1 | /**********************************************************************
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2 | *
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3 | * gdbmclass.cpp --
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4 | * Copyright (C) 1999-2008 The New Zealand Digital Library Project
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5 | *
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6 | * A component of the Greenstone digital library software
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7 | * from the New Zealand Digital Library Project at the
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8 | * University of Waikato, New Zealand.
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9 | *
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10 | * This program is free software; you can redistribute it and/or modify
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11 | * it under the terms of the GNU General Public License as published by
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12 | * the Free Software Foundation; either version 2 of the License, or
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13 | * (at your option) any later version.
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14 | *
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15 | * This program is distributed in the hope that it will be useful,
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16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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18 | * GNU General Public License for more details.
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19 | *
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20 | * You should have received a copy of the GNU General Public License
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21 | * along with this program; if not, write to the Free Software
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22 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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23 | *
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24 | *********************************************************************/
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25 |
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26 | #include "gdbmclass.h"
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27 | #include "gsdltools.h"
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28 | #include "gsdlunicode.h"
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29 | #include "fileutil.h"
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30 | #include "stdlib.h"
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31 | #include <cstring>
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32 |
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33 |
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34 | gdbmclass::gdbmclass(const text_t& gsdlhome)
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35 | : dbclass(gsdlhome)
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36 | {
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37 | gdbmfile = NULL;
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38 | }
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39 |
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40 | gdbmclass::~gdbmclass()
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41 | {
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42 | closedatabase();
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43 | }
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44 |
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45 |
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46 | // returns true if opened
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47 | bool gdbmclass::opendatabase (const text_t &filename, int mode, int num_retrys,
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48 | #ifdef _MSC_VER
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49 | bool need_filelock
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50 | #else
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51 | bool
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52 | #endif
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53 | )
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54 | {
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55 |
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56 | text_t data_location;
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57 | int block_size = 512;
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58 |
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59 | if (gdbmfile != NULL) {
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60 | if (openfile == filename) return true;
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61 | else closedatabase ();
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62 | }
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63 |
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64 | // Map the DB mode values into GDBM mode values
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65 | int gdbm_mode = GDBM_READER;
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66 | if (mode == DB_WRITER)
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67 | {
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68 | gdbm_mode = GDBM_WRITER;
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69 | }
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70 | else if (mode == DB_WRITER_CREATE)
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71 | {
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72 | gdbm_mode = GDBM_WRCREAT;
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73 | }
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74 |
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75 | text_t gdbm_filename = filename;
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76 | if (gdbm_mode == GDBM_READER)
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77 | {
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78 | // make sure we have the right file extension. Should be all gdb now.
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79 | // But need to handle old style ldb/bdb collection dbs
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80 |
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81 | // If the specified GDBM file doesn't exist, (should be gdb) try the other extensions (we can now read both)
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82 | if (!file_exists(gdbm_filename))
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83 | {
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84 | // should be all gdb now
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85 | if (ends_with(gdbm_filename, ".gdb")) {
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86 | gdbm_filename = substr(gdbm_filename.begin(), gdbm_filename.end() - ((text_t) ".gdb").size()) + ".ldb";
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87 |
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88 | if (!file_exists(gdbm_filename)) {
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89 | // try bdb as well
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90 | gdbm_filename = substr(gdbm_filename.begin(), gdbm_filename.end() - ((text_t) ".ldb").size()) + ".bdb";
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91 | }
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92 | }
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93 | }
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94 |
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95 | // The following fall-back is less likely to be needed now that GDBM
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96 | // library reads both little-endian and big-endian files
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97 | if (!file_exists(gdbm_filename))
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98 | {
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99 | // We're desperate, so try generating the desired GDBM file from a txtgz file
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100 | gdbm_filename = filename;
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101 | generate_from_txtgz(gdbm_filename);
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102 | }
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103 | }
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104 |
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105 | char *namebuffer = gdbm_filename.getcstr();
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106 | do {
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107 | #ifdef _MSC_VER
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108 | gdbmfile = gdbm_open (namebuffer, block_size, gdbm_mode, 00664, NULL, (need_filelock) ? 1 : 0);
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109 | #else
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110 | gdbmfile = gdbm_open (namebuffer, block_size, gdbm_mode, 00664, NULL);
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111 | #endif
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112 | --num_retrys;
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113 | } while (num_retrys>0 && gdbmfile==NULL &&
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114 | (gdbm_errno==GDBM_CANT_BE_READER || gdbm_errno==GDBM_CANT_BE_WRITER));
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115 | delete []namebuffer;
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116 |
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117 | if (gdbmfile == NULL && logout != NULL) {
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118 | outconvertclass text_t2ascii;
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119 | (*logout) << text_t2ascii << "database open failed on: " << gdbm_filename << "\n";
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120 | }
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121 |
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122 | openfile = filename;
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123 |
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124 | return (gdbmfile != NULL);
