Media CAS Proxy SDK release: 16.5.0

ubuntu/google/protobuf/io/coded_stream.cc

@@ -0,0 +1,956 @@
+// 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.
+
+// Author: kenton@google.com (Kenton Varda)
+//  Based on original Protocol Buffers design by
+//  Sanjay Ghemawat, Jeff Dean, and others.
+//
+// This implementation is heavily optimized to make reads and writes
+// of small values (especially varints) as fast as possible.  In
+// particular, we optimize for the common case that a read or a write
+// will not cross the end of the buffer, since we can avoid a lot
+// of branching in this case.
+
+#include <google/protobuf/io/coded_stream.h>
+
+#include <limits.h>
+
+#include <algorithm>
+#include <cstring>
+#include <utility>
+
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/arena.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
+#include <google/protobuf/stubs/stl_util.h>
+
+
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+namespace io {
+
+namespace {
+
+static const int kMaxVarintBytes = 10;
+static const int kMaxVarint32Bytes = 5;
+
+
+inline bool NextNonEmpty(ZeroCopyInputStream* input, const void** data,
+                         int* size) {
+  bool success;
+  do {
+    success = input->Next(data, size);
+  } while (success && *size == 0);
+  return success;
+}
+
+}  // namespace
+
+// CodedInputStream ==================================================
+
+CodedInputStream::~CodedInputStream() {
+  if (input_ != NULL) {
+    BackUpInputToCurrentPosition();
+  }
+}
+
+// Static.
+int CodedInputStream::default_recursion_limit_ = 100;
+
+
+void CodedInputStream::BackUpInputToCurrentPosition() {
+  int backup_bytes = BufferSize() + buffer_size_after_limit_ + overflow_bytes_;
+  if (backup_bytes > 0) {
+    input_->BackUp(backup_bytes);
+
+    // total_bytes_read_ doesn't include overflow_bytes_.
+    total_bytes_read_ -= BufferSize() + buffer_size_after_limit_;
+    buffer_end_ = buffer_;
+    buffer_size_after_limit_ = 0;
+    overflow_bytes_ = 0;
+  }
+}
+
+inline void CodedInputStream::RecomputeBufferLimits() {
+  buffer_end_ += buffer_size_after_limit_;
+  int closest_limit = std::min(current_limit_, total_bytes_limit_);
+  if (closest_limit < total_bytes_read_) {
+    // The limit position is in the current buffer.  We must adjust
+    // the buffer size accordingly.
+    buffer_size_after_limit_ = total_bytes_read_ - closest_limit;
+    buffer_end_ -= buffer_size_after_limit_;
+  } else {
+    buffer_size_after_limit_ = 0;
+  }
+}
+
+CodedInputStream::Limit CodedInputStream::PushLimit(int byte_limit) {
+  // Current position relative to the beginning of the stream.
+  int current_position = CurrentPosition();
+
+  Limit old_limit = current_limit_;
+
+  // security: byte_limit is possibly evil, so check for negative values
+  // and overflow. Also check that the new requested limit is before the
+  // previous limit; otherwise we continue to enforce the previous limit.
+  if (PROTOBUF_PREDICT_TRUE(byte_limit >= 0 &&
+                            byte_limit <= INT_MAX - current_position &&
+                            byte_limit < current_limit_ - current_position)) {
+    current_limit_ = current_position + byte_limit;
+    RecomputeBufferLimits();
+  }
+
+  return old_limit;
+}
+
+void CodedInputStream::PopLimit(Limit limit) {
+  // The limit passed in is actually the *old* limit, which we returned from
+  // PushLimit().
+  current_limit_ = limit;
+  RecomputeBufferLimits();
+
+  // We may no longer be at a legitimate message end.  ReadTag() needs to be
+  // called again to find out.
