cw_regexp_instr_4.sqlx

config { hasOutput: true }
/*
 * Copyright 2022 Google LLC
 *
 * 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.
 */

CREATE OR REPLACE FUNCTION ${self()}(haystack STRING, regexp STRING, p INT64, o INT64) RETURNS INT64
LANGUAGE js AS """
  if (haystack == null || regexp == null || o == null) return null;
  p = p -1;
  o = o -1;
  var str = haystack.substring(p);
  var a;
  var r = new RegExp(regexp, 'g');
  var count = 0;
  while ((a = r.exec(str)) !== null && count++ < o) {
    }
  if (a == null)
     return 0;
  return a.index+1+Number(p);
""";