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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA */
/* Routines to handle mallocing of results which will be freed the same time */
#include <global.h>
#include <my_sys.h>
#include <m_string.h>
void init_alloc_root(MEM_ROOT *mem_root, uint block_size, uint pre_alloc_size)
{
mem_root->free=mem_root->used=0;
mem_root->min_malloc=32;
mem_root->block_size=block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8;
mem_root->error_handler=0;
#if !(defined(HAVE_purify) && defined(EXTRA_DEBUG))
if (pre_alloc_size)
{
if ((mem_root->free = mem_root->pre_alloc=
(USED_MEM*) my_malloc(pre_alloc_size+ ALIGN_SIZE(sizeof(USED_MEM)),
MYF(0))))
{
mem_root->free->size=pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM));
mem_root->free->left=pre_alloc_size;
mem_root->free->next=0;
}
}
#endif
}
gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size)
{
#if defined(HAVE_purify) && defined(EXTRA_DEBUG)
reg1 USED_MEM *next;
Size+=ALIGN_SIZE(sizeof(USED_MEM));
if (!(next = (USED_MEM*) my_malloc(Size,MYF(MY_WME))))
{
if (mem_root->error_handler)
(*mem_root->error_handler)();
return((gptr) 0); /* purecov: inspected */
}
next->next=mem_root->used;
mem_root->used=next;
return (gptr) (((char*) next)+ALIGN_SIZE(sizeof(USED_MEM)));
#else
uint get_size,max_left;
gptr point;
reg1 USED_MEM *next;
reg2 USED_MEM **prev;
Size= ALIGN_SIZE(Size);
prev= &mem_root->free;
max_left=0;
for (next= *prev ; next && next->left < Size ; next= next->next)
{
if (next->left > max_left)
max_left=next->left;
prev= &next->next;
}
if (! next)
{ /* Time to alloc new block */
get_size= Size+ALIGN_SIZE(sizeof(USED_MEM));
if (max_left*4 < mem_root->block_size && get_size < mem_root->block_size)
get_size=mem_root->block_size; /* Normal alloc */
if (!(next = (USED_MEM*) my_malloc(get_size,MYF(MY_WME))))
{
if (mem_root->error_handler)
(*mem_root->error_handler)();
return((gptr) 0); /* purecov: inspected */
}
next->next= *prev;
next->size= get_size;
next->left= get_size-ALIGN_SIZE(sizeof(USED_MEM));
*prev=next;
}
point= (gptr) ((char*) next+ (next->size-next->left));
if ((next->left-= Size) < mem_root->min_malloc)
{ /* Full block */
*prev=next->next; /* Remove block from list */
next->next=mem_root->used;
mem_root->used=next;
}
return(point);
#endif
}
static inline void mark_blocks_free(MEM_ROOT* root)
{
reg1 USED_MEM *next,*last = 0;
/* iterate through (partially) free blocks, mark them fully free */
for(next = root->free; next; next = next->next )
{
last = next;
next->left = next->size - ALIGN_SIZE(sizeof(USED_MEM));
}
/* if free block list was not empty, point the next of the
last free block to the beginning of the used list */
next = root->used; /* a little optimization to avoid dereferencing root
twice - we will shortly start iterating through used
list */
if(last)
last->next = next;
else /* if free list is empty, just point it to the current used*/
root->free = next;
/* now go through the current used list, and mark each block
as fully free. Note that because of our optimization, we do not
need to initialize next here - see above
*/
for(;next; next = next->next)
next->left = next->size - ALIGN_SIZE(sizeof(USED_MEM));
/* Now everything is set - we just need to indicate that nothing is used
anymore
*/
root->used = 0;
}
/* deallocate everything used by alloc_root or just move
used blocks to free list if called with MY_USED_TO_FREE */
void free_root(MEM_ROOT *root, myf MyFlags)
{
reg1 USED_MEM *next,*old;
DBUG_ENTER("free_root");
if (!root)
DBUG_VOID_RETURN; /* purecov: inspected */
if(MyFlags & MY_MARK_BLOCKS_FREE)
{
mark_blocks_free(root);
DBUG_VOID_RETURN;
}
if (!(MyFlags & MY_KEEP_PREALLOC))
root->pre_alloc=0;
for ( next=root->used; next ;)
{
old=next; next= next->next ;
if (old != root->pre_alloc)
my_free((gptr) old,MYF(0));
}
for (next= root->free ; next ; )
{
old=next; next= next->next ;
if (old != root->pre_alloc)
my_free((gptr) old,MYF(0));
}
root->used=root->free=0;
if (root->pre_alloc)
{
root->free=root->pre_alloc;
root->free->left=root->pre_alloc->size-ALIGN_SIZE(sizeof(USED_MEM));
root->free->next=0;
}
DBUG_VOID_RETURN;
}
char *strdup_root(MEM_ROOT *root,const char *str)
{
uint len= (uint) strlen(str)+1;
char *pos;
if ((pos=alloc_root(root,len)))
memcpy(pos,str,len);
return pos;
}
char *memdup_root(MEM_ROOT *root,const char *str,uint len)
{
char *pos;
if ((pos=alloc_root(root,len)))
memcpy(pos,str,len);
return pos;
}
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