// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
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// modification, are permitted provided that the following conditions
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// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. 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.
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//    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
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package scala.tools.asm.tree.analysis;

import java.util.Set;
import scala.tools.asm.tree.AbstractInsnNode;

/**
 * A {@link Value} which keeps track of the bytecode instructions that can produce it.
 *
 * @author Eric Bruneton
 */
public class SourceValue implements Value {

  /**
   * The size of this value, in 32 bits words. This size is 1 for byte, boolean, char, short, int,
   * float, object and array types, and 2 for long and double.
   */
  public final int size;

  /**
   * The instructions that can produce this value. For example, for the Java code below, the
   * instructions that can produce the value of {@code i} at line 5 are the two ISTORE instructions
   * at line 1 and 3:
   *
   * <pre>
   * 1: i = 0;
   * 2: if (...) {
   * 3:   i = 1;
   * 4: }
   * 5: return i;
   * </pre>
   */
  public final Set<AbstractInsnNode> insns;

  /**
   * Constructs a new {@link SourceValue}.
   *
   * @param size the size of this value, in 32 bits words. This size is 1 for byte, boolean, char,
   *     short, int, float, object and array types, and 2 for long and double.
   */
  public SourceValue(final int size) {
    this(size, new SmallSet<>());
  }

  /**
   * Constructs a new {@link SourceValue}.
   *
   * @param size the size of this value, in 32 bits words. This size is 1 for byte, boolean, char,
   *     short, int, float, object and array types, and 2 for long and double.
   * @param insnNode an instruction that can produce this value.
   */
  public SourceValue(final int size, final AbstractInsnNode insnNode) {
    this.size = size;
    this.insns = new SmallSet<>(insnNode);
  }

  /**
   * Constructs a new {@link SourceValue}.
   *
   * @param size the size of this value, in 32 bits words. This size is 1 for byte, boolean, char,
   *     short, int, float, object and array types, and 2 for long and double.
   * @param insnSet the instructions that can produce this value.
   */
  public SourceValue(final int size, final Set<AbstractInsnNode> insnSet) {
    this.size = size;
    this.insns = insnSet;
  }

  /**
   * Returns the size of this value.
   *
   * @return the size of this value, in 32 bits words. This size is 1 for byte, boolean, char,
   *     short, int, float, object and array types, and 2 for long and double.
   */
  @Override
  public int getSize() {
    return size;
  }

  @Override
  public boolean equals(final Object value) {
    if (!(value instanceof SourceValue)) {
      return false;
    }
    SourceValue sourceValue = (SourceValue) value;
    return size == sourceValue.size && insns.equals(sourceValue.insns);
  }

  @Override
  public int hashCode() {
    return insns.hashCode();
  }
}
