[PATCH 4/7] Add a memory pool library
- From
Ramkumar Ramachandra <artagnon@gmail.com>
- Date
- May 23, 2010, 21:40 UTC
- Message-ID
- <1274650832-7411-5-git-send-email-artagnon@gmail.com>
- In-Reply-To
- <1274650832-7411-1-git-send-email-artagnon@gmail.com>
Add a memory pool library implemented using cpp macros. The macro can be used to create a type-specific memory pool API. The memory nodes themselves are stored in a treap, using macros in trp.h. Taken directly from David Michael Barr's svn-dump-fast-export repository.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> --- vcs-svn/obj_pool.h | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 61 insertions(+), 0 deletions(-) create mode 100644 vcs-svn/obj_pool.h
diff --git a/vcs-svn/obj_pool.h b/vcs-svn/obj_pool.h new file mode 100644 index 0000000..d8b0842 --- /dev/null +++ b/vcs-svn/obj_pool.h @@ -0,0 +1,61 @@ +#ifndef OBJ_POOL_H_ +#define OBJ_POOL_H_ + +#include <stdint.h> +#include <stdlib.h> + +/* + * The obj_pool_gen() macro generates a type-specific memory pool + * implementation. + * + * Arguments: + * + * pre : Prefix for generated functions (ex: string_). + * obj_t : Type for treap data structure (ex: char). + * intial_capacity : The initial size of the memory pool (ex: 4096). + * + */ +#define obj_pool_gen(pre, obj_t, initial_capacity) \ +static struct { \ + uint32_t size; \ + uint32_t capacity; \ + obj_t *base; \ +} pre##_pool = { 0, 0, NULL}; \ +static uint32_t pre##_alloc(uint32_t count) \ +{ \ + uint32_t offset; \ + while (pre##_pool.size + count > pre##_pool.capacity) { \ + if (pre##_pool.capacity) { \ + pre##_pool.capacity *= 2; \ + } else { \ + pre##_pool.capacity = initial_capacity; \ + } \ + pre##_pool.base = \ + realloc(pre##_pool.base, pre##_pool.capacity * sizeof(obj_t)); \ + } \ + offset = pre##_pool.size; \ + pre##_pool.size += count; \ + return offset; \ +} \ +static void pre##_free(uint32_t count) \ +{ \ + pre##_pool.size -= count; \ +} \ +static uint32_t pre##_offset(obj_t *obj) \ +{ \ + return obj == NULL ? ~0 : obj - pre##_pool.base; \ +} \ +static obj_t *pre##_pointer(uint32_t offset) \ +{ \ + return offset >= pre##_pool.size ? NULL : &pre##_pool.base[offset]; \ +} \ +static void pre##_reset(void) \ +{ \ + if (pre##_pool.base) \ + free(pre##_pool.base); \ + pre##_pool.base = NULL; \ + pre##_pool.size = 0; \ + pre##_pool.capacity = 0; \ +} \ + +#endif
-- 1.7.1