Guardedalloc: added MEM_reallocN function to do simple alloc/memcpy/free,

not as optimized as a system realloc but I've had to do this often enough
manually to justify a utility function.

intern/guardedalloc/MEM_guardedalloc.h

@@ -84,6 +84,13 @@ extern "C" {
 	 * newly allocated block.  */
 	void *MEM_dupallocN(void *vmemh);
 
+	/**
+	  * Reallocates a block of memory, and returns pointer to the newly
+	  * allocated block, the old one is freed. this is not as optimized
+	  * as a system realloc but just makes a new allocation and copies
+	  * over from existing memory. */
+	void *MEM_reallocN(void *vmemh, unsigned int len);
+
 	/**
 	 * Allocate a block of memory of size len, with tag name str. The
 	 * memory is cleared. The name must be static, because only a

intern/guardedalloc/intern/mallocn.c

@@ -225,6 +225,28 @@ void *MEM_dupallocN(void *vmemh)
 	return newp;
 }
 
+void *MEM_reallocN(void *vmemh, unsigned int len)
+{
+	void *newp= NULL;
+	
+	if (vmemh) {
+		MemHead *memh= vmemh;
+		memh--;
+
+		newp= MEM_mallocN(len, memh->name);
+		if(newp) {
+			if(len < memh->len)
+				memcpy(newp, vmemh, len);
+			else
+				memcpy(newp, vmemh, memh->len);
+		}
+
+		MEM_freeN(vmemh);
+	}
+
+	return newp;
+}
+
 static void make_memhead_header(MemHead *memh, unsigned int len, const char *str)
 {
 	MemTail *memt;