1 | /* |
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2 | ------------------------------------------------------------------------------- |
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3 | lookup3.c, by Bob Jenkins, May 2006, Public Domain. |
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4 | Original: http://burtleburtle.net/bob/c/lookup3.c |
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5 | Modified by Russ Rew for adaption in netCDF. |
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6 | - Make use of Paul Hsieh's pstdint.h, if stdint.h not available. |
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7 | - Declare unused functions static to keep global namespace clean. |
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8 | - Provide function hash_fast() that uses either hashlittle() or |
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9 | hashbig(), depending on endianness. |
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10 | - Because portability is more important than speed for netCDF use, |
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11 | we define VALGRIND to skip "#ifndef VALGRIND" code, so reads of |
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12 | strings don't access extra bytes after end of string. This may |
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13 | slow it down enough to justify a simpler hash, but blame me, not |
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14 | original author! |
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15 | |
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16 | These are functions for producing 32-bit hashes for hash table lookup. |
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17 | hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() |
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18 | are externally useful functions. Routines to test the hash are included |
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19 | if SELF_TEST is defined. You can use this free for any purpose. It's in |
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20 | the public domain. It has no warranty. |
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21 | |
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22 | You probably want to use hashlittle(). hashlittle() and hashbig() |
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23 | hash byte arrays. hashlittle() is is faster than hashbig() on |
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24 | little-endian machines. Intel and AMD are little-endian machines. |
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25 | On second thought, you probably want hashlittle2(), which is identical to |
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26 | hashlittle() except it returns two 32-bit hashes for the price of one. |
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27 | You could implement hashbig2() if you wanted but I haven't bothered here. |
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28 | |
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29 | If you want to find a hash of, say, exactly 7 integers, do |
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30 | a = i1; b = i2; c = i3; |
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31 | mix(a,b,c); |
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32 | a += i4; b += i5; c += i6; |
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33 | mix(a,b,c); |
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34 | a += i7; |
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35 | final(a,b,c); |
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36 | then use c as the hash value. If you have a variable length array of |
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37 | 4-byte integers to hash, use hashword(). If you have a byte array (like |
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38 | a character string), use hashlittle(). If you have several byte arrays, or |
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39 | a mix of things, see the comments above hashlittle(). |
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40 | |
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41 | Why is this so big? I read 12 bytes at a time into 3 4-byte integers, |
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42 | then mix those integers. This is fast (you can do a lot more thorough |
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43 | mixing with 12*3 instructions on 3 integers than you can with 3 instructions |
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44 | on 1 byte), but shoehorning those bytes into integers efficiently is messy. |
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45 | ------------------------------------------------------------------------------- |
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46 | */ |
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47 | /* #define SELF_TEST 1 */ |
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48 | |
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49 | #include <config.h> |
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50 | #include <stdio.h> /* defines printf for tests */ |
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51 | #include <time.h> /* defines time_t for timings in the test */ |
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52 | #ifndef HAVE_STDINT_H |
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53 | # include "pstdint.h" /* attempts to define uint32_t etc portably */ |
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54 | #else |
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55 | # include <stdint.h> |
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56 | #endif /* HAVE_STDINT_H */ |
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57 | #ifdef HAVE_SYS_PARAM_H |
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58 | #include <sys/param.h> /* attempt to define endianness */ |
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59 | #endif /* HAVE_SYS_PARAM_H */ |
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60 | #ifdef linux |
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61 | # include <endian.h> /* attempt to define endianness */ |
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62 | #endif |
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63 | |
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64 | #define VALGRIND /* added by Russ Rew, for portability over speed */ |
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65 | |
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66 | #ifndef WORDS_BIGENDIAN /* from config.h */ |
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67 | #define HASH_LITTLE_ENDIAN 1 |
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68 | #define HASH_BIG_ENDIAN 0 |
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69 | #else |
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70 | #define HASH_LITTLE_ENDIAN 0 |
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71 | #define HASH_BIG_ENDIAN 1 |
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72 | #endif |
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73 | |
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74 | #define hashsize(n) ((uint32_t)1<<(n)) |
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75 | #define hashmask(n) (hashsize(n)-1) |
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76 | #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) |
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77 | |
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78 | /* |
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79 | ------------------------------------------------------------------------------- |
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80 | mix -- mix 3 32-bit values reversibly. |
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81 | |
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82 | This is reversible, so any information in (a,b,c) before mix() is |
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83 | still in (a,b,c) after mix(). |
