Adds checking to unicode characters that are \uXXXX where X is a hexidecimal digit

Adds new tests for unicode character coverage

jsmn.c

@@ -115,7 +115,19 @@ static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
 					break;
 				/* Allows escaped symbol \uXXXX */
 				case 'u':
-					/* TODO */
+                    parser->pos++;
+                    int i=0;
+                    for(;i<4&&js[parser->pos] != '\0';i++) {
+                        // If it isn't a hex character we have an error
+                        if(!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || // 0-9
+                                (js[parser->pos] >= 65 && js[parser->pos] <= 70) || // A-F
+                                (js[parser->pos] >= 97 && js[parser->pos] <= 102))) { // a-f
+                            parser->pos = start;
+                            return JSMN_ERROR_INVAL;
+                        }
+                        parser->pos++;
+                    }
+                    parser->pos--;
 					break;
 				/* Unexpected symbol */
 				default:

jsmn_test.c

@@ -348,6 +348,50 @@ int test_objects_arrays() {
 	return 0;
 }
 
+int test_unicode_characters() {
+    jsmn_parser p;
+    jsmntok_t tokens[10];
+    const char *js;
+
+    int r;
+    js = "{\"a\":\"\\uAbcD\"}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_SUCCESS);
+
+    js = "{\"a\":\"str\\u0000\"}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_SUCCESS);
+
+    js = "{\"a\":\"\\uFFFFstr\"}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_SUCCESS);
+
+    js = "{\"a\":\"str\\uFFGFstr\"}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_ERROR_INVAL);
+
+    js = "{\"a\":\"str\\u@FfF\"}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_ERROR_INVAL);
+
+    js = "{\"a\":[\"\\u028\"]}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_ERROR_INVAL);
+
+    js = "{\"a\":[\"\\u0280\"]}";
+    jsmn_init(&p);
+    r = jsmn_parse(&p, js, tokens, 10);
+    check(r == JSMN_SUCCESS);
+
+    return 0;
+}
+
 int main() {
 	test(test_empty, "general test for a empty JSON objects/arrays");
 	test(test_simple, "general test for a simple JSON string");
@@ -358,6 +402,7 @@ int main() {
 	test(test_array_nomem, "test array reading with a smaller number of tokens");
 	test(test_unquoted_keys, "test unquoted keys (like in JavaScript)");
 	test(test_objects_arrays, "test objects and arrays");
+    test(test_unicode_characters, "test unicode characters");
 	printf("\nPASSED: %d\nFAILED: %d\n", test_passed, test_failed);
 	return 0;
 }