Check in php implementation. (#2052)

This pull request includes two implementation: C extension and PHP
package. Both implementations support encode/decode of singular,
repeated and map fields.

15 files changed, 3254 insertions, 0 deletions

diff --git a/php/src/Google/Protobuf/Internal/DescriptorPool.php b/php/src/Google/Protobuf/Internal/DescriptorPool.php
new file mode 100644
index 00000000..23b304ac
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/DescriptorPool.php
@@ -0,0 +1,162 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\Descriptor;
+use Google\Protobuf\Internal\FileDescriptor;
+use Google\Protobuf\Internal\FileDescriptorSet;
+use Google\Protobuf\Internal\MessageBuilderContext;
+use Google\Protobuf\Internal\EnumBuilderContext;
+
+class DescriptorPool
+{
+    private static $pool;
+    // Map from message names to sub-maps, which are maps from field numbers to
+    // field descriptors.
+    private $class_to_desc = [];
+    private $class_to_enum_desc = [];
+    private $proto_to_class = [];
+
+    public static function getGeneratedPool()
+    {
+        if (!isset(self::$pool)) {
+            self::$pool = new DescriptorPool();
+        }
+        return self::$pool;
+    }
+
+    public function internalAddGeneratedFile($data)
+    {
+        $files = new FileDescriptorSet();
+        $files->decode($data);
+        $file = FileDescriptor::buildFromProto($files->getFile()[0]);
+
+        foreach ($file->getMessageType() as &$desc) {
+            $this->addDescriptor($desc);
+        }
+        unset($desc);
+
+        foreach ($file->getEnumType() as &$desc) {
+            $this->addEnumDescriptor($desc);
+        }
+        unset($desc);
+
+        foreach ($file->getMessageType() as &$desc) {
+            $this->crossLink($desc);
+        }
+        unset($desc);
+    }
+
+    public function addMessage($name, $klass)
+    {
+        return new MessageBuilderContext($name, $klass, $this);
+    }
+
+    public function addEnum($name, $klass)
+    {
+        return new EnumBuilderContext($name, $klass, $this);
+    }
+
+    public function addDescriptor($descriptor)
+    {
+        $this->proto_to_class[$descriptor->getFullName()] =
+            $descriptor->getClass();
+        $this->class_to_desc[$descriptor->getClass()] = $descriptor;
+        foreach ($descriptor->getNestedType() as $nested_type) {
+            $this->addDescriptor($nested_type);
+        }
+    }
+
+    public function addEnumDescriptor($descriptor)
+    {
+        $this->proto_to_class[$descriptor->getFullName()] =
+            $descriptor->getClass();
+        $this->class_to_enum_desc[$descriptor->getClass()] = $descriptor;
+    }
+
+    public function getDescriptorByClassName($klass)
+    {
+        return $this->class_to_desc[$klass];
+    }
+
+    public function getEnumDescriptorByClassName($klass)
+    {
+        return $this->class_to_enum_desc[$klass];
+    }
+
+    public function getDescriptorByProtoName($proto)
+    {
+        $klass = $this->proto_to_class[$proto];
+        return $this->class_to_desc[$klass];
+    }
+
+    public function getEnumDescriptorByProtoName($proto)
+    {
+        $klass = $this->proto_to_class[$proto];
+        return $this->class_to_enum_desc[$klass];
+    }
+
+    private function crossLink(&$desc)
+    {
+        foreach ($desc->getField() as &$field) {
+            switch ($field->getType()) {
+                case GPBType::MESSAGE:
+                    $proto = $field->getMessageType();
+                    $field->setMessageType(
+                        $this->getDescriptorByProtoName($proto));
+                    break;
+                case GPBType::ENUM:
+                    $proto = $field->getEnumType();
+                    $field->setEnumType(
+                        $this->getEnumDescriptorByProtoName($proto));
+                    break;
+                default:
+                    break;
+            }
+        }
+        unset($field);
+
+        foreach ($desc->getNestedType() as &$nested_type) {
+            $this->crossLink($nested_type);
+        }
+        unset($nested_type);
+    }
+
+    public function finish()
+    {
+        foreach ($this->class_to_desc as $klass => &$desc) {
+            $this->crossLink($desc);
+        }
+        unset($desc);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/EnumBuilderContext.php b/php/src/Google/Protobuf/Internal/EnumBuilderContext.php
new file mode 100644
index 00000000..c1dac24d
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/EnumBuilderContext.php
@@ -0,0 +1,63 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\EnumDescriptor;
+use Google\Protobuf\Internal\EnumValueDescriptor;
+
+class EnumBuilderContext
+{
+
+    private $descriptor;
+    private $pool;
+
+    public function __construct($full_name, $klass, $pool)
+    {
+        $this->descriptor = new EnumDescriptor();
+        $this->descriptor->setFullName($full_name);
+        $this->descriptor->setClass($klass);
+        $this->pool = $pool;
+    }
+
+    public function value($name, $number)
+    {
+        $value = new EnumValueDescriptor();
+        $this->descriptor->addValue($number, $value);
+        return $this;
+    }
+
+    public function finalizeToPool()
+    {
+        $this->pool->addEnumDescriptor($this->descriptor);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/GPBLabel.php b/php/src/Google/Protobuf/Internal/GPBLabel.php
new file mode 100644
index 00000000..0fb23841
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/GPBLabel.php
@@ -0,0 +1,40 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+class GPBLabel
+{
+    const OPTIONAL = 1;
+    const REQUIRED = 2;
+    const REPEATED = 3;
+}
diff --git a/php/src/Google/Protobuf/Internal/GPBType.php b/php/src/Google/Protobuf/Internal/GPBType.php
new file mode 100644
index 00000000..fa849ceb
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/GPBType.php
@@ -0,0 +1,55 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+class GPBType
+{
+    const DOUBLE   =  1;
+    const FLOAT    =  2;
+    const INT64    =  3;
+    const UINT64   =  4;
+    const INT32    =  5;
+    const FIXED64  =  6;
+    const FIXED32  =  7;
+    const BOOL     =  8;
+    const STRING   =  9;
+    const GROUP    = 10;
+    const MESSAGE  = 11;
+    const BYTES    = 12;
+    const UINT32   = 13;
+    const ENUM     = 14;
+    const SFIXED32 = 15;
+    const SFIXED64 = 16;
+    const SINT32   = 17;
+    const SINT64   = 18;
+}
diff --git a/php/src/Google/Protobuf/Internal/GPBUtil.php b/php/src/Google/Protobuf/Internal/GPBUtil.php
new file mode 100644
index 00000000..417a9729
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/GPBUtil.php
@@ -0,0 +1,161 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\RepeatedField;
+
+class GPBUtil
+{
+
+    public static function checkString(&$var, $check_utf8)
+    {
+        if (is_array($var) || is_object($var)) {
+            trigger_error("Expect string.", E_USER_ERROR);
+            return;
+        }
+        if (!is_string($var)) {
+            $var = strval($var);
+        }
+        if ($check_utf8 && !preg_match('//u', $var)) {
+            trigger_error("Expect utf-8 encoding.", E_USER_ERROR);
+            return;
+        }
+    }
+
+    public static function checkEnum(&$var)
+    {
+      static::checkInt32($var);
+    }
+
+    public static function checkInt32(&$var)
+    {
+        if (is_numeric($var)) {
+            $var = intval($var);
+        } else {
+            trigger_error("Expect integer.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkUint32(&$var)
+    {
+        if (is_numeric($var)) {
+            $var = intval($var);
+            if (PHP_INT_SIZE === 8) {
+                $var |= ((-(($var >> 31) & 0x1)) & ~0xFFFFFFFF);
+            }
+        } else {
+            trigger_error("Expect integer.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkInt64(&$var)
+    {
+        if (is_numeric($var)) {
+            $var = intval($var);
+        } else {
+            trigger_error("Expect integer.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkUint64(&$var)
+    {
+        if (is_numeric($var)) {
+            $var = intval($var);
+        } else {
+            trigger_error("Expect integer.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkFloat(&$var)
+    {
+        if (is_float($var) || is_numeric($var)) {
+            $var = floatval($var);
+        } else {
+            trigger_error("Expect float.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkDouble(&$var)
+    {
+        if (is_float($var) || is_numeric($var)) {
+            $var = floatval($var);
+        } else {
+            trigger_error("Expect float.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkBool(&$var)
+    {
+        if (is_array($var) || is_object($var)) {
+            trigger_error("Expect boolean.", E_USER_ERROR);
+            return;
+        }
+        $var = boolval($var);
+    }
+
+    public static function checkMessage(&$var, $klass)
+    {
+        if (!$var instanceof $klass && !is_null($var)) {
+            trigger_error("Expect message.", E_USER_ERROR);
+        }
+    }
+
+    public static function checkRepeatedField(&$var, $type, $klass = null)
+    {
+        if (!$var instanceof RepeatedField) {
+            trigger_error("Expect repeated field.", E_USER_ERROR);
+        }
+        if ($var->getType() != $type) {
+            trigger_error(
+                "Expect repeated field of different type.",
+                E_USER_ERROR);
+        }
+        if ($var->getType() === GPBType::MESSAGE &&
+            $var->getClass() !== $klass) {
+            trigger_error(
+                "Expect repeated field of different message.",
+                E_USER_ERROR);
+        }
+    }
+
+    public static function Int64($value)
+    {
+        return new Int64($value);
+    }
+
+    public static function Uint64($value)
+    {
+        return new Uint64($value);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/GPBWire.php b/php/src/Google/Protobuf/Internal/GPBWire.php
new file mode 100644
index 00000000..0e741e15
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/GPBWire.php
@@ -0,0 +1,583 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\GPBUtil;
+use Google\Protobuf\Internal\Int64;
+use Google\Protobuf\Internal\Uint64;
+
+class GPBWire
+{
+
+    const TAG_TYPE_BITS = 3;
+
+    const WIRETYPE_VARINT  = 0;
+    const WIRETYPE_FIXED64 = 1;
+    const WIRETYPE_LENGTH_DELIMITED = 2;
+    const WIRETYPE_START_GROUP = 3;
+    const WIRETYPE_END_GROUP = 4;
+    const WIRETYPE_FIXED32 = 5;
+
+    const UNKNOWN = 0;
+    const NORMAL_FORMAT = 1;
+    const PACKED_FORMAT = 2;
+
+    public static function getTagFieldNumber($tag)
+    {
+        return ($tag >> self::TAG_TYPE_BITS) &
+            (1 << ((PHP_INT_SIZE * 8) - self::TAG_TYPE_BITS)) - 1;
+    }
+
+    public static function getTagWireType($tag)
+    {
+        return $tag & 0x7;
+    }
+
+    public static function getWireType($type)
+    {
+        switch ($type) {
+            case GPBType::FLOAT:
+            case GPBType::FIXED32:
+            case GPBType::SFIXED32:
+                return self::WIRETYPE_FIXED32;
+            case GPBType::DOUBLE:
+            case GPBType::FIXED64:
+            case GPBType::SFIXED64:
+                return self::WIRETYPE_FIXED64;
+            case GPBType::UINT32:
+            case GPBType::UINT64:
+            case GPBType::INT32:
+            case GPBType::INT64:
+            case GPBType::SINT32:
+            case GPBType::SINT64:
+            case GPBType::ENUM:
+            case GPBType::BOOL:
+                return self::WIRETYPE_VARINT;
+            case GPBType::STRING:
+            case GPBType::BYTES:
+            case GPBType::MESSAGE:
+                return self::WIRETYPE_LENGTH_DELIMITED;
+            case GPBType::GROUP:
+                user_error("Unsupported type.");
+                return 0;
+            default:
+                user_error("Unsupported type.");
+                return 0;
+        }
+    }
+
+  // ZigZag Transform:  Encodes signed integers so that they can be effectively
+  // used with varint encoding.
