Check in protobuf java code and generate lite jar.

third_party/protobuf/java/src/main/java/com/google/protobuf/CodedInputStream.java

Index: third_party/protobuf/java/src/main/java/com/google/protobuf/CodedInputStream.java
diff --git a/third_party/protobuf/java/src/main/java/com/google/protobuf/CodedInputStream.java b/third_party/protobuf/java/src/main/java/com/google/protobuf/CodedInputStream.java
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index 0000000000000000000000000000000000000000..b3e08555dc38b7736d0632b709851fabf0df096b
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@@ -0,0 +1,885 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// 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 java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Reads and decodes protocol message fields.
+ *
+ * This class contains two kinds of methods:  methods that read specific
+ * protocol message constructs and field types (e.g. {@link #readTag()} and
+ * {@link #readInt32()}) and methods that read low-level values (e.g.
+ * {@link #readRawVarint32()} and {@link #readRawBytes}).  If you are reading
+ * encoded protocol messages, you should use the former methods, but if you are
+ * reading some other format of your own design, use the latter.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public final class CodedInputStream {
+  /**
+   * Create a new CodedInputStream wrapping the given InputStream.
+   */
+  public static CodedInputStream newInstance(final InputStream input) {
+    return new CodedInputStream(input);
+  }
+
+  /**
+   * Create a new CodedInputStream wrapping the given byte array.
+   */
+  public static CodedInputStream newInstance(final byte[] buf) {
+    return newInstance(buf, 0, buf.length);
+  }
+
+  /**
+   * Create a new CodedInputStream wrapping the given byte array slice.
+   */
+  public static CodedInputStream newInstance(final byte[] buf, final int off,
+                                             final int len) {
+    CodedInputStream result = new CodedInputStream(buf, off, len);
+    try {
+      // Some uses of CodedInputStream can be more efficient if they know
+      // exactly how many bytes are available.  By pushing the end point of the
+      // buffer as a limit, we allow them to get this information via
+      // getBytesUntilLimit().  Pushing a limit that we know is at the end of
+      // the stream can never hurt, since we can never past that point anyway.
+      result.pushLimit(len);
+    } catch (InvalidProtocolBufferException ex) {
+      // The only reason pushLimit() might throw an exception here is if len
+      // is negative. Normally pushLimit()'s parameter comes directly off the
+      // wire, so it's important to catch exceptions in case of corrupt or
+      // malicious data. However, in this case, we expect that len is not a
+      // user-supplied value, so we can assume that it being negative indicates
+      // a programming error. Therefore, throwing an unchecked exception is
+      // appropriate.
+      throw new IllegalArgumentException(ex);
+    }
+    return result;
+  }
+
+  // -----------------------------------------------------------------
+
+  /**
+   * Attempt to read a field tag, returning zero if we have reached EOF.
+   * Protocol message parsers use this to read tags, since a protocol message
+   * may legally end wherever a tag occurs, and zero is not a valid tag number.
+   */
+  public int readTag() throws IOException {
+    if (isAtEnd()) {
+      lastTag = 0;
+      return 0;
+    }
+
+    lastTag = readRawVarint32();
+    if (WireFormat.getTagFieldNumber(lastTag) == 0) {
+      // If we actually read zero (or any tag number corresponding to field
+      // number zero), that's not a valid tag.
+      throw InvalidProtocolBufferException.invalidTag();
+    }
+    return lastTag;
+  }
+
+  /**
+   * Verifies that the last call to readTag() returned the given tag value.
+   * This is used to verify that a nested group ended with the correct
+   * end tag.
+   *
+   * @throws InvalidProtocolBufferException {@code value} does not match the
+   *                                        last tag.
+   */
+  public void checkLastTagWas(final int value)
+                              throws InvalidProtocolBufferException {
+    if (lastTag != value) {
+      throw InvalidProtocolBufferException.invalidEndTag();
+    }
+  }
+
+  /**
+   * Reads and discards a single field, given its tag value.
+   *
+   * @return {@code false} if the tag is an endgroup tag, in which case
+   *         nothing is skipped.  Otherwise, returns {@code true}.
