nsz Git - libfirm/blob - ir/adt/plist.c

   1 /**
   2  * Simple, non circular, double linked pointer list.
   3  * Created because the properties of the standard circular list were not
   4  * very well suited for the interference graph implementation.
   5  * This list uses an obstack and a free-list to efficiently manage its
   6  * elements.
   7  * @author Kimon Hoffmann
   8  * @date   14.07.2005
   9  * @cvs-id $Id$
  10  * @note Until now the code is entirely untested so it probably contains
  11  *              plenty of errors.
  12  */
  13 #include <stdlib.h>
  14
  15 #include "plist.h"
  16
  17 /**
  18  * Helper macro that returns a new uninitialized list element by either
  19  * fetching one from the free-list or allocating a new one on the lists
  20  * obstack.
  21  * @param list the list for which to allocate the element.
  22  * @return the newly allocated, uninitialized element.
  23  */
  24 static plist_element_t *allocate_element(plist_t* list) {
  25         plist_element_t *new_element;
  26
  27         if (list->first_free_element != NULL) {
  28                 new_element              = list->first_free_element;
  29                 list->first_free_element = new_element->next;
  30                 new_element->next        = NULL;
  31         }
  32         else {
  33                 new_element = obstack_alloc(list->obst, sizeof(*new_element));
  34         }
  35
  36         return new_element;
  37 }
  38
  39 plist_t *plist_new(void) {
  40         plist_t *list = xmalloc(sizeof(*list) + sizeof(*list->obst));
  41
  42         list->obst               = (struct obstack *)&list[1];
  43         list->foreign_obstack    = 0;
  44         list->first_element      = NULL;
  45         list->last_element       = NULL;
  46         list->first_free_element = NULL;
  47         list->element_count      = 0;
  48
  49         obstack_init(list->obst);
  50         return list;
  51 }
  52
  53 plist_t *plist_obstack_new(struct obstack *obst) {
  54         plist_t *list = obstack_alloc(obst, sizeof(*list));
  55
  56         list->obst               = obst;
  57         list->foreign_obstack    = 1;
  58         list->first_element      = NULL;
  59         list->last_element       = NULL;
  60         list->first_free_element = NULL;
  61         list->element_count      = 0;
  62
  63         return list;
  64 }
  65
  66 void plist_free(plist_t *list) {
  67         list->first_element      = NULL;
  68         list->last_element       = NULL;
  69         list->first_free_element = NULL;
  70         list->element_count      = 0;
  71
  72         if (! list->foreign_obstack) {
  73                 obstack_free(list->obst, NULL);
  74                 xfree(list);
  75         }
  76 }
  77
  78 void plist_insert_back(plist_t *list, void *value) {
  79         if (list->last_element != NULL) {
  80                 plist_insert_after(list, list->last_element, value);
  81         }
  82         else {
  83                 plist_element_t *newElement = allocate_element(list);
  84
  85                 newElement->data    = value;
  86                 newElement->prev    = NULL;
  87                 newElement->next    = NULL;
  88                 list->first_element = list->last_element = newElement;
  89                 list->element_count = 1;
  90         }
  91 }
  92
  93 void plist_insert_front(plist_t *list, void *value) {
  94         if (list->first_element != NULL) {
  95                 plist_insert_before(list, list->first_element, value);
  96         }
  97         else {
  98                 plist_element_t *newElement = allocate_element(list);
  99
 100                 newElement->data    = value;
 101                 newElement->prev    = NULL;
 102                 newElement->next    = NULL;
 103                 list->first_element = list->last_element = newElement;
 104                 list->element_count = 1;
 105         }
 106 }
 107
 108 void plist_insert_before(plist_t *list, plist_element_t *element, void *value) {
 109         plist_element_t *prevElement;
 110         plist_element_t *newElement = allocate_element(list);
 111
 112         newElement->data = value;
 113         newElement->next = element;
 114         prevElement      = element->prev;
 115         newElement->prev = prevElement;
 116
 117         if (prevElement != NULL) {
 118                 prevElement->next = newElement;
 119         }
 120         else {
 121                 list->first_element = newElement;
 122         }
 123
 124         element->prev = newElement;
 125         ++list->element_count;
 126 }
 127
 128 void plist_insert_after(plist_t* list, plist_element_t* element, void* value) {
 129         plist_element_t *nextElement;
 130         plist_element_t *newElement = allocate_element(list);
 131
 132         newElement->data = value;
 133         newElement->prev = element;
 134         nextElement      = element->next;
 135         newElement->next = nextElement;
 136
 137         if (nextElement != NULL) {
 138                 nextElement->prev = newElement;
 139         }
 140         else {
 141                 list->last_element = newElement;
 142         }
 143
 144         element->next = newElement;
 145         ++list->element_count;
 146 }
 147
 148 int plist_has_value(plist_t *list, void *value) {
 149         plist_element_t *iter;
 150
 151         for (iter = plist_first(list); iter; iter = plist_element_get_next(iter)) {
 152                 if (plist_element_get_value(iter) == value)
 153                         return 1;
 154         }
 155
 156         return 0;
 157 }
 158
 159 plist_element_t *plist_find_value(plist_t *list, void *value) {
 160         plist_element_t *iter;
 161
 162         for (iter = plist_first(list); iter; iter = plist_element_get_next(iter)) {
 163                 if (plist_element_get_value(iter) == value)
 164                         return iter;
 165         }
 166
 167         return NULL;
 168 }
 169
 170 void plist_erase(plist_t *list, plist_element_t *element) {
 171         plist_element_t *next_element = element->next;
 172         plist_element_t *prev_element = element->prev;
 173
 174         if (next_element != NULL) {
 175                 next_element->prev = prev_element;
 176         }
 177         else {
 178                 list->last_element = prev_element;
 179         }
 180
 181         if (prev_element != NULL) {
 182                 prev_element->next = next_element;
 183         }
 184         else {
 185                 list->first_element = next_element;
 186         }
 187
 188         --list->element_count;
 189
 190         /* Clean the element and prepend it to the free list */
 191         element->prev            = NULL; /* The allocation code expects prev to be NULL */
 192         element->next            = list->first_free_element;
 193         list->first_free_element = element;
 194 }
 195
 196 void plist_clear(plist_t *list) {
 197         plist_element_t *curr_element = list->first_element;
 198
 199         while (curr_element != NULL) {
 200                 curr_element->prev = NULL;
 201                 curr_element       = curr_element->next;
 202         }
 203
 204         curr_element = list->last_element;
 205
 206         if (curr_element != NULL) {
 207                 curr_element->next = list->first_free_element;
 208         }
 209
 210         list->first_free_element = list->first_element;
 211         list->first_element      = 0;
 212         list->last_element       = 0;
 213         list->element_count      = 0;
 214 }