+  //
+  // varint operates on unsigned integers, encoding smaller numbers into fewer
+  // bytes.  If you try to use it on a signed integer, it will treat this
+  // number as a very large unsigned integer, which means that even small
+  // signed numbers like -1 will take the maximum number of bytes (10) to
+  // encode.  zigZagEncode() maps signed integers to unsigned in such a way
+  // that those with a small absolute value will have smaller encoded values,
+  // making them appropriate for encoding using varint.
+  //
+  // int32 ->     uint32
+  // -------------------------
+  //           0 ->          0
+  //          -1 ->          1
+  //           1 ->          2
+  //          -2 ->          3
+  //         ... ->        ...
+  //  2147483647 -> 4294967294
+  // -2147483648 -> 4294967295
+  //
+  //        >> encode >>
+  //        << decode <<
+  public static function zigZagEncode32($int32)
+  {
+      // Fill high 32 bits.
+      if (PHP_INT_SIZE === 8) {
+          $int32 |= ((($int32 << 32) >> 31) & (0xFFFFFFFF << 32));
+      }
+
+      $uint32 = ($int32 << 1) ^ ($int32 >> 31);
+
+      // Fill high 32 bits.
+      if (PHP_INT_SIZE === 8) {
+          $uint32 |= ((($uint32 << 32) >> 31) & (0xFFFFFFFF << 32));
+      }
+
+      return $uint32;
+  }
+
+    public static function zigZagDecode32($uint32)
+    {
+        // Fill high 32 bits.
+        if (PHP_INT_SIZE === 8) {
+            $uint32 |= ($uint32 & 0xFFFFFFFF);
+        }
+
+        $int32 = (($uint32 >> 1) & 0x7FFFFFFF) ^ (-($uint32 & 1));
+
+        return $int32;
+    }
+
+    public static function zigZagEncode64($int64)
+    {
+        $a = $int64->copy()->leftShift(1);
+        $b = $int64->copy()->rightShift(63);
+        $result = $a->bitXor($b);
+        $uint64 = Uint64::newValue($result->high, $result->low);
+        return $uint64;
+    }
+
+    public static function zigZagDecode64($uint64)
+    {
+        $a = $uint64->copy()->rightShift(1);
+        $b = $uint64->oddMask();
+        $result = $a->bitXor($b);
+        $int64 = Int64::newValue($result->high, $result->low);
+        return $int64;
+    }
+
+    public static function readInt32(&$input, &$value)
+    {
+        return $input->readVarint32($value);
+    }
+
+    public static function readInt64(&$input, &$value)
+    {
+        return $input->readVarint64($value);
+    }
+
+    public static function readUint32(&$input, &$value)
+    {
+        return self::readInt32($input, $value);
+    }
+
+    public static function readUint64(&$input, &$value)
+    {
+        return self::readInt64($input, $value);
+    }
+
+    public static function readSint32(&$input, &$value)
+    {
+        if (!$input->readVarint32($value)) {
+            return false;
+        }
+        $value = GPBWire::zigZagDecode32($value);
+        return true;
+    }
+
+    public static function readSint64(&$input, &$value)
+    {
+        if (!$input->readVarint64($value)) {
+            return false;
+        }
+        $value = GPBWire::zigZagDecode64($value);
+        return true;
+    }
+
+    public static function readFixed32(&$input, &$value)
+    {
+        return $input->readLittleEndian32($value);
+    }
+
+    public static function readFixed64(&$input, &$value)
+    {
+        return $input->readLittleEndian64($value);
+    }
+
+    public static function readSfixed32(&$input, &$value)
+    {
+        if (!self::readFixed32($input, $value)) {
+            return false;
+        }
+        if (PHP_INT_SIZE === 8) {
+            $value |= (-($value >> 31) << 32);
+        }
+        return true;
+    }
+
+    public static function readSfixed64(&$input, &$value)
+    {
+        if (!self::readFixed64($input, $value)) {
+            return false;
+        }
+        $value = Int64::newValue($value->high, $value->low);
+        return true;
+    }
+
+    public static function readFloat(&$input, &$value)
+    {
+        $data = null;
+        if (!$input->readRaw(4, $data)) {
+            return false;
+        }
+        $value = unpack('f', $data)[1];
+        return true;
+    }
+
+    public static function readDouble(&$input, &$value)
+    {
+        $data = null;
+        if (!$input->readRaw(8, $data)) {
+            return false;
+        }
+        $value = unpack('d', $data)[1];
+        return true;
+    }
+
+    public static function readBool(&$input, &$value)
+    {
+        if (!$input->readVarint64($value)) {
+            return false;
+        }
+        if ($value->high === 0 && $value->low === 0) {
+            $value = false;
+        } else {
+            $value = true;
+        }
+        return true;
+    }
+
+    public static function readString(&$input, &$value)
+    {
+        $length = 0;
+        return $input->readVarintSizeAsInt($length) && $input->readRaw($length, $value);
+    }
+
+    public static function readMessage(&$input, &$message)
+    {
+        $length = 0;
+        if (!$input->readVarintSizeAsInt($length)) {
+            return false;
+        }
+        $old_limit = 0;
+        $recursion_limit = 0;
+        $input->incrementRecursionDepthAndPushLimit(
+            $length,
+            $old_limit,
+            $recursion_limit);
+        if ($recursion_limit < 0 || !$message->parseFromStream($input)) {
+            return false;
+        }
+        return $input->decrementRecursionDepthAndPopLimit($old_limit);
+    }
+
+    public static function writeTag(&$output, $tag)
+    {
+        return $output->writeTag($tag);
+    }
+
+    public static function writeInt32(&$output, $value)
+    {
+        return $output->writeVarint32($value);
+    }
+
+    public static function writeInt64(&$output, $value)
+    {
+        return $output->writeVarint64($value);
+    }
+
+    public static function writeUint32(&$output, $value)
+    {
+        return $output->writeVarint32($value);
+    }
+
+    public static function writeUint64(&$output, $value)
+    {
+        return $output->writeVarint64($value);
+    }
+
+    public static function writeSint32(&$output, $value)
+    {
+        $value = GPBWire::zigZagEncode32($value);
+        return $output->writeVarint64($value);
+    }
+
+    public static function writeSint64(&$output, $value)
+    {
+        $value = GPBWire::zigZagEncode64(GPBUtil::Int64($value));
+        return $output->writeVarint64($value->toInteger());
+    }
+
+    public static function writeFixed32(&$output, $value)
+    {
+        return $output->writeLittleEndian32($value);
+    }
+
+    public static function writeFixed64(&$output, $value)
+    {
+        return $output->writeLittleEndian64($value);
+    }
+
+    public static function writeSfixed32(&$output, $value)
+    {
+        return $output->writeLittleEndian32($value);
+    }
+
+    public static function writeSfixed64(&$output, $value)
+    {
+        return $output->writeLittleEndian64($value);
+    }
+
+    public static function writeBool(&$output, $value)
+    {
+        if ($value) {
+            return $output->writeVarint32(1);
+        } else {
+            return $output->writeVarint32(0);
+        }
+    }
+
+    public static function writeFloat(&$output, $value)
+    {
+        $data = pack("f", $value);
+        return $output->writeRaw($data, 4);
+    }
+
+    public static function writeDouble(&$output, $value)
+    {
+        $data = pack("d", $value);
+        return $output->writeRaw($data, 8);
+    }
+
+    public static function writeString(&$output, $value)
+    {
+        return self::writeBytes($output, $value);
+    }
+
+    public static function writeBytes(&$output, $value)
+    {
+        $size = strlen($value);
+        if (!$output->writeVarint32($size)) {
+            return false;
+        }
+        return $output->writeRaw($value, $size);
+    }
+
+    public static function writeMessage(&$output, $value)
+    {
+        $size = $value->byteSize();
+        if (!$output->writeVarint32($size)) {
+            return false;
+        }
+        return $value->serializeToStream($output);
+    }
+
+    public static function makeTag($number, $type)
+    {
+        return ($number << 3) | self::getWireType($type);
+    }
+
+    public static function tagSize($field)
+    {
+        $tag = self::makeTag($field->getNumber(), $field->getType());
+        return self::varint32Size($tag);
+    }
+
+    public static function varint32Size($value)
+    {
+        if ($value < 0) {
+            return 5;
