1 | /*- |
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2 | * Copyright (c) 1990, 1993, 1994 |
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3 | * The Regents of the University of California. All rights reserved. |
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4 | * |
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5 | * This code is derived from software contributed to Berkeley by |
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6 | * Margo Seltzer. |
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7 | * |
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8 | * Redistribution and use in source and binary forms, with or without |
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9 | * modification, are permitted provided that the following conditions |
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10 | * are met: |
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11 | * 1. Redistributions of source code must retain the above copyright |
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12 | * notice, this list of conditions and the following disclaimer. |
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13 | * 2. Redistributions in binary form must reproduce the above copyright |
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14 | * notice, this list of conditions and the following disclaimer in the |
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15 | * documentation and/or other materials provided with the distribution. |
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16 | * 3. All advertising materials mentioning features or use of this software |
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17 | * must display the following acknowledgement: |
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18 | * This product includes software developed by the University of |
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19 | * California, Berkeley and its contributors. |
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20 | * 4. Neither the name of the University nor the names of its contributors |
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21 | * may be used to endorse or promote products derived from this software |
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22 | * without specific prior written permission. |
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23 | * |
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24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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34 | * SUCH DAMAGE. |
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35 | * |
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36 | * @(#)hash.h 8.3 (Berkeley) 5/31/94 |
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37 | * $FreeBSD: src/lib/libc/db/hash/hash.h,v 1.6 2002/03/21 22:46:26 obrien Exp $ |
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38 | */ |
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39 | |
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40 | #include <sys/param.h> |
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41 | #define __need_size_t |
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42 | #include <stddef.h> |
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43 | |
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44 | /* Check that newlib understands the byte order of its target system. */ |
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45 | #ifndef BYTE_ORDER |
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46 | #error BYTE_ORDER not defined by sys/param.h |
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47 | #endif |
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48 | |
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49 | /* Define DB endianness constants based on target endianness. */ |
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50 | #define DB_LITTLE_ENDIAN 1234 |
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51 | #define DB_BIG_ENDIAN 4321 |
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52 | #if (BYTE_ORDER == LITTLE_ENDIAN) |
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53 | #define DB_BYTE_ORDER DB_LITTLE_ENDIAN |
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54 | #else |
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55 | #define DB_BYTE_ORDER DB_BIG_ENDIAN |
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56 | #endif |
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57 | |
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58 | /* Operations */ |
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59 | typedef enum { |
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60 | HASH_GET, HASH_PUT, HASH_PUTNEW, HASH_DELETE, HASH_FIRST, HASH_NEXT |
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61 | } ACTION; |
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62 | |
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63 | /* Buffer Management structures */ |
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64 | typedef struct _bufhead BUFHEAD; |
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65 | |
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66 | struct _bufhead { |
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67 | BUFHEAD *prev; /* LRU links */ |
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68 | BUFHEAD *next; /* LRU links */ |
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69 | BUFHEAD *ovfl; /* Overflow page buffer header */ |
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70 | __uint32_t addr; /* Address of this page */ |
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71 | char *page; /* Actual page data */ |
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72 | char flags; |
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73 | #define BUF_MOD 0x0001 |
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74 | #define BUF_DISK 0x0002 |
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75 | #define BUF_BUCKET 0x0004 |
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76 | #define BUF_PIN 0x0008 |
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77 | }; |
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78 | |
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79 | #define IS_BUCKET(X) ((X) & BUF_BUCKET) |
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80 | |
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81 | typedef BUFHEAD **SEGMENT; |
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82 | |
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83 | /* Hash Table Information */ |
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84 | typedef struct hashhdr { /* Disk resident portion */ |
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85 | int magic; /* Magic NO for hash tables */ |
