auto import from //depot/cupcake/@135843
diff --git a/libcutils/buffer.c b/libcutils/buffer.c
new file mode 100644
index 0000000..f34b8f8
--- /dev/null
+++ b/libcutils/buffer.c
@@ -0,0 +1,116 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "buffer"
+
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "buffer.h"
+#include "loghack.h"
+
+Buffer* bufferCreate(size_t capacity) {
+ Buffer* buffer = malloc(sizeof(Buffer));
+ if (buffer == NULL) {
+ return NULL;
+ }
+ buffer->capacity = capacity;
+ buffer->expected = 0;
+ buffer->data = malloc(capacity);
+ if (buffer->data == NULL) {
+ free(buffer);
+ return NULL;
+ }
+ return buffer;
+}
+
+void bufferFree(Buffer* buffer) {
+ free(buffer->data);
+ free(buffer);
+}
+
+Buffer* bufferWrap(char* data, size_t capacity, size_t size) {
+ Buffer* buffer = malloc(sizeof(Buffer));
+ if (buffer == NULL) {
+ return NULL;
+ }
+
+ buffer->data = data;
+ buffer->capacity = capacity;
+ buffer->size = size;
+ buffer->expected = 0;
+ return buffer;
+}
+
+int bufferPrepareForRead(Buffer* buffer, size_t expected) {
+ if (expected > buffer->capacity) {
+ // Expand buffer.
+ char* expanded = realloc(buffer->data, expected);
+ if (expanded == NULL) {
+ errno = ENOMEM;
+ return -1;
+ }
+ buffer->capacity = expected;
+ buffer->data = expanded;
+ }
+
+ buffer->size = 0;
+ buffer->expected = expected;
+ return 0;
+}
+
+ssize_t bufferRead(Buffer* buffer, int fd) {
+ assert(buffer->size < buffer->expected);
+
+ ssize_t bytesRead = read(fd,
+ buffer->data + buffer->size,
+ buffer->expected - buffer->size);
+
+ if (bytesRead > 0) {
+ buffer->size += bytesRead;
+ return buffer->size;
+ }
+
+ return bytesRead;
+}
+
+void bufferPrepareForWrite(Buffer* buffer) {
+ buffer->remaining = buffer->size;
+}
+
+ssize_t bufferWrite(Buffer* buffer, int fd) {
+ assert(buffer->remaining > 0);
+ assert(buffer->remaining <= buffer->size);
+
+ ssize_t bytesWritten = write(fd,
+ buffer->data + buffer->size - buffer->remaining,
+ buffer->remaining);
+
+ if (bytesWritten >= 0) {
+ buffer->remaining -= bytesWritten;
+
+ LOGD("Buffer bytes written: %d", (int) bytesWritten);
+ LOGD("Buffer size: %d", (int) buffer->size);
+ LOGD("Buffer remaining: %d", (int) buffer->remaining);
+
+ return buffer->remaining;
+ }
+
+ return bytesWritten;
+}
+