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84 | |
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85 | If four pairs of (a,b,c) inputs are run through mix(), or through |
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86 | mix() in reverse, there are at least 32 bits of the output that |
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87 | are sometimes the same for one pair and different for another pair. |
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88 | This was tested for: |
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89 | * pairs that differed by one bit, by two bits, in any combination |
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90 | of top bits of (a,b,c), or in any combination of bottom bits of |
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91 | (a,b,c). |
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92 | * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed |
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93 | the output delta to a Gray code (a^(a>>1)) so a string of 1's (as |
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94 | is commonly produced by subtraction) look like a single 1-bit |
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95 | difference. |
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96 | * the base values were pseudorandom, all zero but one bit set, or |
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97 | all zero plus a counter that starts at zero. |
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98 | |
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99 | Some k values for my "a-=c; a^=rot(c,k); c+=b;" arrangement that |
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100 | satisfy this are |
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101 | 4 6 8 16 19 4 |
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102 | 9 15 3 18 27 15 |
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103 | 14 9 3 7 17 3 |
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104 | Well, "9 15 3 18 27 15" didn't quite get 32 bits diffing |
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105 | for "differ" defined as + with a one-bit base and a two-bit delta. I |
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106 | used http://burtleburtle.net/bob/hash/avalanche.html to choose |
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107 | the operations, constants, and arrangements of the variables. |
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108 | |
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109 | This does not achieve avalanche. There are input bits of (a,b,c) |
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110 | that fail to affect some output bits of (a,b,c), especially of a. The |
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111 | most thoroughly mixed value is c, but it doesn't really even achieve |
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112 | avalanche in c. |
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113 | |
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114 | This allows some parallelism. Read-after-writes are good at doubling |
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115 | the number of bits affected, so the goal of mixing pulls in the opposite |
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116 | direction as the goal of parallelism. I did what I could. Rotates |
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117 | seem to cost as much as shifts on every machine I could lay my hands |
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118 | on, and rotates are much kinder to the top and bottom bits, so I used |
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119 | rotates. |
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120 | ------------------------------------------------------------------------------- |
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121 | */ |
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122 | #define mix(a,b,c) \ |
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123 | { \ |
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124 | a -= c; a ^= rot(c, 4); c += b; \ |
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125 | b -= a; b ^= rot(a, 6); a += c; \ |
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126 | c -= b; c ^= rot(b, 8); b += a; \ |
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127 | a -= c; a ^= rot(c,16); c += b; \ |
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128 | b -= a; b ^= rot(a,19); a += c; \ |
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129 | c -= b; c ^= rot(b, 4); b += a; \ |
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130 | } |
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131 | |
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132 | /* |
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133 | ------------------------------------------------------------------------------- |
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134 | final -- final mixing of 3 32-bit values (a,b,c) into c |
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135 | |
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136 | Pairs of (a,b,c) values differing in only a few bits will usually |
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137 | produce values of c that look totally different. This was tested for |
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138 | * pairs that differed by one bit, by two bits, in any combination |
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139 | of top bits of (a,b,c), or in any combination of bottom bits of |
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140 | (a,b,c). |
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141 | * "differ" is defined as +, -, ^, or ~^. For + and -, I transformed |
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142 | the output delta to a Gray code (a^(a>>1)) so a string of 1's (as |
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143 | is commonly produced by subtraction) look like a single 1-bit |
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144 | difference. |
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145 | * the base values were pseudorandom, all zero but one bit set, or |
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146 | all zero plus a counter that starts at zero. |
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147 | |
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148 | These constants passed: |
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149 | 14 11 25 16 4 14 24 |
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150 | 12 14 25 16 4 14 24 |
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151 | and these came close: |
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152 | 4 8 15 26 3 22 24 |
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153 | 10 8 15 26 3 22 24 |
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154 | 11 8 15 26 3 22 24 |
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155 | ------------------------------------------------------------------------------- |
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156 | */ |
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157 | #define final(a,b,c) \ |
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158 | { \ |
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159 | c ^= b; c -= rot(b,14); \ |
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160 | a ^= c; a -= rot(c,11); \ |
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161 | b ^= a; b -= rot(a,25); \ |
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162 | c ^= b; c -= rot(b,16); \ |
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163 | a ^= c; a -= rot(c,4); \ |
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164 | b ^= a; b -= rot(a,14); \ |
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165 | c ^= b; c -= rot(b,24); \ |
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166 | } |
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167 | |