+  legitimate_message_end_ = false;
+}
+
+std::pair<CodedInputStream::Limit, int>
+CodedInputStream::IncrementRecursionDepthAndPushLimit(int byte_limit) {
+  return std::make_pair(PushLimit(byte_limit), --recursion_budget_);
+}
+
+CodedInputStream::Limit CodedInputStream::ReadLengthAndPushLimit() {
+  uint32 length;
+  return PushLimit(ReadVarint32(&length) ? length : 0);
+}
+
+bool CodedInputStream::DecrementRecursionDepthAndPopLimit(Limit limit) {
+  bool result = ConsumedEntireMessage();
+  PopLimit(limit);
+  GOOGLE_DCHECK_LT(recursion_budget_, recursion_limit_);
+  ++recursion_budget_;
+  return result;
+}
+
+bool CodedInputStream::CheckEntireMessageConsumedAndPopLimit(Limit limit) {
+  bool result = ConsumedEntireMessage();
+  PopLimit(limit);
+  return result;
+}
+
+int CodedInputStream::BytesUntilLimit() const {
+  if (current_limit_ == INT_MAX) return -1;
+  int current_position = CurrentPosition();
+
+  return current_limit_ - current_position;
+}
+
+void CodedInputStream::SetTotalBytesLimit(int total_bytes_limit) {
+  // Make sure the limit isn't already past, since this could confuse other
+  // code.
+  int current_position = CurrentPosition();
+  total_bytes_limit_ = std::max(current_position, total_bytes_limit);
+  RecomputeBufferLimits();
+}
+
+int CodedInputStream::BytesUntilTotalBytesLimit() const {
+  if (total_bytes_limit_ == INT_MAX) return -1;
+  return total_bytes_limit_ - CurrentPosition();
+}
+
+void CodedInputStream::PrintTotalBytesLimitError() {
+  GOOGLE_LOG(ERROR)
+      << "A protocol message was rejected because it was too "
+         "big (more than "
+      << total_bytes_limit_
+      << " bytes).  To increase the limit (or to disable these "
+         "warnings), see CodedInputStream::SetTotalBytesLimit() "
+         "in third_party/protobuf/src/google/protobuf/io/coded_stream.h.";
+}
+
+bool CodedInputStream::SkipFallback(int count, int original_buffer_size) {
+  if (buffer_size_after_limit_ > 0) {
+    // We hit a limit inside this buffer.  Advance to the limit and fail.
+    Advance(original_buffer_size);
+    return false;
+  }
+
+  count -= original_buffer_size;
+  buffer_ = NULL;
+  buffer_end_ = buffer_;
+
+  // Make sure this skip doesn't try to skip past the current limit.
+  int closest_limit = std::min(current_limit_, total_bytes_limit_);
+  int bytes_until_limit = closest_limit - total_bytes_read_;
+  if (bytes_until_limit < count) {
+    // We hit the limit.  Skip up to it then fail.
+    if (bytes_until_limit > 0) {
+      total_bytes_read_ = closest_limit;
+      input_->Skip(bytes_until_limit);
+    }
+    return false;
+  }
+
+  if (!input_->Skip(count)) {
+    total_bytes_read_ = input_->ByteCount();
+    return false;
+  }
+  total_bytes_read_ += count;
+  return true;
+}
+
+bool CodedInputStream::GetDirectBufferPointer(const void** data, int* size) {
+  if (BufferSize() == 0 && !Refresh()) return false;
+
+  *data = buffer_;
+  *size = BufferSize();
+  return true;
+}
+
+bool CodedInputStream::ReadRaw(void* buffer, int size) {
+  int current_buffer_size;
+  while ((current_buffer_size = BufferSize()) < size) {
+    // Reading past end of buffer.  Copy what we have, then refresh.
+    memcpy(buffer, buffer_, current_buffer_size);
+    buffer = reinterpret_cast<uint8*>(buffer) + current_buffer_size;
+    size -= current_buffer_size;
+    Advance(current_buffer_size);
+    if (!Refresh()) return false;
+  }
+
+  memcpy(buffer, buffer_, size);
+  Advance(size);
+
+  return true;
+}
+
+bool CodedInputStream::ReadString(std::string* buffer, int size) {
+  if (size < 0) return false;  // security: size is often user-supplied
+
+  if (BufferSize() >= size) {
+    STLStringResizeUninitialized(buffer, size);
+    std::pair<char*, bool> z = as_string_data(buffer);
+    if (z.second) {
+      // Oddly enough, memcpy() requires its first two args to be non-NULL even
+      // if we copy 0 bytes.  So, we have ensured that z.first is non-NULL here.
+      GOOGLE_DCHECK(z.first != NULL);
+      memcpy(z.first, buffer_, size);
+      Advance(size);
+    }
+    return true;
+  }
+
+  return ReadStringFallback(buffer, size);
+}
+
+bool CodedInputStream::ReadStringFallback(std::string* buffer, int size) {
+  if (!buffer->empty()) {
+    buffer->clear();
+  }
+
+  int closest_limit = std::min(current_limit_, total_bytes_limit_);
+  if (closest_limit != INT_MAX) {
+    int bytes_to_limit = closest_limit - CurrentPosition();
+    if (bytes_to_limit > 0 && size > 0 && size <= bytes_to_limit) {
+      buffer->reserve(size);
+    }
+  }
+
+  int current_buffer_size;
+  while ((current_buffer_size = BufferSize()) < size) {
+    // Some STL implementations "helpfully" crash on buffer->append(NULL, 0).
