root / logic / trunk / src / mxml / mxml-index.c @ 71
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1 | 49 | Janez1 | /*
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2 | * "$Id: mxml-index.c 184 2005-01-29 07:21:44Z mike $"
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3 | *
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4 | * Index support code for Mini-XML, a small XML-like file parsing library.
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5 | *
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6 | * Copyright 2003-2005 by Michael Sweet.
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7 | *
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8 | * This program is free software; you can redistribute it and/or
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9 | * modify it under the terms of the GNU Library General Public
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10 | * License as published by the Free Software Foundation; either
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11 | * version 2, or (at your option) any later version.
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12 | *
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13 | * This program is distributed in the hope that it will be useful,
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14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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16 | * GNU General Public License for more details.
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17 | *
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18 | * Contents:
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19 | *
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20 | * mxmlIndexDelete() - Delete an index.
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21 | * mxmlIndexEnum() - Return the next node in the index.
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22 | * mxmlIndexFind() - Find the next matching node.
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23 | * mxmlIndexNew() - Create a new index.
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24 | * mxmlIndexReset() - Reset the enumeration/find pointer in the index and
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25 | * return the first node in the index.
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26 | * index_compare() - Compare two nodes.
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27 | * index_find() - Compare a node with index values.
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28 | * index_sort() - Sort the nodes in the index...
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29 | */
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30 | |||
31 | /*
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32 | * Include necessary headers...
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33 | */
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34 | |||
35 | #include "config.h" |
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36 | #include "mxml.h" |
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37 | |||
38 | |||
39 | /*
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40 | * Sort functions...
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41 | */
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42 | |||
43 | static int index_compare(mxml_index_t *ind, mxml_node_t *first, |
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44 | mxml_node_t *second); |
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45 | static int index_find(mxml_index_t *ind, const char *element, |
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46 | const char *value, mxml_node_t *node); |
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47 | static void index_sort(mxml_index_t *ind, int left, int right); |
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48 | |||
49 | |||
50 | /*
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51 | * 'mxmlIndexDelete()' - Delete an index.
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52 | */
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53 | |||
54 | void
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55 | mxmlIndexDelete(mxml_index_t *ind) /* I - Index to delete */
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56 | { |
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57 | /*
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58 | * Range check input..
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59 | */
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60 | |||
61 | if (!ind)
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62 | return;
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63 | |||
64 | /*
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65 | * Free memory...
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66 | */
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67 | |||
68 | if (ind->attr)
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69 | free(ind->attr); |
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70 | |||
71 | if (ind->alloc_nodes)
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72 | free(ind->nodes); |
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73 | |||
74 | free(ind); |
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75 | } |
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76 | |||
77 | |||
78 | /*
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79 | * 'mxmlIndexEnum()' - Return the next node in the index.
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80 | *
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81 | * Nodes are returned in the sorted order of the index.
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82 | */
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83 | |||
84 | mxml_node_t * /* O - Next node or NULL if there is none */
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85 | mxmlIndexEnum(mxml_index_t *ind) /* I - Index to enumerate */
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86 | { |
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87 | /*
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88 | * Range check input...
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89 | */
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90 | |||
91 | if (!ind)
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92 | return (NULL); |
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93 | |||
94 | /*
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95 | * Return the next node...
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96 | */
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97 | |||
98 | if (ind->cur_node < ind->num_nodes)
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99 | return (ind->nodes[ind->cur_node ++]);
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100 | else
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101 | return (NULL); |
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102 | } |
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103 | |||
104 | |||
105 | /*
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106 | * 'mxmlIndexFind()' - Find the next matching node.
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107 | *
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108 | * You should call mxmlIndexReset() prior to using this function for
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109 | * the first time with a particular set of "element" and "value"
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110 | * strings. Passing NULL for both "element" and "value" is equivalent
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111 | * to calling mxmlIndexEnum().
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112 | */
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113 | |||
114 | mxml_node_t * /* O - Node or NULL if none found */
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115 | mxmlIndexFind(mxml_index_t *ind, /* I - Index to search */
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116 | const char *element, /* I - Element name to find, if any */ |
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117 | const char *value) /* I - Attribute value, if any */ |
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118 | { |
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119 | int diff, /* Difference between names */ |
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120 | current, /* Current entity in search */
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121 | first, /* First entity in search */
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122 | last; /* Last entity in search */
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123 | |||
124 | |||
125 | #ifdef DEBUG
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126 | printf("mxmlIndexFind(ind=%p, element=\"%s\", value=\"%s\")\n",
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127 | ind, element ? element : "(null)", value ? value : "(null)"); |
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128 | #endif /* DEBUG */ |
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129 | |||
130 | /*
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131 | * Range check input...