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168 | /* |
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169 | -------------------------------------------------------------------- |
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170 | This works on all machines. To be useful, it requires |
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171 | -- that the key be an array of uint32_t's, and |
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172 | -- that the length be the number of uint32_t's in the key |
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173 | |
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174 | The function hashword() is identical to hashlittle() on little-endian |
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175 | machines, and identical to hashbig() on big-endian machines, |
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176 | except that the length has to be measured in uint32_ts rather than in |
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177 | bytes. hashlittle() is more complicated than hashword() only because |
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178 | hashlittle() has to dance around fitting the key bytes into registers. |
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179 | -------------------------------------------------------------------- |
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180 | */ |
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181 | #ifdef SELF_TEST |
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182 | static |
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183 | uint32_t hashword( |
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184 | const uint32_t *k, /* the key, an array of uint32_t values */ |
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185 | size_t length, /* the length of the key, in uint32_ts */ |
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186 | uint32_t initval) /* the previous hash, or an arbitrary value */ |
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187 | { |
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188 | uint32_t a,b,c; |
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189 | |
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190 | /* Set up the internal state */ |
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191 | a = b = c = 0xdeadbeef + (((uint32_t)length)<<2) + initval; |
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192 | |
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193 | /*------------------------------------------------- handle most of the key */ |
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194 | while (length > 3) |
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195 | { |
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196 | a += k[0]; |
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197 | b += k[1]; |
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198 | c += k[2]; |
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199 | mix(a,b,c); |
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200 | length -= 3; |
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201 | k += 3; |
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202 | } |
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203 | |
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204 | /*------------------------------------------- handle the last 3 uint32_t's */ |
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205 | switch(length) /* all the case statements fall through */ |
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206 | { |
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207 | case 3 : c+=k[2]; |
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208 | case 2 : b+=k[1]; |
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209 | case 1 : a+=k[0]; |
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210 | final(a,b,c); |
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211 | case 0: /* case 0: nothing left to add */ |
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212 | break; |
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213 | } |
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214 | /*------------------------------------------------------ report the result */ |
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215 | return c; |
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216 | } |
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217 | |
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218 | /* |
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219 | -------------------------------------------------------------------- |
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220 | hashword2() -- same as hashword(), but take two seeds and return two |
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221 | 32-bit values. pc and pb must both be nonnull, and *pc and *pb must |
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222 | both be initialized with seeds. If you pass in (*pb)==0, the output |
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223 | (*pc) will be the same as the return value from hashword(). |
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224 | -------------------------------------------------------------------- |
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225 | */ |
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226 | static |
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227 | void hashword2 ( |
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228 | const uint32_t *k, /* the key, an array of uint32_t values */ |
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229 | size_t length, /* the length of the key, in uint32_ts */ |
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230 | uint32_t *pc, /* IN: seed OUT: primary hash value */ |
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231 | uint32_t *pb) /* IN: more seed OUT: secondary hash value */ |
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232 | { |
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233 | uint32_t a,b,c; |
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234 | |
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235 | /* Set up the internal state */ |
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236 | a = b = c = 0xdeadbeef + ((uint32_t)(length<<2)) + *pc; |
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237 | c += *pb; |
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238 | |
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239 | /*------------------------------------------------- handle most of the key */ |
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240 | while (length > 3) |
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241 | { |
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242 | a += k[0]; |
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243 | b += k[1]; |
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244 | c += k[2]; |
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245 | mix(a,b,c); |
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246 | length -= 3; |
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247 | k += 3; |
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248 | } |
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249 | |
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250 | /*------------------------------------------- handle the last 3 uint32_t's */ |
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251 | switch(length) /* all the case statements fall through */ |
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252 | { |
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253 | case 3 : c+=k[2]; |
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254 | case 2 : b+=k[1]; |
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255 | case 1 : a+=k[0]; |
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256 | final(a,b,c); |
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257 | case 0: /* case 0: nothing left to add */ |
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258 | break; |
