1 | /**************************************** |
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2 | * Computer Algebra System SINGULAR * |
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3 | ****************************************/ |
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4 | |
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5 | //**************************************************************************/ |
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6 | // |
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7 | // $Id: ndbm.cc,v 1.3 1997-08-12 17:14:41 Singular Exp $ |
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8 | // |
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9 | //**************************************************************************/ |
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10 | // 'ndbm.cc' containes all low-level functions to manipulate dbm-files |
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11 | // for the original Copyright of this file and 'ndbm.h' see below . |
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12 | // |
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13 | // some minor change where needed to compile and run under MacOS/MPW |
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14 | // |
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15 | //**************************************************************************/ |
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16 | |
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17 | #include "mod2.h" |
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18 | #ifdef HAVE_DBM |
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19 | /* |
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20 | * Copyright (c) 1983 Regents of the University of California. |
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21 | * All rights reserved. The Berkeley software License Agreement |
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22 | * specifies the terms and conditions for redistribution. |
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23 | */ |
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24 | |
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25 | #if defined(LIBC_SCCS) && !defined(lint) |
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26 | static char sccsid[] = "@(#)ndbm.c 5.3 (Berkeley) 3/9/86"; |
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27 | #endif LIBC_SCCS and not lint |
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28 | |
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29 | //**************************************************************************/ |
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30 | |
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31 | #include <stdio.h> |
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32 | #ifdef macintosh |
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33 | # include <stdlib.h> |
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34 | # include <errno.h> |
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35 | # include "fcntl.h" |
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36 | # include <string.h> |
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37 | # include <stat.h> |
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38 | # define L_SET SEEK_SET |
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39 | # define EPERM 1 |
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40 | # define ENOSPC 28 |
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41 | # define bcopy(a,b,c) memcpy(b,a,c) |
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42 | # define bzero(a,b) memset(a,0,b) |
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43 | # define bcmp(a,b,c) memcmp(a,b,c) |
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44 | #else /* not macintosh */ |
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45 | # include <sys/types.h> |
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46 | # include <sys/stat.h> |
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47 | # include <sys/file.h> |
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48 | # include <errno.h> |
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49 | # include <stdlib.h> |
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50 | # include <string.h> |
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51 | # include <unistd.h> |
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52 | #endif /* macintosh */ |
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53 | #include "ndbm.h" |
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54 | |
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55 | #define BYTESIZ 8 |
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56 | #undef setbit |
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57 | |
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58 | static void dbm_access(register DBM *db, long hash); |
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59 | static int getbit(register DBM *db); |
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60 | static void setbit(register DBM *db); |
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61 | static datum makdatum(char buf[PBLKSIZ], int n); |
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62 | static int finddatum(char buf[PBLKSIZ], datum item); |
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63 | static long hashinc(register DBM *db, long hash); |
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64 | static long dcalchash(datum item); |
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65 | static int delitem(char buf[PBLKSIZ], int n); |
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66 | static int additem(char buf[PBLKSIZ], datum item, datum item1); |
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67 | extern int errno; |
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68 | |
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69 | |
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70 | DBM * |
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71 | dbm_open(char *file, int flags, int mode) |
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72 | { |
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73 | struct stat statb; |
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74 | register DBM *db; |
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75 | |
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76 | if ((db = (DBM *)malloc(sizeof *db)) == 0) { |
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77 | errno = ENOMEM; |
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78 | return ((DBM *)0); |
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79 | } |
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80 | #ifdef macintosh |
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81 | // It seems that the compile has some problems to commit the flags properly |
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82 | // O_RDWR | O_CREAT = 0x102 change to 0x200. We don't know why. |
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83 | // setting flags to O_RDWR | O_CREAT solved our problem. :-( |
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84 | flags = O_RDWR | O_CREAT; |
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85 | #endif /* macintosh */ |
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86 | |
