/**
* Copyright (C) 2009-2013 FoundationDB, LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.foundationdb.server.types.mcompat.mfuncs;
import com.foundationdb.server.types.*;
import com.foundationdb.server.types.common.types.StringAttribute;
import com.foundationdb.server.types.mcompat.mtypes.MNumeric;
import com.foundationdb.server.types.mcompat.mtypes.MString;
import com.foundationdb.server.types.texpressions.Matchers.IndexMatcher;
import com.foundationdb.server.types.value.ValueSource;
import com.foundationdb.server.types.value.ValueTarget;
import com.foundationdb.server.types.texpressions.TInputSetBuilder;
import com.foundationdb.server.types.texpressions.TScalarBase;
import java.util.List;
public class MSubstringIndex extends TScalarBase {
public static final TScalar INSTANCE = new MSubstringIndex();
private static final int MATCHER_INDEX = 0;
private MSubstringIndex(){}
@Override
protected void buildInputSets(TInputSetBuilder builder) {
builder.covers(MString.VARCHAR, 0).covers(MString.VARCHAR, 1);
builder.covers(MNumeric.INT, 2);
}
@Override
protected void doEvaluate(TExecutionContext context, LazyList<? extends ValueSource> inputs, ValueTarget output) {
String str = inputs.get(0).getString();
String substr = inputs.get(1).getString();
int count = inputs.get(2).getInt32();
boolean signed;
if (count == 0 || str.isEmpty() || substr.isEmpty()) {
output.putString("", null);
return;
} else if (signed = count < 0) {
count = -count;
str = new StringBuilder(str).reverse().toString();
substr = new StringBuilder(substr).reverse().toString();
}
// try to reuse compiled pattern if possible
IndexMatcher matcher = (IndexMatcher)context.exectimeObjectAt(MATCHER_INDEX);
if (matcher == null || !matcher.sameState(substr, '\\')) {
context.putExectimeObject(MATCHER_INDEX, matcher = new IndexMatcher(substr));
}
int index = matcher.matchesAt(str, count);
String ret = index < 0 // no match found
? str
: str.substring(0, index);
if (signed) {
ret = new StringBuilder(ret).reverse().toString();
}
output.putString(ret, null);
}
@Override
public String displayName() {
return "SUBSTRING_INDEX";
}
@Override
public TOverloadResult resultType() {
return TOverloadResult.custom(new TCustomOverloadResult() {
@Override
public TInstance resultInstance(List<TPreptimeValue> inputs, TPreptimeContext context) {
TInstance stringInstance = inputs.get(0).type();
return MString.VARCHAR.instance(
stringInstance.attribute(StringAttribute.MAX_LENGTH),
anyContaminatingNulls(inputs));
}
});
}
}