+        }
+        if ($value < (1 <<  7)) {
+            return 1;
+        }
+        if ($value < (1 << 14)) {
+            return 2;
+        }
+        if ($value < (1 << 21)) {
+            return 3;
+        }
+        if ($value < (1 << 28)) {
+            return 4;
+        }
+        return 5;
+    }
+
+    public static function sint32Size($value)
+    {
+        $value = self::zigZagEncode32($value);
+        return self::varint32Size($value);
+    }
+
+    public static function sint64Size($value)
+    {
+        $value = GPBUtil::Int64($value);
+        $value = self::zigZagEncode64($value);
+        return self::varint64Size($value->toInteger());
+    }
+
+    public static function varint64Size($value)
+    {
+        if ($value < 0) {
+            return 10;
+        }
+        if ($value < (1 <<  7)) {
+            return 1;
+        }
+        if ($value < (1 << 14)) {
+            return 2;
+        }
+        if ($value < (1 << 21)) {
+            return 3;
+        }
+        if ($value < (1 << 28)) {
+            return 4;
+        }
+        if ($value < (1 << 35)) {
+            return 5;
+        }
+        if ($value < (1 << 42)) {
+            return 6;
+        }
+        if ($value < (1 << 49)) {
+            return 7;
+        }
+        if ($value < (1 << 56)) {
+            return 8;
+        }
+        return 9;
+    }
+
+    public static function serializeFieldToStream(
+        $value,
+        $field,
+        $need_tag,
+        &$output)
+    {
+        if ($need_tag) {
+            if (!GPBWire::writeTag(
+                $output,
+                self::makeTag(
+                    $field->getNumber(),
+                    $field->getType()))) {
+                return false;
+            }
+        }
+        switch ($field->getType()) {
+            case GPBType::DOUBLE:
+                if (!GPBWire::writeDouble($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::FLOAT:
+                if (!GPBWire::writeFloat($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::INT64:
+                if (!GPBWire::writeInt64($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::UINT64:
+                if (!GPBWire::writeUint64($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::INT32:
+                if (!GPBWire::writeInt32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::FIXED32:
+                if (!GPBWire::writeFixed32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::FIXED64:
+                if (!GPBWire::writeFixed64($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::BOOL:
+                if (!GPBWire::writeBool($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::STRING:
+                if (!GPBWire::writeString($output, $value)) {
+                    return false;
+                }
+                break;
+            //    case GPBType::GROUP:
+            //      echo "GROUP\xA";
+            //      trigger_error("Not implemented.", E_ERROR);
+            //      break;
+            case GPBType::MESSAGE:
+                if (!GPBWire::writeMessage($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::BYTES:
+                if (!GPBWire::writeBytes($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::UINT32:
+                if (!GPBWire::writeUint32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::ENUM:
+                if (!GPBWire::writeInt32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SFIXED32:
+                if (!GPBWire::writeSfixed32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SFIXED64:
+                if (!GPBWire::writeSfixed64($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SINT32:
+                if (!GPBWire::writeSint32($output, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SINT64:
+                if (!GPBWire::writeSint64($output, $value)) {
+                    return false;
+                }
+                break;
+            default:
+                user_error("Unsupported type.");
+                return false;
+        }
+
+        return true;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/InputStream.php b/php/src/Google/Protobuf/Internal/InputStream.php
new file mode 100644
index 00000000..18d07075
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/InputStream.php
@@ -0,0 +1,323 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\Uint64;
+
+class InputStream
+{
+
+    private $buffer;
+    private $buffer_size_after_limit;
+    private $buffer_end;
+    private $current;
+    private $current_limit;
+    private $legitimate_message_end;
+    private $recursion_budget;
+    private $recursion_limit;
+    private $total_bytes_limit;
+    private $total_bytes_read;
+
+    const MAX_VARINT_BYTES = 10;
+    const MAX_VARINT32_BYTES = 5;
+    const DEFAULT_RECURSION_LIMIT = 100;
+    const DEFAULT_TOTAL_BYTES_LIMIT = 33554432; // 32 << 20, 32MB
+
+    public function __construct($buffer)
+    {
+        $start = 0;
+        $end = strlen($buffer);
+        $this->buffer = $buffer;
+        $this->buffer_size_after_limit = 0;
+        $this->buffer_end = $end;
+        $this->current = $start;
+        $this->current_limit = $end;
+        $this->legitimate_message_end = false;
+        $this->recursion_budget = self::DEFAULT_RECURSION_LIMIT;
+        $this->recursion_limit = self::DEFAULT_RECURSION_LIMIT;
+        $this->total_bytes_limit = self::DEFAULT_TOTAL_BYTES_LIMIT;
+        $this->total_bytes_read = $end - $start;
+    }
+
+    private function advance($amount)
+    {
+        $this->current += $amount;
+    }
+
+    private function bufferSize()
+    {
+        return $this->buffer_end - $this->current;
+    }
+
+    private function current()
+    {
+        return $this->total_bytes_read -
+            ($this->buffer_end - $this->current +
+            $this->buffer_size_after_limit);
+    }
+
+    private function recomputeBufferLimits()
+    {
+        $this->buffer_end += $this->buffer_size_after_limit;
+        $closest_limit = min($this->current_limit, $this->total_bytes_limit);
+        if ($closest_limit < $this->total_bytes_read) {
+            // The limit position is in the current buffer.  We must adjust the
+            // buffer size accordingly.
+            $this->buffer_size_after_limit = $this->total_bytes_read -
+                $closest_limit;
+            $this->buffer_end -= $this->buffer_size_after_limit;
+        } else {
+            $this->buffer_size_after_limit = 0;
+        }
+    }
+
+    private function consumedEntireMessage()
+    {
+        return $this->legitimate_message_end;
+    }
+
+    /**
+     * Read uint32 into $var. Advance buffer with consumed bytes. If the
+     * contained varint is larger than 32 bits, discard the high order bits.
+     * @param $var.
+     */
+    public function readVarint32(&$var)
+    {
+        if (!$this->readVarint64($var)) {
+            return false;
+        }
+        $var = $var->toInteger() & 0xFFFFFFFF;
+        // Convert large uint32 to int32.
+        if (PHP_INT_SIZE === 8 && ($var > 0x7FFFFFFF)) {
+            $var = $var | (0xFFFFFFFF << 32);
+        }
+        return true;
+    }
+
+    /**
+     * Read Uint64 into $var. Advance buffer with consumed bytes.
+     * @param $var.
+     */
+    public function readVarint64(&$var)
+    {
+        $result = new Uint64(0);
+        $count = 0;
+        $b = 0;
+
+        do {
+            if ($this->current === $this->buffer_end) {
+                return false;
+            }
+            if ($count === self::MAX_VARINT_BYTES) {
+                return false;
+            }
+            $b = ord($this->buffer[$this->current]);
+            $result->bitOr((new Uint64($b & 0x7F))->leftShift(7 * $count));
+            $this->advance(1);
+            $count += 1;
+        } while ($b & 0x80);
+
+        $var = $result;
+        return true;
+    }
+
+    /**
+     * Read int into $var. If the result is larger than the largest integer, $var
+     * will be -1. Advance buffer with consumed bytes.
+     * @param $var.
+     */
+    public function readVarintSizeAsInt(&$var)
+    {
+        if (!$this->readVarint64($var)) {
+            return false;
+        }
+        $var = $var->toInteger();
+        return true;
+    }
+
+    /**
+     * Read 32-bit unsiged integer to $var. If the buffer has less than 4 bytes,
+     * return false. Advance buffer with consumed bytes.
+     * @param $var.