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132 | */
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133 | |||
134 | if (!ind || (!ind->attr && value))
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135 | { |
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136 | #ifdef DEBUG
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137 | puts(" returning NULL...");
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138 | printf(" ind->attr=\"%s\"\n", ind->attr ? ind->attr : "(null)"); |
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139 | #endif /* DEBUG */ |
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140 | |||
141 | return (NULL); |
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142 | } |
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143 | |||
144 | /*
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145 | * If both element and value are NULL, just enumerate the nodes in the
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146 | * index...
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147 | */
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148 | |||
149 | if (!element && !value)
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150 | return (mxmlIndexEnum(ind));
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151 | |||
152 | /*
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153 | * If there are no nodes in the index, return NULL...
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154 | */
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155 | |||
156 | if (!ind->num_nodes)
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157 | { |
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158 | #ifdef DEBUG
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159 | puts(" returning NULL...");
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160 | puts(" no nodes!");
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161 | #endif /* DEBUG */ |
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162 | |||
163 | return (NULL); |
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164 | } |
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165 | |||
166 | /*
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167 | * If cur_node == 0, then find the first matching node...
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168 | */
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169 | |||
170 | if (ind->cur_node == 0) |
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171 | { |
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172 | /*
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173 | * Find the first node using a modified binary search algorithm...
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174 | */
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175 | |||
176 | first = 0;
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177 | last = ind->num_nodes - 1;
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178 | |||
179 | #ifdef DEBUG
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180 | printf(" find first time, num_nodes=%d...\n", ind->num_nodes);
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181 | #endif /* DEBUG */ |
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182 | |||
183 | while ((last - first) > 1) |
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184 | { |
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185 | current = (first + last) / 2;
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186 | |||
187 | #ifdef DEBUG
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188 | printf(" first=%d, last=%d, current=%d\n", first, last, current);
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189 | #endif /* DEBUG */ |
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190 | |||
191 | if ((diff = index_find(ind, element, value, ind->nodes[current])) == 0) |
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192 | { |
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193 | /*
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194 | * Found a match, move back to find the first...
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195 | */
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196 | |||
197 | #ifdef DEBUG
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198 | puts(" match!");
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199 | #endif /* DEBUG */ |
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200 | |||
201 | while (current > 0 && |
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202 | !index_find(ind, element, value, ind->nodes[current - 1]))
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203 | current --; |
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204 | |||
205 | #ifdef DEBUG
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206 | printf(" returning first match=%d\n", current);
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207 | #endif /* DEBUG */ |
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208 | |||
209 | /*
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210 | * Return the first match and save the index to the next...
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211 | */
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212 | |||
213 | ind->cur_node = current + 1;
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214 | |||
215 | return (ind->nodes[current]);
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216 | } |
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217 | else if (diff < 0) |
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218 | last = current; |
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219 | else
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220 | first = current; |
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221 | |||
222 | #ifdef DEBUG
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223 | printf(" diff=%d\n", diff);
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224 | #endif /* DEBUG */ |
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225 | } |
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226 | |||
227 | /*
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228 | * If we get this far, then we found exactly 0 or 1 matches...
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229 | */
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230 | |||
231 | for (current = first; current <= last; current ++)
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232 | if (!index_find(ind, element, value, ind->nodes[current]))
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233 | { |
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234 | /*
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235 | * Found exactly one (or possibly two) match...
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236 | */
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237 | |||
238 | #ifdef DEBUG
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239 | printf(" returning only match %d...\n", current);
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240 | #endif /* DEBUG */ |
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241 | |||
242 | ind->cur_node = current + 1;
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243 | |||
244 | return (ind->nodes[current]);
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245 | } |
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246 | |||
247 | /*
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248 | * No matches...
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249 | */
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250 | |||
251 | ind->cur_node = ind->num_nodes; |
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252 | |||
253 | #ifdef DEBUG
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254 | puts(" returning NULL...");
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255 | #endif /* DEBUG */ |
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256 | |||
257 | return (NULL); |
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258 | } |
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259 | else if (ind->cur_node < ind->num_nodes && |
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260 | !index_find(ind, element, value, ind->nodes[ind->cur_node])) |
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261 | { |
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262 | /*
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263 | * Return the next matching node...
