diff options
Diffstat (limited to 'ext/mysqlnd/mysqlnd_block_alloc.c')
| -rw-r--r-- | ext/mysqlnd/mysqlnd_block_alloc.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/ext/mysqlnd/mysqlnd_block_alloc.c b/ext/mysqlnd/mysqlnd_block_alloc.c new file mode 100644 index 0000000..b9d7887 --- /dev/null +++ b/ext/mysqlnd/mysqlnd_block_alloc.c @@ -0,0 +1,194 @@ +/* + +----------------------------------------------------------------------+ + | PHP Version 5 | + +----------------------------------------------------------------------+ + | Copyright (c) 2006-2013 The PHP Group | + +----------------------------------------------------------------------+ + | This source file is subject to version 3.01 of the PHP license, | + | that is bundled with this package in the file LICENSE, and is | + | available through the world-wide-web at the following url: | + | http://www.php.net/license/3_01.txt | + | If you did not receive a copy of the PHP license and are unable to | + | obtain it through the world-wide-web, please send a note to | + | license@php.net so we can mail you a copy immediately. | + +----------------------------------------------------------------------+ + | Authors: Georg Richter <georg@mysql.com> | + | Andrey Hristov <andrey@mysql.com> | + | Ulf Wendel <uwendel@mysql.com> | + +----------------------------------------------------------------------+ +*/ + +/* $Id$ */ + +#include "php.h" +#include "mysqlnd.h" +#include "mysqlnd_block_alloc.h" +#include "mysqlnd_debug.h" +#include "mysqlnd_priv.h" + + +/* {{{ mysqlnd_mempool_free_chunk */ +static void +mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk TSRMLS_DC) +{ + MYSQLND_MEMORY_POOL * pool = chunk->pool; + DBG_ENTER("mysqlnd_mempool_free_chunk"); + if (chunk->from_pool) { + /* Try to back-off and guess if this is the last block allocated */ + if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) { + /* + This was the last allocation. Lucky us, we can free + a bit of memory from the pool. Next time we will return from the same ptr. + */ + pool->free_size += chunk->size; + } + pool->refcount--; + } else { + mnd_free(chunk->ptr); + } + mnd_free(chunk); + DBG_VOID_RETURN; +} +/* }}} */ + + +/* {{{ mysqlnd_mempool_resize_chunk */ +static enum_func_status +mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL_CHUNK * chunk, unsigned int size TSRMLS_DC) +{ + DBG_ENTER("mysqlnd_mempool_resize_chunk"); + if (chunk->from_pool) { + MYSQLND_MEMORY_POOL * pool = chunk->pool; + /* Try to back-off and guess if this is the last block allocated */ + if (chunk->ptr == (pool->arena + (pool->arena_size - pool->free_size - chunk->size))) { + /* + This was the last allocation. Lucky us, we can free + a bit of memory from the pool. Next time we will return from the same ptr. + */ + if ((chunk->size + pool->free_size) < size) { + zend_uchar *new_ptr; + new_ptr = mnd_malloc(size); + if (!new_ptr) { + DBG_RETURN(FAIL); + } + memcpy(new_ptr, chunk->ptr, chunk->size); + chunk->ptr = new_ptr; + pool->free_size += chunk->size; + chunk->size = size; + chunk->pool = NULL; /* now we have no pool memory */ + pool->refcount--; + } else { + /* If the chunk is > than asked size then free_memory increases, otherwise decreases*/ + pool->free_size += (chunk->size - size); + } + } else { + /* Not last chunk, if the user asks for less, give it to him */ + if (chunk->size >= size) { + ; /* nop */ + } else { + zend_uchar *new_ptr; + new_ptr = mnd_malloc(size); + if (!new_ptr) { + DBG_RETURN(FAIL); + } + memcpy(new_ptr, chunk->ptr, chunk->size); + chunk->ptr = new_ptr; + chunk->size = size; + chunk->pool = NULL; /* now we have non-pool memory */ + pool->refcount--; + } + } + } else { + zend_uchar *new_ptr = mnd_realloc(chunk->ptr, size); + if (!new_ptr) { + DBG_RETURN(FAIL); + } + chunk->ptr = new_ptr; + } + DBG_RETURN(PASS); +} +/* }}} */ + + +/* {{{ mysqlnd_mempool_get_chunk */ +static +MYSQLND_MEMORY_POOL_CHUNK * mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool, unsigned int size TSRMLS_DC) +{ + MYSQLND_MEMORY_POOL_CHUNK *chunk = NULL; + DBG_ENTER("mysqlnd_mempool_get_chunk"); + + chunk = mnd_malloc(sizeof(MYSQLND_MEMORY_POOL_CHUNK)); + if (chunk) { + chunk->free_chunk = mysqlnd_mempool_free_chunk; + chunk->resize_chunk = mysqlnd_mempool_resize_chunk; + chunk->size = size; + /* + Should not go over MYSQLND_MAX_PACKET_SIZE, since we + expect non-arena memory in mysqlnd_wireprotocol.c . We + realloc the non-arena memory. + */ + chunk->pool = pool; + if (size > pool->free_size) { + chunk->from_pool = FALSE; + chunk->ptr = mnd_malloc(size); + if (!chunk->ptr) { + chunk->free_chunk(chunk TSRMLS_CC); + chunk = NULL; + } + } else { + chunk->from_pool = TRUE; + ++pool->refcount; + chunk->ptr = pool->arena + (pool->arena_size - pool->free_size); + /* Last step, update free_size */ + pool->free_size -= size; + } + } + DBG_RETURN(chunk); +} +/* }}} */ + + +/* {{{ mysqlnd_mempool_create */ +PHPAPI MYSQLND_MEMORY_POOL * +mysqlnd_mempool_create(size_t arena_size TSRMLS_DC) +{ + /* We calloc, because we free(). We don't mnd_calloc() for a reason. */ + MYSQLND_MEMORY_POOL * ret = mnd_calloc(1, sizeof(MYSQLND_MEMORY_POOL)); + DBG_ENTER("mysqlnd_mempool_create"); + if (ret) { + ret->get_chunk = mysqlnd_mempool_get_chunk; + ret->free_size = ret->arena_size = arena_size ? arena_size : 0; + ret->refcount = 0; + /* OOM ? */ + ret->arena = mnd_malloc(ret->arena_size); + if (!ret->arena) { + mysqlnd_mempool_destroy(ret TSRMLS_CC); + ret = NULL; + } + } + DBG_RETURN(ret); +} +/* }}} */ + + +/* {{{ mysqlnd_mempool_destroy */ +PHPAPI void +mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool TSRMLS_DC) +{ + DBG_ENTER("mysqlnd_mempool_destroy"); + /* mnd_free will reference LOCK_access and might crash, depending on the caller...*/ + mnd_free(pool->arena); + mnd_free(pool); + DBG_VOID_RETURN; +} +/* }}} */ + + +/* + * Local variables: + * tab-width: 4 + * c-basic-offset: 4 + * End: + * vim600: noet sw=4 ts=4 fdm=marker + * vim<600: noet sw=4 ts=4 + */ |