* device/lib/libsdcc.lib,

[fw/sdcc] / device / lib / _realloc.c

diff --git a/device/lib/_realloc.c b/device/lib/_realloc.c
new file mode 100644 (file)
index 0000000..357063b
--- /dev/null
+++ b/device/lib/_realloc.c
@@ -0,0 +1,137 @@
+/*-------------------------------------------------------------------------
+   realloc.c - reallocate allocated memory.
+
+   Copyright (C) 2004 - Maarten Brock, sourceforge.brock@dse.nl
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser 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
+-------------------------------------------------------------------------*/
+
+#include <sdcc-lib.h>
+#include <malloc.h>
+#include <string.h>
+
+#if defined(SDCC_STACK_AUTO) || defined(SDCC_z80) || defined(SDCC_gbz80)
+  #define CRITICAL __critical
+#else
+  #define CRITICAL
+#endif
+
+//--------------------------------------------------------------------
+//realloc function implementation for embedded system
+//Non-ANSI keywords are C51 specific.
+// __xdata - variable in external memory (just RAM)
+//--------------------------------------------------------------------
+
+#if _SDCC_MALLOC_TYPE_MLH
+
+#define __xdata
+
+typedef struct _MEMHEADER MEMHEADER;
+
+struct _MEMHEADER
+{
+  MEMHEADER *   next;
+  MEMHEADER *   prev;
+  unsigned int  len;
+  unsigned char mem;
+};
+
+#define HEADER_SIZE (sizeof(MEMHEADER)-sizeof(char))
+#define MEM(x)      (&x->mem)
+
+#else
+
+#define MEMHEADER   struct MAH// Memory Allocation Header
+
+MEMHEADER
+{
+  MEMHEADER __xdata *  next;
+  unsigned int         len;
+  unsigned char        mem[];
+};
+
+#define HEADER_SIZE sizeof(MEMHEADER)
+#define MEM(x)      (x->mem)
+
+#endif
+
+extern MEMHEADER __xdata * _sdcc_prev_memheader;
+
+// apart from finding the header
+// this function also finds it's predecessor
+extern MEMHEADER __xdata * _sdcc_find_memheader(void __xdata * p);
+
+void __xdata * realloc (void * p, size_t size)
+{
+  register MEMHEADER __xdata * pthis;
+  register MEMHEADER __xdata * pnew;
+  register void __xdata * ret;
+
+  CRITICAL
+  {
+    pthis = _sdcc_find_memheader(p);
+    if (pthis)
+    {
+      if (size > (0xFFFF-HEADER_SIZE))
+      {
+        ret = (void __xdata *) NULL; //To prevent overflow in next line
+      }
+      else
+      {
+        size += HEADER_SIZE; //We need a memory for header too
+
+        if ((((unsigned int)pthis->next) - ((unsigned int)pthis)) >= size)
+        {//if spare is more than needed
+          pthis->len = size;
+          ret = p;
+        }
+        else
+        {
+          if ((_sdcc_prev_memheader) &&
+              ((((unsigned int)pthis->next) -
+                ((unsigned int)_sdcc_prev_memheader) -
+                _sdcc_prev_memheader->len) >= size))
+          {
+            pnew = (MEMHEADER __xdata * )((char __xdata *)_sdcc_prev_memheader + _sdcc_prev_memheader->len);
+            _sdcc_prev_memheader->next = pnew;
+
+#if _SDCC_MALLOC_TYPE_MLH
+            pthis->next->prev = pnew;
+#endif
+
+            memmove(pnew, pthis, pthis->len);
+            pnew->len = size;
+            ret = MEM(pnew);
+          }
+          else
+          {
+            ret = malloc(size - HEADER_SIZE);
+            if (ret)
+            {
+              memcpy(ret, MEM(pthis), pthis->len - HEADER_SIZE);
+              free(p);
+            }
+          }
+        }
+      }
+    }
+    else
+    {
+      ret = malloc(size);
+    }
+  }
+  return ret;
+}
+//END OF MODULE