diff --git a/applypatch/utils.c b/applypatch/utils.c
new file mode 100644
index 0000000..912229b
--- /dev/null
+++ b/applypatch/utils.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+
+#include "utils.h"
+
+/** Write a 4-byte value to f in little-endian order. */
+void Write4(int value, FILE* f) {
+  fputc(value & 0xff, f);
+  fputc((value >> 8) & 0xff, f);
+  fputc((value >> 16) & 0xff, f);
+  fputc((value >> 24) & 0xff, f);
+}
+
+/** Write an 8-byte value to f in little-endian order. */
+void Write8(long long value, FILE* f) {
+  fputc(value & 0xff, f);
+  fputc((value >> 8) & 0xff, f);
+  fputc((value >> 16) & 0xff, f);
+  fputc((value >> 24) & 0xff, f);
+  fputc((value >> 32) & 0xff, f);
+  fputc((value >> 40) & 0xff, f);
+  fputc((value >> 48) & 0xff, f);
+  fputc((value >> 56) & 0xff, f);
+}
+
+int Read2(unsigned char* p) {
+  return (int)(((unsigned int)p[1] << 8) |
+               (unsigned int)p[0]);
+}
+
+int Read4(unsigned char* p) {
+  return (int)(((unsigned int)p[3] << 24) |
+               ((unsigned int)p[2] << 16) |
+               ((unsigned int)p[1] << 8) |
+               (unsigned int)p[0]);
+}
+
+long long Read8(unsigned char* p) {
+  return (long long)(((unsigned long long)p[7] << 56) |
+                     ((unsigned long long)p[6] << 48) |
+                     ((unsigned long long)p[5] << 40) |
+                     ((unsigned long long)p[4] << 32) |
+                     ((unsigned long long)p[3] << 24) |
+                     ((unsigned long long)p[2] << 16) |
+                     ((unsigned long long)p[1] << 8) |
+                     (unsigned long long)p[0]);
+}