XEmacs 21.2-b1

[chise/xemacs-chise.git.1] / src / blocktype.c

diff --git a/src/blocktype.c b/src/blocktype.c
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+/* Fixed-size block allocator.
+   Copyright (C) 1994 Free Software Foundation, Inc.
+
+This file is part of XEmacs.
+
+XEmacs 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; either version 2, or (at your option) any
+later version.
+
+XEmacs 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 XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.
+*/
+
+/* Synched up with: Not in FSF. */
+
+/* Authorship:
+
+   Ben Wing: December 1994, for 19.12.
+ */
+
+/*
+
+------------------------------------------------------------------------------
+
+A "block-type object" is used to efficiently allocate and free blocks
+of a particular size.  Freed blocks are remembered in a free list and
+are reused as necessary to allocate new blocks, so as to avoid as
+much as possible making calls to malloc() and free().
+
+This is a container object.  Declare a block-type object of a specific type
+as follows:
+
+struct mytype_blocktype {
+  Blocktype_declare (mytype);
+};
+
+Use the following functions/macros:
+
+   structype *Blocktype_new(structype)
+      [MACRO] Create a new block-type object of the specified type.
+      The argument to this call should be the type of object to be
+      created, e.g. foobar_blocktype.
+   type *Blocktype_alloc(b)
+      [MACRO] Allocate a block of the proper type for the specified
+      block-type object and return a pointer to it.
+   Blocktype_free(b, block)
+      Free a block of the type corresponding to the specified block-type
+      object.
+   Blocktype_delete(b)
+      Destroy a block-type object and the memory allocated to it.
+
+*/
+
+/* This file has been Mule-ized. */
+
+#include <config.h>
+#include "lisp.h"
+
+#include "blocktype.h"
+
+typedef struct blocktype
+{
+  Blocktype_declare (void);
+} Blocktype;
+
+struct block_internal
+{
+  void *next;
+};
+
+void *
+Blocktype_newf (size_t elsize)
+{
+  Blocktype *b = xnew (Blocktype);
+  b->elsize = max (elsize, sizeof (void *));
+  b->free = 0;
+  return (void *) b;
+}
+
+void
+Blocktype_allocf (void *bbb)
+{
+  Blocktype *b = (Blocktype *) bbb;
+  if (b->free)
+    {
+      b->tempel = b->free;
+      b->free = ((struct block_internal *) (b->free))->next;
+    }
+  else
+    b->tempel = (void *) xmalloc (b->elsize);
+}
+
+void
+Blocktype_free (void *bbb, void *el)
+{
+  Blocktype *b = (Blocktype *) bbb;
+  ((struct block_internal *) el)->next = b->free;
+  b->free = el;
+}