ostrich.cesolver.preop.PreOpUtil.scala Maven / Gradle / Ivy

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OSTRICH is an SMT solver for string constraints.
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/**
 * This file is part of Ostrich, an SMT solver for strings.
 * Copyright (c) 2023 Denghang Hu. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * 
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * 
 * * Neither the name of the authors nor the names of their
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package ostrich.cesolver.preop
import ostrich.cesolver.automata.CostEnrichedAutomatonBase
import ostrich.cesolver.automata.BricsAutomatonWrapper.{makeEmpty, makeEmptyString}

object PreOpUtil {
    def automatonWithLen(len: Int): CostEnrichedAutomatonBase = {
    if (len < 0) return makeEmpty()
    if (len == 0) return makeEmptyString()
    val automaton = new CostEnrichedAutomatonBase
    val sigma = automaton.LabelOps.sigmaLabel
    val states =
      automaton.initialState +: (for (_ <- 0 to len) yield automaton.newState())
    for (i <- 0 until len) {
      automaton.addTransition(states(i), sigma, states(i + 1), Seq())
    }
    automaton.setAccept(states(len), true)
    automaton
  }

  def automatonWithLenLessThan(len: Int): CostEnrichedAutomatonBase = {
    if (len <= 0) return makeEmpty()
    val automaton = new CostEnrichedAutomatonBase
    val sigma = automaton.LabelOps.sigmaLabel
    val states =
      automaton.initialState +: (for (_ <- 0 to len) yield automaton.newState())
    for (i <- 0 until len - 1) {
      automaton.setAccept(states(i), true)
      automaton.addTransition(states(i), sigma, states(i + 1), Seq())
    }
    automaton.setAccept(states(len - 1), true)
    automaton
  }
}