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87 | db->dbm_flags = (flags & 03) == O_RDONLY ? _DBM_RDONLY : 0; |
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88 | if ((flags & 03) == O_WRONLY) |
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89 | flags = (flags & ~03) | O_RDWR; |
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90 | strcpy(db->dbm_pagbuf, file); |
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91 | strcat(db->dbm_pagbuf, ".pag"); |
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92 | #ifdef macintosh |
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93 | db->dbm_pagf = open(db->dbm_pagbuf, flags); |
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94 | #else /* not macintosh */ |
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95 | db->dbm_pagf = open(db->dbm_pagbuf, flags, mode); |
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96 | #endif /* macintosh */ |
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97 | if (db->dbm_pagf < 0) |
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98 | goto bad; |
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99 | strcpy(db->dbm_pagbuf, file); |
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100 | strcat(db->dbm_pagbuf, ".dir"); |
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101 | #ifdef macintosh |
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102 | db->dbm_dirf = open(db->dbm_pagbuf, flags); |
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103 | #else /* not macintosh */ |
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104 | db->dbm_dirf = open(db->dbm_pagbuf, flags, mode); |
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105 | #endif /* macintosh */ |
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106 | if (db->dbm_dirf < 0) |
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107 | goto bad1; |
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108 | fstat(db->dbm_dirf, &statb); |
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109 | db->dbm_maxbno = statb.st_size*BYTESIZ-1; |
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110 | db->dbm_pagbno = db->dbm_dirbno = -1; |
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111 | return (db); |
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112 | bad1: |
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113 | (void) close(db->dbm_pagf); |
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114 | bad: |
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115 | free((char *)db); |
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116 | return ((DBM *)0); |
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117 | } |
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118 | |
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119 | void |
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120 | dbm_close(DBM *db) |
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121 | { |
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122 | (void) close(db->dbm_dirf); |
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123 | (void) close(db->dbm_pagf); |
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124 | free((char *)db); |
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125 | } |
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126 | |
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127 | long |
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128 | dbm_forder(register DBM *db, datum key) |
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129 | { |
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130 | long hash; |
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131 | |
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132 | hash = dcalchash(key); |
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133 | for (db->dbm_hmask=0;; db->dbm_hmask=(db->dbm_hmask<<1)+1) { |
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134 | db->dbm_blkno = hash & db->dbm_hmask; |
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135 | db->dbm_bitno = db->dbm_blkno + db->dbm_hmask; |
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136 | if (getbit(db) == 0) |
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137 | break; |
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138 | } |
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139 | return (db->dbm_blkno); |
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140 | } |
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141 | |
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142 | datum |
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143 | dbm_fetch(register DBM *db, datum key) |
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144 | { |
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145 | register i; |
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146 | datum item; |
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147 | |
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148 | if (dbm_error(db)) |
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149 | goto err; |
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150 | dbm_access(db, dcalchash(key)); |
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151 | if ((i = finddatum(db->dbm_pagbuf, key)) >= 0) { |
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152 | item = makdatum(db->dbm_pagbuf, i+1); |
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153 | if (item.dptr != NULL) |
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154 | return (item); |
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155 | } |
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156 | err: |
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157 | item.dptr = NULL; |
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158 | item.dsize = 0; |
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159 | return (item); |
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160 | } |
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161 | |
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162 | int dbm_delete(register DBM *db, datum key) |
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163 | { |
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164 | register i; |
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165 | datum item; |
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166 | |
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167 | if (dbm_error(db)) |
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168 | return (-1); |
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169 | if (dbm_rdonly(db)) { |
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170 | errno = EPERM; |
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171 | return (-1); |
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172 | } |
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173 | dbm_access(db, dcalchash(key)); |
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174 | if ((i = finddatum(db->dbm_pagbuf, key)) < 0) |
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175 | return (-1); |
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176 | if (!delitem(db->dbm_pagbuf, i)) |
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177 | goto err; |
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178 | db->dbm_pagbno = db->dbm_blkno; |
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179 | (void) lseek(db->dbm_pagf, db->dbm_blkno*PBLKSIZ, L_SET); |