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125 | }
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126 |
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127 |
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128 | void gdbmclass::closedatabase ()
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129 | {
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130 | if (gdbmfile == NULL) return;
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131 |
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132 | gdbm_close (gdbmfile);
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133 | gdbmfile = NULL;
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134 | openfile.clear();
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135 | }
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136 |
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137 |
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138 | void gdbmclass::deletekey (const text_t &key)
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139 | {
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140 | if (gdbmfile == NULL) return;
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141 |
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142 | // get a utf-8 encoded c string of the unicode key
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143 | datum key_data;
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144 | key_data.dptr = (to_utf8(key)).getcstr();
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145 | if (key_data.dptr == NULL) return;
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146 | key_data.dsize = strlen (key_data.dptr);
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147 |
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148 | // delete the key
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149 | gdbm_delete (gdbmfile, key_data);
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150 |
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151 | // free up the key memory
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152 | delete []key_data.dptr;
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153 | }
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154 |
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155 |
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156 | // returns file extension string
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157 | text_t gdbmclass::getfileextension ()
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158 | {
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159 | // now we always use gdb for gdbm files. later on, if we can't find it, we'll try ldb and bdb for backwards compatibility
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160 | return ".gdb";
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161 | //if (littleEndian()) return ".ldb";
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162 | //return ".bdb";
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163 | }
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164 |
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165 |
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166 | // returns true on success
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167 | bool gdbmclass::getkeydata (const text_t& key, text_t &data)
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168 | {
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169 | datum key_data;
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170 | datum return_data;
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171 |
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172 | if (gdbmfile == NULL) return false;
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173 |
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174 | // get a utf-8 encoded c string of the unicode key
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175 | key_data.dptr = (to_utf8(key)).getcstr();
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176 | if (key_data.dptr == NULL) {
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177 | if (logout != NULL) (*logout) << "gdbmclass: out of memory" << endl;
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178 | return false;
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179 | }
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180 | key_data.dsize = strlen (key_data.dptr);
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181 |
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182 | // fetch the result
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183 | return_data = gdbm_fetch (gdbmfile, key_data);
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184 | delete []key_data.dptr;
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185 |
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186 | if (return_data.dptr == NULL) return false;
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187 |
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188 | data.setcarr (return_data.dptr, return_data.dsize);
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189 | free (return_data.dptr);
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190 | data = to_uni(data); // convert to unicode
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191 |
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192 | return true;
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193 | }
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194 |
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195 |
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196 | // returns array of keys
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197 | text_tarray gdbmclass::getkeys ()
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198 | {
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199 | text_tarray keys;
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200 |
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201 | text_t key = getfirstkey();
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202 | while (!key.empty())
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203 | {
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204 | keys.push_back(key);
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205 | key = getnextkey(key);
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206 | }
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207 |
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208 | return keys;
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209 | }
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210 |
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211 |
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212 | // returns true on success
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213 | bool gdbmclass::setkeydata (const text_t &key, const text_t &data)
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214 | {
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215 | if (gdbmfile == NULL) return false;
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216 |
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217 | // store the value
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218 | datum key_data;
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219 | datum data_data;
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220 |
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221 | // get a utf-8 encoded c string of the unicode key
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222 | key_data.dptr = (to_utf8(key)).getcstr();
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223 | if (key_data.dptr == NULL) {
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224 | if (logout != NULL) (*logout) << "gdbmclass: out of memory" << endl;
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225 | return false;
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226 | }
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227 | key_data.dsize = strlen (key_data.dptr);
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228 |
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229 | data_data.dptr = (to_utf8(data)).getcstr();
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230 | if (data_data.dptr == NULL) {
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231 | if (logout != NULL) (*logout) << "gdbmclass: out of memory" << endl;
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232 | delete []key_data.dptr;
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233 | return false;
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234 | }
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235 | data_data.dsize = strlen (data_data.dptr);
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236 |
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237 | int ret = gdbm_store (gdbmfile, key_data, data_data, GDBM_REPLACE);
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238 | delete []key_data.dptr;
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239 | delete []data_data.dptr;
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240 |
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241 | return (ret == 0);
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242 | }
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243 |
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244 |
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245 | // ----------------------------------------------------------------------------------------
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246 | // GDBM-ONLY FUNCTIONS
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247 | // ----------------------------------------------------------------------------------------
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248 |
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249 | // getfirstkey and getnextkey are used for traversing the database
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250 | // no insertions or deletions should be carried out while traversing
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251 | // the database. when there are no keys left to visit in the database
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252 | // an empty string is returned.
