infer_clone/infer/tests/codetoanalyze/java/performance/Loops.java

/*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
package codetoanalyze.java.performance;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class Loops {

  static int do_while_independent_of_p_constant(int p) {
    int a = 0;
    do {
      if (p == 15) {
        p = p + 1;
      }
      a++;
    } while (a < 25);

    return 0;
  }

  /* can't handle this type of nested loops properly, but control vars
  of both loops must be {a, b} */
  static void nested_do_while_FP(int p) {
    int a = 10;
    int b = 0;
    do {
      do {
        if (p == 15) {
          p = p + 1;
        }
        b++;
      } while (b < 10);
      a++;
    } while (a < 20);
  }

  static void dumb_linear(long[] a, int length) {
    for (int i = 1; i < length; i++) {
      if (a[i] < a[i - 1]) {
        a[i - 1] = 0;
      } else {
        a[i] = 1;
      }
    }
  }

  static void dumbSort_quadratic(long[] a, long[] b, int length) {
    for (int i = length - 1; i >= 0; --i) {
      for (int j = 0; j < i; ++j) {
        if (a[j] * b[j + 1] > a[j + 1] * b[j]) {
          long temp = a[j + 1];
          a[j + 1] = a[j];
          a[j] = temp;
          temp = b[j + 1];
          b[j + 1] = b[j];
          b[j] = temp;
        }
      }
    }
  }

  public static class C {
    public char c;
    public float[] f;
  }

  static boolean similar_linear(C[] x, C[] y) {
    if (x == null || y == null || x.length != y.length) {
      return false;
    }
    for (int i = 0; i < x.length; i++) {
      if (x[i].c != y[i].c || x[i].f.length != y[i].f.length) {
        return false;
      }
    }
    return true;
  }

  static void loop_linear(int x) {
    for (int i = 0; i < x; i++) {}
  }

  static void unboundedSymbol_FP() {
    int infinite = 9;
    for (int i = 0; i < 999; i++) {
      infinite *= infinite;
    }
    loop_linear(infinite);
  }

  void string_length_linear(String s) {
    for (int i = 0; i < s.length(); i++) {}
  }

  void string_concat_linear(String s, String p) {
    p = p.concat(s);
    for (int i = 0; i < p.length(); i++) {}
  }

  void zeropad_linear_FN(String s, String p) {
    // control variable for the loop is the result of equals which is
    // in [0,1]. It should be p instead.
    while (s.equals(p)) {
      p = p.concat("0");
    }
  }

  void charsequence_length_linear(CharSequence seq) {
    for (int i = 0; i < seq.length(); i++) {}
  }

  void modeled_range_linear(FileChannel fc, ByteBuffer bb) throws IOException {
    int i;
    int offset = 0;
    do {
      int numBytesRead = fc.read(bb, offset);
      if (numBytesRead == -1) {
        break;
      }
      i = bb.getInt();
      offset += 8;
    } while (i != 0);
  }

  class MyLinkedList {
    MyLinkedList next;

    MyLinkedList getNext() {
      return next;
    }
  }

  void length_of_linked_list_linear_FP(MyLinkedList p) {
    int n = 0;
    while (p != null) {
      n++;
      p = p.getNext();
    }
    loop_linear(n);
  }
}