+     */
+    public function readLittleEndian32(&$var)
+    {
+        $data = null;
+        if (!$this->readRaw(4, $data)) {
+            return false;
+        }
+        $var = unpack('V', $data);
+        $var = $var[1];
+        return true;
+    }
+
+    /**
+     * Read 64-bit unsiged integer to $var. If the buffer has less than 8 bytes,
+     * return false. Advance buffer with consumed bytes.
+     * @param $var.
+     */
+    public function readLittleEndian64(&$var)
+    {
+        $data = null;
+        if (!$this->readRaw(4, $data)) {
+            return false;
+        }
+        $low = unpack('V', $data)[1];
+        if (!$this->readRaw(4, $data)) {
+            return false;
+        }
+        $high = unpack('V', $data)[1];
+        $var = Uint64::newValue($high, $low);
+        return true;
+    }
+
+    /**
+     * Read tag into $var. Advance buffer with consumed bytes.
+     * @param $var.
+     */
+    public function readTag()
+    {
+        if ($this->current === $this->buffer_end) {
+            // 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.
+            $current_position = $this->total_bytes_read -
+                $this->buffer_size_after_limit;
+            if ($current_position >= $this->total_bytes_limit) {
+                // Hit total_bytes_limit_.  But if we also hit the normal limit,
+                // we're still OK.
+                $this->legitimate_message_end =
+                    ($this->current_limit === $this->total_bytes_limit);
+            } else {
+                $this->legitimate_message_end = true;
+            }
+            return 0;
+        }
+
+        $result = 0;
+        // The larget tag is 2^29 - 1, which can be represented by int32.
+        $success = $this->readVarint32($result);
+        if ($success) {
+            return $result;
+        } else {
+            return 0;
+        }
+    }
+
+    public function readRaw($size, &$buffer)
+    {
+        $current_buffer_size = 0;
+        if ($this->bufferSize() < $size) {
+            return false;
+        }
+
+        $buffer = substr($this->buffer, $this->current, $size);
+        $this->advance($size);
+
+        return true;
+    }
+
+    /* Places a limit on the number of bytes that the stream may read, starting
+     * from the current position.  Once the stream hits this limit, it will act
+     * like the end of the input has been reached until popLimit() is called.
+     *
+     * As the names imply, the stream conceptually has a stack of limits.  The
+     * shortest limit on the stack is always enforced, even if it is not the top
+     * limit.
+     *
+     * The value returned by pushLimit() is opaque to the caller, and must be
+     * passed unchanged to the corresponding call to popLimit().
+     *
+     * @param integer $byte_limit
+     */
+    public function pushLimit($byte_limit)
+    {
+        // Current position relative to the beginning of the stream.
+        $current_position = $this->current();
+        $old_limit = $this->current_limit;
+
+        // security: byte_limit is possibly evil, so check for negative values
+        // and overflow.
+        if ($byte_limit >= 0 && $byte_limit <= PHP_INT_MAX - $current_position) {
+            $this->current_limit = $current_position + $byte_limit;
+        } else {
+            // Negative or overflow.
+            $this->current_limit = PHP_INT_MAX;
+        }
+
+        // We need to enforce all limits, not just the new one, so if the previous
+        // limit was before the new requested limit, we continue to enforce the
+        // previous limit.
+        $this->current_limit = min($this->current_limit, $old_limit);
+
+        $this->recomputeBufferLimits();
+        return $old_limit;
+    }
+
+    /* The limit passed in is actually the *old* limit, which we returned from
+     * PushLimit().
+     *
+     * @param integer $byte_limit
+     */
+    public function popLimit($byte_limit)
+    {
+        $this->current_limit = $byte_limit;
+        $this->recomputeBufferLimits();
+        // We may no longer be at a legitimate message end.  ReadTag() needs to
+        // be called again to find out.
+        $this->legitimate_message_end = false;
+    }
+
+    public function incrementRecursionDepthAndPushLimit(
+    $byte_limit, &$old_limit, &$recursion_budget)
+    {
+        $old_limit = $this->pushLimit($byte_limit);
+        $recursion_limit = --$this->recursion_limit;
+    }
+
+    public function decrementRecursionDepthAndPopLimit($byte_limit)
+    {
+        $result = $this->consumedEntireMessage();
+        $this->popLimit($byte_limit);
+        ++$this->recursion_budget;
+        return $result;
+    }
+
+    public function bytesUntilLimit()
+    {
+        if ($this->current_limit === PHP_INT_MAX) {
+            return -1;
+        }
+        return $this->current_limit - $this->current;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/MapEntry.php b/php/src/Google/Protobuf/Internal/MapEntry.php
new file mode 100644
index 00000000..926645e1
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/MapEntry.php
@@ -0,0 +1,57 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\Message;
+
+class MapEntry extends Message
+{
+    public $key;
+    public $value;
+
+    public function setKey(&$key) {
+      $this->key = $key;
+    }
+
+    public function getKey() {
+      return $this->key;
+    }
+
+    public function setValue(&$value) {
+      $this->value = $value;
+    }
+
+    public function getValue() {
+      return $this->value;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/MapField.php b/php/src/Google/Protobuf/Internal/MapField.php
new file mode 100644
index 00000000..14ee7ebe
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/MapField.php
@@ -0,0 +1,321 @@
+<?php
+
+// 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.
+
+/**
+ * MapField and MapFieldIter are used by generated protocol message classes to
+ * manipulate map fields.
+ */
+
+namespace Google\Protobuf\Internal;
+
+/**
+ * MapFieldIter is used to iterate MapField. It is also need for the foreach
+ * syntax.
+ */
+class MapFieldIter implements \Iterator
+{
+
+    /**
+     * @ignore
+     */
+    private $container;
+
+    /**
+     * Create iterator instance for MapField.
+     *
+     * @param MapField The MapField instance for which this iterator is
+     * created.
+     * @ignore
+     */
+    public function __construct($container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Reset the status of the iterator
+     *
+     * @return void
+     */
+    public function rewind()
+    {
+        return reset($this->container);
+    }
+
+    /**
+     * Return the element at the current position.
+     *
+     * @return object The element at the current position.
+     */
+    public function current()
+    {
+        return current($this->container);
+    }
+
+    /**
+     * Return the current key.
+     *
+     * @return object The current key.
+     */
+    public function key()
+    {
+        return key($this->container);
+    }
+
+    /**
+     * Move to the next position.
+     *
+     * @return void
+     */
+    public function next()
+    {
+        return next($this->container);
+    }
+
+    /**
+     * Check whether there are more elements to iterate.
+     *
+     * @return bool True if there are more elements to iterate.
+     */
+    public function valid()
+    {
+        return key($this->container) !== null;
+    }
+}
+
+/**
+ * @ignore
+ */
+function checkKey($key_type, &$key)
+{
+    switch ($key_type) {
+        case GPBType::INT32:
+            GPBUtil::checkInt32($key);
+            break;
+        case GPBType::UINT32:
+            GPBUtil::checkUint32($key);
+            break;
+        case GPBType::INT64:
+            GPBUtil::checkInt64($key);
+            break;
+        case GPBType::UINT64:
+            GPBUtil::checkUint64($key);
+            break;
+        case GPBType::FIXED64:
+            GPBUtil::checkUint64($key);
+            break;
+        case GPBType::FIXED32:
+            GPBUtil::checkUint32($key);
+            break;
+        case GPBType::SFIXED64:
+            GPBUtil::checkInt64($key);
+            break;
+        case GPBType::SFIXED32:
+            GPBUtil::checkInt32($key);
+            break;
+        case GPBType::SINT64:
+            GPBUtil::checkInt64($key);
+            break;
+        case GPBType::SINT32:
+            GPBUtil::checkInt32($key);
+            break;
+        case GPBType::BOOL:
+            GPBUtil::checkBool($key);
+            break;
+        case GPBType::STRING:
+            GPBUtil::checkString($key, true);
+            break;
+        default:
+            var_dump($key_type);
+            trigger_error(
+                "Given type cannot be map key.",
+                E_USER_ERROR);
+            break;
+    }
+}
+
+/**
+ * MapField is used by generated protocol message classes to manipulate map
+ * fields. It can be used like native PHP array.
+ */
+class MapField implements \ArrayAccess, \IteratorAggregate, \Countable
+{
+    /**
+     * @ignore
+     */
+    private $container;
+    /**
+     * @ignore
+     */
+    private $key_type;
+    /**
+     * @ignore
+     */
+    private $value_type;
+    /**
+     * @ignore
+     */
+    private $value_klass;
+
+    /**
+     * Constructs an instance of MapField.
+     *
+     * @param long $key_type Type of the stored key element.
+     * @param long $value_type Type of the stored value element.
+     * @param string $klass Message/Enum class name of value instance
+     * (message/enum fields only).
+     * @ignore
+     */
+    public function __construct($key_type, $value_type, $klass = null)
+    {
+        $this->container = [];
+        $this->key_type = $key_type;
+        $this->value_type = $value_type;
+        $this->klass = $klass;
+    }
+
+    /**
+     * Return the element at the given key.
+     *
+     * This will also be called for: $ele = $arr[$key]
+     *
+     * @param object $key The key of the element to be fetched.
+     * @return object The stored element at given key.
+     * @throws ErrorException Invalid type for index.
+     * @throws ErrorException Non-existing index.
+     */
+    public function offsetGet($key)
+    {
+        return $this->container[$key];
+    }
+
+    /**
+     * Assign the element at the given key.