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259 | } |
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260 | /*------------------------------------------------------ report the result */ |
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261 | *pc=c; *pb=b; |
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262 | } |
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263 | |
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264 | /* |
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265 | * hashlittle2: return 2 32-bit hash values |
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266 | * |
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267 | * This is identical to hashlittle(), except it returns two 32-bit hash |
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268 | * values instead of just one. This is good enough for hash table |
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269 | * lookup with 2^^64 buckets, or if you want a second hash if you're not |
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270 | * happy with the first, or if you want a probably-unique 64-bit ID for |
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271 | * the key. *pc is better mixed than *pb, so use *pc first. If you want |
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272 | * a 64-bit value do something like "*pc + (((uint64_t)*pb)<<32)". |
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273 | */ |
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274 | static void |
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275 | hashlittle2( |
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276 | const void *key, /* the key to hash */ |
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277 | size_t length, /* length of the key */ |
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278 | uint32_t *pc, /* IN: primary initval, OUT: primary hash */ |
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279 | uint32_t *pb) /* IN: secondary initval, OUT: secondary hash */ |
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280 | { |
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281 | uint32_t a,b,c; /* internal state */ |
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282 | union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */ |
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283 | |
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284 | /* Set up the internal state */ |
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285 | a = b = c = 0xdeadbeef + ((uint32_t)length) + *pc; |
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286 | c += *pb; |
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287 | |
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288 | u.ptr = key; |
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289 | if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { |
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290 | const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ |
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291 | const uint8_t *k8; |
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292 | |
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293 | /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ |
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294 | while (length > 12) |
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295 | { |
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296 | a += k[0]; |
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297 | b += k[1]; |
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298 | c += k[2]; |
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299 | mix(a,b,c); |
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300 | length -= 12; |
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301 | k += 3; |
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302 | } |
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303 | |
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304 | /*----------------------------- handle the last (probably partial) block */ |
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305 | /* |
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306 | * "k[2]&0xffffff" actually reads beyond the end of the string, but |
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307 | * then masks off the part it's not allowed to read. Because the |
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308 | * string is aligned, the masked-off tail is in the same word as the |
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309 | * rest of the string. Every machine with memory protection I've seen |
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310 | * does it on word boundaries, so is OK with this. But VALGRIND will |
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311 | * still catch it and complain. The masking trick does make the hash |
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312 | * noticably faster for short strings (like English words). |
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313 | */ |
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314 | #ifndef VALGRIND |
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315 | |
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316 | switch(length) |
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317 | { |
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318 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
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319 | case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break; |
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320 | case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break; |
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321 | case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break; |
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322 | case 8 : b+=k[1]; a+=k[0]; break; |
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323 | case 7 : b+=k[1]&0xffffff; a+=k[0]; break; |
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324 | case 6 : b+=k[1]&0xffff; a+=k[0]; break; |
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325 | case 5 : b+=k[1]&0xff; a+=k[0]; break; |
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326 | case 4 : a+=k[0]; break; |
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327 | case 3 : a+=k[0]&0xffffff; break; |
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328 | case 2 : a+=k[0]&0xffff; break; |
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329 | case 1 : a+=k[0]&0xff; break; |
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330 | case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ |
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331 | } |
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332 | |
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333 | #else /* make valgrind happy */ |
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334 | |
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335 | k8 = (const uint8_t *)k; |
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336 | switch(length) |
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337 | { |
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338 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
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339 | case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ |
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340 | case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ |
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341 | case 9 : c+=k8[8]; /* fall through */ |
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342 | case 8 : b+=k[1]; a+=k[0]; break; |
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343 | case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ |
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344 | case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ |
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345 | case 5 : b+=k8[4]; /* fall through */ |
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346 | case 4 : a+=k[0]; break; |