+   */
+  public boolean skipField(final int tag) throws IOException {
+    switch (WireFormat.getTagWireType(tag)) {
+      case WireFormat.WIRETYPE_VARINT:
+        readInt32();
+        return true;
+      case WireFormat.WIRETYPE_FIXED64:
+        readRawLittleEndian64();
+        return true;
+      case WireFormat.WIRETYPE_LENGTH_DELIMITED:
+        skipRawBytes(readRawVarint32());
+        return true;
+      case WireFormat.WIRETYPE_START_GROUP:
+        skipMessage();
+        checkLastTagWas(
+          WireFormat.makeTag(WireFormat.getTagFieldNumber(tag),
+                             WireFormat.WIRETYPE_END_GROUP));
+        return true;
+      case WireFormat.WIRETYPE_END_GROUP:
+        return false;
+      case WireFormat.WIRETYPE_FIXED32:
+        readRawLittleEndian32();
+        return true;
+      default:
+        throw InvalidProtocolBufferException.invalidWireType();
+    }
+  }
+
+  /**
+   * Reads and discards an entire message.  This will read either until EOF
+   * or until an endgroup tag, whichever comes first.
+   */
+  public void skipMessage() throws IOException {
+    while (true) {
+      final int tag = readTag();
+      if (tag == 0 || !skipField(tag)) {
+        return;
+      }
+    }
+  }
+
+  // -----------------------------------------------------------------
+
+  /** Read a {@code double} field value from the stream. */
+  public double readDouble() throws IOException {
+    return Double.longBitsToDouble(readRawLittleEndian64());
+  }
+
+  /** Read a {@code float} field value from the stream. */
+  public float readFloat() throws IOException {
+    return Float.intBitsToFloat(readRawLittleEndian32());
+  }
+
+  /** Read a {@code uint64} field value from the stream. */
+  public long readUInt64() throws IOException {
+    return readRawVarint64();
+  }
+
+  /** Read an {@code int64} field value from the stream. */
+  public long readInt64() throws IOException {
+    return readRawVarint64();
+  }
+
+  /** Read an {@code int32} field value from the stream. */
+  public int readInt32() throws IOException {
+    return readRawVarint32();
+  }
+
+  /** Read a {@code fixed64} field value from the stream. */
+  public long readFixed64() throws IOException {
+    return readRawLittleEndian64();
+  }
+
+  /** Read a {@code fixed32} field value from the stream. */
+  public int readFixed32() throws IOException {
+    return readRawLittleEndian32();
+  }
+
+  /** Read a {@code bool} field value from the stream. */
+  public boolean readBool() throws IOException {
+    return readRawVarint32() != 0;
+  }
+
+  /** Read a {@code string} field value from the stream. */
+  public String readString() throws IOException {
+    final int size = readRawVarint32();
+    if (size <= (bufferSize - bufferPos) && size > 0) {
+      // Fast path:  We already have the bytes in a contiguous buffer, so
+      //   just copy directly from it.
+      final String result = new String(buffer, bufferPos, size, "UTF-8");
+      bufferPos += size;
+      return result;
+    } else {
+      // Slow path:  Build a byte array first then copy it.
+      return new String(readRawBytes(size), "UTF-8");
+    }
+  }
+
+  /** Read a {@code group} field value from the stream. */
+  public void readGroup(final int fieldNumber,
+                        final MessageLite.Builder builder,
+                        final ExtensionRegistryLite extensionRegistry)
+      throws IOException {
+    if (recursionDepth >= recursionLimit) {
+      throw InvalidProtocolBufferException.recursionLimitExceeded();
+    }
+    ++recursionDepth;
+    builder.mergeFrom(this, extensionRegistry);
+    checkLastTagWas(
+      WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP));
+    --recursionDepth;
+  }
+
+  /**
+   * Reads a {@code group} field value from the stream and merges it into the
+   * given {@link UnknownFieldSet}.
+   *
+   * @deprecated UnknownFieldSet.Builder now implements MessageLite.Builder, so
+   *             you can just call {@link #readGroup}.
+   */
+  @Deprecated
+  public void readUnknownGroup(final int fieldNumber,
+                               final MessageLite.Builder builder)
+      throws IOException {
+    // We know that UnknownFieldSet will ignore any ExtensionRegistry so it
+    // is safe to pass null here.  (We can't call
+    // ExtensionRegistry.getEmptyRegistry() because that would make this
+    // class depend on ExtensionRegistry, which is not part of the lite
+    // library.)