+     *
+     * This will also be called for: $arr[$key] = $value
+     *
+     * @param object $key The key of the element to be fetched.
+     * @param object $value The element to be assigned.
+     * @return void
+     * @throws ErrorException Invalid type for key.
+     * @throws ErrorException Invalid type for value.
+     * @throws ErrorException Non-existing key.
+     */
+    public function offsetSet($key, $value)
+    {
+        checkKey($this->key_type, $key);
+
+        switch ($this->value_type) {
+            case GPBType::INT32:
+                GPBUtil::checkInt32($value);
+                break;
+            case GPBType::UINT32:
+                GPBUtil::checkUint32($value);
+                break;
+            case GPBType::INT64:
+                GPBUtil::checkInt64($value);
+                break;
+            case GPBType::UINT64:
+                GPBUtil::checkUint64($value);
+                break;
+            case GPBType::FLOAT:
+                GPBUtil::checkFloat($value);
+                break;
+            case GPBType::DOUBLE:
+                GPBUtil::checkDouble($value);
+                break;
+            case GPBType::BOOL:
+                GPBUtil::checkBool($value);
+                break;
+            case GPBType::STRING:
+                GPBUtil::checkString($value, true);
+                break;
+            case GPBType::MESSAGE:
+                GPBUtil::checkMessage($value, $this->klass);
+                break;
+            default:
+                break;
+        }
+
+        $this->container[$key] = $value;
+    }
+
+    /**
+     * Remove the element at the given key.
+     *
+     * This will also be called for: unset($arr)
+     *
+     * @param object $key The key of the element to be removed.
+     * @return void
+     * @throws ErrorException Invalid type for key.
+     */
+    public function offsetUnset($key)
+    {
+        checkKey($this->key_type, $key);
+        unset($this->container[$key]);
+    }
+
+    /**
+     * Check the existence of the element at the given key.
+     *
+     * This will also be called for: isset($arr)
+     *
+     * @param object $key The key of the element to be removed.
+     * @return bool True if the element at the given key exists.
+     * @throws ErrorException Invalid type for key.
+     */
+    public function offsetExists($key)
+    {
+        checkKey($this->key_type, $key);
+        return isset($this->container[$key]);
+    }
+
+    /**
+     * @ignore
+     */
+    public function getIterator()
+    {
+        return new MapFieldIter($this->container);
+    }
+
+    /**
+     * Return the number of stored elements.
+     *
+     * This will also be called for: count($arr)
+     *
+     * @return integer The number of stored elements.
+     */
+    public function count()
+    {
+        return count($this->container);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/Message.php b/php/src/Google/Protobuf/Internal/Message.php
new file mode 100644
index 00000000..a8de6a11
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/Message.php
@@ -0,0 +1,671 @@
+<?php
+
+// 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.
+
+/**
+ * Defines Message, the parent class extended by all protocol message classes.
+ */
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\InputStream;
+use Google\Protobuf\Internal\OutputStream;
+use Google\Protobuf\Internal\DescriptorPool;
+use Google\Protobuf\Internal\GPBLabel;
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\GPBWire;
+use Google\Protobuf\Internal\MapEntry;
+use Google\Protobuf\Internal\RepeatedField;
+
+/**
+ * Parent class of all proto messages. Users should not instantiate this class
+ * or extend this class or its child classes by their own.  See the comment of
+ * specific functions for more details.
+ */
+class Message
+{
+
+    /**
+     * @ignore
+     */
+    private $desc;
+
+    /**
+     * @ignore
+     */
+    public function __construct($desc = NULL)
+    {
+        // MapEntry message is shared by all types of map fields, whose
+        // descriptors are different from each other. Thus, we cannot find a
+        // specific descriptor from the descriptor pool.
+        if (get_class($this) === 'Google\Protobuf\Internal\MapEntry') {
+            $this->desc = $desc;
+            return;
+        }
+        $pool = DescriptorPool::getGeneratedPool();
+        $this->desc = $pool->getDescriptorByClassName(get_class($this));
+        foreach ($this->desc->getField() as $field) {
+            $setter = $field->getSetter();
+            if ($field->isMap()) {
+                $message_type = $field->getMessageType();
+                $key_field = $message_type->getFieldByNumber(1);
+                $value_field = $message_type->getFieldByNumber(2);
+                switch ($value_field->getType()) {
+                    case GPBType::MESSAGE:
+                    case GPBType::GROUP:
+                        $this->$setter(
+                            new MapField(
+                                $key_field->getType(),
+                                $value_field->getType(),
+                                $value_field->getMessageType()->getClass()));
+                        break;
+                    case GPBType::ENUM:
+                        $this->$setter(
+                            new MapField(
+                                $key_field->getType(),
+                                $value_field->getType(),
+                                $value_field->getEnumType()->getClass()));
+                        break;
+                    default:
+                        $this->$setter(new MapField($key_field->getType(),
+                                                    $value_field->getType()));
+                        break;
+                }
+            } else if ($field->getLabel() === GPBLabel::REPEATED) {
+                switch ($field->getType()) {
+                    case GPBType::MESSAGE:
+                    case GPBType::GROUP:
+                        $this->$setter(
+                            new RepeatedField(
+                                $field->getType(),
+                                $field->getMessageType()->getClass()));
+                        break;
+                    case GPBType::ENUM:
+                        $this->$setter(
+                            new RepeatedField(
+                                $field->getType(),
+                                $field->getEnumType()->getClass()));
+                        break;
+                    default:
+                        $this->$setter(new RepeatedField($field->getType()));
+                        break;
+                }
+            } else if ($field->getOneofIndex() !== -1) {
+                $oneof = $this->desc->getOneofDecl()[$field->getOneofIndex()];
+                $oneof_name = $oneof->getName();
+                $this->$oneof_name = new OneofField($oneof);
+            }
+        }
+    }
+
+    protected function readOneof($number)
+    {
+        $field = $this->desc->getFieldByNumber($number);
+        $oneof = $this->desc->getOneofDecl()[$field->getOneofIndex()];
+        $oneof_name = $oneof->getName();
+        $oneof_field = $this->$oneof_name;
+        if ($number === $oneof_field->getNumber()) {
+            return $oneof_field->getValue();
+        } else {
+            return $this->defaultValue($field);
+        }
+    }
+
+    protected function writeOneof($number, $value)
+    {
+        $field = $this->desc->getFieldByNumber($number);
+        $oneof = $this->desc->getOneofDecl()[$field->getOneofIndex()];
+        $oneof_name = $oneof->getName();
+        $oneof_field = $this->$oneof_name;
+        $oneof_field->setValue($value);
+        $oneof_field->setFieldName($field->getName());
+        $oneof_field->setNumber($number);
+    }
+
+    /**
+     * @ignore
+     */
+    private function defaultValue($field)
+    {
+        $value = null;
+
+        switch ($field->getType()) {
+            case GPBType::DOUBLE:
+            case GPBType::FLOAT:
+                return 0.0;
+            case GPBType::UINT32:
+            case GPBType::UINT64:
+            case GPBType::INT32:
+            case GPBType::INT64:
+            case GPBType::FIXED32:
+            case GPBType::FIXED64:
+            case GPBType::SFIXED32:
+            case GPBType::SFIXED64:
+            case GPBType::SINT32:
+            case GPBType::SINT64:
+            case GPBType::ENUM:
+                return 0;
+            case GPBType::BOOL:
+                return false;
+            case GPBType::STRING:
+            case GPBType::BYTES:
+                return "";
+            case GPBType::GROUP:
+            case GPBType::MESSAGE:
+                return null;
+            default:
+                user_error("Unsupported type.");
+                return false;
+        }
+    }
+
+    /**
+     * @ignore
+     */
+    private static function parseFieldFromStreamNoTag($input, $field, &$value)
+    {
+        switch ($field->getType()) {
+            case GPBType::DOUBLE:
+                if (!GPBWire::readDouble($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::FLOAT:
+                if (!GPBWire::readFloat($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::INT64:
+                if (!GPBWire::readInt64($input, $value)) {
+                    return false;
+                }
+                $value = $value->toInteger();
+                break;
+            case GPBType::UINT64:
+                if (!GPBWire::readUint64($input, $value)) {
+                    return false;
+                }
+                $value = $value->toInteger();
+                break;
+            case GPBType::INT32:
+                if (!GPBWire::readInt32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::FIXED64:
+                if (!GPBWire::readFixed64($input, $value)) {
+                    return false;
+                }
+                $value = $value->toInteger();
+                break;
+            case GPBType::FIXED32:
+                if (!GPBWire::readFixed32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::BOOL:
+                if (!GPBWire::readBool($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::STRING:
+                // TODO(teboring): Add utf-8 check.
+                if (!GPBWire::readString($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::GROUP:
+                echo "GROUP\xA";
+                trigger_error("Not implemented.", E_ERROR);
+                break;
+            case GPBType::MESSAGE:
+                if ($field->isMap()) {
+                    $value = new MapEntry($field->getMessageType());
+                } else {
+                    $klass = $field->getMessageType()->getClass();
+                    $value = new $klass;
+                }
+                if (!GPBWire::readMessage($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::BYTES:
+                if (!GPBWire::readString($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::UINT32:
+                if (!GPBWire::readUint32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::ENUM:
+                // TODO(teboring): Check unknown enum value.