+    if (current_buffer_size != 0) {
+      // Note:  string1.append(string2) is O(string2.size()) (as opposed to
+      //   O(string1.size() + string2.size()), which would be bad).
+      buffer->append(reinterpret_cast<const char*>(buffer_),
+                     current_buffer_size);
+    }
+    size -= current_buffer_size;
+    Advance(current_buffer_size);
+    if (!Refresh()) return false;
+  }
+
+  buffer->append(reinterpret_cast<const char*>(buffer_), size);
+  Advance(size);
+
+  return true;
+}
+
+
+bool CodedInputStream::ReadLittleEndian32Fallback(uint32* value) {
+  uint8 bytes[sizeof(*value)];
+
+  const uint8* ptr;
+  if (BufferSize() >= sizeof(*value)) {
+    // Fast path:  Enough bytes in the buffer to read directly.
+    ptr = buffer_;
+    Advance(sizeof(*value));
+  } else {
+    // Slow path:  Had to read past the end of the buffer.
+    if (!ReadRaw(bytes, sizeof(*value))) return false;
+    ptr = bytes;
+  }
+  ReadLittleEndian32FromArray(ptr, value);
+  return true;
+}
+
+bool CodedInputStream::ReadLittleEndian64Fallback(uint64* value) {
+  uint8 bytes[sizeof(*value)];
+
+  const uint8* ptr;
+  if (BufferSize() >= sizeof(*value)) {
+    // Fast path:  Enough bytes in the buffer to read directly.
+    ptr = buffer_;
+    Advance(sizeof(*value));
+  } else {
+    // Slow path:  Had to read past the end of the buffer.
+    if (!ReadRaw(bytes, sizeof(*value))) return false;
+    ptr = bytes;
+  }
+  ReadLittleEndian64FromArray(ptr, value);
+  return true;
+}
+
+namespace {
+
+// Decodes varint64 with known size, N, and returns next pointer. Knowing N at
+// compile time, compiler can generate optimal code. For example, instead of
+// subtracting 0x80 at each iteration, it subtracts properly shifted mask once.
+template <size_t N>
+const uint8* DecodeVarint64KnownSize(const uint8* buffer, uint64* value) {
+  GOOGLE_DCHECK_GT(N, 0);
+  uint64 result = static_cast<uint64>(buffer[N - 1]) << (7 * (N - 1));
+  for (int i = 0, offset = 0; i < N - 1; i++, offset += 7) {
+    result += static_cast<uint64>(buffer[i] - 0x80) << offset;
+  }
+  *value = result;
+  return buffer + N;
+}
+
+// Read a varint from the given buffer, write it to *value, and return a pair.
+// The first part of the pair is true iff the read was successful.  The second
+// part is buffer + (number of bytes read).  This function is always inlined,
+// so returning a pair is costless.
+PROTOBUF_ALWAYS_INLINE
+::std::pair<bool, const uint8*> ReadVarint32FromArray(uint32 first_byte,
+                                                      const uint8* buffer,
+                                                      uint32* value);
+inline ::std::pair<bool, const uint8*> ReadVarint32FromArray(
+    uint32 first_byte, const uint8* buffer, uint32* value) {
+  // Fast path:  We have enough bytes left in the buffer to guarantee that
+  // this read won't cross the end, so we can skip the checks.
+  GOOGLE_DCHECK_EQ(*buffer, first_byte);
+  GOOGLE_DCHECK_EQ(first_byte & 0x80, 0x80) << first_byte;
+  const uint8* ptr = buffer;
+  uint32 b;
+  uint32 result = first_byte - 0x80;
+  ++ptr;  // We just processed the first byte.  Move on to the second.
+  b = *(ptr++);
+  result += b << 7;
+  if (!(b & 0x80)) goto done;
+  result -= 0x80 << 7;
+  b = *(ptr++);
+  result += b << 14;
+  if (!(b & 0x80)) goto done;
+  result -= 0x80 << 14;
+  b = *(ptr++);
+  result += b << 21;
+  if (!(b & 0x80)) goto done;
+  result -= 0x80 << 21;
+  b = *(ptr++);
+  result += b << 28;
+  if (!(b & 0x80)) goto done;
+  // "result -= 0x80 << 28" is irrevelant.
