MGMDB/MySQL/my_once.c

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2011-10-02 20:48:43 -05:00
/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Not MT-SAFE */
#ifdef SAFEMALLOC /* We don't need SAFEMALLOC here */
#undef SAFEMALLOC
#endif
#include "mysys_priv.h"
#include "my_static.h"
#include "mysys_err.h"
#include <m_string.h>
/*
Alloc for things we don't nead to free
SYNOPSIS
my_once_alloc()
Size
MyFlags
NOTES
No DBUG_ENTER... here to get smaller dbug-startup
*/
void* my_once_alloc(size_t Size, myf MyFlags)
{
size_t get_size, max_left;
uchar* point;
reg1 USED_MEM *next;
reg2 USED_MEM **prev;
Size= ALIGN_SIZE(Size);
prev= &my_once_root_block;
max_left=0;
for (next=my_once_root_block ; 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 < my_once_extra && get_size < my_once_extra)
get_size=my_once_extra; /* Normal alloc */
if ((next = (USED_MEM*) malloc(get_size)) == 0)
{
my_errno=errno;
if (MyFlags & (MY_FAE+MY_WME))
my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG),get_size);
return((uchar*) 0);
}
DBUG_PRINT("test",("my_once_malloc %lu byte malloced", (ulong) get_size));
next->next= 0;
next->size= get_size;
next->left= get_size-ALIGN_SIZE(sizeof(USED_MEM));
*prev=next;
}
point= (uchar*) ((char*) next+ (next->size-next->left));
next->left-= Size;
if (MyFlags & MY_ZEROFILL)
bzero(point, Size);
return((void*) point);
} /* my_once_alloc */
char *my_once_strdup(const char *src,myf myflags)
{
size_t len= strlen(src)+1;
uchar *dst= my_once_alloc(len, myflags);
if (dst)
memcpy(dst, src, len);
return (char*) dst;
}
void *my_once_memdup(const void *src, size_t len, myf myflags)
{
uchar *dst= my_once_alloc(len, myflags);
if (dst)
memcpy(dst, src, len);
return dst;
}
/*
Deallocate everything used by my_once_alloc
SYNOPSIS
my_once_free()
*/
void my_once_free(void)
{
reg1 USED_MEM *next,*old;
DBUG_ENTER("my_once_free");
for (next=my_once_root_block ; next ; )
{
old=next; next= next->next ;
free((uchar*) old);
}
my_once_root_block=0;
DBUG_VOID_RETURN;
} /* my_once_free */