+    readGroup(fieldNumber, builder, null);
+  }
+
+  /** Read an embedded message field value from the stream. */
+  public void readMessage(final MessageLite.Builder builder,
+                          final ExtensionRegistryLite extensionRegistry)
+      throws IOException {
+    final int length = readRawVarint32();
+    if (recursionDepth >= recursionLimit) {
+      throw InvalidProtocolBufferException.recursionLimitExceeded();
+    }
+    final int oldLimit = pushLimit(length);
+    ++recursionDepth;
+    builder.mergeFrom(this, extensionRegistry);
+    checkLastTagWas(0);
+    --recursionDepth;
+    popLimit(oldLimit);
+  }
+
+  /** Read a {@code bytes} field value from the stream. */
+  public ByteString readBytes() throws IOException {
+    final int size = readRawVarint32();
+    if (size == 0) {
+      return ByteString.EMPTY;
+    } else if (size <= (bufferSize - bufferPos) && size > 0) {
+      // Fast path:  We already have the bytes in a contiguous buffer, so
+      //   just copy directly from it.
+      final ByteString result = ByteString.copyFrom(buffer, bufferPos, size);
+      bufferPos += size;
+      return result;
+    } else {
+      // Slow path:  Build a byte array first then copy it.
+      return ByteString.copyFrom(readRawBytes(size));
+    }
+  }
+
+  /** Read a {@code uint32} field value from the stream. */
+  public int readUInt32() throws IOException {
+    return readRawVarint32();
+  }
+
+  /**
+   * Read an enum field value from the stream.  Caller is responsible
+   * for converting the numeric value to an actual enum.
+   */
+  public int readEnum() throws IOException {
+    return readRawVarint32();
+  }
+
+  /** Read an {@code sfixed32} field value from the stream. */
+  public int readSFixed32() throws IOException {
+    return readRawLittleEndian32();
+  }
+
+  /** Read an {@code sfixed64} field value from the stream. */
+  public long readSFixed64() throws IOException {
+    return readRawLittleEndian64();
+  }
+
+  /** Read an {@code sint32} field value from the stream. */
+  public int readSInt32() throws IOException {
+    return decodeZigZag32(readRawVarint32());
+  }
+
+  /** Read an {@code sint64} field value from the stream. */
+  public long readSInt64() throws IOException {
+    return decodeZigZag64(readRawVarint64());
+  }
+
+  // =================================================================
+
+  /**
+   * Read a raw Varint from the stream.  If larger than 32 bits, discard the
+   * upper bits.
+   */
+  public int readRawVarint32() throws IOException {
+    byte tmp = readRawByte();
+    if (tmp >= 0) {
+      return tmp;
+    }
+    int result = tmp & 0x7f;
+    if ((tmp = readRawByte()) >= 0) {
+      result |= tmp << 7;
+    } else {
+      result |= (tmp & 0x7f) << 7;
+      if ((tmp = readRawByte()) >= 0) {
+        result |= tmp << 14;
+      } else {
+        result |= (tmp & 0x7f) << 14;
+        if ((tmp = readRawByte()) >= 0) {
+          result |= tmp << 21;
+        } else {
+          result |= (tmp & 0x7f) << 21;
+          result |= (tmp = readRawByte()) << 28;
+          if (tmp < 0) {
+            // Discard upper 32 bits.
+            for (int i = 0; i < 5; i++) {
+              if (readRawByte() >= 0) {
+                return result;
+              }
+            }
+            throw InvalidProtocolBufferException.malformedVarint();
+          }
+        }
+      }
+    }
+    return result;
+  }
+
+  /**
+   * Reads a varint from the input one byte at a time, so that it does not
+   * read any bytes after the end of the varint.  If you simply wrapped the
+   * stream in a CodedInputStream and used {@link #readRawVarint32(InputStream)}
+   * then you would probably end up reading past the end of the varint since
+   * CodedInputStream buffers its input.
+   */
+  static int readRawVarint32(final InputStream input) throws IOException {
+    final int firstByte = input.read();
+    if (firstByte == -1) {
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+    return readRawVarint32(firstByte, input);
+  }
+
+  /**
+   * Like {@link #readRawVarint32(InputStream)}, but expects that the caller
+   * has already read one byte.  This allows the caller to determine if EOF
+   * has been reached before attempting to read.