+                if (!GPBWire::readInt32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SFIXED32:
+                if (!GPBWire::readSfixed32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SFIXED64:
+                if (!GPBWire::readSfixed64($input, $value)) {
+                    return false;
+                }
+                $value = $value->toInteger();
+                break;
+            case GPBType::SINT32:
+                if (!GPBWire::readSint32($input, $value)) {
+                    return false;
+                }
+                break;
+            case GPBType::SINT64:
+                if (!GPBWire::readSint64($input, $value)) {
+                    return false;
+                }
+                $value = $value->toInteger();
+                break;
+            default:
+                user_error("Unsupported type.");
+                return false;
+        }
+        return true;
+    }
+
+    /**
+     * @ignore
+     */
+    private function parseFieldFromStream($tag, $input, $field)
+    {
+        $value = null;
+        $field_type = $field->getType();
+
+        $value_format = GPBWire::UNKNOWN;
+        if (GPBWire::getTagWireType($tag) ===
+            GPBWire::getWireType($field_type)) {
+            $value_format = GPBWire::NORMAL_FORMAT;
+        } elseif ($field->isPackable() &&
+            GPBWire::getTagWireType($tag) ===
+            GPBWire::WIRETYPE_LENGTH_DELIMITED) {
+            $value_format = GPBWire::PACKED_FORMAT;
+        }
+
+        if ($value_format === GPBWire::NORMAL_FORMAT) {
+            if (!self::parseFieldFromStreamNoTag($input, $field, $value)) {
+                return false;
+            }
+        } elseif ($value_format === GPBWire::PACKED_FORMAT) {
+            $length = 0;
+            if (!GPBWire::readInt32($input, $length)) {
+                return false;
+            }
+            $limit = $input->pushLimit($length);
+            $getter = $field->getGetter();
+            while ($input->bytesUntilLimit() > 0) {
+                if (!self::parseFieldFromStreamNoTag($input, $field, $value)) {
+                    return false;
+                }
+                $this->$getter()[] = $value;
+            }
+            $input->popLimit($limit);
+            return true;
+        } else {
+            return false;
+        }
+
+        if ($field->isMap()) {
+            $getter = $field->getGetter();
+            $this->$getter()[$value->getKey()] = $value->getValue();
+        } else if ($field->isRepeated()) {
+            $getter = $field->getGetter();
+            $this->$getter()[] = $value;
+        } else {
+            $setter = $field->getSetter();
+            $this->$setter($value);
+        }
+
+        return true;
+    }
+
+    /**
+     * Parses a protocol buffer contained in a string.
+     *
+     * This function takes a string in the (non-human-readable) binary wire
+     * format, matching the encoding output by encode().
+     *
+     * @param string $data Binary protobuf data.
+     * @return bool Return true on success.
+     */
+    public function decode($data)
+    {
+        $input = new InputStream($data);
+        $this->parseFromStream($input);
+    }
+
+    /**
+     * @ignore
+     */
+    public function parseFromStream($input)
+    {
+        while (true) {
+            $tag = $input->readTag();
+            // End of input.  This is a valid place to end, so return true.
+            if ($tag === 0) {
+                return true;
+            }
+
+            $number = GPBWire::getTagFieldNumber($tag);
+            $field = $this->desc->getFieldByNumber($number);
+
+            if (!$this->parseFieldFromStream($tag, $input, $field)) {
+                return false;
+            }
+        }
+    }
+
+    /**
+     * @ignore
+     */
+    private function serializeSingularFieldToStream($field, &$output)
+    {
+        if (!$this->existField($field)) {
+            return true;
+        }
+        $getter = $field->getGetter();
+        $value = $this->$getter();
+        if (!GPBWire::serializeFieldToStream($value, $field, true, $output)) {
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * @ignore
+     */
+    private function serializeRepeatedFieldToStream($field, &$output)
+    {
+        $getter = $field->getGetter();
+        $values = $this->$getter();
+        $count = count($values);
+        if ($count === 0) {
+            return true;
+        }
+
+        $packed = $field->getPacked();
+        if ($packed) {
+            if (!GPBWire::writeTag(
+                $output,
+                GPBWire::makeTag($field->getNumber(), GPBType::STRING))) {
+                return false;
+            }
+            $size = 0;
+            foreach ($values as $value) {
+                $size += $this->fieldDataOnlyByteSize($field, $value);
+            }
+            if (!$output->writeVarint32($size)) {
+                return false;
+            }
+        }
+
+        foreach ($values as $value) {
+            if (!GPBWire::serializeFieldToStream(
+                $value,
+                $field,
+                !$packed,
+                $output)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * @ignore
+     */
+    private function serializeMapFieldToStream($field, $output)
+    {
+        $getter = $field->getGetter();
+        $values = $this->$getter();
+        $count = count($values);
+        if ($count === 0) {
+            return true;
+        }
+
+        foreach ($values as $key => $value) {
+            $map_entry = new MapEntry($field->getMessageType());
+            $map_entry->setKey($key);
+            $map_entry->setValue($value);
+            if (!GPBWire::serializeFieldToStream(
+                $map_entry,
+                $field,
+                true,
+                $output)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * @ignore
+     */
+    private function serializeFieldToStream(&$output, $field)
+    {
+        if ($field->isMap()) {
+            return $this->serializeMapFieldToStream($field, $output);
+        } elseif ($field->isRepeated()) {
+            return $this->serializeRepeatedFieldToStream($field, $output);
+        } else {
+            return $this->serializeSingularFieldToStream($field, $output);
+        }
+    }
+
+    /**
+     * @ignore
+     */
+    public function serializeToStream(&$output)
+    {
+        $fields = $this->desc->getField();
+        foreach ($fields as $field) {
+            if (!$this->serializeFieldToStream($output, $field)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Serialize the message to string.
+     * @return string Serialized binary protobuf data.
+     */
+    public function encode()
+    {
+        $output = new OutputStream($this->byteSize());
+        $this->serializeToStream($output);
+        return $output->getData();
+    }
+
+    /**
+     * @ignore
+     */
+    private function existField($field)
+    {
+        $getter = $field->getGetter();
+        $value = $this->$getter();
+        return $value !== $this->defaultValue($field);
+    }
+
+    /**
+     * @ignore
+     */
+    private function repeatedFieldDataOnlyByteSize($field)
+    {
+        $size = 0;
+
+        $getter = $field->getGetter();
+        $values = $this->$getter();
+        $count = count($values);
+        if ($count !== 0) {
+            $size += $count * GPBWire::tagSize($field);
+            foreach ($values as $value) {
+                $size += $this->singularFieldDataOnlyByteSize($field);
+            }
+        }
+    }
+
+    /**
+     * @ignore
+     */
+    private function fieldDataOnlyByteSize($field, $value)
+    {
+        $size = 0;
+
+        switch ($field->getType()) {
+            case GPBType::BOOL:
+                $size += 1;
+                break;
+            case GPBType::FLOAT:
+            case GPBType::FIXED32:
+            case GPBType::SFIXED32:
+                $size += 4;
+                break;
+            case GPBType::DOUBLE:
+            case GPBType::FIXED64:
+            case GPBType::SFIXED64:
+                $size += 8;
+                break;
+            case GPBType::UINT32:
+            case GPBType::INT32:
+            case GPBType::ENUM:
+                $size += GPBWire::varint32Size($value);
+                break;
+            case GPBType::UINT64:
+            case GPBType::INT64:
+                $size += GPBWire::varint64Size($value);
+                break;
+            case GPBType::SINT32:
+                $size += GPBWire::sint32Size($value);
+                break;
+            case GPBType::SINT64:
+                $size += GPBWire::sint64Size($value);
+                break;
+            case GPBType::STRING:
+            case GPBType::BYTES:
+                $size += strlen($value);
+                $size += GPBWire::varint32Size($size);
+                break;
+            case GPBType::MESSAGE:
+                $size += $value->byteSize();
+                $size += GPBWire::varint32Size($size);
+                break;
+            case GPBType::GROUP:
+                // TODO(teboring): Add support.