+
+  // If the input is larger than 32 bits, we still need to read it all
+  // and discard the high-order bits.
+  for (int i = 0; i < kMaxVarintBytes - kMaxVarint32Bytes; i++) {
+    b = *(ptr++);
+    if (!(b & 0x80)) goto done;
+  }
+
+  // We have overrun the maximum size of a varint (10 bytes).  Assume
+  // the data is corrupt.
+  return std::make_pair(false, ptr);
+
+done:
+  *value = result;
+  return std::make_pair(true, ptr);
+}
+
+PROTOBUF_ALWAYS_INLINE::std::pair<bool, const uint8*> ReadVarint64FromArray(
+    const uint8* buffer, uint64* value);
+inline ::std::pair<bool, const uint8*> ReadVarint64FromArray(
+    const uint8* buffer, uint64* value) {
+  // Assumes varint64 is at least 2 bytes.
+  GOOGLE_DCHECK_GE(buffer[0], 128);
+
+  const uint8* next;
+  if (buffer[1] < 128) {
+    next = DecodeVarint64KnownSize<2>(buffer, value);
+  } else if (buffer[2] < 128) {
+    next = DecodeVarint64KnownSize<3>(buffer, value);
+  } else if (buffer[3] < 128) {
+    next = DecodeVarint64KnownSize<4>(buffer, value);
+  } else if (buffer[4] < 128) {
+    next = DecodeVarint64KnownSize<5>(buffer, value);
+  } else if (buffer[5] < 128) {
+    next = DecodeVarint64KnownSize<6>(buffer, value);
+  } else if (buffer[6] < 128) {
+    next = DecodeVarint64KnownSize<7>(buffer, value);
+  } else if (buffer[7] < 128) {
+    next = DecodeVarint64KnownSize<8>(buffer, value);
+  } else if (buffer[8] < 128) {
+    next = DecodeVarint64KnownSize<9>(buffer, value);
+  } else if (buffer[9] < 128) {
+    next = DecodeVarint64KnownSize<10>(buffer, value);
+  } else {
+    // We have overrun the maximum size of a varint (10 bytes). Assume
+    // the data is corrupt.
+    return std::make_pair(false, buffer + 11);
+  }
+
+  return std::make_pair(true, next);
+}
+
+}  // namespace
+
+bool CodedInputStream::ReadVarint32Slow(uint32* value) {
+  // Directly invoke ReadVarint64Fallback, since we already tried to optimize
+  // for one-byte varints.
+  std::pair<uint64, bool> p = ReadVarint64Fallback();
+  *value = static_cast<uint32>(p.first);
+  return p.second;
+}
+
+int64 CodedInputStream::ReadVarint32Fallback(uint32 first_byte_or_zero) {
+  if (BufferSize() >= kMaxVarintBytes ||
+      // Optimization:  We're also safe if the buffer is non-empty and it ends
+      // with a byte that would terminate a varint.
+      (buffer_end_ > buffer_ && !(buffer_end_[-1] & 0x80))) {
+    GOOGLE_DCHECK_NE(first_byte_or_zero, 0)
+        << "Caller should provide us with *buffer_ when buffer is non-empty";
+    uint32 temp;
+    ::std::pair<bool, const uint8*> p =
+        ReadVarint32FromArray(first_byte_or_zero, buffer_, &temp);
+    if (!p.first) return -1;
+    buffer_ = p.second;
+    return temp;
+  } else {
+    // Really slow case: we will incur the cost of an extra function call here,
+    // but moving this out of line reduces the size of this function, which
+    // improves the common case. In micro benchmarks, this is worth about 10-15%
+    uint32 temp;
+    return ReadVarint32Slow(&temp) ? static_cast<int64>(temp) : -1;
+  }
+}
+
+int CodedInputStream::ReadVarintSizeAsIntSlow() {
+  // Directly invoke ReadVarint64Fallback, since we already tried to optimize
+  // for one-byte varints.
+  std::pair<uint64, bool> p = ReadVarint64Fallback();
+  if (!p.second || p.first > static_cast<uint64>(INT_MAX)) return -1;
+  return p.first;
+}
+
+int CodedInputStream::ReadVarintSizeAsIntFallback() {
+  if (BufferSize() >= kMaxVarintBytes ||
+      // Optimization:  We're also safe if the buffer is non-empty and it ends
+      // with a byte that would terminate a varint.