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86 | int version; /* Version ID */ |
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87 | __uint32_t lorder; /* Byte Order */ |
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88 | int bsize; /* Bucket/Page Size */ |
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89 | int bshift; /* Bucket shift */ |
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90 | int dsize; /* Directory Size */ |
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91 | int ssize; /* Segment Size */ |
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92 | int sshift; /* Segment shift */ |
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93 | int ovfl_point; /* Where overflow pages are being |
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94 | * allocated */ |
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95 | int last_freed; /* Last overflow page freed */ |
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96 | int max_bucket; /* ID of Maximum bucket in use */ |
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97 | int high_mask; /* Mask to modulo into entire table */ |
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98 | int low_mask; /* Mask to modulo into lower half of |
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99 | * table */ |
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100 | int ffactor; /* Fill factor */ |
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101 | int nkeys; /* Number of keys in hash table */ |
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102 | int hdrpages; /* Size of table header */ |
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103 | int h_charkey; /* value of hash(CHARKEY) */ |
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104 | #define NCACHED 32 /* number of bit maps and spare |
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105 | * points */ |
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106 | int spares[NCACHED];/* spare pages for overflow */ |
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107 | __uint16_t bitmaps[NCACHED]; /* address of overflow page |
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108 | * bitmaps */ |
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109 | } HASHHDR; |
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110 | |
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111 | typedef struct htab { /* Memory resident data structure */ |
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112 | HASHHDR hdr; /* Header */ |
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113 | int nsegs; /* Number of allocated segments */ |
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114 | int exsegs; /* Number of extra allocated |
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115 | * segments */ |
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116 | __uint32_t /* Hash function */ |
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117 | (*hash)(const void *, size_t); |
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118 | int flags; /* Flag values */ |
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119 | int fp; /* File pointer */ |
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120 | char *tmp_buf; /* Temporary Buffer for BIG data */ |
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121 | char *tmp_key; /* Temporary Buffer for BIG keys */ |
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122 | BUFHEAD *cpage; /* Current page */ |
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123 | int cbucket; /* Current bucket */ |
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124 | int cndx; /* Index of next item on cpage */ |
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125 | int error; /* Error Number -- for DBM |
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126 | * compatibility */ |
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127 | int new_file; /* Indicates if fd is backing store |
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128 | * or no */ |
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129 | int save_file; /* Indicates whether we need to flush |
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130 | * file at |
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131 | * exit */ |
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132 | __uint32_t *mapp[NCACHED]; /* Pointers to page maps */ |
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133 | int nmaps; /* Initial number of bitmaps */ |
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134 | int nbufs; /* Number of buffers left to |
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135 | * allocate */ |
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136 | BUFHEAD bufhead; /* Header of buffer lru list */ |
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137 | SEGMENT *dir; /* Hash Bucket directory */ |
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138 | } HTAB; |
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139 | |
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140 | /* |
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141 | * Constants |
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142 | */ |
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143 | #define MAX_BSIZE 65536 /* 2^16 */ |
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144 | #define MIN_BUFFERS 6 |
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145 | #define MINHDRSIZE 512 |
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146 | #define DEF_BUFSIZE 65536 /* 64 K */ |
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147 | #define DEF_BUCKET_SIZE 4096 |
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148 | #define DEF_BUCKET_SHIFT 12 /* log2(BUCKET) */ |
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149 | #define DEF_SEGSIZE 256 |
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150 | #define DEF_SEGSIZE_SHIFT 8 /* log2(SEGSIZE) */ |
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151 | #define DEF_DIRSIZE 256 |
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152 | #define DEF_FFACTOR 65536 |
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153 | #define MIN_FFACTOR 4 |
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154 | #define SPLTMAX 8 |
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155 | #define CHARKEY "%$sniglet^&" |
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156 | #define NUMKEY 1038583 |
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157 | #define BYTE_SHIFT 3 |
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158 | #define INT_TO_BYTE 2 |
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159 | #define INT_BYTE_SHIFT 5 |
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160 | #define ALL_SET ((__uint32_t)0xFFFFFFFF) |
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161 | #define ALL_CLEAR 0 |
