first setup

ext/json/json.c

@@ -70,6 +70,7 @@ static PHP_GINIT_FUNCTION(json)
 static PHP_RINIT_FUNCTION(json)
 {
 	JSON_G(error_code) = 0;
+	JSON_G(error_pos) = 0;
 	return SUCCESS;
 }
 
@@ -133,6 +134,7 @@ PHP_JSON_API zend_result php_json_encode_ex(smart_str *buf, zval *val, int optio
 
 	return_code = php_json_encode_zval(buf, val, options, &encoder);
 	JSON_G(error_code) = encoder.error_code;
+	JSON_G(error_pos) = encoder.error_pos;
 
 	return return_code;
 }
@@ -156,7 +158,11 @@ static const char *php_json_get_error_msg(php_json_error_code error_code) /* {{{
 		case PHP_JSON_ERROR_CTRL_CHAR:
 			return "Control character error, possibly incorrectly encoded";
 		case PHP_JSON_ERROR_SYNTAX:
-			return "Syntax error";
+			char *msg;
+			spprintf(&msg, 0, "Syntax error at character %zu", JSON_G(error_pos));
+			return msg;
+			//efree(msg);
+			//return "Syntax error";
 		case PHP_JSON_ERROR_UTF8:
 			return "Malformed UTF-8 characters, possibly incorrectly encoded";
 		case PHP_JSON_ERROR_RECURSION:
@@ -185,11 +191,15 @@ PHP_JSON_API zend_result php_json_decode_ex(zval *return_value, const char *str,
 
 	if (php_json_yyparse(&parser)) {
 		php_json_error_code error_code = php_json_parser_error_code(&parser);
+		size_t error_pos = php_json_parser_error_pos(&parser);
+
 		if (!(options & PHP_JSON_THROW_ON_ERROR)) {
 			JSON_G(error_code) = error_code;
+			JSON_G(error_pos) = error_pos;
 		} else {
 			zend_throw_exception(php_json_exception_ce, php_json_get_error_msg(error_code), error_code);
 		}
+
 		RETVAL_NULL();
 		return FAILURE;
 	}
@@ -208,7 +218,9 @@ PHP_JSON_API bool php_json_validate_ex(const char *str, size_t str_len, zend_lon
 
 	if (php_json_yyparse(&parser)) {
 		php_json_error_code error_code = php_json_parser_error_code(&parser);
+		size_t error_pos = php_json_parser_error_pos(&parser);
 		JSON_G(error_code) = error_code;
+		JSON_G(error_pos) = error_pos;
 		return false;
 	}
 
@@ -238,6 +250,7 @@ PHP_FUNCTION(json_encode)
 
 	if (!(options & PHP_JSON_THROW_ON_ERROR) || (options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR)) {
 		JSON_G(error_code) = encoder.error_code;
+		JSON_G(error_pos) = encoder.error_pos;
 		if (encoder.error_code != PHP_JSON_ERROR_NONE && !(options & PHP_JSON_PARTIAL_OUTPUT_ON_ERROR)) {
 			smart_str_free(&buf);
 			RETURN_FALSE;

ext/json/json_parser.y

@@ -300,6 +300,7 @@ static void php_json_yyerror(php_json_parser *parser, char const *msg)
 {
 	if (!parser->scanner.errcode) {
 		parser->scanner.errcode = PHP_JSON_ERROR_SYNTAX;
+		parser->scanner.errpos = (size_t)(parser->scanner.cursor - parser->scanner.str_start);
 	}
 }
 
@@ -308,6 +309,11 @@ PHP_JSON_API php_json_error_code php_json_parser_error_code(const php_json_parse
 	return parser->scanner.errcode;
 }
 
+PHP_JSON_API size_t php_json_parser_error_pos(const php_json_parser *parser)
+{
+	return parser->scanner.errpos;
+}
+
 static const php_json_parser_methods default_parser_methods =
 {
 	php_json_parser_array_create,

ext/json/php_json.h

@@ -90,6 +90,7 @@ ZEND_BEGIN_MODULE_GLOBALS(json)
 	int encoder_depth;
 	int encode_max_depth;
 	php_json_error_code error_code;
+	size_t error_pos;
 ZEND_END_MODULE_GLOBALS(json)
 
 PHP_JSON_API ZEND_EXTERN_MODULE_GLOBALS(json)

ext/json/php_json_encoder.h

@@ -26,6 +26,7 @@ struct _php_json_encoder {
 	int depth;
 	int max_depth;
 	php_json_error_code error_code;
+  size_t error_pos;
 };
 
 static inline void php_json_encode_init(php_json_encoder *encoder)

ext/json/php_json_scanner.h

@@ -35,6 +35,7 @@ typedef struct _php_json_scanner {
 	int state;                      /* condition state */
 	int options;                    /* options */
 	php_json_error_code errcode;    /* error type if there is an error */
+	size_t errpos;
 	int utf8_invalid;               /* whether utf8 is invalid */
 	int utf8_invalid_count;         /* number of extra character for invalid utf8 */
 } php_json_scanner;

ext/json/tests/json_validate_002.phpt

@@ -8,6 +8,7 @@ require_once("json_validate_requires.inc");
 json_validate_trycatchdump("");
 json_validate_trycatchdump("-");
 json_validate_trycatchdump("", -1);
+json_validate_trycatchdump('{"key1":"value1", "value2"}', 2);
 json_validate_trycatchdump('{"key1":"value1", "key2":"value2"}', 1);
 json_validate_trycatchdump('{"key1":"value1", "key2":"value2"}', 2);
 json_validate_trycatchdump("-", 0);