auto import from //depot/cupcake/@135843
diff --git a/libcutils/buffer.h b/libcutils/buffer.h
new file mode 100644
index 0000000..d8bc108
--- /dev/null
+++ b/libcutils/buffer.h
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2007 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.
+ */
+
+/**
+ * Byte buffer utilities.
+ */
+
+#ifndef __BUFFER_H
+#define __BUFFER_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdlib.h>
+
+/**
+ * Byte buffer of known size. Keeps track of how much data has been read
+ * into or written out of the buffer.
+ */
+typedef struct {
+ /** Buffered data. */
+ char* data;
+
+ union {
+ /** For reading. # of bytes we expect. */
+ size_t expected;
+
+ /** For writing. # of bytes to write. */
+ size_t remaining;
+ };
+
+ /** Actual # of bytes in the buffer. */
+ size_t size;
+
+ /** Amount of memory allocated for this buffer. */
+ size_t capacity;
+} Buffer;
+
+/**
+ * Returns true if all data has been read into the buffer.
+ */
+#define bufferReadComplete(buffer) (buffer->expected == buffer->size)
+
+/**
+ * Returns true if the buffer has been completely written.
+ */
+#define bufferWriteComplete(buffer) (buffer->remaining == 0)
+
+/**
+ * Creates a new buffer with the given initial capacity.
+ */
+Buffer* bufferCreate(size_t initialCapacity);
+
+/**
+ * Wraps an existing byte array.
+ */
+Buffer* bufferWrap(char* data, size_t capacity, size_t size);
+
+/**
+ * Frees and its data.
+ */
+void bufferFree(Buffer* buffer);
+
+/**
+ * Prepares buffer to read 'expected' number of bytes. Expands capacity if
+ * necessary. Returns 0 if successful or -1 if an error occurs allocating
+ * memory.
+ */
+int bufferPrepareForRead(Buffer* buffer, size_t expected);
+
+/**
+ * Reads some data into a buffer. Returns -1 in case of an error and sets
+ * errno (see read()). Returns 0 for EOF. Updates buffer->size and returns
+ * the new size after a succesful read.
+ *
+ * Precondition: buffer->size < buffer->expected
+ */
+ssize_t bufferRead(Buffer* buffer, int fd);
+
+/**
+ * Prepares a buffer to be written out.
+ */
+void bufferPrepareForWrite(Buffer* buffer);
+
+/**
+ * Writes data from buffer to the given fd. Returns -1 and sets errno in case
+ * of an error. Updates buffer->remaining and returns the number of remaining
+ * bytes to be written after a successful write.
+ *
+ * Precondition: buffer->remaining > 0
+ */
+ssize_t bufferWrite(Buffer* buffer, int fd);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __BUFFER_H */