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162 | |
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163 | #define PTROF(X) ((BUFHEAD *)((ptrdiff_t)(X)&~0x3)) |
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164 | #define ISMOD(X) ((__uint32_t)(ptrdiff_t)(X)&0x1) |
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165 | #define DOMOD(X) ((X) = (char *)((ptrdiff_t)(X)|0x1)) |
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166 | #define ISDISK(X) ((__uint32_t)(ptrdiff_t)(X)&0x2) |
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167 | #define DODISK(X) ((X) = (char *)((ptrdiff_t)(X)|0x2)) |
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168 | |
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169 | #define BITS_PER_MAP 32 |
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170 | |
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171 | /* Given the address of the beginning of a big map, clear/set the nth bit */ |
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172 | #define CLRBIT(A, N) ((A)[(N)/BITS_PER_MAP] &= ~(1<<((N)%BITS_PER_MAP))) |
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173 | #define SETBIT(A, N) ((A)[(N)/BITS_PER_MAP] |= (1<<((N)%BITS_PER_MAP))) |
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174 | #define ISSET(A, N) ((A)[(N)/BITS_PER_MAP] & (1<<((N)%BITS_PER_MAP))) |
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175 | |
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176 | /* Overflow management */ |
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177 | /* |
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178 | * Overflow page numbers are allocated per split point. At each doubling of |
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179 | * the table, we can allocate extra pages. So, an overflow page number has |
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180 | * the top 5 bits indicate which split point and the lower 11 bits indicate |
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181 | * which page at that split point is indicated (pages within split points are |
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182 | * numberered starting with 1). |
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183 | */ |
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184 | |
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185 | #define SPLITSHIFT 11 |
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186 | #define SPLITMASK 0x7FF |
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187 | #define SPLITNUM(N) (((__uint32_t)(N)) >> SPLITSHIFT) |
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188 | #define OPAGENUM(N) ((N) & SPLITMASK) |
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189 | #define OADDR_OF(S,O) ((__uint32_t)((__uint32_t)(S) << SPLITSHIFT) + (O)) |
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190 | |
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191 | #define BUCKET_TO_PAGE(B) \ |
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192 | (B) + hashp->HDRPAGES + ((B) ? hashp->SPARES[__log2((B)+1)-1] : 0) |
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193 | #define OADDR_TO_PAGE(B) \ |
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194 | BUCKET_TO_PAGE ( (1 << SPLITNUM((B))) -1 ) + OPAGENUM((B)); |
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195 | |
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196 | /* |
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197 | * page.h contains a detailed description of the page format. |
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198 | * |
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199 | * Normally, keys and data are accessed from offset tables in the top of |
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200 | * each page which point to the beginning of the key and data. There are |
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201 | * four flag values which may be stored in these offset tables which indicate |
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202 | * the following: |
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203 | * |
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204 | * |
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205 | * OVFLPAGE Rather than a key data pair, this pair contains |
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206 | * the address of an overflow page. The format of |
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207 | * the pair is: |
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208 | * OVERFLOW_PAGE_NUMBER OVFLPAGE |
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209 | * |
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210 | * PARTIAL_KEY This must be the first key/data pair on a page |
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211 | * and implies that page contains only a partial key. |
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212 | * That is, the key is too big to fit on a single page |
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213 | * so it starts on this page and continues on the next. |
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214 | * The format of the page is: |
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215 | * KEY_OFF PARTIAL_KEY OVFL_PAGENO OVFLPAGE |
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216 | * |
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217 | * KEY_OFF -- offset of the beginning of the key |
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218 | * PARTIAL_KEY -- 1 |
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219 | * OVFL_PAGENO - page number of the next overflow page |
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220 | * OVFLPAGE -- 0 |
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221 | * |
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222 | * FULL_KEY This must be the first key/data pair on the page. It |
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223 | * is used in two cases. |
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224 | * |
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225 | * Case 1: |
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226 | * There is a complete key on the page but no data |
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227 | * (because it wouldn't fit). The next page contains |
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228 | * the data. |
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229 | * |
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230 | * Page format it: |
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231 | * KEY_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE |
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232 | * |
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233 | * KEY_OFF -- offset of the beginning of the key |
