Import changeset

mysys/my_alloc.c

@@ -0,0 +1,129 @@
+/* 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)
+{
+  mem_root->free=mem_root->used=0;
+  mem_root->min_malloc=16;
+  mem_root->block_size=block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8;
+  mem_root->error_handler=0;
+}
+
+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
+}
+
+	/* deallocate everything used by alloc_root */
+
+void free_root(MEM_ROOT *root)
+{
+  reg1 USED_MEM *next,*old;
+  DBUG_ENTER("free_root");
+
+  if (!root)
+    DBUG_VOID_RETURN; /* purecov: inspected */
+  for (next= root->used ; next ; )
+  {
+    old=next; next= next->next ;
+    my_free((gptr) old,MYF(0));
+  }
+  for (next= root->free ; next ; )
+  {
+    old=next; next= next->next ;
+    my_free((gptr) old,MYF(0));
+  }
+  root->used=root->free=0;
+  DBUG_VOID_RETURN;
+}
+
+char *strdup_root(MEM_ROOT *root,const char *str)
+{
+  uint len=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;
+}