Rely on iconv and symfony/polyfill-*

Author: nicolas-grekas

Encoder/JsonDecode.php

@@ -108,7 +108,7 @@ public function decode($data, $format, array $context = array())
         }
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(JsonEncoder::getLastErrorMessage());
+            throw new UnexpectedValueException(json_last_error_message());
         }
 
         return $decodedData;

Encoder/JsonEncode.php

@@ -56,7 +56,7 @@ public function encode($data, $format, array $context = array())
         $encodedJson = json_encode($data, $context['json_encode_options']);
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(JsonEncoder::getLastErrorMessage());
+            throw new UnexpectedValueException(json_last_error_message());
         }
 
         return $encodedJson;

Encoder/JsonEncoder.php

@@ -100,26 +100,13 @@ public function supportsDecoding($format)
      * Resolves json_last_error message.
      *
      * @return string
+     *
+     * @deprecated since 2.8, to be removed in 3.0. Use json_last_error_msg() instead.
      */
     public static function getLastErrorMessage()
     {
-        if (function_exists('json_last_error_msg')) {
-            return json_last_error_msg();
-        }
-
-        switch (json_last_error()) {
-            case JSON_ERROR_DEPTH:
-                return 'Maximum stack depth exceeded';
-            case JSON_ERROR_STATE_MISMATCH:
-                return 'Underflow or the modes mismatch';
-            case JSON_ERROR_CTRL_CHAR:
-                return 'Unexpected control character found';
-            case JSON_ERROR_SYNTAX:
-                return 'Syntax error, malformed JSON';
-            case JSON_ERROR_UTF8:
-                return 'Malformed UTF-8 characters, possibly incorrectly encoded';
-            default:
-                return 'Unknown error';
-        }
+        @trigger_error('The '.__METHOD__.' method is deprecated since version 2.8 and will be removed in 3.0. Use json_last_error_msg() instead.', E_USER_DEPRECATED);
+
+        return json_last_error_msg();
     }
 }

composer.json

@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-php54": "~1.0"
     },
     "require-dev": {
         "symfony/yaml": "~2.0,>=2.0.5|~3.0.0",