+   */
+  public static int readRawVarint32(
+      final int firstByte, final InputStream input) throws IOException {
+    if ((firstByte & 0x80) == 0) {
+      return firstByte;
+    }
+
+    int result = firstByte & 0x7f;
+    int offset = 7;
+    for (; offset < 32; offset += 7) {
+      final int b = input.read();
+      if (b == -1) {
+        throw InvalidProtocolBufferException.truncatedMessage();
+      }
+      result |= (b & 0x7f) << offset;
+      if ((b & 0x80) == 0) {
+        return result;
+      }
+    }
+    // Keep reading up to 64 bits.
+    for (; offset < 64; offset += 7) {
+      final int b = input.read();
+      if (b == -1) {
+        throw InvalidProtocolBufferException.truncatedMessage();
+      }
+      if ((b & 0x80) == 0) {
+        return result;
+      }
+    }
+    throw InvalidProtocolBufferException.malformedVarint();
+  }
+
+  /** Read a raw Varint from the stream. */
+  public long readRawVarint64() throws IOException {
+    int shift = 0;
+    long result = 0;
+    while (shift < 64) {
+      final byte b = readRawByte();
+      result |= (long)(b & 0x7F) << shift;
+      if ((b & 0x80) == 0) {
+        return result;
+      }
+      shift += 7;
+    }
+    throw InvalidProtocolBufferException.malformedVarint();
+  }
+
+  /** Read a 32-bit little-endian integer from the stream. */
+  public int readRawLittleEndian32() throws IOException {
+    final byte b1 = readRawByte();
+    final byte b2 = readRawByte();
+    final byte b3 = readRawByte();
+    final byte b4 = readRawByte();
+    return (((int)b1 & 0xff)      ) |
+           (((int)b2 & 0xff) <<  8) |
+           (((int)b3 & 0xff) << 16) |
+           (((int)b4 & 0xff) << 24);
+  }
+
+  /** Read a 64-bit little-endian integer from the stream. */
+  public long readRawLittleEndian64() throws IOException {
+    final byte b1 = readRawByte();
+    final byte b2 = readRawByte();
+    final byte b3 = readRawByte();
+    final byte b4 = readRawByte();
+    final byte b5 = readRawByte();
+    final byte b6 = readRawByte();
+    final byte b7 = readRawByte();
+    final byte b8 = readRawByte();
+    return (((long)b1 & 0xff)      ) |
+           (((long)b2 & 0xff) <<  8) |
+           (((long)b3 & 0xff) << 16) |
+           (((long)b4 & 0xff) << 24) |
+           (((long)b5 & 0xff) << 32) |
+           (((long)b6 & 0xff) << 40) |
+           (((long)b7 & 0xff) << 48) |
+           (((long)b8 & 0xff) << 56);
+  }
+
+  /**
+   * Decode a ZigZag-encoded 32-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n An unsigned 32-bit integer, stored in a signed int because
+   *          Java has no explicit unsigned support.
+   * @return A signed 32-bit integer.
+   */
+  public static int decodeZigZag32(final int n) {
+    return (n >>> 1) ^ -(n & 1);
+  }
+
+  /**
+   * Decode a ZigZag-encoded 64-bit value.  ZigZag encodes signed integers
+   * into values that can be efficiently encoded with varint.  (Otherwise,
+   * negative values must be sign-extended to 64 bits to be varint encoded,
+   * thus always taking 10 bytes on the wire.)
+   *
+   * @param n An unsigned 64-bit integer, stored in a signed int because
+   *          Java has no explicit unsigned support.
+   * @return A signed 64-bit integer.
+   */
+  public static long decodeZigZag64(final long n) {
+    return (n >>> 1) ^ -(n & 1);
+  }
+
+  // -----------------------------------------------------------------
+
+  private final byte[] buffer;
+  private int bufferSize;
+  private int bufferSizeAfterLimit;
+  private int bufferPos;
+  private final InputStream input;
+  private int lastTag;
+
+  /**
+   * The total number of bytes read before the current buffer.  The total
+   * bytes read up to the current position can be computed as
+   * {@code totalBytesRetired + bufferPos}.  This value may be negative if
+   * reading started in the middle of the current buffer (e.g. if the
+   * constructor that takes a byte array and an offset was used).
