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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.trino.operator.scalar;
import io.airlift.slice.Slice;
import io.airlift.slice.SliceUtf8;
import io.airlift.slice.Slices;
import io.trino.spi.function.LiteralParameter;
import io.trino.spi.function.LiteralParameters;
import io.trino.spi.function.OperatorType;
import io.trino.spi.function.ScalarOperator;
import io.trino.spi.function.SqlType;
import it.unimi.dsi.fastutil.ints.IntArrayList;
import it.unimi.dsi.fastutil.ints.IntList;
import static com.google.common.base.Verify.verify;
import static io.airlift.slice.SliceUtf8.countCodePoints;
import static io.airlift.slice.SliceUtf8.getCodePointAt;
import static io.airlift.slice.SliceUtf8.lengthOfCodePoint;
import static io.airlift.slice.SliceUtf8.setCodePointAt;
import static io.trino.spi.type.Chars.padSpaces;
import static io.trino.spi.type.Chars.truncateToLengthAndTrimSpaces;
import static io.trino.spi.type.Varchars.truncateToLength;
import static java.lang.Math.toIntExact;
public final class CharacterStringCasts
{
private CharacterStringCasts() {}
@ScalarOperator(OperatorType.CAST)
@SqlType("varchar(y)")
@LiteralParameters({"x", "y"})
public static Slice varcharToVarcharCast(@LiteralParameter("x") Long x, @LiteralParameter("y") Long y, @SqlType("varchar(x)") Slice slice)
{
if (x > y) {
return truncateToLength(slice, y.intValue());
}
return slice;
}
@ScalarOperator(OperatorType.CAST)
@SqlType("char(y)")
@LiteralParameters({"x", "y"})
public static Slice charToCharCast(@LiteralParameter("x") Long x, @LiteralParameter("y") Long y, @SqlType("char(x)") Slice slice)
{
if (x > y) {
return truncateToLength(slice, y.intValue());
}
return slice;
}
@ScalarOperator(OperatorType.CAST)
@SqlType("char(y)")
@LiteralParameters({"x", "y"})
public static Slice varcharToCharCast(@LiteralParameter("y") Long y, @SqlType("varchar(x)") Slice slice)
{
return truncateToLengthAndTrimSpaces(slice, y.intValue());
}
@ScalarOperator(OperatorType.CAST)
@SqlType("varchar(y)")
@LiteralParameters({"x", "y"})
public static Slice charToVarcharCast(@LiteralParameter("x") Long x, @LiteralParameter("y") Long y, @SqlType("char(x)") Slice slice)
{
if (x.intValue() <= y.intValue()) {
return padSpaces(slice, x.intValue());
}
return padSpaces(truncateToLength(slice, y.intValue()), y.intValue());
}
@ScalarOperator(OperatorType.SATURATED_FLOOR_CAST)
@SqlType("char(y)")
@LiteralParameters({"x", "y"})
public static Slice varcharToCharSaturatedFloorCast(@LiteralParameter("y") long y, @SqlType("varchar(x)") Slice slice)
{
IntList codePoints = toCodePoints(slice);
// if Varchar(x) value length (including spaces) is greater than y, we can just truncate it
if (codePoints.size() >= y) {
// char(y) slice representation doesn't contain trailing spaces
codePoints.size(Math.min(toIntExact(y), codePoints.size()));
trimTrailing(codePoints, ' ');
return codePointsToSliceUtf8(codePoints);
}
/*
* Value length is smaller than same-represented char(y) value because input varchar has length lower than y.
* We decrement last character in input (in fact, we decrement last non-zero character) and pad the value with
* max code point up to y characters.
*/
trimTrailing(codePoints, '\0');
if (codePoints.isEmpty()) {
// No non-zero characters in input and input is shorter than y. Input value is smaller than any char(4) casted back to varchar, so we return the smallest char(4) possible
return Slices.allocate(toIntExact(y));
}
int lastCodePoint = codePoints.get(codePoints.size() - 1) - 1;
/*
* UTF-8 reserve codepoints from 0xD800 to 0xDFFF for encoding UTF-16
* If the lastCodePoint after -1 operation is in this range, it will lead to an InvalidCodePointException
* Since the codePoint is originally valid, so the only case will be 0XE00 - 1
* So we let it go through this range and become 0xD7FF
*/
if (lastCodePoint == Character.MAX_SURROGATE) {
lastCodePoint = Character.MIN_SURROGATE - 1;
}
codePoints.set(codePoints.size() - 1, lastCodePoint);
int toAdd = toIntExact(y) - codePoints.size();
for (int i = 0; i < toAdd; i++) {
codePoints.add(Character.MAX_CODE_POINT);
}
verify(codePoints.getInt(codePoints.size() - 1) != ' '); // no trailing spaces to trim
return codePointsToSliceUtf8(codePoints);
}
@ScalarOperator(OperatorType.SATURATED_FLOOR_CAST)
@SqlType("varchar(y)")
@LiteralParameters({"x", "y"})
public static Slice varcharToVarcharSaturatedFloorCast(@LiteralParameter("y") long y, @SqlType("varchar(x)") Slice slice)
{
if (countCodePoints(slice) <= y) {
return slice;
}
IntList codePoints = toCodePoints(slice);
codePoints.size(toIntExact(y));
return codePointsToSliceUtf8(codePoints);
}
private static void trimTrailing(IntList codePoints, int codePointToTrim)
{
int endIndex = codePoints.size();
while (endIndex > 0 && codePoints.get(endIndex - 1) == codePointToTrim) {
endIndex--;
}
codePoints.size(endIndex);
}
private static IntList toCodePoints(Slice slice)
{
IntList codePoints = new IntArrayList(slice.length());
for (int offset = 0; offset < slice.length(); ) {
int codePoint = getCodePointAt(slice, offset);
offset += lengthOfCodePoint(slice, offset);
codePoints.add(codePoint);
}
return codePoints;
}
public static Slice codePointsToSliceUtf8(IntList codePoints)
{
int bufferLength = 0;
for (int codePoint : codePoints) {
bufferLength += SliceUtf8.lengthOfCodePoint(codePoint);
}
Slice result = Slices.wrappedBuffer(new byte[bufferLength]);
int offset = 0;
for (int codePoint : codePoints) {
setCodePointAt(codePoint, result, offset);
offset += lengthOfCodePoint(codePoint);
}
return result;
}
}
