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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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* Routines to handle mallocing of results which will be freed the same time
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#include <drizzled/internal/my_sys.h>
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#include <drizzled/internal/m_string.h>
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Routines to handle mallocing of results which will be freed the same time */
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#include "drizzled/internal/my_sys.h"
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#include "drizzled/internal/m_string.h"
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#include <algorithm>
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static const unsigned int MAX_BLOCK_TO_DROP= 4096;
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static const unsigned int MAX_BLOCK_USAGE_BEFORE_DROP= 10;
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* Initialize memory root
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* This function prepares memory root for further use, sets initial size of
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* chunk for memory allocation and pre-allocates first block if specified.
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* Altough error can happen during execution of this function if
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* pre_alloc_size is non-0 it won't be reported. Instead it will be
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* reported as error in first alloc_root() on this memory root.
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* @param mem_root memory root to initialize
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* @param block_size size of chunks (blocks) used for memory allocation
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* (It is external size of chunk i.e. it should include
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* memory required for internal structures, thus it
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* should be no less than memory::ROOT_MIN_BLOCK_SIZE)
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void memory::Root::init_alloc_root(size_t block_size_arg)
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free= used= pre_alloc= 0;
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block_size= block_size_arg - memory::ROOT_MIN_BLOCK_SIZE;
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block_num= 4; /* We shift this with >>2 */
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* Function aligns and assigns new value to block size; then it tries to
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* reuse one of existing blocks as prealloc block, or malloc new one of
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* requested size. If no blocks can be reused, all unused blocks are freed
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* @param mem_root memory root to change defaults of
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* @param block_size new value of block size. Must be greater or equal
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* than ALLOC_ROOT_MIN_BLOCK_SIZE (this value is about
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* 68 bytes and depends on platform and compilation flags)
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* @param pre_alloc_size new size of preallocated block. If not zero,
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* must be equal to or greater than block size,
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* otherwise means 'no prealloc'.
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void memory::Root::reset_root_defaults(size_t block_size_arg, size_t pre_alloc_size)
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block_size= block_size_arg - memory::ROOT_MIN_BLOCK_SIZE;
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Initialize memory root
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memory::init_alloc_root()
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mem_root - memory root to initialize
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block_size - size of chunks (blocks) used for memory allocation
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(It is external size of chunk i.e. it should include
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memory required for internal structures, thus it
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should be no less than memory::ROOT_MIN_BLOCK_SIZE)
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This function prepares memory root for further use, sets initial size of
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chunk for memory allocation and pre-allocates first block if specified.
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Altough error can happen during execution of this function if
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pre_alloc_size is non-0 it won't be reported. Instead it will be
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reported as error in first alloc_root() on this memory root.
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void memory::init_alloc_root(memory::Root *mem_root, size_t block_size)
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mem_root->free= mem_root->used= mem_root->pre_alloc= 0;
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mem_root->min_malloc= 32;
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mem_root->block_size= block_size - memory::ROOT_MIN_BLOCK_SIZE;
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mem_root->error_handler= 0;
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mem_root->block_num= 4; /* We shift this with >>2 */
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mem_root->first_block_usage= 0;
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mem_root memory root to change defaults of
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block_size new value of block size. Must be greater or equal
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than ALLOC_ROOT_MIN_BLOCK_SIZE (this value is about
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68 bytes and depends on platform and compilation flags)
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pre_alloc_size new size of preallocated block. If not zero,
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must be equal to or greater than block size,
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otherwise means 'no prealloc'.
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Function aligns and assigns new value to block size; then it tries to
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reuse one of existing blocks as prealloc block, or malloc new one of
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requested size. If no blocks can be reused, all unused blocks are freed
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void memory::reset_root_defaults(memory::Root *mem_root, size_t block_size,
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size_t pre_alloc_size)
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assert(alloc_root_inited(mem_root));
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mem_root->block_size= block_size - memory::ROOT_MIN_BLOCK_SIZE;
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if (pre_alloc_size)
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size_t size= pre_alloc_size + ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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if (not pre_alloc || pre_alloc->size != size)
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if (!mem_root->pre_alloc || mem_root->pre_alloc->size != size)
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memory::internal::UsedMemory *mem, **prev= &this->free;
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memory::internal::UsedMemory *mem, **prev= &mem_root->free;
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Free unused blocks, so that consequent calls
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to reset_root_defaults won't eat away memory.