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180 | if (write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ) { |
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181 | err: |
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182 | db->dbm_flags |= _DBM_IOERR; |
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183 | return (-1); |
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184 | } |
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185 | return (0); |
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186 | } |
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187 | |
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188 | int dbm_store(register DBM *db, datum key, datum dat, int replace) |
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189 | { |
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190 | register i; |
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191 | int ret; |
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192 | datum item, item1; |
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193 | char ovfbuf[PBLKSIZ]; |
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194 | |
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195 | if (dbm_error(db)) |
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196 | return (-1); |
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197 | if (dbm_rdonly(db)) { |
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198 | errno = EPERM; |
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199 | return (-1); |
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200 | } |
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201 | loop: |
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202 | dbm_access(db, dcalchash(key)); |
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203 | if ((i = finddatum(db->dbm_pagbuf, key)) >= 0) { |
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204 | if (!replace) |
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205 | return (1); |
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206 | if (!delitem(db->dbm_pagbuf, i)) { |
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207 | db->dbm_flags |= _DBM_IOERR; |
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208 | return (-1); |
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209 | } |
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210 | } |
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211 | if (!additem(db->dbm_pagbuf, key, dat)) |
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212 | goto split; |
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213 | db->dbm_pagbno = db->dbm_blkno; |
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214 | (void) lseek(db->dbm_pagf, db->dbm_blkno*PBLKSIZ, L_SET); |
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215 | if ( (ret=write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ)) != PBLKSIZ) { |
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216 | db->dbm_flags |= _DBM_IOERR; |
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217 | return (-1); |
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218 | } |
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219 | return (0); |
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220 | |
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221 | split: |
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222 | if (key.dsize+dat.dsize+3*sizeof(short) >= PBLKSIZ) { |
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223 | db->dbm_flags |= _DBM_IOERR; |
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224 | errno = ENOSPC; |
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225 | return (-1); |
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226 | } |
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227 | bzero(ovfbuf, PBLKSIZ); |
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228 | for (i=0;;) { |
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229 | item = makdatum(db->dbm_pagbuf, i); |
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230 | if (item.dptr == NULL) |
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231 | break; |
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232 | if (dcalchash(item) & (db->dbm_hmask+1)) { |
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233 | item1 = makdatum(db->dbm_pagbuf, i+1); |
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234 | if (item1.dptr == NULL) { |
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235 | fprintf(stderr, "ndbm: split not paired\n"); |
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236 | db->dbm_flags |= _DBM_IOERR; |
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237 | break; |
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238 | } |
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239 | if (!additem(ovfbuf, item, item1) || |
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240 | !delitem(db->dbm_pagbuf, i)) { |
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241 | db->dbm_flags |= _DBM_IOERR; |
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242 | return (-1); |
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243 | } |
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244 | continue; |
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245 | } |
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246 | i += 2; |
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247 | } |
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248 | db->dbm_pagbno = db->dbm_blkno; |
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249 | (void) lseek(db->dbm_pagf, db->dbm_blkno*PBLKSIZ, L_SET); |
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250 | if (write(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ) { |
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251 | db->dbm_flags |= _DBM_IOERR; |
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252 | return (-1); |
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253 | } |
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254 | (void) lseek(db->dbm_pagf, (db->dbm_blkno+db->dbm_hmask+1)*PBLKSIZ, L_SET); |
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255 | if (write(db->dbm_pagf, ovfbuf, PBLKSIZ) != PBLKSIZ) { |
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256 | db->dbm_flags |= _DBM_IOERR; |
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257 | return (-1); |
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258 | } |
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259 | setbit(db); |
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260 | goto loop; |
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261 | } |
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262 | |
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263 | datum |
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264 | dbm_firstkey(DBM *db) |
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265 | { |
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266 | |
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267 | db->dbm_blkptr = 0L; |
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268 | db->dbm_keyptr = 0; |
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269 | return (dbm_nextkey(db)); |
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270 | } |
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271 | |
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272 | datum |
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273 | dbm_nextkey(register DBM *db) |
