src/basic/alloc-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <stdint.h>
   4 #include <string.h>
   5
   6 #include "alloc-util.h"
   7 #include "macro.h"
   8 #include "memory-util.h"
   9
  10 void* memdup(const void *p, size_t l) {
  11         void *ret;
  12
  13         assert(l == 0 || p);
  14
  15         ret = malloc(l ?: 1);
  16         if (!ret)
  17                 return NULL;
  18
  19         memcpy(ret, p, l);
  20         return ret;
  21 }
  22
  23 void* memdup_suffix0(const void *p, size_t l) {
  24         void *ret;
  25
  26         assert(l == 0 || p);
  27
  28         /* The same as memdup() but place a safety NUL byte after the allocated memory */
  29
  30         ret = malloc(l + 1);
  31         if (!ret)
  32                 return NULL;
  33
  34         *((uint8_t*) mempcpy(ret, p, l)) = 0;
  35         return ret;
  36 }
  37
  38 void* greedy_realloc(void **p, size_t *allocated, size_t need, size_t size) {
  39         size_t a, newalloc;
  40         void *q;
  41
  42         assert(p);
  43         assert(allocated);
  44
  45         if (*allocated >= need)
  46                 return *p;
  47
  48         newalloc = MAX(need * 2, 64u / size);
  49         a = newalloc * size;
  50
  51         /* check for overflows */
  52         if (a < size * need)
  53                 return NULL;
  54
  55         q = realloc(*p, a);
  56         if (!q)
  57                 return NULL;
  58
  59         *p = q;
  60         *allocated = newalloc;
  61         return q;
  62 }
  63
  64 void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size) {
  65         size_t prev;
  66         uint8_t *q;
  67
  68         assert(p);
  69         assert(allocated);
  70
  71         prev = *allocated;
  72
  73         q = greedy_realloc(p, allocated, need, size);
  74         if (!q)
  75                 return NULL;
  76
  77         if (*allocated > prev)
  78                 memzero(q + prev * size, (*allocated - prev) * size);
  79
  80         return q;
  81 }