package org.apache.lucene.util;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

import java.util.Random;

public class TestArrayUtil extends LuceneTestCase {

  // Ensure ArrayUtil.getNextSize gives linear amortized cost of realloc/copy
  public void testGrowth() {
    int currentSize = 0;
    long copyCost = 0;

    // Make sure ArrayUtil hits Integer.MAX_VALUE, if we insist:
    while(currentSize != Integer.MAX_VALUE) {
      int nextSize = ArrayUtil.oversize(1+currentSize, RamUsageEstimator.NUM_BYTES_OBJECT_REF);
      assertTrue(nextSize > currentSize);
      if (currentSize > 0) {
        copyCost += currentSize;
        double copyCostPerElement = ((double) copyCost)/currentSize;
        assertTrue("cost " + copyCostPerElement, copyCostPerElement < 10.0);
      }
      currentSize = nextSize;
    }
  }

  public void testMaxSize() {
    // intentionally pass invalid elemSizes:
    for(int elemSize=0;elemSize<10;elemSize++) {
      assertEquals(Integer.MAX_VALUE, ArrayUtil.oversize(Integer.MAX_VALUE, elemSize));
      assertEquals(Integer.MAX_VALUE, ArrayUtil.oversize(Integer.MAX_VALUE-1, elemSize));
    }
  }

  public void testInvalidElementSizes() {
    final Random r = newRandom();
    int num = 10000 * RANDOM_MULTIPLIER;
    for (int iter = 0; iter < num; iter++) {
      final int minTargetSize = r.nextInt(Integer.MAX_VALUE);
      final int elemSize = r.nextInt(11);
      final int v = ArrayUtil.oversize(minTargetSize, elemSize);
      assertTrue(v >= minTargetSize);
    }
  }

  public void testParseInt() throws Exception {
    int test;
    try {
      test = ArrayUtil.parseInt("".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt("foo".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt(String.valueOf(Long.MAX_VALUE).toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }
    try {
      test = ArrayUtil.parseInt("0.34".toCharArray());
      assertTrue(false);
    } catch (NumberFormatException e) {
      //expected
    }

    try {
      test = ArrayUtil.parseInt("1".toCharArray());
      assertTrue(test + " does not equal: " + 1, test == 1);
      test = ArrayUtil.parseInt("-10000".toCharArray());
      assertTrue(test + " does not equal: " + -10000, test == -10000);
      test = ArrayUtil.parseInt("1923".toCharArray());
      assertTrue(test + " does not equal: " + 1923, test == 1923);
      test = ArrayUtil.parseInt("-1".toCharArray());
      assertTrue(test + " does not equal: " + -1, test == -1);
      test = ArrayUtil.parseInt("foo 1923 bar".toCharArray(), 4, 4);
      assertTrue(test + " does not equal: " + 1923, test == 1923);
    } catch (NumberFormatException e) {
      e.printStackTrace();
      assertTrue(false);
    }

  }

  public void testSliceEquals() {
    String left = "this is equal";
    String right = left;
    char[] leftChars = left.toCharArray();
    char[] rightChars = right.toCharArray();
    assertTrue(left + " does not equal: " + right, ArrayUtil.equals(leftChars, 0, rightChars, 0, left.length()));
    
    assertFalse(left + " does not equal: " + right, ArrayUtil.equals(leftChars, 1, rightChars, 0, left.length()));
    assertFalse(left + " does not equal: " + right, ArrayUtil.equals(leftChars, 1, rightChars, 2, left.length()));

    assertFalse(left + " does not equal: " + right, ArrayUtil.equals(leftChars, 25, rightChars, 0, left.length()));
    assertFalse(left + " does not equal: " + right, ArrayUtil.equals(leftChars, 12, rightChars, 0, left.length()));
  }
}