+      (buffer_end_ > buffer_ && !(buffer_end_[-1] & 0x80))) {
+    uint64 temp;
+    ::std::pair<bool, const uint8*> p = ReadVarint64FromArray(buffer_, &temp);
+    if (!p.first || temp > static_cast<uint64>(INT_MAX)) return -1;
+    buffer_ = p.second;
+    return temp;
+  } else {
+    // Really slow case: we will incur the cost of an extra function call here,
+    // but moving this out of line reduces the size of this function, which
+    // improves the common case. In micro benchmarks, this is worth about 10-15%
+    return ReadVarintSizeAsIntSlow();
+  }
+}
+
+uint32 CodedInputStream::ReadTagSlow() {
+  if (buffer_ == buffer_end_) {
+    // Call refresh.
+    if (!Refresh()) {
+      // Refresh failed.  Make sure that it failed due to EOF, not because
+      // we hit total_bytes_limit_, which, unlike normal limits, is not a
+      // valid place to end a message.
+      int current_position = total_bytes_read_ - buffer_size_after_limit_;
+      if (current_position >= total_bytes_limit_) {
+        // Hit total_bytes_limit_.  But if we also hit the normal limit,
+        // we're still OK.
+        legitimate_message_end_ = current_limit_ == total_bytes_limit_;
+      } else {
+        legitimate_message_end_ = true;
+      }
+      return 0;
+    }
+  }
+
+  // For the slow path, just do a 64-bit read. Try to optimize for one-byte tags
+  // again, since we have now refreshed the buffer.
+  uint64 result = 0;
+  if (!ReadVarint64(&result)) return 0;
+  return static_cast<uint32>(result);
+}
+
+uint32 CodedInputStream::ReadTagFallback(uint32 first_byte_or_zero) {
+  const int buf_size = BufferSize();
+  if (buf_size >= kMaxVarintBytes ||
+      // Optimization:  We're also safe if the buffer is non-empty and it ends
+      // with a byte that would terminate a varint.
+      (buf_size > 0 && !(buffer_end_[-1] & 0x80))) {
+    GOOGLE_DCHECK_EQ(first_byte_or_zero, buffer_[0]);
+    if (first_byte_or_zero == 0) {
+      ++buffer_;
+      return 0;
+    }
+    uint32 tag;
+    ::std::pair<bool, const uint8*> p =
+        ReadVarint32FromArray(first_byte_or_zero, buffer_, &tag);
+    if (!p.first) {
+      return 0;
+    }
+    buffer_ = p.second;
+    return tag;
+  } else {
+    // We are commonly at a limit when attempting to read tags. Try to quickly
+    // detect this case without making another function call.
+    if ((buf_size == 0) &&
+        ((buffer_size_after_limit_ > 0) ||
+         (total_bytes_read_ == current_limit_)) &&
+        // Make sure that the limit we hit is not total_bytes_limit_, since
+        // in that case we still need to call Refresh() so that it prints an
+        // error.
+        total_bytes_read_ - buffer_size_after_limit_ < total_bytes_limit_) {
+      // We hit a byte limit.
+      legitimate_message_end_ = true;
+      return 0;
+    }
+    return ReadTagSlow();
+  }
+}
+
+bool CodedInputStream::ReadVarint64Slow(uint64* value) {
+  // Slow path:  This read might cross the end of the buffer, so we
+  // need to check and refresh the buffer if and when it does.
+
+  uint64 result = 0;
+  int count = 0;
+  uint32 b;
+
+  do {
+    if (count == kMaxVarintBytes) {
+      *value = 0;
+      return false;
+    }
+    while (buffer_ == buffer_end_) {
+      if (!Refresh()) {
+        *value = 0;
+        return false;
+      }
+    }
+    b = *buffer_;
+    result |= static_cast<uint64>(b & 0x7F) << (7 * count);
+    Advance(1);
+    ++count;
+  } while (b & 0x80);
+
+  *value = result;
+  return true;
+}
+
+std::pair<uint64, bool> CodedInputStream::ReadVarint64Fallback() {
+  if (BufferSize() >= kMaxVarintBytes ||
+      // Optimization:  We're also safe if the buffer is non-empty and it ends
+      // with a byte that would terminate a varint.