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264 | */
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265 | |||
266 | #ifdef DEBUG
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267 | printf(" returning next match %d...\n", ind->cur_node);
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268 | #endif /* DEBUG */ |
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269 | |||
270 | return (ind->nodes[ind->cur_node ++]);
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271 | } |
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272 | |||
273 | /*
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274 | * If we get this far, then we have no matches...
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275 | */
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276 | |||
277 | ind->cur_node = ind->num_nodes; |
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278 | |||
279 | #ifdef DEBUG
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280 | puts(" returning NULL...");
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281 | #endif /* DEBUG */ |
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282 | |||
283 | return (NULL); |
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284 | } |
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285 | |||
286 | |||
287 | /*
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288 | * 'mxmlIndexNew()' - Create a new index.
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289 | *
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290 | * The index will contain all nodes that contain the named element and/or
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291 | * attribute. If both "element" and "attr" are NULL, then the index will
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292 | * contain a sorted list of the elements in the node tree. Nodes are
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293 | * sorted by element name and optionally by attribute value if the "attr"
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294 | * argument is not NULL.
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295 | */
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296 | |||
297 | mxml_index_t * /* O - New index */
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298 | mxmlIndexNew(mxml_node_t *node, /* I - XML node tree */
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299 | const char *element, /* I - Element to index or NULL for all */ |
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300 | const char *attr) /* I - Attribute to index or NULL for none */ |
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301 | { |
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302 | mxml_index_t *ind; /* New index */
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303 | mxml_node_t *current, /* Current node in index */
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304 | **temp; /* Temporary node pointer array */
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305 | |||
306 | |||
307 | /*
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308 | * Range check input...
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309 | */
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310 | |||
311 | #ifdef DEBUG
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312 | printf("mxmlIndexNew(node=%p, element=\"%s\", attr=\"%s\")\n",
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313 | node, element ? element : "(null)", attr ? attr : "(null)"); |
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314 | #endif /* DEBUG */ |
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315 | |||
316 | if (!node)
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317 | return (NULL); |
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318 | |||
319 | /*
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320 | * Create a new index...
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321 | */
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322 | |||
323 | if ((ind = calloc(1, sizeof(mxml_index_t))) == NULL) |
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324 | { |
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325 | mxml_error("Unable to allocate %d bytes for index - %s",
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326 | sizeof(mxml_index_t), strerror(errno));
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327 | return (NULL); |
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328 | } |
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329 | |||
330 | if (attr)
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331 | ind->attr = strdup(attr); |
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332 | |||
333 | if (!element && !attr)
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334 | current = node; |
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335 | else
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336 | current = mxmlFindElement(node, node, element, attr, NULL, MXML_DESCEND);
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337 | |||
338 | while (current)
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339 | { |
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340 | if (ind->num_nodes >= ind->alloc_nodes)
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341 | { |
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342 | if (!ind->alloc_nodes)
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343 | temp = malloc(64 * sizeof(mxml_node_t *)); |
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344 | else
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345 | temp = realloc(ind->nodes, (ind->alloc_nodes + 64) * sizeof(mxml_node_t *)); |
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346 | |||
347 | if (!temp)
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348 | { |
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349 | /*
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350 | * Unable to allocate memory for the index, so abort...
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351 | */
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352 | |||
353 | mxml_error("Unable to allocate %d bytes for index: %s",
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354 | (ind->alloc_nodes + 64) * sizeof(mxml_node_t *), |
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355 | strerror(errno)); |
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356 | |||
357 | mxmlIndexDelete(ind); |
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358 | return (NULL); |
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359 | } |
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360 | |||
361 | ind->nodes = temp; |
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362 | ind->alloc_nodes += 64;
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363 | } |
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364 | |||
365 | ind->nodes[ind->num_nodes ++] = current; |
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366 | |||
367 | current = mxmlFindElement(current, node, element, attr, NULL, MXML_DESCEND);
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368 | } |
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369 | |||
370 | /*
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371 | * Sort nodes based upon the search criteria...
