1 files changed, 150 insertions, 0 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/IterableByteBufferInputStream.java b/java/core/src/main/java/com/google/protobuf/IterableByteBufferInputStream.java
new file mode 100644
index 00000000..713e8064
--- /dev/null
+++ b/java/core/src/main/java/com/google/protobuf/IterableByteBufferInputStream.java
@@ -0,0 +1,150 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import static com.google.protobuf.Internal.EMPTY_BYTE_BUFFER;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+import java.util.Iterator;
+
+class IterableByteBufferInputStream extends InputStream {
+  /** The {@link Iterator} with type {@link ByteBuffer} of {@code input} */
+  private Iterator<ByteBuffer> iterator;
+  /** The current ByteBuffer; */
+  private ByteBuffer currentByteBuffer;
+  /** The number of ByteBuffers in the input data. */
+  private int dataSize;
+  /**
+   * Current {@code ByteBuffer}'s index
+   *
+   * <p>If index equals dataSize, then all the data in the InputStream has been consumed
+   */
+  private int currentIndex;
+  /** The current position for current ByteBuffer */
+  private int currentByteBufferPos;
+  /** Whether current ByteBuffer has an array */
+  private boolean hasArray;
+  /**
+   * If the current ByteBuffer is unsafe-direct based, currentArray is null; otherwise should be the
+   * array inside ByteBuffer.
+   */
+  private byte[] currentArray;
+  /** Current ByteBuffer's array offset */
+  private int currentArrayOffset;
+  /**
+   * If the current ByteBuffer is unsafe-direct based, currentAddress is the start address of this
+   * ByteBuffer; otherwise should be zero.
+   */
+  private long currentAddress;
+
+  IterableByteBufferInputStream(Iterable<ByteBuffer> data) {
+    iterator = data.iterator();
+    dataSize = 0;
+    for (ByteBuffer unused : data) {
+      dataSize++;
+    }
+    currentIndex = -1;
+
+    if (!getNextByteBuffer()) {
+      currentByteBuffer = EMPTY_BYTE_BUFFER;
+      currentIndex = 0;
+      currentByteBufferPos = 0;
+      currentAddress = 0;
+    }
+  }
+
+  private boolean getNextByteBuffer() {
+    currentIndex++;
+    if (!iterator.hasNext()) {
+      return false;
+    }
+    currentByteBuffer = iterator.next();
+    currentByteBufferPos = currentByteBuffer.position();
+    if (currentByteBuffer.hasArray()) {
+      hasArray = true;
+      currentArray = currentByteBuffer.array();
+      currentArrayOffset = currentByteBuffer.arrayOffset();
+    } else {
+      hasArray = false;
+      currentAddress = UnsafeUtil.addressOffset(currentByteBuffer);
+      currentArray = null;
+    }
+    return true;
+  }
+
+  private void updateCurrentByteBufferPos(int numberOfBytesRead) {
+    currentByteBufferPos += numberOfBytesRead;
+    if (currentByteBufferPos == currentByteBuffer.limit()) {
+      getNextByteBuffer();
+    }
+  }
+
+  @Override
+  public int read() throws IOException {
+    if (currentIndex == dataSize) {
+      return -1;
+    }
+    if (hasArray) {
+      int result = currentArray[currentByteBufferPos + currentArrayOffset] & 0xFF;
+      updateCurrentByteBufferPos(1);
+      return result;
+    } else {
+      int result = UnsafeUtil.getByte(currentByteBufferPos + currentAddress) & 0xFF;
+      updateCurrentByteBufferPos(1);
+      return result;
+    }
+  }
+
+  @Override
+  public int read(byte[] output, int offset, int length) throws IOException {
+    if (currentIndex == dataSize) {
+      return -1;
+    }
+    int remaining = currentByteBuffer.limit() - currentByteBufferPos;
+    if (length > remaining) {
+      length = remaining;
+    }
+    if (hasArray) {
+      System.arraycopy(
+          currentArray, currentByteBufferPos + currentArrayOffset, output, offset, length);
+      updateCurrentByteBufferPos(length);
+    } else {
+      int prevPos = currentByteBuffer.position();
+      currentByteBuffer.position(currentByteBufferPos);
+      currentByteBuffer.get(output, offset, length);
+      currentByteBuffer.position(prevPos);
+      updateCurrentByteBufferPos(length);
+    }
+    return length;
+  }
+}