1 files changed, 97 insertions, 0 deletions
diff --git a/mmalloc/sbrk-sup.c b/mmalloc/sbrk-sup.c
new file mode 100644
index 0000000..8893175
--- /dev/null
+++ b/mmalloc/sbrk-sup.c
@@ -0,0 +1,97 @@
+/* Support for sbrk() regions.
+   Copyright 1992 Free Software Foundation, Inc.
+   Contributed by Fred Fish at Cygnus Support.   fnf@cygnus.com
+
+This file is part of the GNU C Library.
+
+The GNU C 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 C 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 C 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 <string.h>	/* Prototypes for memcpy, memmove, memset, etc */
+
+#include "mmprivate.h"
+
+static PTR sbrk_morecore PARAMS ((struct mdesc *, int));
+extern PTR sbrk PARAMS ((int));
+
+/* The mmalloc() package can use a single implicit malloc descriptor
+   for mmalloc/mrealloc/mfree operations which do not supply an explicit
+   descriptor.  For these operations, sbrk() is used to obtain more core
+   from the system, or return core.  This allows mmalloc() to provide
+   backwards compatibility with the non-mmap'd version. */
+
+struct mdesc *__mmalloc_default_mdp;
+
+/* Use sbrk() to get more core. */
+
+static PTR
+sbrk_morecore (mdp, size)
+  struct mdesc *mdp;
+  int size;
+{
+  PTR result;
+
+  if ((result = sbrk (size)) == (PTR) -1)
+    {
+      result = NULL;
+    }
+  else
+    {
+      mdp -> breakval += size;
+      mdp -> top += size;
+    }
+  return (result);
+}
+
+/* Initialize the default malloc descriptor if this is the first time
+   a request has been made to use the default sbrk'd region.
+
+   Since no alignment guarantees are made about the initial value returned
+   by sbrk, test the initial value and (if necessary) sbrk enough additional
+   memory to start off with alignment to BLOCKSIZE.  We actually only need
+   it aligned to an alignment suitable for any object, so this is overkill.
+   But at most it wastes just part of one BLOCKSIZE chunk of memory and
+   minimizes portability problems by avoiding us having to figure out
+   what the actual minimal alignment is.  The rest of the malloc code
+   avoids this as well, by always aligning to the minimum of the requested
+   size rounded up to a power of two, or to BLOCKSIZE.
+
+   Note that we are going to use some memory starting at this initial sbrk
+   address for the sbrk region malloc descriptor, which is a struct, so the
+   base address must be suitably aligned. */
+
+struct mdesc *
+__mmalloc_sbrk_init ()
+{
+  PTR base;
+  unsigned int adj;
+
+  base = sbrk (0);
+  adj = RESIDUAL (base, BLOCKSIZE);
+  if (adj != 0)
+    {
+      sbrk (BLOCKSIZE - adj);
+      base = sbrk (0);
+    }
+  __mmalloc_default_mdp = (struct mdesc *) sbrk (sizeof (struct mdesc));
+  memset ((char *) __mmalloc_default_mdp, 0, sizeof (struct mdesc));
+  __mmalloc_default_mdp -> morecore = sbrk_morecore;
+  __mmalloc_default_mdp -> base = base;
+  __mmalloc_default_mdp -> breakval = __mmalloc_default_mdp -> top = sbrk (0);
+  __mmalloc_default_mdp -> fd = -1;
+  return (__mmalloc_default_mdp);
+}
+
+