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274 | { |
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275 | struct stat statb; |
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276 | datum item; |
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277 | |
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278 | if (dbm_error(db) || fstat(db->dbm_pagf, &statb) < 0) |
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279 | goto err; |
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280 | statb.st_size /= PBLKSIZ; |
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281 | for (;;) { |
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282 | if (db->dbm_blkptr != db->dbm_pagbno) { |
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283 | db->dbm_pagbno = db->dbm_blkptr; |
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284 | (void) lseek(db->dbm_pagf, db->dbm_blkptr*PBLKSIZ, L_SET); |
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285 | if (read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ) |
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286 | bzero(db->dbm_pagbuf, PBLKSIZ); |
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287 | #ifdef DEBUG |
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288 | else if (chkblk(db->dbm_pagbuf) < 0) |
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289 | db->dbm_flags |= _DBM_IOERR; |
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290 | #endif |
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291 | } |
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292 | if (((short *)db->dbm_pagbuf)[0] != 0) { |
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293 | item = makdatum(db->dbm_pagbuf, db->dbm_keyptr); |
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294 | if (item.dptr != NULL) { |
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295 | db->dbm_keyptr += 2; |
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296 | return (item); |
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297 | } |
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298 | db->dbm_keyptr = 0; |
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299 | } |
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300 | if (++db->dbm_blkptr >= statb.st_size) |
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301 | break; |
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302 | } |
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303 | err: |
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304 | item.dptr = NULL; |
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305 | item.dsize = 0; |
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306 | return (item); |
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307 | } |
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308 | |
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309 | static void |
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310 | dbm_access(register DBM *db, long hash) |
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311 | { |
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312 | for (db->dbm_hmask=0;; db->dbm_hmask=(db->dbm_hmask<<1)+1) { |
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313 | db->dbm_blkno = hash & db->dbm_hmask; |
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314 | db->dbm_bitno = db->dbm_blkno + db->dbm_hmask; |
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315 | if (getbit(db) == 0) |
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316 | break; |
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317 | } |
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318 | if (db->dbm_blkno != db->dbm_pagbno) { |
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319 | db->dbm_pagbno = db->dbm_blkno; |
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320 | (void) lseek(db->dbm_pagf, db->dbm_blkno*PBLKSIZ, L_SET); |
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321 | if (read(db->dbm_pagf, db->dbm_pagbuf, PBLKSIZ) != PBLKSIZ) |
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322 | bzero(db->dbm_pagbuf, PBLKSIZ); |
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323 | #ifdef DEBUG |
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324 | else if (chkblk(db->dbm_pagbuf) < 0) |
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325 | db->dbm_flags |= _DBM_IOERR; |
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326 | #endif |
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327 | } |
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328 | } |
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329 | |
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330 | static |
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331 | int getbit(register DBM *db) |
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332 | { |
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333 | long bn; |
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334 | register b, i, n; |
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335 | |
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336 | |
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337 | if (db->dbm_bitno > db->dbm_maxbno) |
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338 | return (0); |
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339 | n = db->dbm_bitno % BYTESIZ; |
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340 | bn = db->dbm_bitno / BYTESIZ; |
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341 | i = bn % DBLKSIZ; |
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342 | b = bn / DBLKSIZ; |
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343 | if (b != db->dbm_dirbno) { |
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344 | db->dbm_dirbno = b; |
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345 | (void) lseek(db->dbm_dirf, (long)b*DBLKSIZ, L_SET); |
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346 | if (read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ) |
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347 | bzero(db->dbm_dirbuf, DBLKSIZ); |
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348 | } |
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349 | return (db->dbm_dirbuf[i] & (1<<n)); |
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350 | } |
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351 | |
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352 | static void |
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353 | setbit(register DBM *db) |
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354 | { |
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355 | long bn; |
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356 | register i, n, b; |
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357 | |
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358 | if (db->dbm_bitno > db->dbm_maxbno) |
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359 | db->dbm_maxbno = db->dbm_bitno; |
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360 | n = db->dbm_bitno % BYTESIZ; |
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361 | bn = db->dbm_bitno / BYTESIZ; |
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362 | i = bn % DBLKSIZ; |
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363 | b = bn / DBLKSIZ; |
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364 | if (b != db->dbm_dirbno) { |
