Implemented realloc().

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28454 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/runtime_loader/heap.cpp

@@ -237,10 +237,31 @@ dump_chunks(void)
 
 
 void *
-realloc(void *buffer, size_t newSize)
+realloc(void *allocation, size_t newSize)
 {
-	// not implemented
+	// free, if new size is 0
-	return NULL;
+	if (newSize == 0) {
+		free(allocation);
+		return NULL;
+	}
+
+	// just malloc(), if no previous allocation
+	if (allocation == NULL)
+		return malloc(newSize);
+
+	// we're lazy and don't shrink allocations
+	free_chunk* chunk = free_chunk::SetToAllocated(allocation);
+	if (chunk->Size() >= newSize)
+		return allocation;
+
+	// the allocation needs to grow -- allocate a new one and memcpy()
+	void* newAllocation = malloc(newSize);
+	if (newAllocation != NULL) {
+		memcpy(newAllocation, allocation, chunk->Size());
+		free(allocation);
+	}
+
+	return newAllocation;
 }