Fix NettyDataBuffer#lastIndexOf()

Author: sdeleuze

spring-core/src/main/java/org/springframework/core/io/buffer/NettyDataBuffer.java

@@ -91,7 +91,7 @@ public int lastIndexOf(IntPredicate predicate, int fromIndex) {
 			return -1;
 		}
 		fromIndex = Math.min(fromIndex, this.byteBuf.writerIndex() - 1);
-		return this.byteBuf.forEachByteDesc(0, fromIndex, predicate.negate()::test);
+		return this.byteBuf.forEachByteDesc(0, fromIndex + 1, predicate.negate()::test);
 	}
 
 	@Override

spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java

@@ -210,15 +210,24 @@ public void lastIndexOf() {
 		DataBuffer buffer = createDataBuffer(3);
 		buffer.write(new byte[]{'a', 'b', 'c'});
 
-		int result = buffer.lastIndexOf(b -> b == 'b', 3);
+		int result = buffer.lastIndexOf(b -> b == 'b', 2);
 		assertEquals(1, result);
 
+		result = buffer.lastIndexOf(b -> b == 'c', 2);
+		assertEquals(2, result);
+
 		result = buffer.lastIndexOf(b -> b == 'b', Integer.MAX_VALUE);
 		assertEquals(1, result);
 
+		result = buffer.lastIndexOf(b -> b == 'c', Integer.MAX_VALUE);
+		assertEquals(2, result);
+
 		result = buffer.lastIndexOf(b -> b == 'b', Integer.MIN_VALUE);
 		assertEquals(-1, result);
 
+		result = buffer.lastIndexOf(b -> b == 'c', Integer.MIN_VALUE);
+		assertEquals(-1, result);
+
 		result = buffer.lastIndexOf(b -> b == 'z', 0);
 		assertEquals(-1, result);