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372 | */
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373 | |||
374 | #ifdef DEBUG
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375 | { |
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376 | int i; /* Looping var */ |
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377 | |||
378 | |||
379 | printf("%d node(s) in index.\n\n", ind->num_nodes);
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380 | |||
381 | if (attr)
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382 | { |
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383 | printf("Node Address Element %s\n", attr);
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384 | puts("-------- -------- -------------- ------------------------------");
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385 | |||
386 | for (i = 0; i < ind->num_nodes; i ++) |
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387 | printf("%8d %-8p %-14.14s %s\n", i, ind->nodes[i],
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388 | ind->nodes[i]->value.element.name, |
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389 | mxmlElementGetAttr(ind->nodes[i], attr)); |
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390 | } |
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391 | else
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392 | { |
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393 | puts("Node Address Element");
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394 | puts("-------- -------- --------------");
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395 | |||
396 | for (i = 0; i < ind->num_nodes; i ++) |
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397 | printf("%8d %-8p %s\n", i, ind->nodes[i],
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398 | ind->nodes[i]->value.element.name); |
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399 | } |
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400 | |||
401 | putchar('\n');
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402 | } |
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403 | #endif /* DEBUG */ |
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404 | |||
405 | if (ind->num_nodes > 1) |
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406 | index_sort(ind, 0, ind->num_nodes - 1); |
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407 | |||
408 | #ifdef DEBUG
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409 | { |
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410 | int i; /* Looping var */ |
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411 | |||
412 | |||
413 | puts("After sorting:\n");
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414 | |||
415 | if (attr)
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416 | { |
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417 | printf("Node Address Element %s\n", attr);
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418 | puts("-------- -------- -------------- ------------------------------");
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419 | |||
420 | for (i = 0; i < ind->num_nodes; i ++) |
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421 | printf("%8d %-8p %-14.14s %s\n", i, ind->nodes[i],
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422 | ind->nodes[i]->value.element.name, |
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423 | mxmlElementGetAttr(ind->nodes[i], attr)); |
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424 | } |
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425 | else
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426 | { |
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427 | puts("Node Address Element");
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428 | puts("-------- -------- --------------");
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429 | |||
430 | for (i = 0; i < ind->num_nodes; i ++) |
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431 | printf("%8d %-8p %s\n", i, ind->nodes[i],
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432 | ind->nodes[i]->value.element.name); |
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433 | } |
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434 | |||
435 | putchar('\n');
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436 | } |
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437 | #endif /* DEBUG */ |
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438 | |||
439 | /*
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440 | * Return the new index...
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441 | */
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442 | |||
443 | return (ind);
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444 | } |
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445 | |||
446 | |||
447 | /*
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448 | * 'mxmlIndexReset()' - Reset the enumeration/find pointer in the index and
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449 | * return the first node in the index.
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450 | *
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451 | * This function should be called prior to using mxmlIndexEnum() or
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452 | * mxmlIndexFind() for the first time.
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453 | */
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454 | |||
455 | mxml_node_t * /* O - First node or NULL if there is none */
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456 | mxmlIndexReset(mxml_index_t *ind) /* I - Index to reset */
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457 | { |
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458 | #ifdef DEBUG
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459 | printf("mxmlIndexReset(ind=%p)\n", ind);
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460 | #endif /* DEBUG */ |
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461 | |||
462 | /*
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463 | * Range check input...
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464 | */
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465 | |||
466 | if (!ind)
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467 | return (NULL); |
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468 | |||
469 | /*
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470 | * Set the index to the first element...
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471 | */
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472 | |||
473 | ind->cur_node = 0;
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474 | |||
475 | /*
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476 | * Return the first node...
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477 | */
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478 | |||
479 | if (ind->num_nodes)
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480 | return (ind->nodes[0]); |
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481 | else
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482 | return (NULL); |
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483 | } |
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484 | |||
485 | |||
486 | /*
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487 | * 'index_compare()' - Compare two nodes.
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488 | */
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489 | |||
490 | static int /* O - Result of comparison */ |
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491 | index_compare(mxml_index_t *ind, /* I - Index */
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492 | mxml_node_t *first, /* I - First node */
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493 | mxml_node_t *second) /* I - Second node */
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494 | { |
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495 | int diff; /* Difference */ |
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496 | |||
497 | |||
498 | /*
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499 | * Check the element name...
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500 | */
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501 | |||
502 | if ((diff = strcmp(first->value.element.name,
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503 | second->value.element.name)) != 0)
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504 | return (diff);
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505 | |||
506 | /*
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507 | * Check the attribute value...
