1 | /* Dictionary data abstraction. |
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2 | * Maps from strings to pointers. |
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3 | * Stores as a sorted list of key/value pairs. |
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4 | * O(n) on inserts and deletes. |
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5 | * O(log n) on searches |
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6 | */ |
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7 | |
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8 | #include <stdlib.h> |
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9 | #include <string.h> |
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10 | #include <unistd.h> |
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11 | #include "owl.h" |
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12 | |
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13 | |
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14 | #define INITSIZE 30 |
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15 | #define GROWBY 3 / 2 |
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16 | |
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17 | void owl_dict_create(owl_dict *d) { |
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18 | d->size=0; |
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19 | d->els=g_new(owl_dict_el, INITSIZE); |
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20 | d->avail=INITSIZE; |
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21 | } |
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22 | |
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23 | int owl_dict_get_size(const owl_dict *d) { |
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24 | return(d->size); |
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25 | } |
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26 | |
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27 | /* Finds the position of an element with key k, or of the element where |
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28 | * this element would logically go, and stores the index in pos. |
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29 | * Returns 1 if found, else 0. */ |
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30 | int _owl_dict_find_pos(const owl_dict *d, const char *k, int *pos) { |
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31 | int lo = 0, hi = d->size; |
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32 | while (lo < hi) { |
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33 | int mid = (lo + hi)/2; /* lo goes up and we can't hit hi, so no +1 */ |
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34 | int cmp = strcmp(k, d->els[mid].k); |
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35 | if (cmp < 0) { |
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36 | hi = mid; |
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37 | } else if (cmp > 0) { |
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38 | lo = mid+1; |
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39 | } else { |
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40 | *pos = mid; |
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41 | return 1; |
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42 | } |
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43 | } |
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44 | *pos = lo; |
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45 | return 0; |
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46 | } |
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47 | |
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48 | /* returns the value corresponding to key k */ |
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49 | void *owl_dict_find_element(const owl_dict *d, const char *k) { |
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50 | int found, pos; |
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51 | found = _owl_dict_find_pos(d, k, &pos); |
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52 | if (!found) { |
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53 | return(NULL); |
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54 | } |
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55 | return(d->els[pos].v); |
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56 | } |
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57 | |
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58 | /* Appends dictionary keys to a list. Duplicates the keys, |
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59 | * so they will need to be freed by the caller. */ |
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60 | void owl_dict_get_keys(const owl_dict *d, owl_list *l) { |
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61 | int i; |
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62 | for (i=0; i<d->size; i++) { |
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63 | owl_list_append_element(l, g_strdup(d->els[i].k)); |
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64 | } |
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65 | } |
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66 | |
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67 | void owl_dict_noop_delete(void *x) |
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68 | { |
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69 | return; |
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70 | } |
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71 | |
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72 | /* Returns 0 on success. Will copy the key but make |
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73 | a reference to the value. Will clobber an existing |
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74 | entry with the same key iff delete_on_replace!=NULL, |
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75 | and will run delete_on_replace on the old element. |
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76 | Will return -2 if replace=NULL and match was found. |
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77 | */ |
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78 | int owl_dict_insert_element(owl_dict *d, const char *k, void *v, void (*delete_on_replace)(void *old)) |
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79 | { |
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80 | int pos, found; |
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81 | found = _owl_dict_find_pos(d, k, &pos); |
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82 | if (found && delete_on_replace) { |
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83 | delete_on_replace(d->els[pos].v); |
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84 | d->els[pos].v = v; |
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85 | return(0); |
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86 | } else if (found && !delete_on_replace) { |
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87 | return(-2); |
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88 | } else { |
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89 | if (d->size + 1 > d->avail) { |
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90 | int avail = MAX(d->avail * GROWBY, d->size + 1); |
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91 | d->els = g_renew(owl_dict_el, d->els, avail); |
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92 | d->avail = avail; |
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93 | if (d->els==NULL) return(-1); |
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94 | } |
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95 | if (pos!=d->size) { |
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96 | /* shift forward to leave us a slot */ |
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97 | memmove(d->els+pos+1, d->els+pos, |
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98 | sizeof(owl_dict_el)*(d->size-pos)); |
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99 | } |
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100 | d->size++; |
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101 | d->els[pos].k = g_strdup(k); |
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102 | d->els[pos].v = v; |
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103 | return(0); |
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104 | } |
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105 | } |
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106 | |
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107 | /* Doesn't free the value of the element, but does |
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108 | * return it so the caller can free it. */ |
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109 | CALLER_OWN void *owl_dict_remove_element(owl_dict *d, const char *k) |
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110 | { |
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111 | int i; |
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112 | int pos, found; |
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113 | void *v; |
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114 | found = _owl_dict_find_pos(d, k, &pos); |
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115 | if (!found) return(NULL); |
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116 | g_free(d->els[pos].k); |
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117 | v = d->els[pos].v; |
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118 | for (i=pos; i<d->size-1; i++) { |
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119 | d->els[i]=d->els[i+1]; |
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120 | } |
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121 | d->size--; |
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122 | return(v); |
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123 | } |
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124 | |
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125 | /* elefree should free the value as well */ |
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126 | void owl_dict_cleanup(owl_dict *d, void (*elefree)(void *)) |
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127 | { |
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128 | int i; |
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129 | |
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130 | for (i=0; i<d->size; i++) { |
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131 | g_free(d->els[i].k); |
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132 | if (elefree) (elefree)(d->els[i].v); |
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133 | } |
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134 | if (d->els) g_free(d->els); |
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135 | } |
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136 | |
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