re-working RelativeJsonPointerFormatValidator parser

Author: erosb

core/src/main/java/org/everit/json/schema/internal/RelativeJsonPointerFormatValidator.java

@@ -16,6 +16,8 @@ public ParseException(String input) {
 
     private static final class Parser {
 
+        public static final int EOF = 26;
+
         private static boolean isDigit(char c) {
             return '0' <= c && c <= '9';
         }
@@ -44,20 +46,27 @@ private void parseTrailingHashmark() throws ParseException {
             fail();
         }
 
+        private char next() {
+            ++pos;
+            if (pos == input.length()) {
+                return 26;
+            }
+            return curr();
+        }
+
         private char curr() {
-            return input.charAt(pos++);
+            if (pos == input.length()) {
+                return EOF;
+            }
+            return input.charAt(pos);
         }
 
         private void parseUpwardsStepCount() throws ParseException {
             if (!isDigit(curr())) {
                 fail();
             }
-            if (pos == input.length()) {
-                return;
-            }
-            for (char current = curr(); isDigit(current) && pos < input.length() - 1; current = curr())
+            for (char current = next(); isDigit(current) && pos < input.length(); current = next())
                 ;
-            pos--;
         }
 
         private void fail() throws ParseException {
@@ -66,9 +75,10 @@ private void fail() throws ParseException {
 
         private void parseJsonPointer() throws ParseException {
             StringBuilder sb = new StringBuilder();
-            char current;
-            while (pos < input.length() && (current = curr()) != '#') {
+            char current = curr();
+            while (pos < input.length() && current != '#') {
                 sb.append(current);
+                current = next();
             }
             String pointer = sb.toString();
             if (pointer.length() == 0) {

core/src/test/java/org/everit/json/schema/internal/RelativeJsonPointerFormatValidatorTest.java

@@ -20,6 +20,11 @@ public void onlyUpwardsStepCount() {
         assertSuccess("1", SUBJECT);
     }
 
+    @Test
+    public void onlyUpwardsCount_multipleDigits() {
+        assertSuccess("234", SUBJECT);
+    }
+
     @Test
     public void upwardsStepCountWithJsonPointer() {
         assertSuccess("23/foo/bar", SUBJECT);
@@ -65,4 +70,9 @@ public void upwardsStepCountFollowedByURLFormJsonPointer() {
         assertFailure("123#/a/b", SUBJECT, "[123#/a/b] is not a valid relative JSON Pointer");
     }
 
+    @Test
+    public void noUpwardsStepCount() {
+        assertFailure("/foo/bar", SUBJECT, "[/foo/bar] is not a valid relative JSON Pointer");
+    }
+
 }