1 | /** |
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2 | * @file |
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3 | * |
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4 | * Copyright (C) 2008-2009 Timothy D. Morgan |
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5 | * |
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6 | * This program is free software; you can redistribute it and/or modify |
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7 | * it under the terms of the GNU General Public License as published by |
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8 | * the Free Software Foundation; version 3 of the License. |
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9 | * |
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10 | * This program is distributed in the hope that it will be useful, |
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11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 | * GNU General Public License for more details. |
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14 | * |
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15 | * You should have received a copy of the GNU General Public License |
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16 | * along with this program; if not, write to the Free Software |
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17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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18 | * |
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19 | * $Id: range_list.c 168 2010-03-03 00:08:42Z tim $ |
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20 | */ |
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21 | |
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22 | #include "range_list.h" |
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23 | |
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24 | |
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25 | /*******************/ |
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26 | /* Private symbols */ |
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27 | /*******************/ |
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28 | #define RANGE_LIST_ALLOC_SIZE 256 |
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29 | |
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30 | #if 0 /* For debugging */ |
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31 | #include <stdio.h> |
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32 | static void range_list_print(const range_list* rl) |
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33 | { |
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34 | uint32_t i; |
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35 | for(i=0; i<rl->size; i++) |
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36 | fprintf(stderr, " %d=%p,%d,%d,%p", i, (void*)rl->elements[i], |
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37 | rl->elements[i]->offset, rl->elements[i]->length, |
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38 | rl->elements[i]->data); |
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39 | fprintf(stderr, "\n"); |
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40 | } |
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41 | #endif |
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42 | |
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43 | /* |
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44 | * Inserts elem into rl at the specified index and updates rl->size. |
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45 | * Memory reallocation of rl->elements is handled when necessary, and |
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46 | * rl->elem_alloced is updated in this case.. Returns false if memory |
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47 | * could not be allocated. |
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48 | */ |
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49 | static bool range_list_insert(range_list* rl, range_list_element* elem, uint32_t index) |
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50 | { |
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51 | uint32_t i; |
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52 | range_list_element** tmp; |
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53 | |
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54 | if(rl->size == rl->elem_alloced) |
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55 | { |
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56 | tmp = talloc_realloc(rl, rl->elements, range_list_element*, |
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57 | (rl->elem_alloced+RANGE_LIST_ALLOC_SIZE)); |
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58 | if(tmp == NULL) |
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59 | return false; |
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60 | rl->elements = tmp; |
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61 | rl->elem_alloced += RANGE_LIST_ALLOC_SIZE; |
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62 | } |
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63 | |
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64 | /* Do the shuffle to the right. */ |
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65 | for(i=rl->size; i > index; i--) |
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66 | rl->elements[i] = rl->elements[i-1]; |
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67 | rl->elements[index] = elem; |
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68 | |
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69 | rl->size++; |
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70 | return true; |
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71 | } |
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72 | |
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73 | /* |
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74 | * Finds the element with the closest offset to that provided, such that |
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75 | * the element's offset <= the provided offset. If no such element |
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76 | * exists, this returns -1 which indicates that the provided offset |
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77 | * appears before all elements. |
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78 | */ |
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79 | static int32_t range_list_find_previous(const range_list* rl, uint32_t offset) |
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80 | { |
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81 | uint32_t h_idx, l_idx, cur_idx; |
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82 | uint32_t h_val, l_val; |
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83 | range_list_element* cur_elem; |
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84 | |
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85 | if((rl->size == 0) || (offset < rl->elements[0]->offset)) |
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86 | return -1; |
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87 | |
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88 | if(offset >= rl->elements[rl->size-1]->offset) |
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89 | return rl->size-1; |
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90 | |
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91 | h_idx = rl->size-1; |
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92 | l_idx = 0; |
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93 | while(h_idx != l_idx) |
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94 | { |
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95 | h_val = rl->elements[h_idx]->offset + rl->elements[h_idx]->length; |
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96 | l_val = rl->elements[l_idx]->offset; |
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97 | /* Make an educated guess as to the "middle" index based on the |
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98 | * ratios of the offset and high/low values. |
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99 | */ |
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100 | cur_idx = (uint32_t)ceil((((double)offset-l_val)/(h_val-l_val))*(h_idx-l_idx)); |
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101 | if(cur_idx > h_idx) |
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102 | cur_idx = h_idx; |
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103 | if(cur_idx < l_idx) |
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104 | cur_idx = l_idx; |
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105 | cur_elem = rl->elements[cur_idx]; |
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106 | |
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107 | if((offset >= cur_elem->offset) && (offset < rl->elements[cur_idx+1]->offset)) |
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108 | return cur_idx; |