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347 | case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ |
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348 | case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ |
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349 | case 1 : a+=k8[0]; break; |
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350 | case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ |
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351 | } |
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352 | |
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353 | #endif /* !valgrind */ |
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354 | |
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355 | } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) { |
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356 | const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */ |
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357 | const uint8_t *k8; |
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358 | |
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359 | /*--------------- all but last block: aligned reads and different mixing */ |
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360 | while (length > 12) |
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361 | { |
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362 | a += k[0] + (((uint32_t)k[1])<<16); |
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363 | b += k[2] + (((uint32_t)k[3])<<16); |
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364 | c += k[4] + (((uint32_t)k[5])<<16); |
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365 | mix(a,b,c); |
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366 | length -= 12; |
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367 | k += 6; |
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368 | } |
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369 | |
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370 | /*----------------------------- handle the last (probably partial) block */ |
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371 | k8 = (const uint8_t *)k; |
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372 | switch(length) |
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373 | { |
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374 | case 12: c+=k[4]+(((uint32_t)k[5])<<16); |
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375 | b+=k[2]+(((uint32_t)k[3])<<16); |
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376 | a+=k[0]+(((uint32_t)k[1])<<16); |
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377 | break; |
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378 | case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ |
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379 | case 10: c+=k[4]; |
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380 | b+=k[2]+(((uint32_t)k[3])<<16); |
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381 | a+=k[0]+(((uint32_t)k[1])<<16); |
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382 | break; |
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383 | case 9 : c+=k8[8]; /* fall through */ |
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384 | case 8 : b+=k[2]+(((uint32_t)k[3])<<16); |
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385 | a+=k[0]+(((uint32_t)k[1])<<16); |
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386 | break; |
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387 | case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ |
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388 | case 6 : b+=k[2]; |
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389 | a+=k[0]+(((uint32_t)k[1])<<16); |
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390 | break; |
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391 | case 5 : b+=k8[4]; /* fall through */ |
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392 | case 4 : a+=k[0]+(((uint32_t)k[1])<<16); |
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393 | break; |
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394 | case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ |
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395 | case 2 : a+=k[0]; |
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396 | break; |
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397 | case 1 : a+=k8[0]; |
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398 | break; |
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399 | case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ |
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400 | } |
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401 | |
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402 | } else { /* need to read the key one byte at a time */ |
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403 | const uint8_t *k = (const uint8_t *)key; |
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404 | |
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405 | /*--------------- all but the last block: affect some 32 bits of (a,b,c) */ |
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406 | while (length > 12) |
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407 | { |
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408 | a += k[0]; |
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409 | a += ((uint32_t)k[1])<<8; |
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410 | a += ((uint32_t)k[2])<<16; |
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411 | a += ((uint32_t)k[3])<<24; |
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412 | b += k[4]; |
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413 | b += ((uint32_t)k[5])<<8; |
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414 | b += ((uint32_t)k[6])<<16; |
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415 | b += ((uint32_t)k[7])<<24; |
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416 | c += k[8]; |
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417 | c += ((uint32_t)k[9])<<8; |
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418 | c += ((uint32_t)k[10])<<16; |
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419 | c += ((uint32_t)k[11])<<24; |
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420 | mix(a,b,c); |
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421 | length -= 12; |
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422 | k += 12; |
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423 | } |
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424 | |
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425 | /*-------------------------------- last block: affect all 32 bits of (c) */ |
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426 | switch(length) /* all the case statements fall through */ |
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427 | { |
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428 | case 12: c+=((uint32_t)k[11])<<24; |
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429 | case 11: c+=((uint32_t)k[10])<<16; |
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430 | case 10: c+=((uint32_t)k[9])<<8; |
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431 | case 9 : c+=k[8]; |
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432 | case 8 : b+=((uint32_t)k[7])<<24; |
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433 | case 7 : b+=((uint32_t)k[6])<<16; |
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434 | case 6 : b+=((uint32_t)k[5])<<8; |
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435 | case 5 : b+=k[4]; |
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436 | case 4 : a+=((uint32_t)k[3])<<24; |
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437 | case 3 : a+=((uint32_t)k[2])<<16; |
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438 | case 2 : a+=((uint32_t)k[1])<<8; |
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439 | case 1 : a+=k[0]; |
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440 | break; |
