third_party/tcmalloc/chromium/src/tests/realloc_unittest.cc

// Copyright (c) 2004, Google Inc.
// 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 Google Inc. nor the names of its
// 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
// OWNER 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.

// ---
// Author: Sanjay Ghemawat
//
// Test realloc() functionality

#include "config_for_unittests.h"
#include <assert.h>                     // for assert
#include <stdio.h>
#include <stddef.h>                     // for size_t, NULL
#include <stdlib.h>                     // for free, malloc, realloc
#include <algorithm>                    // for min
#include "base/logging.h"

using std::min;


// Fill a buffer of the specified size with a predetermined pattern
static void Fill(unsigned char* buffer, int n) {
  for (int i = 0; i < n; i++) {
    buffer[i] = (i & 0xff);
  }
}

// Check that the specified buffer has the predetermined pattern
// generated by Fill()
static bool Valid(unsigned char* buffer, int n) {
  for (int i = 0; i < n; i++) {
    if (buffer[i] != (i & 0xff)) {
      return false;
    }
  }
  return true;
}

// Return the next interesting size/delta to check.  Returns -1 if no more.
static int NextSize(int size) {
  if (size < 100) {
    return size+1;
  } else if (size < 100000) {
    // Find next power of two
    int power = 1;
    while (power < size) {
      power <<= 1;
    }

    // Yield (power-1, power, power+1)
    if (size < power-1) {
      return power-1;
    } else if (size == power-1) {
      return power;
    } else {
      assert(size == power);
      return power+1;
    }
  } else {
    return -1;
  }
}

int main(int argc, char** argv) {
  for (int src_size = 0; src_size >= 0; src_size = NextSize(src_size)) {
    for (int dst_size = 0; dst_size >= 0; dst_size = NextSize(dst_size)) {
      unsigned char* src = (unsigned char*) malloc(src_size);
      Fill(src, src_size);
      unsigned char* dst = (unsigned char*) realloc(src, dst_size);
      CHECK(Valid(dst, min(src_size, dst_size)));
      Fill(dst, dst_size);
      CHECK(Valid(dst, dst_size));
      if (dst != NULL) free(dst);
    }
  }

  // Now make sure realloc works correctly even when we overflow the
  // packed cache, so some entries are evicted from the cache.
  // The cache has 2^12 entries, keyed by page number.
  const int kNumEntries = 1 << 14;
  int** p = (int**)malloc(sizeof(*p) * kNumEntries);
  int sum = 0;
  for (int i = 0; i < kNumEntries; i++) {
    p[i] = (int*)malloc(8192);   // no page size is likely to be bigger
    p[i][1000] = i;              // use memory deep in the heart of p
  }
  for (int i = 0; i < kNumEntries; i++) {
    p[i] = (int*)realloc(p[i], 9000);
  }
  for (int i = 0; i < kNumEntries; i++) {
    sum += p[i][1000];
    free(p[i]);
  }
  CHECK_EQ(kNumEntries/2 * (kNumEntries - 1), sum);  // assume kNE is even
  free(p);

  printf("PASS\n");
  return 0;
}