Fix #556

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -18,6 +18,9 @@ JSON library.
 
 #540: UTF8StreamJsonParser: fix byte to int conversion for malformed escapes
  (Alex R)
+#556: 'IndexOutOfBoundsException' in UTF8JsonGenerator.writeString(Reader, len)
+  when using a negative length
+ (reported by jacob-alan-ward@github)
 
 2.9.9 (16-May-2019)
 

src/main/java/com/fasterxml/jackson/core/json/UTF8JsonGenerator.java

@@ -475,13 +475,13 @@ public void writeString(Reader reader, int len) throws IOException {
 
         final char[] buf = _charBuffer;
 
-        //Add leading quote
-        if ((_outputTail + len) >= _outputEnd) {
+        // Add leading quote
+        if (_outputTail >= _outputEnd) {
             _flushBuffer();
         }
         _outputBuffer[_outputTail++] = _quoteChar;
 
-        //read
+        // read
         while (toRead > 0){
             int toReadNow = Math.min(toRead, buf.length);
             int numRead = reader.read(buf, 0, toReadNow);
@@ -496,8 +496,8 @@ public void writeString(Reader reader, int len) throws IOException {
             toRead -= numRead;
         }
 
-        //Add trailing quote
-        if ((_outputTail + len) >= _outputEnd) {
+        // Add trailing quote
+        if (_outputTail >= _outputEnd) {
             _flushBuffer();
         }
         _outputBuffer[_outputTail++] = _quoteChar;

src/test/java/com/fasterxml/jackson/core/json/StringGenerationFromReaderTest.java

@@ -2,7 +2,9 @@
 
 import com.fasterxml.jackson.core.*;
 
+import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.InputStreamReader;
 import java.io.StringReader;
 import java.io.StringWriter;
 import java.util.Random;
@@ -274,4 +276,31 @@ private void _testLongerRandomMulti(int readMode, String text, int round)
         assertEquals(JsonToken.END_ARRAY, p.currentToken());
         p.close();
     }
+
+    // [jackson-core#556]
+    public void testIssue556() throws Exception
+    {
+        StringBuilder sb = new StringBuilder(8000);
+        sb.append('"');
+        for (int i = 0; i < 7988; i++) {
+             sb.append("a");
+        }
+        sb.append('"');
+        byte[] bytes = sb.toString().getBytes("UTF-8");
+
+        StringWriter w = new StringWriter(9000);
+        JsonGenerator g = FACTORY.createGenerator(new ByteArrayOutputStream());
+
+        g.writeStartArray();
+        _write556(g, sb.toString());
+        _write556(g, "b");
+        _write556(g, "c");
+        g.writeEndArray();
+        g.close();
+    }
+
+    private void _write556(JsonGenerator g, String value) throws Exception
+    {
+        g.writeString(new StringReader(value), -1);
+    }
 }