Remove round-trip between string and byte[] for LIKE

By using NonStrictUTF8Encoding, joni does not suffer infinite loop
problem with invalid utf8. As a result, the roundtrip between byte[]
and string can be removed.

presto-main/src/main/java/com/facebook/presto/type/LikeFunctions.java

@@ -18,7 +18,7 @@
 import com.facebook.presto.operator.scalar.ScalarOperator;
 import com.facebook.presto.spi.PrestoException;
 import com.facebook.presto.spi.type.StandardTypes;
-import io.airlift.jcodings.specific.UTF8Encoding;
+import io.airlift.jcodings.specific.NonStrictUTF8Encoding;
 import io.airlift.joni.Option;
 import io.airlift.joni.Regex;
 import io.airlift.joni.Syntax;
@@ -55,13 +55,10 @@ private LikeFunctions() {}
     @SqlType(StandardTypes.BOOLEAN)
     public static boolean like(@SqlType(StandardTypes.VARCHAR) Slice value, @SqlType(LikePatternType.NAME) Regex pattern)
     {
-        // Joni doesn't handle invalid UTF-8, so replace invalid characters
+        // Joni can infinite loop with UTF8Encoding when invalid UTF-8 is encountered.
+        // NonStrictUTF8Encoding must be used to avoid this issue.
         byte[] bytes = value.getBytes();
-        if (isAscii(bytes)) {
-            return regexMatches(pattern, bytes);
-        }
-        // convert to a String and back to "fix" any broken UTF-8 sequences
-        return regexMatches(pattern, value.toStringUtf8().getBytes(UTF_8));
+        return regexMatches(pattern, bytes);
     }
 
     @ScalarOperator(OperatorType.CAST)
@@ -123,7 +120,7 @@ private static Regex likeToPattern(String patternString, char escapeChar, boolea
         regex.append('$');
 
         byte[] bytes = regex.toString().getBytes(UTF_8);
-        return new Regex(bytes, 0, bytes.length, Option.MULTILINE, UTF8Encoding.INSTANCE, SYNTAX);
+        return new Regex(bytes, 0, bytes.length, Option.MULTILINE, NonStrictUTF8Encoding.INSTANCE, SYNTAX);
     }
 
     @SuppressWarnings("NumericCastThatLosesPrecision")
@@ -139,14 +136,4 @@ private static char getEscapeChar(Slice escape)
         }
         throw new PrestoException(INVALID_FUNCTION_ARGUMENT, "Escape must be empty or a single character");
     }
-
-    private static boolean isAscii(byte[] bytes)
-    {
-        for (byte b : bytes) {
-            if (b < 0) {
-                return false;
-            }
-        }
-        return true;
-    }
 }