NIFI-3495 polishing

nifi-commons/nifi-utils/src/main/java/org/apache/nifi/stream/io/util/TextLineDemarcator.java

@@ -110,9 +110,7 @@ public OffsetInfo nextOffsetInfo(byte[] startsWith) {
                 for (i = this.index; i < this.bufferLength; i++) {
                     byteVal = this.buffer[i];
                     lineLength++;
-                    int[] eol = computeEol(byteVal, i + 1);
-                    int crlfLength = eol[0];
-                    boolean readAheadPerformed = eol[1] == 1;
+                    int crlfLength = computeEol(byteVal, i + 1);
                     if (crlfLength > 0) {
                         i += crlfLength;
                         if (crlfLength == 2) {
@@ -122,9 +120,6 @@ public OffsetInfo nextOffsetInfo(byte[] startsWith) {
                         if (startsWith != null) {
                             token = this.extractDataToken(lineLength);
                         }
-                        if (!readAheadPerformed) {
-                            this.index = i;
-                        }
                         this.mark = this.index;
                         break lineLoop;
                     }
@@ -155,37 +150,40 @@ public OffsetInfo nextOffsetInfo(byte[] startsWith) {
     }
 
     /**
-     * Determines if the line terminates. Returns int array with two elements.
-     * The first elements specifies the length of the CRLF (only CR or CR and
-     * LF) and therefore can only have values: 0 - not the end of the line 1 -
-     * the end of the line either via CR or LF 2 - the end of the line with both
-     * CR and LF
+     * Determines if the line terminates. Returns int specifying the length of
+     * the CRLF (i.e., only CR or LF or CR and LF) and therefore can only have
+     * values of:
+     *   0 - not the end of the line
+     *   1 - the end of the line either via CR or LF
+     *   2 - the end of the line with both CR and LF
      *
-     * It performs the read ahead on the buffer if need to. If such read ahead
-     * was performed, then second element will carry value of 1 otherwise 0.
+     * It performs the read ahead on the buffer if need to.
      */
-    private int[] computeEol(byte currentByte, int currentIndex) {
+    private int computeEol(byte currentByte, int providedIndex) {
+        int actualIndex = providedIndex - 1;
         boolean readAhead = false;
         int crlfLength = 0;
         if (currentByte == '\n') {
             crlfLength = 1;
         } else if (currentByte == '\r') {
-            if (currentIndex >= this.bufferLength) {
-                this.index = currentIndex;
+            if (providedIndex >= this.bufferLength) {
+                this.index = this.bufferLength;
                 this.fill();
-                currentIndex = this.index;
+                providedIndex = this.index;
                 readAhead = true;
             }
             crlfLength = 1;
-            if (currentIndex < this.buffer.length - 1) {
-                currentByte = this.buffer[currentIndex];
+            if (providedIndex < this.buffer.length - 1) {
+                currentByte = this.buffer[providedIndex];
                 crlfLength = currentByte == '\n' ? 2 : 1;
-                if (readAhead) {
-                    this.index += (crlfLength - 1);
-                }
             }
         }
-        return new int[] { crlfLength, readAhead ? 1 : 0 };
+
+        if (crlfLength > 0) {
+            this.index = readAhead ? this.index + (crlfLength - 1) : (actualIndex + crlfLength);
+        }
+
+        return crlfLength;
     }
 
     private byte[] extractDataToken(int length) {
@@ -209,9 +207,7 @@ private void fill() {
                 this.buffer = newBuff;
             } else { // shuffle
                 int length = this.index - this.mark;
-
                 System.arraycopy(this.buffer, this.mark, this.buffer, 0, length);
-
                 this.index = length;
                 this.mark = 0;
             }