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mem->left= pre_alloc_size;
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mem->next= *prev;
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*prev= pre_alloc= mem;
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*prev= mem_root->pre_alloc= mem;
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mem_root->pre_alloc= 0;
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mem_root->pre_alloc= 0;
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* Allocate a chunk of memory from the Root structure provided,
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* obtaining more memory from the heap if necessary
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* mem_root must have been initialised via init_alloc_root()
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* @param mem_root The memory Root to allocate from
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* @param length The size of the block to allocate
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* @todo Would this be more suitable as a member function on the
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void *memory::Root::alloc_root(size_t length)
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void *memory::alloc_root(memory::Root *mem_root, size_t length)
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size_t get_size, block_size;
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unsigned char* point;
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memory::internal::UsedMemory *next= NULL;
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memory::internal::UsedMemory **prev;
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assert(alloc_root_inited());
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assert(alloc_root_inited(mem_root));
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length= ALIGN_SIZE(length);
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if ((*(prev= &this->free)) != NULL)
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if ((*(prev= &mem_root->free)) != NULL)
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if ((*prev)->left < length &&
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this->first_block_usage++ >= MAX_BLOCK_USAGE_BEFORE_DROP &&
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mem_root->first_block_usage++ >= MAX_BLOCK_USAGE_BEFORE_DROP &&
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(*prev)->left < MAX_BLOCK_TO_DROP)
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*prev= next->next; /* Remove block from list */
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next->next= this->used;
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this->first_block_usage= 0;
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next->next= mem_root->used;
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mem_root->used= next;
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mem_root->first_block_usage= 0;
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for (next= *prev ; next && next->left < length ; next= next->next)
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prev= &next->next;
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{ /* Time to alloc new block */
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size_t get_size, tmp_block_size;
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tmp_block_size= this->block_size * (this->block_num >> 2);
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block_size= mem_root->block_size * (mem_root->block_num >> 2);
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get_size= length+ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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get_size= max(get_size, tmp_block_size);
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get_size= max(get_size, block_size);
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if (!(next = static_cast<memory::internal::UsedMemory *>(malloc(get_size))))
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if (this->error_handler)
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(*this->error_handler)();
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if (mem_root->error_handler)
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(*mem_root->error_handler)();
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mem_root->block_num++;
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next->next= *prev;
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next->size= get_size;
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next->left= get_size-ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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point= (unsigned char*) ((char*) next+ (next->size-next->left));
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/** @todo next part may be unneeded due to this->first_block_usage counter*/
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if ((next->left-= length) < this->min_malloc)
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/*TODO: next part may be unneded due to mem_root->first_block_usage counter*/
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if ((next->left-= length) < mem_root->min_malloc)
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{ /* Full block */
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*prev= next->next; /* Remove block from list */
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next->next= this->used;
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this->first_block_usage= 0;
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next->next= mem_root->used;
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mem_root->used= next;
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mem_root->first_block_usage= 0;
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return((void*) point);
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* Allocate many pointers at the same time.
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* The variable arguments are a list of alternating pointers and lengths,
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* terminated by a null pointer:
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* @li <tt>char ** pointer1</tt>
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* @li <tt>uint length1</tt>
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* @li <tt>char ** pointer2</tt>
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* @li <tt>uint length2</tt>
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* @c pointer1, @c pointer2 etc. all point into big allocated memory area
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* @param root Memory root
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* A pointer to the beginning of the allocated memory block in case of
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* success or NULL if out of memory
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void *memory::Root::multi_alloc_root(int unused, ...)
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Allocate many pointers at the same time.
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ptr1, ptr2, etc all point into big allocated memory area.
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ptr1, length1 Multiple arguments terminated by a NULL pointer
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A pointer to the beginning of the allocated memory block
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in case of success or NULL if out of memory.
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void *memory::multi_alloc_root(memory::Root *root, ...)
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char **ptr, *start, *res;
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size_t tot_length, length;
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(void)unused; // For some reason Sun Studio registers unused as not used.