+                user_error("Unsupported type.");
+                break;
+            default:
+                user_error("Unsupported type.");
+                return 0;
+        }
+
+        return $size;
+    }
+
+    /**
+     * @ignore
+     */
+    private function fieldByteSize($field)
+    {
+        $size = 0;
+        if ($field->isMap()) {
+            $getter = $field->getGetter();
+            $values = $this->$getter();
+            $count = count($values);
+            if ($count !== 0) {
+                $size += $count * GPBWire::tagSize($field);
+                $message_type = $field->getMessageType();
+                $key_field = $message_type->getFieldByNumber(1);
+                $value_field = $message_type->getFieldByNumber(2);
+                foreach ($values as $key => $value) {
+                    $data_size = 0;
+                    $data_size += $this->fieldDataOnlyByteSize($key_field, $key);
+                    $data_size += $this->fieldDataOnlyByteSize(
+                        $value_field,
+                        $value);
+                    $data_size += GPBWire::tagSize($key_field);
+                    $data_size += GPBWire::tagSize($value_field);
+                    $size += GPBWire::varint32Size($data_size) + $data_size;
+                }
+            }
+        } elseif ($field->isRepeated()) {
+            $getter = $field->getGetter();
+            $values = $this->$getter();
+            $count = count($values);
+            if ($count !== 0) {
+                if ($field->getPacked()) {
+                    $data_size = 0;
+                    foreach ($values as $value) {
+                        $data_size += $this->fieldDataOnlyByteSize($field, $value);
+                    }
+                    $size += GPBWire::tagSize($field);
+                    $size += GPBWire::varint32Size($data_size);
+                    $size += $data_size;
+                } else {
+                    $size += $count * GPBWire::tagSize($field);
+                    foreach ($values as $value) {
+                        $size += $this->fieldDataOnlyByteSize($field, $value);
+                    }
+                }
+            }
+        } elseif ($this->existField($field)) {
+            $size += GPBWire::tagSize($field);
+            $getter = $field->getGetter();
+            $value = $this->$getter();
+            $size += $this->fieldDataOnlyByteSize($field, $value);
+        }
+        return $size;
+    }
+
+    /**
+     * @ignore
+     */
+    public function byteSize()
+    {
+        $size = 0;
+
+        $fields = $this->desc->getField();
+        foreach ($fields as $field) {
+            $size += $this->fieldByteSize($field);
+        }
+        return $size;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/MessageBuilderContext.php b/php/src/Google/Protobuf/Internal/MessageBuilderContext.php
new file mode 100644
index 00000000..2724d267
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/MessageBuilderContext.php
@@ -0,0 +1,120 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\GPBLabel;
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\Descriptor;
+use Google\Protobuf\Internal\FieldDescriptor;
+
+class MessageBuilderContext
+{
+
+    private $descriptor;
+    private $pool;
+
+    public function __construct($full_name, $klass, $pool)
+    {
+        $this->descriptor = new Descriptor();
+        $this->descriptor->setFullName($full_name);
+        $this->descriptor->setClass($klass);
+        $this->pool = $pool;
+    }
+
+    private function getFieldDescriptor($name, $label, $type,
+                                      $number, $type_name = null)
+    {
+        $field = new FieldDescriptor();
+        $field->setName($name);
+        $camel_name = implode('', array_map('ucwords', explode('_', $name)));
+        $field->setGetter('get' . $camel_name);
+        $field->setSetter('set' . $camel_name);
+        $field->setType($type);
+        $field->setNumber($number);
+        $field->setLabel($label);
+
+        // At this time, the message/enum type may have not been added to pool.
+        // So we use the type name as place holder and will replace it with the
+        // actual descriptor in cross building.
+        switch ($type) {
+        case GPBType::MESSAGE:
+          $field->setMessageType($type_name);
+          break;
+        case GPBType::ENUM:
+          $field->setEnumType($type_name);
+          break;
+        default:
+          break;
+        }
+
+        return $field;
+    }
+
+    public function optional($name, $type, $number, $type_name = null)
+    {
+        $this->descriptor->addField($this->getFieldDescriptor(
+            $name,
+            GPBLabel::OPTIONAL,
+            $type,
+            $number,
+            $type_name));
+        return $this;
+    }
+
+    public function repeated($name, $type, $number, $type_name = null)
+    {
+        $this->descriptor->addField($this->getFieldDescriptor(
+            $name,
+            GPBLabel::REPEATED,
+            $type,
+            $number,
+            $type_name));
+        return $this;
+    }
+
+    public function required($name, $type, $number, $type_name = null)
+    {
+        $this->descriptor->addField($this->getFieldDescriptor(
+            $name,
+            GPBLabel::REQUIRED,
+            $type,
+            $number,
+            $type_name));
+        return $this;
+    }
+
+    public function finalizeToPool()
+    {
+        $this->pool->addDescriptor($this->descriptor);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/OneofField.php b/php/src/Google/Protobuf/Internal/OneofField.php
new file mode 100644
index 00000000..2c689e83
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/OneofField.php
@@ -0,0 +1,77 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+class OneofField
+{
+
+    private $desc;
+    private $field_name;
+    private $number = 0;
+    private $value;
+
+    public function __construct($desc)
+    {
+        $this->desc = $desc;
+    }
+
+    public function setValue($value)
+    {
+        $this->value = $value;
+    }
+
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    public function setFieldName($field_name)
+    {
+        $this->field_name = $field_name;
+    }
+
+    public function getFieldName()
+    {
+        return $this->field_name;
+    }
+
+    public function setNumber($number)
+    {
+        $this->number = $number;
+    }
+
+    public function getNumber()
+    {
+        return $this->number;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/OutputStream.php b/php/src/Google/Protobuf/Internal/OutputStream.php
new file mode 100644
index 00000000..fcc5ce6d
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/OutputStream.php
@@ -0,0 +1,143 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+class OutputStream
+{
+
+    private $buffer;
+    private $buffer_size;
+    private $current;
+
+    const MAX_VARINT32_BYTES = 5;
+    const MAX_VARINT64_BYTES = 10;
+
+    public function __construct($size)
+    {
+        $this->current = 0;
+        $this->buffer_size = $size;
+        $this->buffer = str_repeat(chr(0), $this->buffer_size);
+    }
+
+    public function getData()
+    {
+        return $this->buffer;
+    }
+
+    public function writeVarint32($value)
+    {
+        $bytes = str_repeat(chr(0), self::MAX_VARINT32_BYTES);
+        $size = self::writeVarintToArray($value, $bytes, true);
+        return $this->writeRaw($bytes, $size);
+    }
+
+    public function writeVarint64($value)
+    {
+        $bytes = str_repeat(chr(0), self::MAX_VARINT64_BYTES);
+        $size = self::writeVarintToArray($value, $bytes);
+        return $this->writeRaw($bytes, $size);
+    }
+
+    public function writeLittleEndian32($value)
+    {
+        $bytes = str_repeat(chr(0), 4);
+        $size = self::writeLittleEndian32ToArray($value, $bytes);
+        return $this->writeRaw($bytes, $size);
+    }
+
+    public function writeLittleEndian64($value)
+    {
+        $bytes = str_repeat(chr(0), 8);
+        $size = self::writeLittleEndian64ToArray($value, $bytes);
+        return $this->writeRaw($bytes, $size);
+    }
+
+    public function writeTag($tag)
+    {
+        return $this->writeVarint32($tag);
+    }
+
+    public function writeRaw($data, $size)
+    {
+        if ($this->buffer_size < $size) {
+            var_dump($this->buffer_size);
+            var_dump($size);
+            trigger_error("Output stream doesn't have enough buffer.");
+            return false;
+        }
+
+        for ($i = 0; $i < $size; $i++) {
+            $this->buffer[$this->current] = $data[$i];
+            $this->current++;
+            $this->buffer_size--;
+        }
+        return true;
+    }
+
+    private static function writeVarintToArray($value, &$buffer, $trim = false)
+    {
+        $current = 0;
+        if ($trim) {
+            $value &= 0xFFFFFFFF;
+        }
+        while ($value >= 0x80 || $value < 0) {
+            $buffer[$current] = chr($value | 0x80);
+            $value = ($value >> 7) & ~(0x7F << ((PHP_INT_SIZE << 3) - 7));
+            $current++;
+        }
+        $buffer[$current] = chr($value);
+        return $current + 1;
+    }
+
+    private static function writeLittleEndian32ToArray($value, &$buffer)
+    {
+        $buffer[0] = chr($value & 0x000000FF);
+        $buffer[1] = chr(($value >> 8) & 0x000000FF);
+        $buffer[2] = chr(($value >> 16) & 0x000000FF);
+        $buffer[3] = chr(($value >> 24) & 0x000000FF);
+        return 4;
+    }
+
+    private static function writeLittleEndian64ToArray($value, &$buffer)
+    {
+        $buffer[0] = chr($value & 0x000000FF);
+        $buffer[1] = chr(($value >> 8) & 0x000000FF);
+        $buffer[2] = chr(($value >> 16) & 0x000000FF);
+        $buffer[3] = chr(($value >> 24) & 0x000000FF);
+        $buffer[4] = chr(($value >> 32) & 0x000000FF);
+        $buffer[5] = chr(($value >> 40) & 0x000000FF);
+        $buffer[6] = chr(($value >> 48) & 0x000000FF);
+        $buffer[7] = chr(($value >> 56) & 0x000000FF);
+        return 8;
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/RepeatedField.php b/php/src/Google/Protobuf/Internal/RepeatedField.php
new file mode 100644
index 00000000..0dc5d9d2
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/RepeatedField.php
@@ -0,0 +1,303 @@
+<?php
+
+// 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.
+
+/**
+ * RepeatedField and RepeatedFieldIter are used by generated protocol message
+ * classes to manipulate repeated fields.
+ */
+
+namespace Google\Protobuf\Internal;
+
+use Google\Protobuf\Internal\GPBType;
+use Google\Protobuf\Internal\GPBUtil;
+
+/**
+ * RepeatedFieldIter is used to iterate RepeatedField. It is also need for the
+ * foreach syntax.
+ */
+class RepeatedFieldIter implements \Iterator
+{
+
+    /**
+     * @ignore
+     */
+    private $position;
+    /**
+     * @ignore
+     */
+    private $container;
+
+    /**
+     * Create iterator instance for RepeatedField.
+     *
+     * @param RepeatedField The RepeatedField instance for which this iterator
+     * is created.
