From 397bc5b1624808b9d036d91d16cccb9e63199878 Mon Sep 17 00:00:00 2001
From: Tatu Saloranta <tatu.saloranta@iki.fi>
Date: Wed, 22 Apr 2020 19:46:57 -0700
Subject: [PATCH] some more #611

---
 .../core/json/UTF8StreamJsonParser.java       | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java b/src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java
index d6aeae0631..a7faa76f8d 100644
--- a/src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java
+++ b/src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java
@@ -780,6 +780,9 @@ public JsonToken nextToken() throws IOException
 
             // Should we have separate handling for plus? Although it is not allowed per se,
             // it may be erroneously used, and could be indicate by a more specific error message.
+        case '.': // [core#611]:
+            t = _parseFloatThatStartsWithPeriod();
+            break;
         case '0':
         case '1':
         case '2':
@@ -845,6 +848,8 @@ private final JsonToken _nextTokenNotInObject(int i) throws IOException
 
             // Should we have separate handling for plus? Although it is not allowed per se,
             // it may be erroneously used, and could be indicate by a more specific error message.
+        case '.': // [core#611]:
+            return (_currToken = _parseFloatThatStartsWithPeriod());
         case '0':
         case '1':
         case '2':
@@ -1046,6 +1051,9 @@ public String nextFieldName() throws IOException
         case '-':
             t = _parseNegNumber();
             break;
+        case '.': // [core#611]:
+            t = _parseFloatThatStartsWithPeriod();
+            break;
         case '0':
         case '1':
         case '2':
@@ -1164,6 +1172,9 @@ private final void _isNextTokenNameYes(int i) throws IOException
         case '-':
             _nextToken = _parseNegNumber();
             return;
+        case '.': // [core#611]:
+            _nextToken = _parseFloatThatStartsWithPeriod();
+            return;
         case '0':
         case '1':
         case '2':
@@ -1221,6 +1232,9 @@ private final boolean _isNextTokenNameMaybe(int i, SerializableString str) throw
         case '-':
             t = _parseNegNumber();
             break;
+        case '.': // [core#611]:
+            t = _parseFloatThatStartsWithPeriod();
+            break;
         case '0':
         case '1':
         case '2':
@@ -1352,6 +1366,17 @@ public Boolean nextBooleanValue() throws IOException
     /**********************************************************
      */
 
+    // @since 2.11, [core#611]
+    protected final JsonToken _parseFloatThatStartsWithPeriod() throws IOException
+    {
+        // [core#611]: allow optionally leading decimal point
+        if (!isEnabled(JsonReadFeature.ALLOW_LEADING_DECIMAL_POINT_FOR_NUMBERS.mappedFeature())) {
+            return _handleUnexpectedValue(INT_PERIOD);
+        }
+        return _parseFloat(_textBuffer.emptyAndGetCurrentSegment(),
+                0, INT_PERIOD, false, 0);
+    }
+
     /**
      * Initial parsing method for number values. It needs to be able
      * to parse enough input to be able to determine whether the
@@ -1538,7 +1563,7 @@ private final int _verifyNoLeadingZeroes() throws IOException
         }
         return ch;
     }
-    
+
     private final JsonToken _parseFloat(char[] outBuf, int outPtr, int c,
             boolean negative, int integerPartLength) throws IOException
     {