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365 | db->dbm_dirbno = b; |
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366 | (void) lseek(db->dbm_dirf, (long)b*DBLKSIZ, L_SET); |
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367 | if (read(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ) |
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368 | bzero(db->dbm_dirbuf, DBLKSIZ); |
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369 | } |
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370 | db->dbm_dirbuf[i] |= 1<<n; |
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371 | db->dbm_dirbno = b; |
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372 | (void) lseek(db->dbm_dirf, (long)b*DBLKSIZ, L_SET); |
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373 | if (write(db->dbm_dirf, db->dbm_dirbuf, DBLKSIZ) != DBLKSIZ) |
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374 | db->dbm_flags |= _DBM_IOERR; |
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375 | } |
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376 | |
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377 | static datum |
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378 | makdatum(char buf[PBLKSIZ], int n) |
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379 | { |
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380 | register short *sp; |
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381 | register t; |
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382 | datum item; |
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383 | |
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384 | sp = (short *)buf; |
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385 | if ((unsigned)n >= sp[0]) { |
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386 | item.dptr = NULL; |
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387 | item.dsize = 0; |
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388 | return (item); |
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389 | } |
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390 | t = PBLKSIZ; |
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391 | if (n > 0) |
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392 | t = sp[n]; |
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393 | item.dptr = buf+sp[n+1]; |
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394 | item.dsize = t - sp[n+1]; |
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395 | return (item); |
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396 | } |
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397 | |
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398 | static |
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399 | int finddatum(char buf[PBLKSIZ], datum item) |
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400 | { |
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401 | register short *sp; |
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402 | register int i, n, j; |
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403 | |
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404 | sp = (short *)buf; |
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405 | n = PBLKSIZ; |
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406 | for (i=0, j=sp[0]; i<j; i+=2, n = sp[i]) { |
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407 | n -= sp[i+1]; |
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408 | if (n != item.dsize) |
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409 | continue; |
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410 | if (n == 0 || bcmp(&buf[sp[i+1]], item.dptr, n) == 0) |
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411 | return (i); |
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412 | } |
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413 | return (-1); |
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414 | } |
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415 | |
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416 | static int hitab[16] |
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417 | /* ken's |
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418 | { |
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419 | 055,043,036,054,063,014,004,005, |
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420 | 010,064,077,000,035,027,025,071, |
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421 | }; |
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422 | */ |
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423 | = { 61, 57, 53, 49, 45, 41, 37, 33, |
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424 | 29, 25, 21, 17, 13, 9, 5, 1, |
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425 | }; |
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426 | static long hltab[64] |
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427 | = { |
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428 | 06100151277L,06106161736L,06452611562L,05001724107L, |
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429 | 02614772546L,04120731531L,04665262210L,07347467531L, |
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430 | 06735253126L,06042345173L,03072226605L,01464164730L, |
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431 | 03247435524L,07652510057L,01546775256L,05714532133L, |
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432 | 06173260402L,07517101630L,02431460343L,01743245566L, |
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433 | 00261675137L,02433103631L,03421772437L,04447707466L, |
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434 | 04435620103L,03757017115L,03641531772L,06767633246L, |
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435 | 02673230344L,00260612216L,04133454451L,00615531516L, |
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436 | 06137717526L,02574116560L,02304023373L,07061702261L, |
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437 | 05153031405L,05322056705L,07401116734L,06552375715L, |
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438 | 06165233473L,05311063631L,01212221723L,01052267235L, |
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439 | 06000615237L,01075222665L,06330216006L,04402355630L, |
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440 | 01451177262L,02000133436L,06025467062L,07121076461L, |
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441 | 03123433522L,01010635225L,01716177066L,05161746527L, |
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442 | 01736635071L,06243505026L,03637211610L,01756474365L, |
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443 | 04723077174L,03642763134L,05750130273L,03655541561L, |
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444 | }; |
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445 | |
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446 | static long |
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447 | hashinc(register DBM *db, long hash) |
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448 | { |
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449 | long bit; |
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450 | |
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451 | hash &= db->dbm_hmask; |
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452 | bit = db->dbm_hmask+1; |
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453 | for (;;) { |
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454 | bit >>= 1; |