+   */
+  private int totalBytesRetired;
+
+  /** The absolute position of the end of the current message. */
+  private int currentLimit = Integer.MAX_VALUE;
+
+  /** See setRecursionLimit() */
+  private int recursionDepth;
+  private int recursionLimit = DEFAULT_RECURSION_LIMIT;
+
+  /** See setSizeLimit() */
+  private int sizeLimit = DEFAULT_SIZE_LIMIT;
+
+  private static final int DEFAULT_RECURSION_LIMIT = 64;
+  private static final int DEFAULT_SIZE_LIMIT = 64 << 20;  // 64MB
+  private static final int BUFFER_SIZE = 4096;
+
+  private CodedInputStream(final byte[] buffer, final int off, final int len) {
+    this.buffer = buffer;
+    bufferSize = off + len;
+    bufferPos = off;
+    totalBytesRetired = -off;
+    input = null;
+  }
+
+  private CodedInputStream(final InputStream input) {
+    buffer = new byte[BUFFER_SIZE];
+    bufferSize = 0;
+    bufferPos = 0;
+    totalBytesRetired = 0;
+    this.input = input;
+  }
+
+  /**
+   * Set the maximum message recursion depth.  In order to prevent malicious
+   * messages from causing stack overflows, {@code CodedInputStream} limits
+   * how deeply messages may be nested.  The default limit is 64.
+   *
+   * @return the old limit.
+   */
+  public int setRecursionLimit(final int limit) {
+    if (limit < 0) {
+      throw new IllegalArgumentException(
+        "Recursion limit cannot be negative: " + limit);
+    }
+    final int oldLimit = recursionLimit;
+    recursionLimit = limit;
+    return oldLimit;
+  }
+
+  /**
+   * Set the maximum message size.  In order to prevent malicious
+   * messages from exhausting memory or causing integer overflows,
+   * {@code CodedInputStream} limits how large a message may be.
+   * The default limit is 64MB.  You should set this limit as small
+   * as you can without harming your app's functionality.  Note that
+   * size limits only apply when reading from an {@code InputStream}, not
+   * when constructed around a raw byte array (nor with
+   * {@link ByteString#newCodedInput}).
+   * <p>
+   * If you want to read several messages from a single CodedInputStream, you
+   * could call {@link #resetSizeCounter()} after each one to avoid hitting the
+   * size limit.
+   *
+   * @return the old limit.
+   */
+  public int setSizeLimit(final int limit) {
+    if (limit < 0) {
+      throw new IllegalArgumentException(
+        "Size limit cannot be negative: " + limit);
+    }
+    final int oldLimit = sizeLimit;
+    sizeLimit = limit;
+    return oldLimit;
+  }
+
+  /**
+   * Resets the current size counter to zero (see {@link #setSizeLimit(int)}).
+   */
+  public void resetSizeCounter() {
+    totalBytesRetired = -bufferPos;
+  }
+
+  /**
+   * Sets {@code currentLimit} to (current position) + {@code byteLimit}.  This
+   * is called when descending into a length-delimited embedded message.
+   *
+   * <p>Note that {@code pushLimit()} does NOT affect how many bytes the
+   * {@code CodedInputStream} reads from an underlying {@code InputStream} when
+   * refreshing its buffer.  If you need to prevent reading past a certain
+   * point in the underlying {@code InputStream} (e.g. because you expect it to
+   * contain more data after the end of the message which you need to handle
+   * differently) then you must place a wrapper around you {@code InputStream}
+   * which limits the amount of data that can be read from it.
+   *
+   * @return the old limit.
+   */
+  public int pushLimit(int byteLimit) throws InvalidProtocolBufferException {
+    if (byteLimit < 0) {
+      throw InvalidProtocolBufferException.negativeSize();
+    }
+    byteLimit += totalBytesRetired + bufferPos;
+    final int oldLimit = currentLimit;
+    if (byteLimit > oldLimit) {
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+    currentLimit = byteLimit;
+
+    recomputeBufferSizeAfterLimit();
+
+    return oldLimit;
+  }
+
+  private void recomputeBufferSizeAfterLimit() {
+    bufferSize += bufferSizeAfterLimit;
+    final int bufferEnd = totalBytesRetired + bufferSize;
+    if (bufferEnd > currentLimit) {
+      // Limit is in current buffer.
+      bufferSizeAfterLimit = bufferEnd - currentLimit;
+      bufferSize -= bufferSizeAfterLimit;
+    } else {
+      bufferSizeAfterLimit = 0;
+    }
+  }
+
+  /**
+   * Discards the current limit, returning to the previous limit.