+      (buffer_end_ > buffer_ && !(buffer_end_[-1] & 0x80))) {
+    uint64 temp;
+    ::std::pair<bool, const uint8*> p = ReadVarint64FromArray(buffer_, &temp);
+    if (!p.first) {
+      return std::make_pair(0, false);
+    }
+    buffer_ = p.second;
+    return std::make_pair(temp, true);
+  } else {
+    uint64 temp;
+    bool success = ReadVarint64Slow(&temp);
+    return std::make_pair(temp, success);
+  }
+}
+
+bool CodedInputStream::Refresh() {
+  GOOGLE_DCHECK_EQ(0, BufferSize());
+
+  if (buffer_size_after_limit_ > 0 || overflow_bytes_ > 0 ||
+      total_bytes_read_ == current_limit_) {
+    // We've hit a limit.  Stop.
+    int current_position = total_bytes_read_ - buffer_size_after_limit_;
+
+    if (current_position >= total_bytes_limit_ &&
+        total_bytes_limit_ != current_limit_) {
+      // Hit total_bytes_limit_.
+      PrintTotalBytesLimitError();
+    }
+
+    return false;
+  }
+
+  const void* void_buffer;
+  int buffer_size;
+  if (NextNonEmpty(input_, &void_buffer, &buffer_size)) {
+    buffer_ = reinterpret_cast<const uint8*>(void_buffer);
+    buffer_end_ = buffer_ + buffer_size;
+    GOOGLE_CHECK_GE(buffer_size, 0);
+
+    if (total_bytes_read_ <= INT_MAX - buffer_size) {
+      total_bytes_read_ += buffer_size;
+    } else {
+      // Overflow.  Reset buffer_end_ to not include the bytes beyond INT_MAX.
+      // We can't get that far anyway, because total_bytes_limit_ is guaranteed
+      // to be less than it.  We need to keep track of the number of bytes
+      // we discarded, though, so that we can call input_->BackUp() to back
+      // up over them on destruction.
+
+      // The following line is equivalent to:
+      //   overflow_bytes_ = total_bytes_read_ + buffer_size - INT_MAX;
+      // except that it avoids overflows.  Signed integer overflow has
+      // undefined results according to the C standard.
+      overflow_bytes_ = total_bytes_read_ - (INT_MAX - buffer_size);
+      buffer_end_ -= overflow_bytes_;
+      total_bytes_read_ = INT_MAX;
+    }
+
+    RecomputeBufferLimits();
+    return true;
+  } else {
+    buffer_ = NULL;
+    buffer_end_ = NULL;
+    return false;
+  }
+}
+
+// CodedOutputStream =================================================
+
+void EpsCopyOutputStream::EnableAliasing(bool enabled) {
+  aliasing_enabled_ = enabled && stream_->AllowsAliasing();
+}
+
+int64 EpsCopyOutputStream::ByteCount(uint8* ptr) const {
+  // Calculate the current offset relative to the end of the stream buffer.
+  int delta = (end_ - ptr) + (buffer_end_ ? 0 : kSlopBytes);
+  return stream_->ByteCount() - delta;
+}
+
+// Flushes what's written out to the underlying ZeroCopyOutputStream buffers.
+// Returns the size remaining in the buffer and sets buffer_end_ to the start
+// of the remaining buffer, ie. [buffer_end_, buffer_end_ + return value)
+int EpsCopyOutputStream::Flush(uint8* ptr) {
+  while (buffer_end_ && ptr > end_) {
+    int overrun = ptr - end_;
+    GOOGLE_DCHECK(!had_error_);
+    GOOGLE_DCHECK(overrun <= kSlopBytes);  // NOLINT
+    ptr = Next() + overrun;
+    if (had_error_) return 0;
+  }
+  int s;
+  if (buffer_end_) {
+    std::memcpy(buffer_end_, buffer_, ptr - buffer_);
+    buffer_end_ += ptr - buffer_;
+    s = end_ - ptr;
+  } else {
+    // The stream is writing directly in the ZeroCopyOutputStream buffer.
