Fix realloc() to match the documented behaviour.

Add a few simple tests for it.

dlls/msvcrt/heap.c

@@ -281,5 +281,8 @@ void* MSVCRT_malloc(MSVCRT_size_t size)
  */
 void* MSVCRT_realloc(void* ptr, MSVCRT_size_t size)
 {
-  return HeapReAlloc(GetProcessHeap(), 0, ptr, size);
+  if (!ptr) return MSVCRT_malloc(size);
+  if (size) return HeapReAlloc(GetProcessHeap(), 0, ptr, size);
+  MSVCRT_free(ptr);
+  return NULL;
 }

dlls/msvcrt/tests/.cvsignore

@@ -1,6 +1,7 @@
 Makefile
 cpp.ok
 file.ok
+heap.ok
 msvcrt_test.exe.spec.c
 scanf.ok
 testlist.c

dlls/msvcrt/tests/Makefile.in

@@ -9,6 +9,7 @@ EXTRAINCL = -I$(TOPSRCDIR)/include/msvcrt
 CTESTS = \
 	cpp.c \
 	file.c \
+	heap.c \
 	scanf.c 
 
 @MAKE_TEST_RULES@

dlls/msvcrt/tests/heap.c

@@ -0,0 +1,41 @@
+/*
+ * Unit test suite for memory functions
+ *
+ * Copyright 2003 Dimitrie O. Paun
+ *
+ * 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 "wine/test.h"
+#include <stdlib.h>
+
+static void test_realloc( void )
+{
+    void *mem = NULL;
+
+    mem = realloc(mem, 10);
+    ok(mem != NULL, "memory not allocated");
+    
+    mem = realloc(mem, 20);
+    ok(mem != NULL, "memory not reallocated");
+ 
+    mem = realloc(mem, 0);
+    ok(mem == NULL, "memory nto freed");
+}
+
+START_TEST(heap)
+{
+    test_realloc();
+}