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508 | */
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509 | |||
510 | if (ind->attr)
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511 | { |
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512 | if ((diff = strcmp(mxmlElementGetAttr(first, ind->attr),
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513 | mxmlElementGetAttr(second, ind->attr))) != 0)
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514 | return (diff);
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515 | } |
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516 | |||
517 | /*
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518 | * No difference, return 0...
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519 | */
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520 | |||
521 | return (0); |
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522 | } |
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523 | |||
524 | |||
525 | /*
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526 | * 'index_find()' - Compare a node with index values.
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527 | */
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528 | |||
529 | static int /* O - Result of comparison */ |
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530 | index_find(mxml_index_t *ind, /* I - Index */
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531 | const char *element, /* I - Element name or NULL */ |
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532 | const char *value, /* I - Attribute value or NULL */ |
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533 | mxml_node_t *node) /* I - Node */
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534 | { |
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535 | int diff; /* Difference */ |
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536 | |||
537 | |||
538 | /*
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539 | * Check the element name...
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540 | */
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541 | |||
542 | if (element)
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543 | { |
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544 | if ((diff = strcmp(element, node->value.element.name)) != 0) |
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545 | return (diff);
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546 | } |
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547 | |||
548 | /*
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549 | * Check the attribute value...
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550 | */
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551 | |||
552 | if (value)
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553 | { |
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554 | if ((diff = strcmp(value, mxmlElementGetAttr(node, ind->attr))) != 0) |
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555 | return (diff);
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556 | } |
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557 | |||
558 | /*
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559 | * No difference, return 0...
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560 | */
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561 | |||
562 | return (0); |
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563 | } |
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564 | |||
565 | |||
566 | /*
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567 | * 'index_sort()' - Sort the nodes in the index...
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568 | *
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569 | * This function implements the classic quicksort algorithm...
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570 | */
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571 | |||
572 | static void |
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573 | index_sort(mxml_index_t *ind, /* I - Index to sort */
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574 | int left, /* I - Left node in partition */ |
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575 | int right) /* I - Right node in partition */ |
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576 | { |
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577 | mxml_node_t *pivot, /* Pivot node */
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578 | *temp; /* Swap node */
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579 | int templ, /* Temporary left node */ |
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580 | tempr; /* Temporary right node */
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581 | |||
582 | |||
583 | /*
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584 | * Loop until we have sorted all the way to the right...
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585 | */
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586 | |||
587 | do
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588 | { |
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589 | /*
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590 | * Sort the pivot in the current partition...
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||
591 | */
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592 | |||
593 | pivot = ind->nodes[left]; |
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594 | |||
595 | for (templ = left, tempr = right; templ < tempr;)
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||
596 | { |
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597 | /*
|
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598 | * Move left while left node <= pivot node...
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||
599 | */
|
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600 | |||
601 | while ((templ < right) &&
|
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602 | index_compare(ind, ind->nodes[templ], pivot) <= 0)
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||
603 | templ ++; |
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604 | |||
605 | /*
|
||
606 | * Move right while right node > pivot node...
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607 | */
|
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608 | |||
609 | while ((tempr > left) &&
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||
610 | index_compare(ind, ind->nodes[tempr], pivot) > 0)
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611 | tempr --; |
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612 | |||
613 | /*
|
||
614 | * Swap nodes if needed...
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||
615 | */
|
||
616 | |||
617 | if (templ < tempr)
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||
618 | { |
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619 | temp = ind->nodes[templ]; |
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620 | ind->nodes[templ] = ind->nodes[tempr]; |
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621 | ind->nodes[tempr] = temp; |
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622 | } |
||
623 | } |
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624 | |||
625 | /*
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||
626 | * When we get here, the right (tempr) node is the new position for the
|
||
627 | * pivot node...
|
||
628 | */
|
||
629 | |||
630 | if (index_compare(ind, pivot, ind->nodes[tempr]) > 0) |
||
631 | { |
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632 | ind->nodes[left] = ind->nodes[tempr]; |
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633 | ind->nodes[tempr] = pivot; |
||
634 | } |
||
635 | |||
636 | /*
|
||
637 | * Recursively sort the left partition as needed...
|
||
638 | */
|
||
639 | |||
640 | if (left < (tempr - 1)) |
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641 | index_sort(ind, left, tempr - 1);
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||
642 | } |
||
643 | while (right > (left = tempr + 1)); |
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644 | } |
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645 | |||
646 | |||
647 | /*
|
||
648 | * End of "$Id: mxml-index.c 184 2005-01-29 07:21:44Z mike $".
|
||
649 | */ |