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441 | case 0 : *pc=c; *pb=b; return; /* zero length strings require no mixing */ |
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442 | } |
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443 | } |
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444 | |
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445 | final(a,b,c); |
---|
446 | *pc=c; *pb=b; |
---|
447 | } |
---|
448 | #endif /*SELF_TEST*/ |
---|
449 | |
---|
450 | |
---|
451 | #ifdef WORDS_BIGENDIAN |
---|
452 | /* |
---|
453 | * hashbig(): |
---|
454 | * This is the same as hashword() on big-endian machines. It is different |
---|
455 | * from hashlittle() on all machines. hashbig() takes advantage of |
---|
456 | * big-endian byte ordering. |
---|
457 | */ |
---|
458 | static uint32_t |
---|
459 | hashbig( const void *key, size_t length, uint32_t initval) |
---|
460 | { |
---|
461 | uint32_t a,b,c; |
---|
462 | union { const void *ptr; size_t i; } u; /* to cast key to (size_t) happily */ |
---|
463 | |
---|
464 | /* Set up the internal state */ |
---|
465 | a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; |
---|
466 | |
---|
467 | u.ptr = key; |
---|
468 | if (HASH_BIG_ENDIAN && ((u.i & 0x3) == 0)) { |
---|
469 | const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ |
---|
470 | const uint8_t *k8; |
---|
471 | |
---|
472 | /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ |
---|
473 | while (length > 12) |
---|
474 | { |
---|
475 | a += k[0]; |
---|
476 | b += k[1]; |
---|
477 | c += k[2]; |
---|
478 | mix(a,b,c); |
---|
479 | length -= 12; |
---|
480 | k += 3; |
---|
481 | } |
---|
482 | |
---|
483 | /*----------------------------- handle the last (probably partial) block */ |
---|
484 | /* |
---|
485 | * "k[2]<<8" actually reads beyond the end of the string, but |
---|
486 | * then shifts out the part it's not allowed to read. Because the |
---|
487 | * string is aligned, the illegal read is in the same word as the |
---|
488 | * rest of the string. Every machine with memory protection I've seen |
---|
489 | * does it on word boundaries, so is OK with this. But VALGRIND will |
---|
490 | * still catch it and complain. The masking trick does make the hash |
---|
491 | * noticably faster for short strings (like English words). |
---|
492 | */ |
---|
493 | #ifndef VALGRIND |
---|
494 | |
---|
495 | switch(length) |
---|
496 | { |
---|
497 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
---|
498 | case 11: c+=k[2]&0xffffff00; b+=k[1]; a+=k[0]; break; |
---|
499 | case 10: c+=k[2]&0xffff0000; b+=k[1]; a+=k[0]; break; |
---|
500 | case 9 : c+=k[2]&0xff000000; b+=k[1]; a+=k[0]; break; |
---|
501 | case 8 : b+=k[1]; a+=k[0]; break; |
---|
502 | case 7 : b+=k[1]&0xffffff00; a+=k[0]; break; |
---|
503 | case 6 : b+=k[1]&0xffff0000; a+=k[0]; break; |
---|
504 | case 5 : b+=k[1]&0xff000000; a+=k[0]; break; |
---|
505 | case 4 : a+=k[0]; break; |
---|
506 | case 3 : a+=k[0]&0xffffff00; break; |
---|
507 | case 2 : a+=k[0]&0xffff0000; break; |
---|
508 | case 1 : a+=k[0]&0xff000000; break; |
---|
509 | case 0 : return c; /* zero length strings require no mixing */ |
---|
510 | } |
---|
511 | |
---|
512 | #else /* make valgrind happy */ |
---|
513 | |
---|
514 | k8 = (const uint8_t *)k; |
---|
515 | switch(length) /* all the case statements fall through */ |
---|
516 | { |
---|
517 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
---|
518 | case 11: c+=((uint32_t)k8[10])<<8; /* fall through */ |
---|
519 | case 10: c+=((uint32_t)k8[9])<<16; /* fall through */ |
---|
520 | case 9 : c+=((uint32_t)k8[8])<<24; /* fall through */ |
---|
521 | case 8 : b+=k[1]; a+=k[0]; break; |
---|
522 | case 7 : b+=((uint32_t)k8[6])<<8; /* fall through */ |
---|
523 | case 6 : b+=((uint32_t)k8[5])<<16; /* fall through */ |
---|
524 | case 5 : b+=((uint32_t)k8[4])<<24; /* fall through */ |
---|
525 | case 4 : a+=k[0]; break; |
---|
526 | case 3 : a+=((uint32_t)k8[2])<<8; /* fall through */ |
---|
527 | case 2 : a+=((uint32_t)k8[1])<<16; /* fall through */ |
---|
528 | case 1 : a+=((uint32_t)k8[0])<<24; break; |
---|
529 | case 0 : return c; |
---|
530 | } |
---|
531 | |
---|
532 | #endif /* !VALGRIND */ |
---|
533 | |
---|
534 | } else { /* need to read the key one byte at a time */ |
---|
535 | const uint8_t *k = (const uint8_t *)key; |
---|
536 | |
---|
537 | /*--------------- all but the last block: affect some 32 bits of (a,b,c) */ |
---|
538 | while (length > 12) |
---|
539 | { |
---|
540 | a += ((uint32_t)k[0])<<24; |
---|
541 | a += ((uint32_t)k[1])<<16; |
---|
542 | a += ((uint32_t)k[2])<<8; |
---|
543 | a += ((uint32_t)k[3]); |
---|
544 | b += ((uint32_t)k[4])<<24; |
---|
545 | b += ((uint32_t)k[5])<<16; |
---|
546 | b += ((uint32_t)k[6])<<8; |
---|
547 | b += ((uint32_t)k[7]); |
---|
548 | c += ((uint32_t)k[8])<<24; |
---|
549 | c += ((uint32_t)k[9])<<16; |
---|
550 | c += ((uint32_t)k[10])<<8; |
---|
551 | c += ((uint32_t)k[11]); |
---|
552 | mix(a,b,c); |
---|
553 | length -= 12; |
---|
554 | k += 12; |
---|
555 | } |
---|
556 | |
---|
557 | /*-------------------------------- last block: affect all 32 bits of (c) */ |
---|
558 | switch(length) /* all the case statements fall through */ |
---|
559 | { |
---|
560 | case 12: c+=k[11]; |
---|
561 | case 11: c+=((uint32_t)k[10])<<8; |
---|
562 | case 10: c+=((uint32_t)k[9])<<16; |
---|
563 | case 9 : c+=((uint32_t)k[8])<<24; |
---|
564 | case 8 : b+=k[7]; |
---|
565 | case 7 : b+=((uint32_t)k[6])<<8; |
---|
566 | case 6 : b+=((uint32_t)k[5])<<16; |
---|
567 | case 5 : b+=((uint32_t)k[4])<<24; |
---|
568 | case 4 : a+=k[3]; |
---|
569 | case 3 : a+=((uint32_t)k[2])<<8; |
---|
570 | case 2 : a+=((uint32_t)k[1])<<16; |
---|
571 | case 1 : a+=((uint32_t)k[0])<<24; |
---|
572 | break; |
---|
573 | case 0 : return c; |
---|
574 | } |
---|
575 | } |
---|
576 | |
---|
577 | final(a,b,c); |
---|
578 | return c; |
---|
579 | } |
---|
580 | #endif /*WORDS_BIGENDIAN*/ |
---|
581 | |
---|
582 | /* |
---|
583 | ------------------------------------------------------------------------------- |
---|
584 | hashlittle() -- hash a variable-length key into a 32-bit value |
---|
585 | k : the key (the unaligned variable-length array of bytes) |
---|
586 | length : the length of the key, counting by bytes |
---|
587 | initval : can be any 4-byte value |
---|
588 | Returns a 32-bit value. Every bit of the key affects every bit of |
---|
589 | the return value. Two keys differing by one or two bits will have |
---|
590 | totally different hash values. |
---|
591 | |
---|
592 | The best hash table sizes are powers of 2. There is no need to do |
---|
593 | mod a prime (mod is sooo slow!). If you need less than 32 bits, |
---|
594 | use a bitmask. For example, if you need only 10 bits, do |
---|
595 | h = (h & hashmask(10)); |
---|
596 | In which case, the hash table should have hashsize(10) elements. |
---|
597 | |
---|
598 | If you are hashing n strings (uint8_t **)k, do it like this: |
---|
599 | for (i=0, h=0; i<n; ++i) h = hashlittle( k[i], len[i], h); |
---|
600 | |
---|
601 | By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this |
---|
602 | code any way you wish, private, educational, or commercial. It's free. |
---|
603 | |
---|
604 | Use for hash table lookup, or anything where one collision in 2^^32 is |
---|
605 | acceptable. Do NOT use for cryptographic purposes. |
---|
606 | ------------------------------------------------------------------------------- |
---|
607 | */ |
---|
608 | |
---|
609 | static uint32_t |
---|
610 | hashlittle( const void *key, size_t length, uint32_t initval) |
---|
611 | { |
---|
612 | uint32_t a,b,c; /* internal state */ |
---|
613 | union { const void *ptr; size_t i; } u; /* needed for Mac Powerbook G4 */ |
---|
614 | |
---|
615 | /* Set up the internal state */ |
---|
616 | a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; |
---|
617 | |
---|
618 | u.ptr = key; |
---|
619 | if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { |
---|
620 | const uint32_t *k = (const uint32_t *)key; /* read 32-bit chunks */ |
---|
621 | const uint8_t *k8; |
---|
622 | |
---|
623 | /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ |
---|
624 | while (length > 12) |
---|
625 | { |
---|
626 | a += k[0]; |
---|