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va_start(args, unused);
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va_start(args, root);
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while ((ptr= va_arg(args, char **)))
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return((void*) start);
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static void trash_mem(memory::internal::UsedMemory *)
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TRASH(((char*)(x) + (x->size - x->left)), x->left);
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* Mark all data in blocks free for reusage
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void memory::Root::mark_blocks_free()
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#define TRASH_MEM(X) TRASH(((char*)(X) + ((X)->size-(X)->left)), (X)->left)
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/* Mark all data in blocks free for reusage */
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static inline void mark_blocks_free(memory::Root* root)
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memory::internal::UsedMemory *next;
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memory::internal::UsedMemory **last;
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/* iterate through (partially) free blocks, mark them free */
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for (next= free; next; next= *(last= &next->next))
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for (next= root->free; next; next= *(last= &next->next))
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next->left= next->size - ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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/* Combine the free and the used list */
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*last= next=root->used;
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/* now go through the used blocks and mark them free */
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for (; next; next= next->next)
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next->left= next->size - ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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/* Now everything is set; Indicate that nothing is used anymore */
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first_block_usage= 0;
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root->first_block_usage= 0;
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* Deallocate everything used by memory::alloc_root or just move
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* used blocks to free list if called with MY_USED_TO_FREE
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* One can call this function either with root block initialised with
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* init_alloc_root() or with a zero:ed block.
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* It's also safe to call this multiple times with the same mem_root.
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* @param root Memory root
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* @param MyFlags Flags for what should be freed:
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* @li MARK_BLOCKS_FREED Don't free blocks, just mark them free
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* @li KEEP_PREALLOC If this is not set, then free also the
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void memory::Root::free_root(myf MyFlags)
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Deallocate everything used by memory::alloc_root or just move
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used blocks to free list if called with MY_USED_TO_FREE
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MyFlags Flags for what should be freed:
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MARK_BLOCKS_FREED Don't free blocks, just mark them free
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KEEP_PREALLOC If this is not set, then free also the
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One can call this function either with root block initialised with
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init_alloc_root() or with a zero:ed block.
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It's also safe to call this multiple times with the same mem_root.
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void memory::free_root(memory::Root *root, myf MyFlags)
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memory::internal::UsedMemory *next,*old;
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if (MyFlags & memory::MARK_BLOCKS_FREE)
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this->mark_blocks_free();
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mark_blocks_free(root);
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if (!(MyFlags & memory::KEEP_PREALLOC))
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for (next=this->used; next ;)
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for (next=root->used; next ;)
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old=next; next= next->next ;
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if (old != this->pre_alloc)
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if (old != root->pre_alloc)
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for (next=this->free ; next ;)
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for (next=root->free ; next ;)
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old=next; next= next->next;
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if (old != this->pre_alloc)
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this->used=this->free=0;
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this->free=this->pre_alloc;
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this->free->left=this->pre_alloc->size-ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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trash_mem(this->pre_alloc);
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this->first_block_usage= 0;
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* Duplicate a null-terminated string into memory allocated from within the
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char *memory::Root::strdup_root(const char *str)
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return strmake_root(str, strlen(str));
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* Copy the (not necessarily null-terminated) string into memory allocated
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* from within the specified Root
365
* Note that the string is copied according to the length specified, so
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* null-termination is ignored. The duplicated string will be null-terminated,
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* even if the original string wasn't (one additional byte is allocated for
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char *memory::Root::strmake_root(const char *str, size_t len)
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if (old != root->pre_alloc)
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root->used=root->free=0;
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root->free=root->pre_alloc;
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root->free->left=root->pre_alloc->size-ALIGN_SIZE(sizeof(memory::internal::UsedMemory));
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TRASH_MEM(root->pre_alloc);
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root->first_block_usage= 0;
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Find block that contains an object and set the pre_alloc to it
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void memory::set_prealloc_root(memory::Root *root, char *ptr)
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memory::internal::UsedMemory *next;
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for (next=root->used; next ; next=next->next)
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if ((char*) next <= ptr && (char*) next + next->size > ptr)
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root->pre_alloc=next;
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for (next=root->free ; next ; next=next->next)
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if ((char*) next <= ptr && (char*) next + next->size > ptr)
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root->pre_alloc=next;
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char *memory::strdup_root(memory::Root *root, const char *str)
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return strmake_root(root, str, strlen(str));
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char *memory::strmake_root(memory::Root *root, const char *str, size_t len)
373
if ((pos= (char *)alloc_root(len+1)))
366
if ((pos=(char *)memory::alloc_root(root,len+1)))
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memcpy(pos,str,len);