+     * @ignore
+     */
+    public function __construct($container)
+    {
+        $this->position = 0;
+        $this->container = $container;
+    }
+
+    /**
+     * Reset the status of the iterator
+     *
+     * @return void
+     */
+    public function rewind()
+    {
+        $this->position = 0;
+    }
+
+    /**
+     * Return the element at the current position.
+     *
+     * @return object The element at the current position.
+     */
+    public function current()
+    {
+        return $this->container[$this->position];
+    }
+
+    /**
+     * Return the current position.
+     *
+     * @return integer The current position.
+     */
+    public function key()
+    {
+        return $this->position;
+    }
+
+    /**
+     * Move to the next position.
+     *
+     * @return void
+     */
+    public function next()
+    {
+        ++$this->position;
+    }
+
+    /**
+     * Check whether there are more elements to iterate.
+     *
+     * @return bool True if there are more elements to iterate.
+     */
+    public function valid()
+    {
+        return isset($this->container[$this->position]);
+    }
+}
+
+/**
+ * RepeatedField is used by generated protocol message classes to manipulate
+ * repeated fields. It can be used like native PHP array.
+ */
+class RepeatedField implements \ArrayAccess, \IteratorAggregate, \Countable
+{
+
+    /**
+     * @ignore
+     */
+    private $container;
+    /**
+     * @ignore
+     */
+    private $type;
+    /**
+     * @ignore
+     */
+    private $klass;
+
+    /**
+     * Constructs an instance of RepeatedField.
+     *
+     * @param long $type Type of the stored element.
+     * @param string $klass Message/Enum class name (message/enum fields only).
+     * @ignore
+     */
+    public function __construct($type, $klass = null)
+    {
+        $this->container = [];
+        $this->type = $type;
+        $this->klass = $klass;
+    }
+
+    /**
+     * @ignore
+     */
+    public function getType()
+    {
+        return $this->type;
+    }
+
+    /**
+     * @ignore
+     */
+    public function getClass()
+    {
+        return $this->klass;
+    }
+
+    /**
+     * Return the element at the given index.
+     *
+     * This will also be called for: $ele = $arr[0]
+     *
+     * @param long $offset The index of the element to be fetched.
+     * @return object The stored element at given index.
+     * @throws ErrorException Invalid type for index.
+     * @throws ErrorException Non-existing index.
+     */
+    public function offsetGet($offset)
+    {
+        return $this->container[$offset];
+    }
+
+    /**
+     * Assign the element at the given index.
+     *
+     * This will also be called for: $arr []= $ele and $arr[0] = ele
+     *
+     * @param long $offset The index of the element to be assigned.
+     * @param object $value The element to be assigned.
+     * @return void
+     * @throws ErrorException Invalid type for index.
+     * @throws ErrorException Non-existing index.
+     * @throws ErrorException Incorrect type of the element.
+     */
+    public function offsetSet($offset, $value)
+    {
+        switch ($this->type) {
+            case GPBType::INT32:
+                GPBUtil::checkInt32($value);
+                break;
+            case GPBType::UINT32:
+                GPBUtil::checkUint32($value);
+                break;
+            case GPBType::INT64:
+                GPBUtil::checkInt64($value);
+                break;
+            case GPBType::UINT64:
+                GPBUtil::checkUint64($value);
+                break;
+            case GPBType::FLOAT:
+                GPBUtil::checkFloat($value);
+                break;
+            case GPBType::DOUBLE:
+                GPBUtil::checkDouble($value);
+                break;
+            case GPBType::BOOL:
+                GPBUtil::checkBool($value);
+                break;
+            case GPBType::STRING:
+                GPBUtil::checkString($value, true);
+                break;
+            case GPBType::MESSAGE:
+                GPBUtil::checkMessage($value, $this->klass);
+                break;
+            default:
+                break;
+        }
+        if (is_null($offset)) {
+            $this->container[] = $value;
+        } else {
+            $count = count($this->container);
+            if (!is_numeric($offset) || $offset < 0 || $offset >= $count) {
+                trigger_error(
+                    "Cannot modify element at the given index",
+                    E_USER_ERROR);
+                return;
+            }
+            $this->container[$offset] = $value;
+        }
+    }
+
+    /**
+     * Remove the element at the given index.
+     *
+     * This will also be called for: unset($arr)
+     *
+     * @param long $offset The index of the element to be removed.
+     * @return void
+     * @throws ErrorException Invalid type for index.
+     * @throws ErrorException The element to be removed is not at the end of the
+     * RepeatedField.
+     */
+    public function offsetUnset($offset)
+    {
+        $count = count($this->container);
+        if (!is_numeric($offset) || $count === 0 || $offset !== $count - 1) {
+            trigger_error(
+                "Cannot remove element at the given index",
+                E_USER_ERROR);
+            return;
+        }
+        array_pop($this->container);
+    }
+
+    /**
+     * Check the existence of the element at the given index.
+     *
+     * This will also be called for: isset($arr)
+     *
+     * @param long $offset The index of the element to be removed.
+     * @return bool True if the element at the given offset exists.
+     * @throws ErrorException Invalid type for index.
+     */
+    public function offsetExists($offset)
+    {
+        return isset($this->container[$offset]);
+    }
+
+    /**
+     * @ignore
+     */
+    public function getIterator()
+    {
+        return new RepeatedFieldIter($this->container);
+    }
+
+    /**
+     * Return the number of stored elements.
+     *
+     * This will also be called for: count($arr)
+     *
+     * @return integer The number of stored elements.
+     */
+    public function count()
+    {
+        return count($this->container);
+    }
+}
diff --git a/php/src/Google/Protobuf/Internal/Type.php b/php/src/Google/Protobuf/Internal/Type.php
new file mode 100644
index 00000000..088f0e0c
--- /dev/null
+++ b/php/src/Google/Protobuf/Internal/Type.php
@@ -0,0 +1,175 @@
+<?php
+
+// 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.
+
+namespace Google\Protobuf\Internal;
+
+class GPBInteger
+{
+    public $high = 0;
+    public $low = 0;
+
+    public function __construct($value = 0)
+    {
+        $this->low = $value & 0xFFFFFFFF;
+        if (PHP_INT_SIZE === 8) {
+            $this->high = ($value >> 32) & 0xFFFFFFFF;
+        }
+    }
+
+    // Return 0 for unsigned integers and 1 for signed integers.
+    protected function sign()
+    {
+        trigger_error("Not implemented", E_ERROR);
+    }
+
+    public function leftShift($count)
+    {
+        if ($count > 63) {
+            $this->low = 0;
+            $this->high = 0;
+            return;
+        }
+        if ($count > 32) {
+            $this->high = $this->low;
+            $this->low = 0;
+            $count -= 32;
+        }
+        $mask = (1 << $count) - 1;
+        $this->high = (($this->high << $count) & 0xFFFFFFFF) |
+                  (($this->low >> (32 - $count)) & $mask);
+        $this->low = ($this->low << $count) & 0xFFFFFFFF;
+
+        $this->high &= 0xFFFFFFFF;
+        $this->low &= 0xFFFFFFFF;
+        return $this;
+    }
+
+    public function rightShift($count)
+    {
+        $sign = (($this->high & 0x80000000) >> 31) & $this->sign();
+        if ($count > 63) {
+            $this->low = -$sign;
+            $this->high = -$sign;
+            return;
+        }
+        if ($count > 32) {
+            $this->low = $this->high;
+            $this->high = -$sign;
+            $count -= 32;
+        }
+        $this->low = (($this->low >> $count) & 0xFFFFFFFF) |
+                 (($this->high << (32 - $count)) & 0xFFFFFFFF);
+        $this->high = (($this->high >> $count) | (-$sign << $count));
+
+        $this->high &= 0xFFFFFFFF;
+        $this->low &= 0xFFFFFFFF;
+
+        return $this;
+    }
+
+    public function bitOr($var)
+    {
+        $this->high |= $var->high;
+        $this->low |= $var->low;
+        return $this;
+    }
+
+    public function bitXor($var)
+    {
+        $this->high ^= $var->high;
+        $this->low ^= $var->low;
+        return $this;
+    }
+
+    public function bitAnd($var)
+    {
+        $this->high &= $var->high;
+        $this->low &= $var->low;
+        return $this;
+    }
+
+    // Even: all zero; Odd: all one.
+    public function oddMask()
+    {
+        $low = (-($this->low & 1)) & 0xFFFFFFFF;
+        $high = $low;
+        return UInt64::newValue($high, $low);
+    }
+
+    public function toInteger()
+    {
+        if (PHP_INT_SIZE === 8) {
+            return ($this->high << 32) | $this->low;
+        } else {
+            return $this->low;
+        }
+    }
+
+    public function copy()
+    {
+        return static::newValue($this->high, $this->low);
+    }
+}
+
+class Uint64 extends GPBInteger
+{
+
+    public static function newValue($high, $low)
+    {
+        $uint64 = new Uint64(0);
+        $uint64->high = $high;
+        $uint64->low = $low;
+        return $uint64;
+    }
+
+    protected function sign()
+    {
+        return 0;
+    }
+}
+
+class Int64 extends GPBInteger
+{
+
+    public static function newValue($high, $low)
+    {
+        $int64 = new Int64(0);
+        $int64->high = $high;
+        $int64->low = $low;
+        return $int64;
+    }
+
+    protected function sign()
+    {
+        return 1;
+    }
+}