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253 | text_t gdbmclass::getfirstkey ()
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254 | {
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255 | if (gdbmfile == NULL) return g_EmptyText;
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256 |
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257 | // get the first key
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258 | datum firstkey_data = gdbm_firstkey (gdbmfile);
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259 | if (firstkey_data.dptr == NULL) return g_EmptyText;
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260 |
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261 | // convert it to text_t
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262 | text_t firstkey;
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263 | firstkey.setcarr (firstkey_data.dptr, firstkey_data.dsize);
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264 | free (firstkey_data.dptr);
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265 | return to_uni(firstkey); // convert to unicode
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266 | }
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267 |
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268 |
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269 | text_t gdbmclass::getnextkey (const text_t &key)
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270 | {
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271 | if (gdbmfile == NULL || key.empty()) return g_EmptyText;
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272 |
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273 | // get a utf-8 encoded c string of the unicode key
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274 | datum key_data;
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275 | key_data.dptr = (to_utf8(key)).getcstr();
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276 | if (key_data.dptr == NULL) return g_EmptyText;
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277 | key_data.dsize = strlen (key_data.dptr);
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278 |
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279 | // get the next key
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280 | datum nextkey_data = gdbm_nextkey (gdbmfile, key_data);
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281 | if (nextkey_data.dptr == NULL) {
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282 | delete []key_data.dptr;
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283 | return g_EmptyText;
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284 | }
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285 |
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286 | // convert it to text_t
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287 | text_t nextkey;
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288 | nextkey.setcarr (nextkey_data.dptr, nextkey_data.dsize);
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289 | free (nextkey_data.dptr);
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290 | delete []key_data.dptr;
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291 | return to_uni(nextkey); // convert to unicode
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292 | }
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293 |
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294 |
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295 | // The following routine was written before the GDBM library was upgraded
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296 | // to read both little-endian and big-endian files, and so the reason for
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297 | // it being developed is not so important now. It's useful to keep around
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298 | // however because the file format for GDBM is not guaranteed to be the
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299 | // same from one computer architecture to the next. Even if they are both
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300 | // the same endian-ness. We encountered this issue on the Mac at one stage.
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301 | // the size of the header data-structure for GDBM was simply a different
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302 | // size to that produced on Linux. The Mac case resolved to be binary
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303 | // compatabile with Linux, but shows that we can't rely on this always being
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304 | // the case. Using this method provides a contingency plan. The databases
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305 | // can be shipped at .txt.gz (i.e. portable), which are then converted on
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306 | // on the host's machine to a native GDBM database that is meaningly to
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307 | // that computer.
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308 |
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309 | void gdbmclass::generate_from_txtgz (text_t filename)
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310 | {
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311 | // Looking to read in the database
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312 | // => check to see if .ldb/.bdb file already there
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313 | // if not (first time) then generate using txt2db
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314 |
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315 | // need to generate architecture native GDBM file using txt2db
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316 |
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317 | // replace sought after gdbm filename ext with ".txt.gz"
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318 |
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319 | text_t::const_iterator begin = filename.begin();
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320 | text_t::const_iterator end= filename.end();
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321 |
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322 | if (begin != end) {
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323 | end = end - 1;
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324 | }
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325 |
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326 | text_t::const_iterator here = end;
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327 |
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328 | bool found_ext = false;
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329 |
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330 | while (here != begin) {
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331 | if (*here == '.') {
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332 | found_ext = true;
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333 | break;
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334 | }
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335 | here--;
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336 | }
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337 |
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338 | text_t filename_root;
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339 |
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340 | if (found_ext) {
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341 | filename_root = substr(begin,here);
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342 | }
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343 | else {
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344 | filename_root = filename;
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345 | }
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346 |
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347 | text_t txtgz_filename = filename_root + ".txt.gz";
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348 | if (file_exists(txtgz_filename))
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349 | {
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350 | //text_t cmd = "gzip --decompress --to-stdout \"" + txtgz_filename + "\"";
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351 | //cmd += " | txt2db \"" + filename + "\"";
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352 |
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353 | // Test to make sure Perl is on the path
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354 | // On Linux, the output of the test goes to STDOUT so redirect it to STDERR
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355 | text_t cmd_test = "perl -v 1>&2";
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356 | int rv_test = gsdl_system(cmd_test, true, cerr);
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357 | if (rv_test != 0) {
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358 | cerr << "Tried to find Perl. Return exit value of running "
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359 | << cmd_test <<": "<< rv_test << ", (expected this to be 0)" << endl;
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360 | cerr << "Check that Perl is set in your environment variable PATH." << endl;
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361 | cerr << "At present, PATH=" << getenv("PATH") << endl;
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362 | }
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363 |
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364 | text_t cmd = "perl -S txtgz-to-gdbm.pl \"" + txtgz_filename + "\" \"" + filename + "\"";
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365 | int rv = gsdl_system(cmd, true, cerr);
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366 | // For some reason, launching this command with gsdl_system() still returns 1
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367 | // even when it returns 0 when run from the command-line. We can check whether
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368 | // we succeeded by looking at whether the output database file was created.
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369 | if (rv != 0) {
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370 | cerr << "Warning, non-zero return value on running command \""
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371 | << cmd << "\": " << rv << endl;
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372 | if (!file_exists(filename)) {
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373 | cerr << "Tried to run command \""<<cmd<<"\", but it failed" << endl;
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374 | }
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375 | }
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376 | }
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377 | }
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