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109 | |
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110 | if(offset < cur_elem->offset) |
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111 | h_idx = cur_idx-1; |
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112 | else |
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113 | l_idx = cur_idx+1; |
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114 | } |
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115 | |
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116 | return h_idx; |
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117 | } |
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118 | |
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119 | |
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120 | /******************/ |
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121 | /* Public symbols */ |
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122 | /******************/ |
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123 | range_list* range_list_new() |
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124 | { |
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125 | range_list* rl; |
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126 | |
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127 | rl = talloc(NULL, range_list); |
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128 | if(rl == NULL) |
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129 | return NULL; |
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130 | |
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131 | rl->elements = talloc_array(rl, range_list_element*, RANGE_LIST_ALLOC_SIZE); |
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132 | if(rl->elements == NULL) |
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133 | { |
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134 | talloc_free(rl); |
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135 | return NULL; |
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136 | } |
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137 | |
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138 | rl->elem_alloced = RANGE_LIST_ALLOC_SIZE; |
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139 | rl->size = 0; |
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140 | |
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141 | return rl; |
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142 | } |
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143 | |
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144 | |
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145 | void range_list_free(range_list* rl) |
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146 | { |
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147 | if(rl != NULL) |
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148 | talloc_free(rl); |
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149 | } |
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150 | |
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151 | |
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152 | uint32_t range_list_size(const range_list* rl) |
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153 | { |
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154 | return rl->size; |
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155 | } |
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156 | |
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157 | |
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158 | |
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159 | bool range_list_add(range_list* rl, uint32_t offset, uint32_t length, void* data) |
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160 | { |
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161 | uint32_t insert_index; |
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162 | range_list_element* elem; |
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163 | range_list_element* prev_elem; |
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164 | /*fprintf(stderr, "DEBUG: rl->size=%d\n", rl->size);*/ |
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165 | /* Sorry, limited to 2**31-1 elements. */ |
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166 | if(rl->size >= 0x7FFFFFFF) |
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167 | return false; |
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168 | |
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169 | /* 0-length ranges aren't allowed. */ |
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170 | if(length == 0) |
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171 | return false; |
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172 | |
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173 | /* Check for integer overflows */ |
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174 | if((uint32_t)(offset+length) < offset || (uint32_t)(offset+length) < length) |
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175 | return false; |
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176 | |
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177 | /* Find insertion point and validate there are no overlaps */ |
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178 | insert_index = range_list_find_previous(rl, offset)+1; |
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179 | |
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180 | /* Does the previous element overlap with this one? */ |
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181 | if(insert_index > 0) |
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182 | { |
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183 | prev_elem = rl->elements[insert_index-1]; |
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184 | if(offset < prev_elem->length + prev_elem->offset) |
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185 | return false; |
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186 | } |
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187 | |
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188 | /* Does this new element overlap with the next one? */ |
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189 | if((insert_index+1 < rl->size) |
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190 | && (offset+length > rl->elements[insert_index+1]->offset)) |
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191 | return false; |
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192 | |
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193 | elem = talloc(rl->elements, range_list_element); |
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194 | if(elem == NULL) |
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195 | return false; |
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196 | elem->offset = offset; |
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197 | elem->length = length; |
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198 | elem->data = data; |
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199 | |
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200 | if(!range_list_insert(rl, elem, insert_index)) |
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201 | { |
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202 | talloc_free(elem); |
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203 | return false; |
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204 | } |
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205 | |
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206 | return true; |
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207 | } |
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208 | |
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209 | |
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210 | bool range_list_remove(range_list* rl, uint32_t index) |
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211 | { |
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212 | uint32_t i; |
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213 | range_list_element** tmp; |
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214 | |
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215 | if(index >= rl->size) |
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216 | return false; |
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217 | |
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218 | talloc_free(rl->elements[index]); |
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219 | |
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220 | /* Do the shuffle to the left. */ |
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221 | for(i=index; i < (rl->size-1); i++) |
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222 | rl->elements[i] = rl->elements[i+1]; |
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223 | rl->elements[rl->size-1] = NULL; |
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224 | rl->size--; |
