vcs-svn/obj_pool.h

   1 /*
   2  * Licensed under a two-clause BSD-style license.
   3  * See LICENSE for details.
   4  */
   5
   6 #ifndef OBJ_POOL_H_
   7 #define OBJ_POOL_H_
   8
   9 #include "git-compat-util.h"
  10
  11 #define MAYBE_UNUSED __attribute__((__unused__))
  12
  13 #define obj_pool_gen(pre, obj_t, initial_capacity) \
  14 static struct { \
  15         uint32_t committed; \
  16         uint32_t size; \
  17         uint32_t capacity; \
  18         obj_t *base; \
  19 } pre##_pool = {0, 0, 0, NULL}; \
  20 static MAYBE_UNUSED uint32_t pre##_alloc(uint32_t count) \
  21 { \
  22         uint32_t offset; \
  23         if (pre##_pool.size + count > pre##_pool.capacity) { \
  24                 while (pre##_pool.size + count > pre##_pool.capacity) \
  25                         if (pre##_pool.capacity) \
  26                                 pre##_pool.capacity *= 2; \
  27                         else \
  28                                 pre##_pool.capacity = initial_capacity; \
  29                 pre##_pool.base = realloc(pre##_pool.base, \
  30                                         pre##_pool.capacity * sizeof(obj_t)); \
  31         } \
  32         offset = pre##_pool.size; \
  33         pre##_pool.size += count; \
  34         return offset; \
  35 } \
  36 static MAYBE_UNUSED void pre##_free(uint32_t count) \
  37 { \
  38         pre##_pool.size -= count; \
  39 } \
  40 static MAYBE_UNUSED uint32_t pre##_offset(obj_t *obj) \
  41 { \
  42         return obj == NULL ? ~0 : obj - pre##_pool.base; \
  43 } \
  44 static MAYBE_UNUSED obj_t *pre##_pointer(uint32_t offset) \
  45 { \
  46         return offset >= pre##_pool.size ? NULL : &pre##_pool.base[offset]; \
  47 } \
  48 static MAYBE_UNUSED void pre##_commit(void) \
  49 { \
  50         pre##_pool.committed = pre##_pool.size; \
  51 } \
  52 static MAYBE_UNUSED void pre##_reset(void) \
  53 { \
  54         free(pre##_pool.base); \
  55         pre##_pool.base = NULL; \
  56         pre##_pool.size = 0; \
  57         pre##_pool.capacity = 0; \
  58         pre##_pool.committed = 0; \
  59 }
  60
  61 #endif