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234 | * FULL_KEY -- 2 |
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235 | * OVFL_PAGENO - page number of the next overflow page |
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236 | * OVFLPAGE -- 0 |
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237 | * |
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238 | * Case 2: |
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239 | * This page contains no key, but part of a large |
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240 | * data field, which is continued on the next page. |
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241 | * |
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242 | * Page format it: |
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243 | * DATA_OFF FULL_KEY OVFL_PAGENO OVFL_PAGE |
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244 | * |
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245 | * KEY_OFF -- offset of the beginning of the data on |
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246 | * this page |
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247 | * FULL_KEY -- 2 |
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248 | * OVFL_PAGENO - page number of the next overflow page |
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249 | * OVFLPAGE -- 0 |
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250 | * |
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251 | * FULL_KEY_DATA |
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252 | * This must be the first key/data pair on the page. |
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253 | * There are two cases: |
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254 | * |
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255 | * Case 1: |
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256 | * This page contains a key and the beginning of the |
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257 | * data field, but the data field is continued on the |
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258 | * next page. |
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259 | * |
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260 | * Page format is: |
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261 | * KEY_OFF FULL_KEY_DATA OVFL_PAGENO DATA_OFF |
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262 | * |
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263 | * KEY_OFF -- offset of the beginning of the key |
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264 | * FULL_KEY_DATA -- 3 |
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265 | * OVFL_PAGENO - page number of the next overflow page |
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266 | * DATA_OFF -- offset of the beginning of the data |
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267 | * |
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268 | * Case 2: |
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269 | * This page contains the last page of a big data pair. |
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270 | * There is no key, only the tail end of the data |
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271 | * on this page. |
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272 | * |
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273 | * Page format is: |
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274 | * DATA_OFF FULL_KEY_DATA <OVFL_PAGENO> <OVFLPAGE> |
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275 | * |
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276 | * DATA_OFF -- offset of the beginning of the data on |
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277 | * this page |
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278 | * FULL_KEY_DATA -- 3 |
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279 | * OVFL_PAGENO - page number of the next overflow page |
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280 | * OVFLPAGE -- 0 |
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281 | * |
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282 | * OVFL_PAGENO and OVFLPAGE are optional (they are |
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283 | * not present if there is no next page). |
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284 | */ |
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285 | |
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286 | #define OVFLPAGE 0 |
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287 | #define PARTIAL_KEY 1 |
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288 | #define FULL_KEY 2 |
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289 | #define FULL_KEY_DATA 3 |
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290 | #define REAL_KEY 4 |
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291 | |
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292 | /* Short hands for accessing structure */ |
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293 | #define BSIZE hdr.bsize |
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294 | #define BSHIFT hdr.bshift |
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295 | #define DSIZE hdr.dsize |
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296 | #define SGSIZE hdr.ssize |
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297 | #define SSHIFT hdr.sshift |
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298 | #define LORDER hdr.lorder |
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299 | #define OVFL_POINT hdr.ovfl_point |
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300 | #define LAST_FREED hdr.last_freed |
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301 | #define MAX_BUCKET hdr.max_bucket |
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302 | #define FFACTOR hdr.ffactor |
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303 | #define HIGH_MASK hdr.high_mask |
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304 | #define LOW_MASK hdr.low_mask |
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305 | #define NKEYS hdr.nkeys |
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306 | #define HDRPAGES hdr.hdrpages |
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307 | #define SPARES hdr.spares |
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308 | #define BITMAPS hdr.bitmaps |
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309 | #define HASH_VERSION hdr.version |
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310 | #define MAGIC hdr.magic |
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311 | #define NEXT_FREE hdr.next_free |
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312 | #define H_CHARKEY hdr.h_charkey |
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