+   *
+   * @param oldLimit The old limit, as returned by {@code pushLimit}.
+   */
+  public void popLimit(final int oldLimit) {
+    currentLimit = oldLimit;
+    recomputeBufferSizeAfterLimit();
+  }
+
+  /**
+   * Returns the number of bytes to be read before the current limit.
+   * If no limit is set, returns -1.
+   */
+  public int getBytesUntilLimit() {
+    if (currentLimit == Integer.MAX_VALUE) {
+      return -1;
+    }
+
+    final int currentAbsolutePosition = totalBytesRetired + bufferPos;
+    return currentLimit - currentAbsolutePosition;
+  }
+
+  /**
+   * Returns true if the stream has reached the end of the input.  This is the
+   * case if either the end of the underlying input source has been reached or
+   * if the stream has reached a limit created using {@link #pushLimit(int)}.
+   */
+  public boolean isAtEnd() throws IOException {
+    return bufferPos == bufferSize && !refillBuffer(false);
+  }
+
+  /**
+   * The total bytes read up to the current position. Calling
+   * {@link #resetSizeCounter()} resets this value to zero.
+   */
+  public int getTotalBytesRead() {
+      return totalBytesRetired + bufferPos;
+  }
+
+  /**
+   * Called with {@code this.buffer} is empty to read more bytes from the
+   * input.  If {@code mustSucceed} is true, refillBuffer() gurantees that
+   * either there will be at least one byte in the buffer when it returns
+   * or it will throw an exception.  If {@code mustSucceed} is false,
+   * refillBuffer() returns false if no more bytes were available.
+   */
+  private boolean refillBuffer(final boolean mustSucceed) throws IOException {
+    if (bufferPos < bufferSize) {
+      throw new IllegalStateException(
+        "refillBuffer() called when buffer wasn't empty.");
+    }
+
+    if (totalBytesRetired + bufferSize == currentLimit) {
+      // Oops, we hit a limit.
+      if (mustSucceed) {
+        throw InvalidProtocolBufferException.truncatedMessage();
+      } else {
+        return false;
+      }
+    }
+
+    totalBytesRetired += bufferSize;
+
+    bufferPos = 0;
+    bufferSize = (input == null) ? -1 : input.read(buffer);
+    if (bufferSize == 0 || bufferSize < -1) {
+      throw new IllegalStateException(
+          "InputStream#read(byte[]) returned invalid result: " + bufferSize +
+          "\nThe InputStream implementation is buggy.");
+    }
+    if (bufferSize == -1) {
+      bufferSize = 0;
+      if (mustSucceed) {
+        throw InvalidProtocolBufferException.truncatedMessage();
+      } else {
+        return false;
+      }
+    } else {
+      recomputeBufferSizeAfterLimit();
+      final int totalBytesRead =
+        totalBytesRetired + bufferSize + bufferSizeAfterLimit;
+      if (totalBytesRead > sizeLimit || totalBytesRead < 0) {
+        throw InvalidProtocolBufferException.sizeLimitExceeded();
+      }
+      return true;
+    }
+  }
+
+  /**
+   * Read one byte from the input.
+   *
+   * @throws InvalidProtocolBufferException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public byte readRawByte() throws IOException {
+    if (bufferPos == bufferSize) {
+      refillBuffer(true);
+    }
+    return buffer[bufferPos++];
+  }
+
+  /**
+   * Read a fixed size of bytes from the input.
+   *
+   * @throws InvalidProtocolBufferException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public byte[] readRawBytes(final int size) throws IOException {
+    if (size < 0) {
+      throw InvalidProtocolBufferException.negativeSize();
+    }
+
+    if (totalBytesRetired + bufferPos + size > currentLimit) {
+      // Read to the end of the stream anyway.
+      skipRawBytes(currentLimit - totalBytesRetired - bufferPos);
+      // Then fail.
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+
+    if (size <= bufferSize - bufferPos) {
+      // We have all the bytes we need already.
+      final byte[] bytes = new byte[size];
+      System.arraycopy(buffer, bufferPos, bytes, 0, size);
+      bufferPos += size;
+      return bytes;
+    } else if (size < BUFFER_SIZE) {
+      // Reading more bytes than are in the buffer, but not an excessive number
+      // of bytes.  We can safely allocate the resulting array ahead of time.