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225 | |
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226 | /* Try to keep memory usage down */ |
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227 | if(rl->size + 2 * RANGE_LIST_ALLOC_SIZE < rl->elem_alloced) |
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228 | { |
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229 | tmp = talloc_realloc(rl, rl->elements, range_list_element*, |
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230 | (rl->elem_alloced-2*RANGE_LIST_ALLOC_SIZE)); |
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231 | if(tmp != NULL) |
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232 | { |
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233 | rl->elements = tmp; |
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234 | rl->elem_alloced -= 2*RANGE_LIST_ALLOC_SIZE; |
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235 | } |
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236 | } |
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237 | |
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238 | return true; |
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239 | } |
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240 | |
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241 | |
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242 | const range_list_element* range_list_get(const range_list* rl, uint32_t index) |
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243 | { |
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244 | if(index >= rl->size) |
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245 | return NULL; |
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246 | |
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247 | return rl->elements[index]; |
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248 | } |
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249 | |
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250 | |
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251 | int32_t range_list_find(const range_list* rl, uint32_t offset) |
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252 | { |
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253 | uint32_t prev_idx; |
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254 | range_list_element* elem; |
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255 | |
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256 | if(rl->size == 0) |
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257 | return -1; |
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258 | |
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259 | if((offset < rl->elements[0]->offset) |
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260 | || (offset > rl->elements[rl->size-1]->offset |
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261 | + rl->elements[rl->size-1]->length)) |
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262 | return -2; |
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263 | |
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264 | prev_idx = range_list_find_previous(rl, offset); |
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265 | elem = rl->elements[prev_idx]; |
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266 | if(offset < elem->offset+elem->length) |
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267 | return prev_idx; |
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268 | |
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269 | return -3; |
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270 | } |
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271 | |
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272 | |
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273 | void* range_list_find_data(const range_list* rl, uint32_t offset) |
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274 | { |
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275 | int32_t index = range_list_find(rl, offset); |
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276 | if(index < 0) |
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277 | return NULL; |
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278 | |
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279 | return rl->elements[index]->data; |
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280 | } |
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281 | |
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282 | |
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283 | bool range_list_split_element(range_list* rl, uint32_t index, uint32_t offset) |
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284 | { |
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285 | range_list_element* cur_elem; |
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286 | range_list_element* new_elem; |
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287 | |
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288 | if(index >= rl->size) |
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289 | return false; |
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290 | |
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291 | cur_elem = rl->elements[index]; |
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292 | if((offset <= cur_elem->offset) |
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293 | || (offset >= cur_elem->offset+cur_elem->length)) |
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294 | return false; |
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295 | |
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296 | new_elem = talloc(rl->elements, range_list_element); |
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297 | if(new_elem == NULL) |
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298 | return false; |
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299 | |
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300 | new_elem->offset = offset; |
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301 | new_elem->length = cur_elem->offset + cur_elem->length - offset; |
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302 | new_elem->data = cur_elem->data; |
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303 | |
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304 | if(!range_list_insert(rl, new_elem, index+1)) |
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305 | { |
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306 | talloc_free(new_elem); |
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307 | return false; |
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308 | } |
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309 | |
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310 | cur_elem->length = new_elem->offset - cur_elem->offset; |
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311 | |
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312 | return true; |
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313 | } |
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314 | |
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315 | |
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316 | bool range_list_has_range(range_list* rl, uint32_t start, uint32_t length) |
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317 | { |
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318 | int32_t idx1, idx2; |
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319 | |
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320 | idx1 = range_list_find(rl, start); |
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321 | if(idx1 < 0) |
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322 | return false; |
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323 | |
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324 | idx2 = range_list_find(rl, start+length); |
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325 | if(idx2 < 0) |
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326 | return false; |
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327 | |
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328 | if(idx1 == idx2) |
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329 | return true; |
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330 | |
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331 | while(idx1 != idx2) |
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332 | { |
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333 | if(rl->elements[idx1]->offset + rl->elements[idx1]->length |
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334 | != rl->elements[idx1+1]->offset) |
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335 | return false; |
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336 | idx1++; |
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337 | } |
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338 | |
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339 | return true; |
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340 | } |
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