mem-pool.c

   1 /*
   2  * Memory Pool implementation logic.
   3  */
   4
   5 #include "cache.h"
   6 #include "mem-pool.h"
   7
   8 static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc)
   9 {
  10         struct mp_block *p;
  11
  12         mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
  13         p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
  14         p->next_block = mem_pool->mp_block;
  15         p->next_free = (char *)p->space;
  16         p->end = p->next_free + block_alloc;
  17         mem_pool->mp_block = p;
  18
  19         return p;
  20 }
  21
  22 void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
  23 {
  24         struct mp_block *p;
  25         void *r;
  26
  27         /* round up to a 'uintmax_t' alignment */
  28         if (len & (sizeof(uintmax_t) - 1))
  29                 len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
  30
  31         for (p = mem_pool->mp_block; p; p = p->next_block)
  32                 if (p->end - p->next_free >= len)
  33                         break;
  34
  35         if (!p) {
  36                 if (len >= (mem_pool->block_alloc / 2)) {
  37                         mem_pool->pool_alloc += len;
  38                         return xmalloc(len);
  39                 }
  40
  41                 p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc);
  42         }
  43
  44         r = p->next_free;
  45         p->next_free += len;
  46         return r;
  47 }
  48
  49 void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
  50 {
  51         size_t len = st_mult(count, size);
  52         void *r = mem_pool_alloc(mem_pool, len);
  53         memset(r, 0, len);
  54         return r;
  55 }