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129 lines
3.5 KiB
C
129 lines
3.5 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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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 <global.h>
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#include <my_sys.h>
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#include <m_string.h>
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void init_alloc_root(MEM_ROOT *mem_root,uint block_size)
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{
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mem_root->free=mem_root->used=0;
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mem_root->min_malloc=16;
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mem_root->block_size=block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8;
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mem_root->error_handler=0;
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}
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gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size)
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{
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#if defined(HAVE_purify) && defined(EXTRA_DEBUG)
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reg1 USED_MEM *next;
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Size+=ALIGN_SIZE(sizeof(USED_MEM));
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if (!(next = (USED_MEM*) my_malloc(Size,MYF(MY_WME))))
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{
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if (mem_root->error_handler)
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(*mem_root->error_handler)();
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return((gptr) 0); /* purecov: inspected */
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}
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next->next=mem_root->used;
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mem_root->used=next;
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return (gptr) (((char*) next)+ALIGN_SIZE(sizeof(USED_MEM)));
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#else
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uint get_size,max_left;
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gptr point;
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reg1 USED_MEM *next;
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reg2 USED_MEM **prev;
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Size= ALIGN_SIZE(Size);
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prev= &mem_root->free;
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max_left=0;
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for (next= *prev ; next && next->left < Size ; next= next->next)
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{
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if (next->left > max_left)
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max_left=next->left;
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prev= &next->next;
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}
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if (! next)
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{ /* Time to alloc new block */
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get_size= Size+ALIGN_SIZE(sizeof(USED_MEM));
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if (max_left*4 < mem_root->block_size && get_size < mem_root->block_size)
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get_size=mem_root->block_size; /* Normal alloc */
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if (!(next = (USED_MEM*) my_malloc(get_size,MYF(MY_WME))))
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{
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if (mem_root->error_handler)
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(*mem_root->error_handler)();
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return((gptr) 0); /* purecov: inspected */
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}
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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(USED_MEM));
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*prev=next;
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}
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point= (gptr) ((char*) next+ (next->size-next->left));
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if ((next->left-= Size) < 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=mem_root->used;
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mem_root->used=next;
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}
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return(point);
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#endif
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}
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/* deallocate everything used by alloc_root */
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void free_root(MEM_ROOT *root)
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{
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reg1 USED_MEM *next,*old;
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DBUG_ENTER("free_root");
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if (!root)
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DBUG_VOID_RETURN; /* purecov: inspected */
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for (next= root->used ; next ; )
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{
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old=next; next= next->next ;
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my_free((gptr) old,MYF(0));
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}
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for (next= root->free ; next ; )
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{
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old=next; next= next->next ;
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my_free((gptr) old,MYF(0));
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}
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root->used=root->free=0;
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DBUG_VOID_RETURN;
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}
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char *strdup_root(MEM_ROOT *root,const char *str)
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{
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uint len= (uint) strlen(str)+1;
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char *pos;
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if ((pos=alloc_root(root,len)))
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memcpy(pos,str,len);
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return pos;
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}
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char *memdup_root(MEM_ROOT *root,const char *str,uint len)
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{
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char *pos;
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if ((pos=alloc_root(root,len)))
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memcpy(pos,str,len);
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return pos;
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}
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