Add support for leading 0's

Author: mythz

src/ServiceStack.Text/StringSegmentExtensions.cs

@@ -221,12 +221,26 @@ public static ulong ParseUnsignedInteger(this StringSegment value, ulong maxValu
                 throw new FormatException(BadFormat);
 
             ulong result = 0;
-            int i = 0;
+            int i = value.Offset;
+            int end = value.Offset + value.Length;
             var state = ParseState.LeadingWhite;
 
-            while (i < value.Length)
+            //skip leading whitespaces
+            while (i < end && JsonUtils.IsWhiteSpace(value.Buffer[i])) i++;
+
+            if (i == end)
+                throw new FormatException(BadFormat);
+
+            //skip leading zeros
+            while (i < end && value.Buffer[i] == '0')
             {
-                var c = value.GetChar(i++);
+                state = ParseState.Number;
+                i++;
+            }
+
+            while (i < end)
+            {
+                var c = value.Buffer[i++];
 
                 switch (state)
                 {
@@ -292,9 +306,17 @@ public static long ParseSignedInteger(this StringSegment value, long maxValue, l
 
             //skip leading whitespaces
             while (i < end && JsonUtils.IsWhiteSpace(value.Buffer[i])) i++;
+
             if (i == end)
                 throw new FormatException(BadFormat);
 
+            //skip leading zeros
+            while (i < end && value.Buffer[i] == '0')
+            {
+                state = ParseState.Number;
+                i++;
+            }
+
             while (i < end)
             {
                 var c = value.Buffer[i++];

tests/ServiceStack.Text.Tests/BasicStringSerializerTests.cs

@@ -571,7 +571,7 @@ public void Can_convert_Field_Map_or_List_with_single_invalid_char()
         {
             foreach (var invalidChar in allCharsUsed)
             {
-                var singleInvalidChar = string.Format("a {0} b", invalidChar);
+                var singleInvalidChar = $"a {invalidChar} b";
 
                 var instance = new ModelWithMapAndList<string>
                 {
@@ -616,6 +616,14 @@ public void Can_convert_List_Guid()
 
             Assert.That(toModel, Is.EquivalentTo(model));
         }
+
+        [Test]
+        public void Can_deserialize_int_with_leading_zeros()
+        {
+            Assert.That("01".FromJson<int>(), Is.EqualTo(1));
+            Assert.That("01".FromJson<long>(), Is.EqualTo(1));
+            Assert.That("01".FromJson<ulong>(), Is.EqualTo(1));
+        }
 #endif
     }
 }

tests/ServiceStack.Text.Tests/Support/StringSegmentParse.cs

@@ -20,14 +20,12 @@ public void Can_parse_int32()
             Assert.That(new StringSegment("1").ParseInt32(), Is.EqualTo(1));
             Assert.That(new StringSegment(int.MaxValue.ToString()).ParseInt32(), Is.EqualTo(int.MaxValue));
             Assert.That(new StringSegment(int.MinValue.ToString()).ParseInt32(), Is.EqualTo(int.MinValue));
-            Assert.Throws<FormatException>(() => new StringSegment("01").ParseInt32());
             Assert.That(new StringSegment("234").ParseInt32(), Is.EqualTo(234));
             Assert.That(new StringSegment("    234  ").ParseInt32(), Is.EqualTo(234));
             Assert.That(new StringSegment("234  ").ParseInt32(), Is.EqualTo(234));
             Assert.That(new StringSegment("   234").ParseInt32(), Is.EqualTo(234));
             Assert.That(new StringSegment("   -234    ").ParseInt32(), Is.EqualTo(-234));
             Assert.Throws<FormatException>(() => new StringSegment("").ParseInt32());
-            Assert.Throws<FormatException>(() => new StringSegment("01").ParseInt32());
             Assert.Throws<FormatException>(() => new StringSegment("-01").ParseInt32());
             Assert.Throws<FormatException>(() => new StringSegment("   - 234    ").ParseInt32());
             Assert.Throws<FormatException>(() => new StringSegment("   2.34    ").ParseInt32());