+    s = end_ + kSlopBytes - ptr;
+    buffer_end_ = ptr;
+  }
+  GOOGLE_DCHECK(s >= 0);  // NOLINT
+  return s;
+}
+
+uint8* EpsCopyOutputStream::Trim(uint8* ptr) {
+  if (had_error_) return ptr;
+  int s = Flush(ptr);
+  if (s) stream_->BackUp(s);
+  // Reset to initial state (expecting new buffer)
+  buffer_end_ = end_ = buffer_;
+  return buffer_;
+}
+
+
+uint8* EpsCopyOutputStream::FlushAndResetBuffer(uint8* ptr) {
+  if (had_error_) return buffer_;
+  int s = Flush(ptr);
+  if (had_error_) return buffer_;
+  return SetInitialBuffer(buffer_end_, s);
+}
+
+bool EpsCopyOutputStream::Skip(int count, uint8** pp) {
+  if (count < 0) return false;
+  if (had_error_) {
+    *pp = buffer_;
+    return false;
+  }
+  int size = Flush(*pp);
+  if (had_error_) {
+    *pp = buffer_;
+    return false;
+  }
+  void* data = buffer_end_;
+  while (count > size) {
+    count -= size;
+    if (!stream_->Next(&data, &size)) {
+      *pp = Error();
+      return false;
+    }
+  }
+  *pp = SetInitialBuffer(static_cast<uint8*>(data) + count, size - count);
+  return true;
+}
+
+bool EpsCopyOutputStream::GetDirectBufferPointer(void** data, int* size,
+                                                 uint8** pp) {
+  if (had_error_) {
+    *pp = buffer_;
+    return false;
+  }
+  *size = Flush(*pp);
+  if (had_error_) {
+    *pp = buffer_;
+    return false;
+  }
+  *data = buffer_end_;
+  while (*size == 0) {
+    if (!stream_->Next(data, size)) {
+      *pp = Error();
+      return false;
+    }
+  }
+  *pp = SetInitialBuffer(*data, *size);
+  return true;
+}
+
+uint8* EpsCopyOutputStream::GetDirectBufferForNBytesAndAdvance(int size,
+                                                               uint8** pp) {
+  if (had_error_) {
+    *pp = buffer_;
+    return nullptr;
+  }
+  int s = Flush(*pp);
+  if (had_error_) {
+    *pp = buffer_;
+    return nullptr;
+  }
+  if (s >= size) {
+    auto res = buffer_end_;
+    *pp = SetInitialBuffer(buffer_end_ + size, s - size);
+    return res;
+  } else {
+    *pp = SetInitialBuffer(buffer_end_, s);
+    return nullptr;
+  }
+}
+
+uint8* EpsCopyOutputStream::Next() {
+  GOOGLE_DCHECK(!had_error_);  // NOLINT
+  if (PROTOBUF_PREDICT_FALSE(stream_ == nullptr)) return Error();
+  if (buffer_end_) {
+    // We're in the patch buffer and need to fill up the previous buffer.
+    std::memcpy(buffer_end_, buffer_, end_ - buffer_);
+    uint8* ptr;
+    int size;
+    do {
+      void* data;
+      if (PROTOBUF_PREDICT_FALSE(!stream_->Next(&data, &size))) {
+        // Stream has an error, we use the patch buffer to continue to be
+        // able to write.
+        return Error();
+      }
+      ptr = static_cast<uint8*>(data);
+    } while (size == 0);
+    if (PROTOBUF_PREDICT_TRUE(size > kSlopBytes)) {
+      std::memcpy(ptr, end_, kSlopBytes);
+      end_ = ptr + size - kSlopBytes;
+      buffer_end_ = nullptr;
+      return ptr;
+    } else {
+      GOOGLE_DCHECK(size > 0);  // NOLINT
+      // Buffer to small
+      std::memmove(buffer_, end_, kSlopBytes);
+      buffer_end_ = ptr;
+      end_ = buffer_ + size;
+      return buffer_;
+    }
+  } else {
+    std::memcpy(buffer_, end_, kSlopBytes);
+    buffer_end_ = end_;
+    end_ = buffer_ + kSlopBytes;
+    return buffer_;
+  }
+}
+
+uint8* EpsCopyOutputStream::EnsureSpaceFallback(uint8* ptr) {
+  do {
+    if (PROTOBUF_PREDICT_FALSE(had_error_)) return buffer_;
+    int overrun = ptr - end_;
+    GOOGLE_DCHECK(overrun >= 0);           // NOLINT
+    GOOGLE_DCHECK(overrun <= kSlopBytes);  // NOLINT
+    ptr = Next() + overrun;
+  } while (ptr >= end_);
+  GOOGLE_DCHECK(ptr < end_);  // NOLINT
+  return ptr;
+}
+
+uint8* EpsCopyOutputStream::WriteRawFallback(const void* data, int size,
+                                             uint8* ptr) {