+
+      // First copy what we have.
+      final byte[] bytes = new byte[size];
+      int pos = bufferSize - bufferPos;
+      System.arraycopy(buffer, bufferPos, bytes, 0, pos);
+      bufferPos = bufferSize;
+
+      // We want to use refillBuffer() and then copy from the buffer into our
+      // byte array rather than reading directly into our byte array because
+      // the input may be unbuffered.
+      refillBuffer(true);
+
+      while (size - pos > bufferSize) {
+        System.arraycopy(buffer, 0, bytes, pos, bufferSize);
+        pos += bufferSize;
+        bufferPos = bufferSize;
+        refillBuffer(true);
+      }
+
+      System.arraycopy(buffer, 0, bytes, pos, size - pos);
+      bufferPos = size - pos;
+
+      return bytes;
+    } else {
+      // The size is very large.  For security reasons, we can't allocate the
+      // entire byte array yet.  The size comes directly from the input, so a
+      // maliciously-crafted message could provide a bogus very large size in
+      // order to trick the app into allocating a lot of memory.  We avoid this
+      // by allocating and reading only a small chunk at a time, so that the
+      // malicious message must actually *be* extremely large to cause
+      // problems.  Meanwhile, we limit the allowed size of a message elsewhere.
+
+      // Remember the buffer markers since we'll have to copy the bytes out of
+      // it later.
+      final int originalBufferPos = bufferPos;
+      final int originalBufferSize = bufferSize;
+
+      // Mark the current buffer consumed.
+      totalBytesRetired += bufferSize;
+      bufferPos = 0;
+      bufferSize = 0;
+
+      // Read all the rest of the bytes we need.
+      int sizeLeft = size - (originalBufferSize - originalBufferPos);
+      final List<byte[]> chunks = new ArrayList<byte[]>();
+
+      while (sizeLeft > 0) {
+        final byte[] chunk = new byte[Math.min(sizeLeft, BUFFER_SIZE)];
+        int pos = 0;
+        while (pos < chunk.length) {
+          final int n = (input == null) ? -1 :
+            input.read(chunk, pos, chunk.length - pos);
+          if (n == -1) {
+            throw InvalidProtocolBufferException.truncatedMessage();
+          }
+          totalBytesRetired += n;
+          pos += n;
+        }
+        sizeLeft -= chunk.length;
+        chunks.add(chunk);
+      }
+
+      // OK, got everything.  Now concatenate it all into one buffer.
+      final byte[] bytes = new byte[size];
+
+      // Start by copying the leftover bytes from this.buffer.
+      int pos = originalBufferSize - originalBufferPos;
+      System.arraycopy(buffer, originalBufferPos, bytes, 0, pos);
+
+      // And now all the chunks.
+      for (final byte[] chunk : chunks) {
+        System.arraycopy(chunk, 0, bytes, pos, chunk.length);
+        pos += chunk.length;
+      }
+
+      // Done.
+      return bytes;
+    }
+  }
+
+  /**
+   * Reads and discards {@code size} bytes.
+   *
+   * @throws InvalidProtocolBufferException The end of the stream or the current
+   *                                        limit was reached.
+   */
+  public void skipRawBytes(final int size) throws IOException {
+    if (size < 0) {
+      throw InvalidProtocolBufferException.negativeSize();
+    }
+
+    if (totalBytesRetired + bufferPos + size > currentLimit) {
+      // Read to the end of the stream anyway.
+      skipRawBytes(currentLimit - totalBytesRetired - bufferPos);
+      // Then fail.
+      throw InvalidProtocolBufferException.truncatedMessage();
+    }
+
+    if (size <= bufferSize - bufferPos) {
+      // We have all the bytes we need already.
+      bufferPos += size;
+    } else {
+      // Skipping more bytes than are in the buffer.  First skip what we have.
+      int pos = bufferSize - bufferPos;
+      bufferPos = bufferSize;
+
+      // Keep refilling the buffer until we get to the point we wanted to skip
+      // to.  This has the side effect of ensuring the limits are updated
+      // correctly.
+      refillBuffer(true);
+      while (size - pos > bufferSize) {
+        pos += bufferSize;
+        bufferPos = bufferSize;
+        refillBuffer(true);
+      }
+
+      bufferPos = size - pos; 
+    }
+  }
+}