com.facebook.presto.jdbc.internal.spi.type.Varchars Maven / Gradle / Ivy
/*
* 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 com.facebook.presto.jdbc.internal.spi.type;
import com.facebook.presto.jdbc.internal.io.airlift.slice.Slice;
import com.facebook.presto.jdbc.internal.io.airlift.slice.Slices;
import static com.facebook.presto.jdbc.internal.io.airlift.slice.SliceUtf8.offsetOfCodePoint;
import static java.lang.Math.min;
import static java.util.Objects.requireNonNull;
public final class Varchars
{
private Varchars() {}
public static boolean isVarcharType(Type type)
{
return type instanceof VarcharType;
}
public static Slice truncateToLength(Slice slice, Type type)
{
requireNonNull(type, "type is null");
if (!isVarcharType(type)) {
throw new IllegalArgumentException("type must be the instance of VarcharType");
}
return truncateToLength(slice, VarcharType.class.cast(type));
}
public static Slice truncateToLength(Slice slice, VarcharType varcharType)
{
requireNonNull(varcharType, "varcharType is null");
return truncateToLength(slice, varcharType.getLength());
}
public static Slice truncateToLength(Slice slice, int maxLength)
{
requireNonNull(slice, "slice is null");
if (maxLength < 0) {
throw new IllegalArgumentException("Max length must be greater or equal than zero");
}
if (maxLength == 0) {
return Slices.EMPTY_SLICE;
}
return slice.slice(0, byteCount(slice, 0, slice.length(), maxLength));
}
/**
* Get the byte count of a given {@param slice} with in range {@param offset} to {@param offset} + {@param length}
* for at most {@param codePointCount} many code points
*/
public static int byteCount(Slice slice, int offset, int length, int codePointCount)
{
requireNonNull(slice, "slice is null");
if (length < 0) {
throw new IllegalArgumentException("length must be greater than or equal to zero");
}
if (offset < 0 || offset + length > slice.length()) {
throw new IllegalArgumentException("invalid offset/length");
}
if (codePointCount < 0) {
throw new IllegalArgumentException("codePointsCount must be greater than or equal to zero");
}
if (codePointCount == 0) {
return 0;
}
// min codepoint size is 1 byte.
// if size in bytes is less than the max length
// we don't need to decode codepoints
if (codePointCount > length) {
return length;
}
// get the end index with respect to code point count
int endIndex = offsetOfCodePoint(slice, offset, codePointCount);
if (endIndex < 0) {
// end index runs over the slice's length
return length;
}
if (offset > endIndex) {
throw new AssertionError("offset cannot be smaller than or equal to endIndex");
}
// end index could run over length because of large code points (e.g., 4-byte code points)
// or within length because of small code points (e.g., 1-byte code points)
return min(endIndex - offset, length);
}
}