summaryrefslogtreecommitdiffstats
path: root/gnu/lib/libgmp/stack-alloc.c
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/lib/libgmp/stack-alloc.c')
-rw-r--r--gnu/lib/libgmp/stack-alloc.c108
1 files changed, 108 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/stack-alloc.c b/gnu/lib/libgmp/stack-alloc.c
new file mode 100644
index 0000000..d9619f6
--- /dev/null
+++ b/gnu/lib/libgmp/stack-alloc.c
@@ -0,0 +1,108 @@
+/* Stack allocation routines. This is intended for machines without support
+ for the `alloca' function.
+
+Copyright (C) 1996 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP 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.
+
+The GNU MP 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 the GNU MP Library; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "stack-alloc.h"
+
+typedef struct tmp_stack tmp_stack;
+
+void *malloc ();
+static unsigned long max_total_allocation = 0;
+static unsigned long current_total_allocation = 0;
+
+static tmp_stack xxx = {&xxx, &xxx, 0};
+static tmp_stack *current = &xxx;
+
+/* Allocate a block of exactly <size> bytes. This should only be called
+ through the TMP_ALLOC macro, which takes care of rounding/alignment. */
+void *
+__tmp_alloc (size)
+ unsigned long size;
+{
+ void *this;
+
+ if (size > (char *) current->end - (char *) current->alloc_point)
+ {
+ void *chunk;
+ tmp_stack *header;
+ unsigned long chunk_size;
+ unsigned long now;
+
+ /* Allocate a chunk that makes the total current allocation somewhat
+ larger than the maximum allocation ever. If size is very large, we
+ allocate that much. */
+
+ now = current_total_allocation + size;
+ if (now > max_total_allocation)
+ {
+ /* We need more temporary memory than ever before. Increase
+ for future needs. */
+ now = now * 3 / 2;
+ chunk_size = now - current_total_allocation + sizeof (tmp_stack);
+ current_total_allocation = now;
+ max_total_allocation = current_total_allocation;
+ }
+ else
+ {
+ chunk_size = max_total_allocation - current_total_allocation + sizeof (tmp_stack);
+ current_total_allocation = max_total_allocation;
+ }
+
+ chunk = malloc (chunk_size);
+ header = chunk;
+ header->end = (char *) chunk + chunk_size;
+ header->alloc_point = (char *) chunk + sizeof (tmp_stack);
+ header->prev = current;
+ current = header;
+ }
+
+ this = current->alloc_point;
+ current->alloc_point = (char *) this + size;
+ return this;
+}
+
+/* Typically called at function entry. <mark> is assigned so that __tmp_free
+ can later be used to reclaim all subsecuently allocated storage. */
+void
+__tmp_mark (mark)
+ tmp_marker *mark;
+{
+ mark->which_chunk = current;
+ mark->alloc_point = current->alloc_point;
+}
+
+/* Free everything allocated since <mark> was assigned by __tmp_mark */
+void
+__tmp_free (mark)
+ tmp_marker *mark;
+{
+ while (mark->which_chunk != current)
+ {
+ tmp_stack *tmp;
+
+ tmp = current;
+ current = tmp->prev;
+ current_total_allocation -= (((char *) (tmp->end) - (char *) tmp)
+ - sizeof (tmp_stack));
+ free (tmp);
+ }
+ current->alloc_point = mark->alloc_point;
+}
OpenPOWER on IntegriCloud