TestBloomFilter.cpp

Enable keyboard shortcuts

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this file,

 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/Assertions.h"

#include "mozilla/BloomFilter.h"

#include "mozilla/UniquePtr.h"

#include <stddef.h>

#include <stdint.h>

using mozilla::BitBloomFilter;

using mozilla::CountingBloomFilter;

class FilterChecker {

 public:

  explicit FilterChecker(uint32_t aHash) : mHash(aHash) {}

  uint32_t hash() const { return mHash; }

 private:

  uint32_t mHash;

};

void testBitBloomFilter() {

  const mozilla::UniquePtr filter =

      mozilla::MakeUnique<BitBloomFilter<12, FilterChecker>>();

  MOZ_RELEASE_ASSERT(filter);

  FilterChecker one(1);

  FilterChecker two(0x20000);

  filter->add(&one);

  MOZ_RELEASE_ASSERT(filter->mightContain(&one), "Filter should contain 'one'");

  MOZ_RELEASE_ASSERT(!filter->mightContain(&two),

                     "Filter claims to contain 'two' when it should not");

  // Test multiple addition

  filter->add(&two);

  MOZ_RELEASE_ASSERT(filter->mightContain(&two),

                     "Filter should contain 'two' after 'two' is added");

  filter->add(&two);

  MOZ_RELEASE_ASSERT(filter->mightContain(&two),

                     "Filter should contain 'two' after 'two' is added again");

  filter->clear();

  MOZ_RELEASE_ASSERT(!filter->mightContain(&one), "clear() failed to work");

  MOZ_RELEASE_ASSERT(!filter->mightContain(&two), "clear() failed to work");

void testCountingBloomFilter() {

  const mozilla::UniquePtr filter =

      mozilla::MakeUnique<CountingBloomFilter<12, FilterChecker>>();

  MOZ_RELEASE_ASSERT(filter);

  FilterChecker one(1);

  FilterChecker two(0x20000);

  FilterChecker many(0x10000);

  FilterChecker multiple(0x20001);

  filter->add(&one);

  MOZ_RELEASE_ASSERT(filter->mightContain(&one), "Filter should contain 'one'");

  MOZ_RELEASE_ASSERT(!filter->mightContain(&multiple),

                     "Filter claims to contain 'multiple' when it should not");

  MOZ_RELEASE_ASSERT(filter->mightContain(&many),

                     "Filter should contain 'many' (false positive)");

  filter->add(&two);

  MOZ_RELEASE_ASSERT(filter->mightContain(&multiple),

                     "Filter should contain 'multiple' (false positive)");

  // Test basic removals

  filter->remove(&two);

  MOZ_RELEASE_ASSERT(

      !filter->mightContain(&multiple),

      "Filter claims to contain 'multiple' when it should not after two "

      "was removed");

  // Test multiple addition/removal

  const size_t FILTER_SIZE = 255;

  for (size_t i = 0; i < FILTER_SIZE - 1; ++i) {

    filter->add(&two);

  MOZ_RELEASE_ASSERT(

      filter->mightContain(&multiple),

      "Filter should contain 'multiple' after 'two' added lots of times "

      "(false positive)");

  for (size_t i = 0; i < FILTER_SIZE - 1; ++i) {

    filter->remove(&two);

  MOZ_RELEASE_ASSERT(

      !filter->mightContain(&multiple),

      "Filter claims to contain 'multiple' when it should not after two "

      "was removed lots of times");

  // Test overflowing the filter buckets

  for (size_t i = 0; i < FILTER_SIZE + 1; ++i) {

    filter->add(&two);

  MOZ_RELEASE_ASSERT(

      filter->mightContain(&multiple),

      "Filter should contain 'multiple' after 'two' added lots more "

      "times (false positive)");

  for (size_t i = 0; i < FILTER_SIZE + 1; ++i) {

    filter->remove(&two);

  MOZ_RELEASE_ASSERT(

      filter->mightContain(&multiple),

      "Filter claims to not contain 'multiple' even though we should "

      "have run out of space in the buckets (false positive)");

  MOZ_RELEASE_ASSERT(

      filter->mightContain(&two),

      "Filter claims to not contain 'two' even though we should have "

      "run out of space in the buckets (false positive)");

  filter->remove(&one);

  MOZ_RELEASE_ASSERT(

      !filter->mightContain(&one),

      "Filter should not contain 'one', because we didn't overflow its "

      "bucket");

  filter->clear();

  MOZ_RELEASE_ASSERT(!filter->mightContain(&multiple),

                     "clear() failed to work");

int main() {

  testBitBloomFilter();

  testCountingBloomFilter();

  return 0;