627 | b += k[1]; |
---|
628 | c += k[2]; |
---|
629 | mix(a,b,c); |
---|
630 | length -= 12; |
---|
631 | k += 3; |
---|
632 | } |
---|
633 | |
---|
634 | /*----------------------------- handle the last (probably partial) block */ |
---|
635 | /* |
---|
636 | * "k[2]&0xffffff" actually reads beyond the end of the string, but |
---|
637 | * then masks off the part it's not allowed to read. Because the |
---|
638 | * string is aligned, the masked-off tail is in the same word as the |
---|
639 | * rest of the string. Every machine with memory protection I've seen |
---|
640 | * does it on word boundaries, so is OK with this. But VALGRIND will |
---|
641 | * still catch it and complain. The masking trick does make the hash |
---|
642 | * noticably faster for short strings (like English words). |
---|
643 | */ |
---|
644 | #ifndef VALGRIND |
---|
645 | |
---|
646 | switch(length) |
---|
647 | { |
---|
648 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
---|
649 | case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break; |
---|
650 | case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break; |
---|
651 | case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break; |
---|
652 | case 8 : b+=k[1]; a+=k[0]; break; |
---|
653 | case 7 : b+=k[1]&0xffffff; a+=k[0]; break; |
---|
654 | case 6 : b+=k[1]&0xffff; a+=k[0]; break; |
---|
655 | case 5 : b+=k[1]&0xff; a+=k[0]; break; |
---|
656 | case 4 : a+=k[0]; break; |
---|
657 | case 3 : a+=k[0]&0xffffff; break; |
---|
658 | case 2 : a+=k[0]&0xffff; break; |
---|
659 | case 1 : a+=k[0]&0xff; break; |
---|
660 | case 0 : return c; /* zero length strings require no mixing */ |
---|
661 | } |
---|
662 | |
---|
663 | #else /* make valgrind happy */ |
---|
664 | |
---|
665 | k8 = (const uint8_t *)k; |
---|
666 | switch(length) |
---|
667 | { |
---|
668 | case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; |
---|
669 | case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ |
---|
670 | case 10: c+=((uint32_t)k8[9])<<8; /* fall through */ |
---|
671 | case 9 : c+=k8[8]; /* fall through */ |
---|
672 | case 8 : b+=k[1]; a+=k[0]; break; |
---|
673 | case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ |
---|
674 | case 6 : b+=((uint32_t)k8[5])<<8; /* fall through */ |
---|
675 | case 5 : b+=k8[4]; /* fall through */ |
---|
676 | case 4 : a+=k[0]; break; |
---|
677 | case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ |
---|
678 | case 2 : a+=((uint32_t)k8[1])<<8; /* fall through */ |
---|
679 | case 1 : a+=k8[0]; break; |
---|
680 | case 0 : return c; |
---|
681 | } |
---|
682 | |
---|
683 | #endif /* !valgrind */ |
---|
684 | |
---|
685 | } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) { |
---|
686 | const uint16_t *k = (const uint16_t *)key; /* read 16-bit chunks */ |
---|
687 | const uint8_t *k8; |
---|
688 | |
---|
689 | /*--------------- all but last block: aligned reads and different mixing */ |
---|
690 | while (length > 12) |
---|
691 | { |
---|
692 | a += k[0] + (((uint32_t)k[1])<<16); |
---|
693 | b += k[2] + (((uint32_t)k[3])<<16); |
---|
694 | c += k[4] + (((uint32_t)k[5])<<16); |
---|
695 | mix(a,b,c); |
---|
696 | length -= 12; |
---|
697 | k += 6; |
---|
698 | } |
---|
699 | |
---|
700 | /*----------------------------- handle the last (probably partial) block */ |
---|
701 | k8 = (const uint8_t *)k; |
---|
702 | switch(length) |
---|
703 | { |
---|
704 | case 12: c+=k[4]+(((uint32_t)k[5])<<16); |
---|
705 | b+=k[2]+(((uint32_t)k[3])<<16); |
---|
706 | a+=k[0]+(((uint32_t)k[1])<<16); |
---|
707 | break; |
---|
708 | case 11: c+=((uint32_t)k8[10])<<16; /* fall through */ |
---|
709 | case 10: c+=k[4]; |
---|
710 | b+=k[2]+(((uint32_t)k[3])<<16); |
---|
711 | a+=k[0]+(((uint32_t)k[1])<<16); |
---|
712 | break; |
---|
713 | case 9 : c+=k8[8]; /* fall through */ |
---|
714 | case 8 : b+=k[2]+(((uint32_t)k[3])<<16); |
---|
715 | a+=k[0]+(((uint32_t)k[1])<<16); |
---|
716 | break; |
---|
717 | case 7 : b+=((uint32_t)k8[6])<<16; /* fall through */ |
---|
718 | case 6 : b+=k[2]; |
---|
719 | a+=k[0]+(((uint32_t)k[1])<<16); |
---|
720 | break; |
---|
721 | case 5 : b+=k8[4]; /* fall through */ |
---|
722 | case 4 : a+=k[0]+(((uint32_t)k[1])<<16); |
---|
723 | break; |
---|
724 | case 3 : a+=((uint32_t)k8[2])<<16; /* fall through */ |
---|
725 | case 2 : a+=k[0]; |
---|
726 | break; |
---|
727 | case 1 : a+=k8[0]; |
---|
728 | break; |
---|
729 | case 0 : return c; /* zero length requires no mixing */ |
---|
730 | } |
---|
731 | |
---|
732 | } else { /* need to read the key one byte at a time */ |
---|
733 | const uint8_t *k = (const uint8_t *)key; |
---|
734 | |
---|
735 | /*--------------- all but the last block: affect some 32 bits of (a,b,c) */ |
---|
736 | while (length > 12) |
---|
737 | { |
---|
738 | a += k[0]; |
---|
739 | a += ((uint32_t)k[1])<<8; |
---|
740 | a += ((uint32_t)k[2])<<16; |
---|
741 | a += ((uint32_t)k[3])<<24; |
---|
742 | b += k[4]; |
---|
743 | b += ((uint32_t)k[5])<<8; |
---|
744 | b += ((uint32_t)k[6])<<16; |
---|
745 | b += ((uint32_t)k[7])<<24; |
---|
746 | c += k[8]; |
---|
747 | c += ((uint32_t)k[9])<<8; |
---|
748 | c += ((uint32_t)k[10])<<16; |
---|
749 | c += ((uint32_t)k[11])<<24; |
---|
750 | mix(a,b,c); |
---|
751 | length -= 12; |
---|
752 | k += 12; |
---|
753 | } |
---|
754 | |
---|
755 | /*-------------------------------- last block: affect all 32 bits of (c) */ |
---|
756 | switch(length) /* all the case statements fall through */ |
---|
757 | { |
---|
758 | case 12: c+=((uint32_t)k[11])<<24; |
---|
759 | case 11: c+=((uint32_t)k[10])<<16; |
---|
760 | case 10: c+=((uint32_t)k[9])<<8; |
---|
761 | case 9 : c+=k[8]; |
---|
762 | case 8 : b+=((uint32_t)k[7])<<24; |
---|
763 | case 7 : b+=((uint32_t)k[6])<<16; |
---|
764 | case 6 : b+=((uint32_t)k[5])<<8; |
---|
765 | case 5 : b+=k[4]; |
---|
766 | case 4 : a+=((uint32_t)k[3])<<24; |
---|
767 | case 3 : a+=((uint32_t)k[2])<<16; |
---|
768 | case 2 : a+=((uint32_t)k[1])<<8; |
---|
769 | case 1 : a+=k[0]; |
---|
770 | break; |
---|
771 | case 0 : return c; |
---|
772 | } |
---|
773 | } |
---|
774 | |
---|
775 | final(a,b,c); |
---|
776 | return c; |
---|
777 | } |
---|
778 | |
---|
779 | |
---|
780 | /* |
---|
781 | * hash_fast(key, length, initval) |
---|
782 | * Wrapper that calls either hashlittle or hashbig, depending on endianness. |
---|
783 | */ |
---|
784 | uint32_t |
---|
785 | hash_fast( const void *key, size_t length) { |
---|
786 | #define NC_ARBITRARY_UINT (992099683U) |
---|
787 | #ifndef WORDS_BIGENDIAN |
---|
788 | return hashlittle(key, length, NC_ARBITRARY_UINT); |
---|
789 | #else |
---|
790 | return hashbig(key, length, NC_ARBITRARY_UINT); |
---|
791 | #endif |
---|
792 | } |
---|
793 | |
---|
794 | #ifdef SELF_TEST |
---|
795 | /* used for timings */ |
---|
796 | void driver1() |
---|
797 | { |
---|
798 | uint8_t buf[256]; |
---|
799 | uint32_t i; |
---|
800 | uint32_t h=0; |
---|
801 | time_t a,z; |
---|
802 | |
---|
803 | time(&a); |
---|
804 | for (i=0; i<256; ++i) buf[i] = 'x'; |
---|
805 | for (i=0; i<1; ++i) |
---|
806 | { |
---|
807 | h = hashlittle(&buf[0],1,h); |
---|
808 | } |
---|
809 | time(&z); |
---|
810 | if (z-a > 0) printf("time %d %.8x\n", z-a, h); |
---|
811 | } |
---|
812 | |
---|
813 | /* check that every input bit changes every output bit half the time */ |
---|
814 | #define HASHSTATE 1 |
---|
815 | #define HASHLEN 1 |
---|
816 | #define MAXPAIR 60 |
---|
817 | #define MAXLEN 70 |
---|
818 | void driver2() |
---|
819 | { |
---|
820 | uint8_t qa[MAXLEN+1], qb[MAXLEN+2], *a = &qa[0], *b = &qb[1]; |
---|
821 | uint32_t c[HASHSTATE], d[HASHSTATE], i=0, j=0, k, l, m=0, z; |
---|
822 | uint32_t e[HASHSTATE],f[HASHSTATE],g[HASHSTATE],h[HASHSTATE]; |
---|
823 | uint32_t x[HASHSTATE],y[HASHSTATE]; |
---|
824 | uint32_t hlen; |
---|
825 | |
---|
826 | printf("No more than %d trials should ever be needed \n",MAXPAIR/2); |
---|
827 | for (hlen=0; hlen < MAXLEN; ++hlen) |
---|
828 | { |
---|
829 | z=0; |
---|
830 | for (i=0; i<hlen; ++i) /*----------------------- for each input byte, */ |
---|
831 | { |
---|
832 | for (j=0; j<8; ++j) /*------------------------ for each input bit, */ |
---|
833 | { |
---|
834 | for (m=1; m<8; ++m) /*------------ for serveral possible initvals, */ |
---|
835 | { |
