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70 | |
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71 | static IDISA_ALWAYS_INLINE uint64_t bit_slice(const uint8_t * base, const int32_t bit_idx, const uint32_t slice_bits) { |
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72 | assert(slice_bits >= 0 && slice_bits <= bytes2bits(sizeof(uint64_t))); |
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73 | assert(bit_idx >= 0); |
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74 | |
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75 | uint64_t shift = *((uint64_t *)(base + (bit_idx/8))) >> (bit_idx & (8-1)); |
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76 | uint64_t mask = gen_mask(slice_bits); |
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77 | uint64_t r = shift & mask; |
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78 | |
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79 | #ifdef HASH_HPP_DEBUG |
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80 | print_register<uint64_t>("base", *(uint64_t *)base); |
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81 | std::cout << " bit index = " << bit_idx << std::endl; |
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82 | print_register<uint64_t>("shift", *(uint64_t *)&shift); |
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83 | print_register<uint64_t>("mask", mask); |
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84 | print_register<uint64_t>("r", r); |
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85 | #endif |
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86 | |
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87 | return r; |
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88 | } |
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89 | |
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90 | static IDISA_ALWAYS_INLINE uint64_t bit_compress_hash(const uint8_t * h0, const uint8_t * h1, const int32_t bit_idx, const uint32_t slice_bits, const uint32_t hash_bits) { |
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91 | |
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92 | assert(hash_bits > 0 && hash_bits <= 64); |
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93 | assert(slice_bits >= hash_bits); |
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94 | |
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95 | uint64_t x0 = bit_slice(h0,bit_idx,hash_bits); |
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96 | uint64_t x1 = bit_slice(h1,bit_idx+slice_bits-hash_bits,hash_bits); |
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97 | |
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98 | //assert(x0 != x1); |
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99 | uint64_t mask = gen_mask(slice_bits); |
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100 | uint64_t r = x0 ^ x1; |
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101 | |
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102 | #ifdef HASH_HPP_DEBUG |
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103 | print_register<uint64_t>("h0", *(uint64_t *)(h0)); |
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104 | print_register<uint64_t>("h1", *(uint64_t *)(h1)); |
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105 | print_register<uint64_t>("x0", x0); |
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106 | print_register<uint64_t>("x1", x1); |
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107 | print_register<uint64_t>("r", r); |
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108 | #endif |
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109 | |
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110 | return r & mask; |
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111 | } |
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112 | |
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113 | #endif // HASH_HPP |
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114 | |
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115 | /* |
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116 | static IDISA_ALWAYS_INLINE uint64_t bit_expand_hash(const uint8_t * base, const uint8_t * base1, const int32_t offset, const uint32_t slice_size, const uint32_t hash_size); |
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117 | static IDISA_ALWAYS_INLINE uint64_t bit_expand_hash(const uint8_t * base, const uint8_t * base1, const int32_t offset, const uint32_t slice_size, const uint32_t hash_size) { |
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118 | assert(slice_size > 0 && slice_size <= 64); |
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119 | //assert(slice_size <= hash_size); |
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120 | |
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121 | uint64_t x0 = bit_slice(base,offset,slice_size); |
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122 | uint64_t x1 = bit_slice(base1,offset,slice_size); |
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123 | uint64_t mask = gen_mask(hash_size); |
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124 | |
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125 | assert(x0 != x1); |
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126 | |
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127 | uint64_t t = x0 ^ x1; |
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128 | uint64_t r = t; |
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129 | int32_t shift = slice_size; |
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130 | |
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131 | print_register<uint64_t>("t", t); |
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132 | print_register<uint64_t>("r", r); |
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133 | |
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134 | while(shift > 0) { |
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135 | |
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136 | #ifndef NDEBUG |
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137 | std::cout << "Stream offset (bit): " << offset << std::endl; |
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138 | std::cout << "Symbol lgth (bits): " << slice_size << std::endl; |
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139 | std::cout << "Hash size (bits): " << hash_size << std::endl; |
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140 | std::cout << "Shift (bits): " << shift << std::endl; |
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141 | |
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142 | print_register<uint64_t>("base", *(uint64_t *)base); |
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143 | print_register<uint64_t>("base1", *(uint64_t *)base1); |
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144 | print_register<uint64_t>("x0", x0); |
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145 | print_register<uint64_t>("x1", x1); |
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146 | print_register<uint64_t>("r", r); |
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147 | #endif |
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148 | r = r | (r << (uint32_t)shift); |
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149 | shift -= slice_size; |
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150 | print_register<uint64_t>("r", r); |
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151 | } |
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152 | |
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153 | return r & mask; |
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154 | } |
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155 | */ |
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