diff --git a/tools/applypatch/applypatch.h b/tools/applypatch/applypatch.h
new file mode 100644
index 0000000..76fc80a
--- /dev/null
+++ b/tools/applypatch/applypatch.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef _APPLYPATCH_H
+#define _APPLYPATCH_H
+
+#include "mincrypt/sha.h"
+
+typedef struct _Patch {
+  uint8_t sha1[SHA_DIGEST_SIZE];
+  const char* patch_filename;
+} Patch;
+
+typedef struct _FileContents {
+  uint8_t sha1[SHA_DIGEST_SIZE];
+  unsigned char* data;
+  size_t size;
+  struct stat st;
+} FileContents;
+
+// When there isn't enough room on the target filesystem to hold the
+// patched version of the file, we copy the original here and delete
+// it to free up space.  If the expected source file doesn't exist, or
+// is corrupted, we look to see if this file contains the bits we want
+// and use it as the source instead.
+#define CACHE_TEMP_SOURCE "/cache/saved.file"
+
+// applypatch.c
+size_t FreeSpaceForFile(const char* filename);
+
+// bsdiff.c
+void ShowBSDiffLicense();
+int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
+                     const char* patch_filename,
+                     FILE* output, SHA_CTX* ctx);
+
+// freecache.c
+int MakeFreeSpaceOnCache(size_t bytes_needed);
+
+#endif