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455 | if (bit == 0) |
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456 | return (0L); |
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457 | if ((hash & bit) == 0) |
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458 | return (hash | bit); |
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459 | hash &= ~bit; |
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460 | } |
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461 | } |
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462 | |
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463 | static long |
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464 | dcalchash(datum item) |
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465 | { |
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466 | register int s, c, j; |
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467 | register char *cp; |
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468 | register long hashl; |
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469 | register int hashi; |
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470 | |
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471 | hashl = 0; |
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472 | hashi = 0; |
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473 | for (cp = item.dptr, s=item.dsize; --s >= 0; ) { |
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474 | c = *cp++; |
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475 | for (j=0; j<BYTESIZ; j+=4) { |
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476 | hashi += hitab[c&017]; |
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477 | hashl += hltab[hashi&63]; |
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478 | c >>= 4; |
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479 | } |
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480 | } |
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481 | return (hashl); |
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482 | } |
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483 | |
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484 | /* |
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485 | * Delete pairs of items (n & n+1). |
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486 | */ |
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487 | static |
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488 | int delitem(char buf[PBLKSIZ], int n) |
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489 | { |
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490 | register short *sp, *sp1; |
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491 | register i1, i2; |
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492 | |
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493 | sp = (short *)buf; |
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494 | i2 = sp[0]; |
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495 | if ((unsigned)n >= i2 || (n & 1)) |
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496 | return (0); |
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497 | if (n == i2-2) { |
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498 | sp[0] -= 2; |
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499 | return (1); |
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500 | } |
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501 | i1 = PBLKSIZ; |
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502 | if (n > 0) |
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503 | i1 = sp[n]; |
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504 | i1 -= sp[n+2]; |
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505 | if (i1 > 0) { |
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506 | i2 = sp[i2]; |
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507 | bcopy(&buf[i2], &buf[i2 + i1], sp[n+2] - i2); |
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508 | } |
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509 | sp[0] -= 2; |
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510 | for (sp1 = sp + sp[0], sp += n+1; sp <= sp1; sp++) |
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511 | sp[0] = sp[2] + i1; |
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512 | return (1); |
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513 | } |
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514 | |
---|
515 | /* |
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516 | * Add pairs of items (item & item1). |
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517 | */ |
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518 | static |
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519 | int additem(char buf[PBLKSIZ], datum item, datum item1) |
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520 | { |
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521 | register short *sp; |
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522 | register i1, i2; |
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523 | |
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524 | sp = (short *)buf; |
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525 | i1 = PBLKSIZ; |
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526 | i2 = sp[0]; |
---|
527 | if (i2 > 0) |
---|
528 | i1 = sp[i2]; |
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529 | i1 -= item.dsize + item1.dsize; |
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530 | if (i1 <= (i2+3) * sizeof(short)) |
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531 | return (0); |
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532 | sp[0] += 2; |
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533 | sp[++i2] = i1 + item1.dsize; |
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534 | bcopy(item.dptr, &buf[i1 + item1.dsize], item.dsize); |
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535 | sp[++i2] = i1; |
---|
536 | bcopy(item1.dptr, &buf[i1], item1.dsize); |
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537 | return (1); |
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538 | } |
---|
539 | |
---|
540 | #ifdef DEBUG |
---|
541 | static |
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542 | chkblk(char buf[PBLKSIZ]) |
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543 | { |
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544 | register short *sp; |
---|
545 | register t, i; |
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546 | |
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547 | sp = (short *)buf; |
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548 | t = PBLKSIZ; |
---|
549 | for (i=0; i<sp[0]; i++) { |
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550 | if (sp[i+1] > t) |
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551 | return (-1); |
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552 | t = sp[i+1]; |
---|
553 | } |
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554 | if (t < (sp[0]+1)*sizeof(short)) |
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555 | return (-1); |
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556 | return (0); |
---|
557 | } |
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558 | #endif |
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559 | |
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560 | #endif /* HAVE_DBM */ |
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