+  int s = GetSize(ptr);
+  while (s < size) {
+    std::memcpy(ptr, data, s);
+    size -= s;
+    data = static_cast<const uint8*>(data) + s;
+    ptr = EnsureSpaceFallback(ptr + s);
+    s = GetSize(ptr);
+  }
+  std::memcpy(ptr, data, size);
+  return ptr + size;
+}
+
+uint8* EpsCopyOutputStream::WriteAliasedRaw(const void* data, int size,
+                                            uint8* ptr) {
+  if (size < GetSize(ptr)
+  ) {
+    return WriteRaw(data, size, ptr);
+  } else {
+    ptr = Trim(ptr);
+    if (stream_->WriteAliasedRaw(data, size)) return ptr;
+    return Error();
+  }
+}
+
+#ifndef PROTOBUF_LITTLE_ENDIAN
+uint8* EpsCopyOutputStream::WriteRawLittleEndian32(const void* data, int size,
+                                                   uint8* ptr) {
+  auto p = static_cast<const uint8*>(data);
+  auto end = p + size;
+  while (end - p >= kSlopBytes) {
+    ptr = EnsureSpace(ptr);
+    uint32 buffer[4];
+    static_assert(sizeof(buffer) == kSlopBytes, "Buffer must be kSlopBytes");
+    std::memcpy(buffer, p, kSlopBytes);
+    p += kSlopBytes;
+    for (auto x : buffer)
+      ptr = CodedOutputStream::WriteLittleEndian32ToArray(x, ptr);
+  }
+  while (p < end) {
+    ptr = EnsureSpace(ptr);
+    uint32 buffer;
+    std::memcpy(&buffer, p, 4);
+    p += 4;
+    ptr = CodedOutputStream::WriteLittleEndian32ToArray(buffer, ptr);
+  }
+  return ptr;
+}
+
+uint8* EpsCopyOutputStream::WriteRawLittleEndian64(const void* data, int size,
+                                                   uint8* ptr) {
+  auto p = static_cast<const uint8*>(data);
+  auto end = p + size;
+  while (end - p >= kSlopBytes) {
+    ptr = EnsureSpace(ptr);
+    uint64 buffer[2];
+    static_assert(sizeof(buffer) == kSlopBytes, "Buffer must be kSlopBytes");
+    std::memcpy(buffer, p, kSlopBytes);
+    p += kSlopBytes;
+    for (auto x : buffer)
+      ptr = CodedOutputStream::WriteLittleEndian64ToArray(x, ptr);
+  }
+  while (p < end) {
+    ptr = EnsureSpace(ptr);
+    uint64 buffer;
+    std::memcpy(&buffer, p, 8);
+    p += 8;
+    ptr = CodedOutputStream::WriteLittleEndian64ToArray(buffer, ptr);
+  }
+  return ptr;
+}
+#endif
+
+
+uint8* EpsCopyOutputStream::WriteStringMaybeAliasedOutline(uint32 num,
+                                                           const std::string& s,
+                                                           uint8* ptr) {
+  ptr = EnsureSpace(ptr);
+  uint32 size = s.size();
+  ptr = WriteLengthDelim(num, size, ptr);
+  return WriteRawMaybeAliased(s.data(), size, ptr);
+}
+
+uint8* EpsCopyOutputStream::WriteStringOutline(uint32 num, const std::string& s,
+                                               uint8* ptr) {
+  ptr = EnsureSpace(ptr);
+  uint32 size = s.size();
+  ptr = WriteLengthDelim(num, size, ptr);
+  return WriteRaw(s.data(), size, ptr);
+}
+
+std::atomic<bool> CodedOutputStream::default_serialization_deterministic_{
+    false};
+
+CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* stream,
+                                     bool do_eager_refresh)
+    : impl_(stream, IsDefaultSerializationDeterministic(), &cur_),
+      start_count_(stream->ByteCount()) {
+  if (do_eager_refresh) {
+    void* data;
+    int size;
+    if (!stream->Next(&data, &size) || size == 0) return;
+    cur_ = impl_.SetInitialBuffer(data, size);
+  }
+}
+
+CodedOutputStream::~CodedOutputStream() { Trim(); }
+
+
+uint8* CodedOutputStream::WriteStringWithSizeToArray(const std::string& str,
+                                                     uint8* target) {
+  GOOGLE_DCHECK_LE(str.size(), kuint32max);
+  target = WriteVarint32ToArray(str.size(), target);
+  return WriteStringToArray(str, target);
+}
+
+}  // namespace io
+}  // namespace protobuf
+}  // namespace google