git.ozlabs.org Git - ccan/blob - ccan/take/take.c

   1 /* CC0 (Public domain) - see LICENSE file for details */
   2 #include <ccan/take/take.h>
   3 #include <ccan/likely/likely.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 static const void **takenarr;
   8 static size_t max_taken, num_taken;
   9 static size_t allocfail;
  10 static void (*allocfailfn)(const void *p);
  11
  12 void *take_(const void *p)
  13 {
  14         if (unlikely(num_taken == max_taken)) {
  15                 const void **new;
  16
  17                 new = realloc(takenarr, sizeof(*takenarr) * (max_taken+1));
  18                 if (unlikely(!new)) {
  19                         if (allocfailfn) {
  20                                 allocfail++;
  21                                 allocfailfn(p);
  22                                 return NULL;
  23                         }
  24                         /* Otherwise we leak p. */
  25                         return (void *)p;
  26                 }
  27                 takenarr = new;
  28                 max_taken++;
  29         }
  30         takenarr[num_taken++] = p;
  31         return (void *)p;
  32 }
  33
  34 static size_t find_taken(const void *p)
  35 {
  36         size_t i;
  37
  38         for (i = 0; i < num_taken; i++) {
  39                 if (takenarr[i] == p)
  40                         return i+1;
  41         }
  42         return 0;
  43 }
  44
  45 bool taken(const void *p)
  46 {
  47         size_t i;
  48
  49         if (!p && unlikely(allocfail)) {
  50                 allocfail--;
  51                 return true;
  52         }
  53
  54         i = find_taken(p);
  55         if (!i)
  56                 return false;
  57
  58         memmove(&takenarr[i-1], &takenarr[i],
  59                 (--num_taken - (i - 1))*sizeof(takenarr[0]));
  60         return true;
  61 }
  62
  63 bool is_taken(const void *p)
  64 {
  65         if (!p && unlikely(allocfail))
  66                 return true;
  67
  68         return find_taken(p) > 0;
  69 }
  70
  71 bool taken_any(void)
  72 {
  73         return num_taken != 0;
  74 }
  75
  76 void take_cleanup(void)
  77 {
  78         max_taken = num_taken = 0;
  79         free(takenarr);
  80         takenarr = NULL;
  81 }
  82
  83 void take_allocfail(void (*fn)(const void *p))
  84 {
  85         allocfailfn = fn;
  86 }