---|
836 | for (l=0; l<HASHSTATE; ++l) |
---|
837 | e[l]=f[l]=g[l]=h[l]=x[l]=y[l]=~((uint32_t)0); |
---|
838 | |
---|
839 | /*---- check that every output bit is affected by that input bit */ |
---|
840 | for (k=0; k<MAXPAIR; k+=2) |
---|
841 | { |
---|
842 | uint32_t finished=1; |
---|
843 | /* keys have one bit different */ |
---|
844 | for (l=0; l<hlen+1; ++l) {a[l] = b[l] = (uint8_t)0;} |
---|
845 | /* have a and b be two keys differing in only one bit */ |
---|
846 | a[i] ^= (k<<j); |
---|
847 | a[i] ^= (k>>(8-j)); |
---|
848 | c[0] = hashlittle(a, hlen, m); |
---|
849 | b[i] ^= ((k+1)<<j); |
---|
850 | b[i] ^= ((k+1)>>(8-j)); |
---|
851 | d[0] = hashlittle(b, hlen, m); |
---|
852 | /* check every bit is 1, 0, set, and not set at least once */ |
---|
853 | for (l=0; l<HASHSTATE; ++l) |
---|
854 | { |
---|
855 | e[l] &= (c[l]^d[l]); |
---|
856 | f[l] &= ~(c[l]^d[l]); |
---|
857 | g[l] &= c[l]; |
---|
858 | h[l] &= ~c[l]; |
---|
859 | x[l] &= d[l]; |
---|
860 | y[l] &= ~d[l]; |
---|
861 | if (e[l]|f[l]|g[l]|h[l]|x[l]|y[l]) finished=0; |
---|
862 | } |
---|
863 | if (finished) break; |
---|
864 | } |
---|
865 | if (k>z) z=k; |
---|
866 | if (k==MAXPAIR) |
---|
867 | { |
---|
868 | printf("Some bit didn't change: "); |
---|
869 | printf("%.8x %.8x %.8x %.8x %.8x %.8x ", |
---|
870 | e[0],f[0],g[0],h[0],x[0],y[0]); |
---|
871 | printf("i %d j %d m %d len %d\n", i, j, m, hlen); |
---|
872 | } |
---|
873 | if (z==MAXPAIR) goto done; |
---|
874 | } |
---|
875 | } |
---|
876 | } |
---|
877 | done: |
---|
878 | if (z < MAXPAIR) |
---|
879 | { |
---|
880 | printf("Mix success %2d bytes %2d initvals ",i,m); |
---|
881 | printf("required %d trials\n", z/2); |
---|
882 | } |
---|
883 | } |
---|
884 | printf("\n"); |
---|
885 | } |
---|
886 | |
---|
887 | /* Check for reading beyond the end of the buffer and alignment problems */ |
---|
888 | void driver3() |
---|
889 | { |
---|
890 | uint8_t buf[MAXLEN+20], *b; |
---|
891 | uint32_t len; |
---|
892 | uint8_t q[] = "This is the time for all good men to come to the aid of their country..."; |
---|
893 | uint32_t h; |
---|
894 | uint8_t qq[] = "xThis is the time for all good men to come to the aid of their country..."; |
---|
895 | uint32_t i; |
---|
896 | uint8_t qqq[] = "xxThis is the time for all good men to come to the aid of their country..."; |
---|
897 | uint32_t j; |
---|
898 | uint8_t qqqq[] = "xxxThis is the time for all good men to come to the aid of their country..."; |
---|
899 | uint32_t ref,x,y; |
---|
900 | uint8_t *p; |
---|
901 | |
---|
902 | printf("Endianness. These lines should all be the same (for values filled in):\n"); |
---|
903 | printf("%.8x %.8x %.8x\n", |
---|
904 | hashword((const uint32_t *)q, (sizeof(q)-1)/4, 13), |
---|
905 | hashword((const uint32_t *)q, (sizeof(q)-5)/4, 13), |
---|
906 | hashword((const uint32_t *)q, (sizeof(q)-9)/4, 13)); |
---|
907 | p = q; |
---|
908 | printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", |
---|
909 | hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), |
---|
910 | hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), |
---|
911 | hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), |
---|
912 | hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), |
---|
913 | hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), |
---|
914 | hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); |
---|
915 | p = &qq[1]; |
---|
916 | printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", |
---|
917 | hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), |
---|
918 | hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), |
---|
919 | hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), |
---|
920 | hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), |
---|
921 | hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), |
---|
922 | hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); |
---|
923 | p = &qqq[2]; |
---|
924 | printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", |
---|
925 | hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), |
---|
926 | hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), |
---|
927 | hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), |
---|
928 | hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), |
---|
929 | hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), |
---|
930 | hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); |
---|
931 | p = &qqqq[3]; |
---|
932 | printf("%.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x %.8x\n", |
---|
933 | hashlittle(p, sizeof(q)-1, 13), hashlittle(p, sizeof(q)-2, 13), |
---|
934 | hashlittle(p, sizeof(q)-3, 13), hashlittle(p, sizeof(q)-4, 13), |
---|
935 | hashlittle(p, sizeof(q)-5, 13), hashlittle(p, sizeof(q)-6, 13), |
---|
936 | hashlittle(p, sizeof(q)-7, 13), hashlittle(p, sizeof(q)-8, 13), |
---|
937 | hashlittle(p, sizeof(q)-9, 13), hashlittle(p, sizeof(q)-10, 13), |
---|
938 | hashlittle(p, sizeof(q)-11, 13), hashlittle(p, sizeof(q)-12, 13)); |
---|
939 | printf("\n"); |
---|
940 | |
---|
941 | /* check that hashlittle2 and hashlittle produce the same results */ |
---|
942 | i=47; j=0; |
---|
943 | hashlittle2(q, sizeof(q), &i, &j); |
---|
944 | if (hashlittle(q, sizeof(q), 47) != i) |
---|
945 | printf("hashlittle2 and hashlittle mismatch\n"); |
---|
946 | |
---|
947 | /* check that hashword2 and hashword produce the same results */ |
---|
948 | len = 0xdeadbeef; |
---|
949 | i=47, j=0; |
---|
950 | hashword2(&len, 1, &i, &j); |
---|
951 | if (hashword(&len, 1, 47) != i) |
---|
952 | printf("hashword2 and hashword mismatch %x %x\n", |
---|
953 | i, hashword(&len, 1, 47)); |
---|
954 | |
---|
955 | /* check hashlittle doesn't read before or after the ends of the string */ |
---|
956 | for (h=0, b=buf+1; h<8; ++h, ++b) |
---|
957 | { |
---|
958 | for (i=0; i<MAXLEN; ++i) |
---|
959 | { |
---|
960 | len = i; |
---|
961 | for (j=0; j<i; ++j) *(b+j)=0; |
---|
962 | |
---|
963 | /* these should all be equal */ |
---|
964 | ref = hashlittle(b, len, (uint32_t)1); |
---|
965 | *(b+i)=(uint8_t)~0; |
---|
966 | *(b-1)=(uint8_t)~0; |
---|
967 | x = hashlittle(b, len, (uint32_t)1); |
---|
968 | y = hashlittle(b, len, (uint32_t)1); |
---|
969 | if ((ref != x) || (ref != y)) |
---|
970 | { |
---|
971 | printf("alignment error: %.8x %.8x %.8x %d %d\n",ref,x,y, |
---|
972 | h, i); |
---|
973 | } |
---|
974 | } |
---|
975 | } |
---|
976 | } |
---|
977 | |
---|
978 | /* check for problems with nulls */ |
---|
979 | void driver4() |
---|
980 | { |
---|
981 | uint8_t buf[1]; |
---|
982 | uint32_t h,i,state[HASHSTATE]; |
---|
983 | |
---|
984 | |
---|
985 | buf[0] = ~0; |
---|
986 | for (i=0; i<HASHSTATE; ++i) state[i] = 1; |
---|
987 | printf("These should all be different\n"); |
---|
988 | for (i=0, h=0; i<8; ++i) |
---|
989 | { |
---|
990 | h = hashlittle(buf, 0, h); |
---|
991 | printf("%2ld 0-byte strings, hash is %.8x\n", i, h); |
---|
992 | } |
---|
993 | } |
---|
994 | |
---|
995 | void driver5() |
---|
996 | { |
---|
997 | uint32_t b,c; |
---|
998 | b=0, c=0, hashlittle2("", 0, &c, &b); |
---|
999 | printf("hash is %.8lx %.8lx\n", c, b); /* deadbeef deadbeef */ |
---|
1000 | b=0xdeadbeef, c=0, hashlittle2("", 0, &c, &b); |
---|
1001 | printf("hash is %.8lx %.8lx\n", c, b); /* bd5b7dde deadbeef */ |
---|
1002 | b=0xdeadbeef, c=0xdeadbeef, hashlittle2("", 0, &c, &b); |
---|
1003 | printf("hash is %.8lx %.8lx\n", c, b); /* 9c093ccd bd5b7dde */ |
---|
1004 | b=0, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b); |
---|
1005 | printf("hash is %.8lx %.8lx\n", c, b); /* 17770551 ce7226e6 */ |
---|
1006 | b=1, c=0, hashlittle2("Four score and seven years ago", 30, &c, &b); |
---|
1007 | printf("hash is %.8lx %.8lx\n", c, b); /* e3607cae bd371de4 */ |
---|
1008 | b=0, c=1, hashlittle2("Four score and seven years ago", 30, &c, &b); |
---|
1009 | printf("hash is %.8lx %.8lx\n", c, b); /* cd628161 6cbea4b3 */ |
---|
1010 | c = hashlittle("Four score and seven years ago", 30, 0); |
---|
1011 | printf("hash is %.8lx\n", c); /* 17770551 */ |
---|
1012 | c = hashlittle("Four score and seven years ago", 30, 1); |
---|
1013 | printf("hash is %.8lx\n", c); /* cd628161 */ |
---|
1014 | } |
---|
1015 | |
---|
1016 | |
---|
1017 | #endif /* SELF_TEST */ |
---|