--- a/lib/Protobuf-PHP/library/DrSlump/Protobuf/Codec/JsonIndexed.php
+++ b/lib/Protobuf-PHP/library/DrSlump/Protobuf/Codec/JsonIndexed.php
@@ -1,1 +1,140 @@
+<?php
 
+namespace DrSlump\Protobuf\Codec;
+
+use DrSlump\Protobuf;
+
+/**
+ * This codec serializes and unserializes from/to Json strings
+ * where the keys are packed as the first element of numeric arrays,
+ * optimizing the resulting payload size.
+ *
+ */
+class JsonIndexed extends Json
+    implements Protobuf\CodecInterface
+{
+
+    protected function encodeMessage(Protobuf\Message $message)
+    {
+        $descriptor = Protobuf::getRegistry()->getDescriptor($message);
+
+        $index = '';
+        $data = array();
+        foreach ($descriptor->getFields() as $tag=>$field) {
+            $empty = !$message->_has($tag);
+            if ($field->isRequired() && $empty) {
+                throw new \UnexpectedValueException(
+                    'Message ' . get_class($message) . '\'s field tag ' . $tag . '(' . $field->getName() . ') is required but has no value'
+                );
+            }
+
+            if ($empty) {
+                continue;
+            }
+
+            $index .= $this->i2c($tag + 48);
+
+            $value = $message->_get($tag);
+
+            if ($field->isRepeated()) {
+                $repeats = array();
+                foreach ($value as $val) {
+                    if ($field->getType() !== Protobuf::TYPE_MESSAGE) {
+                        $repeats[] = $val;
+                    } else {
+                        $repeats[] = $this->encodeMessage($val);
+                    }
+                }
+                $data[] = $repeats;
+            } else {
+                if ($field->getType() === Protobuf::TYPE_MESSAGE) {
+                    $data[] = $this->encodeMessage($value);
+                } else {
+                    $data[] = $value;
+                }
+            }
+        }
+
+        // Insert the index at first element
+        array_unshift($data, $index);
+
+        return $data;
+    }
+
+    protected function decodeMessage(Protobuf\Message $message, $data)
+    {
+        // Get message descriptor
+        $descriptor = Protobuf::getRegistry()->getDescriptor($message);
+
+        // Split the index in UTF8 characters
+        preg_match_all('/./u', $data[0], $chars);
+
+        $chars = $chars[0];
+        for ($i=1; $i<count($data); $i++) {
+
+            $k = $this->c2i($chars[$i-1]) - 48;
+            $v = $data[$i];
+
+            $field = $descriptor->getField($k);
+
+            if (NULL === $field) {
+                // Unknown
+                $unknown = new PhpArray\Unknown($k, gettype($v), $v);
+                $message->addUnknown($unknown);
+                continue;
+            }
+
+            if ($field->getType() === Protobuf::TYPE_MESSAGE) {
+                $nested = $field->getReference();
+                if ($field->isRepeated()) {
+                    foreach ($v as $vv) {
+                        $obj = $this->decodeMessage(new $nested, $vv);
+                        $message->_add($k, $obj);
+                    }
+                } else {
+                    $obj = $this->decodeMessage(new $nested, $v);
+                    $message->_set($k, $obj);
+                }
+            } else {
+                $message->_set($k, $v);
+            }
+        }
+
+        return $message;
+    }
+
+    /**
+     * Converts an Unicode codepoint number to an UTF-8 character
+     *
+     * @param int $codepoint
+     * @return string
+     */
+    protected function i2c($codepoint)
+    {
+        return $codepoint < 128
+               ? chr($codepoint)
+               : html_entity_decode("&#$codepoint;", ENT_NOQUOTES, 'UTF-8');
+    }
+
+    /**
+     * Converts an UTF-8 character to an Unicode codepoint number
+     *
+     * @param string $char
+     * @return int
+     */
+    protected function c2i($char)
+    {
+        $value = ord($char[0]);
+        if ($value < 128) return $value;
+
+        if ($value < 224) {
+            return (($value % 32) * 64) + (ord($char[1]) % 64);
+        } else {
+            return (($value % 16) * 4096) +
+                   ((ord($char[1]) % 64) * 64) +
+                   (ord($char[2]) % 64);
+        }
+    }
+
+}
+