gecko/mfbt/tests/TestBloomFilter.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 <stddef.h>
#include <stdio.h>
using mozilla::BloomFilter;
class FilterChecker
{
public:
FilterChecker(uint32_t hash) : mHash(hash) { }
uint32_t hash() const { return mHash; }
private:
uint32_t mHash;
};
int
main()
{
BloomFilter<12, FilterChecker> *filter = new BloomFilter<12, FilterChecker>();
MOZ_ASSERT(filter);
FilterChecker one(1);
FilterChecker two(0x20000);
FilterChecker many(0x10000);
FilterChecker multiple(0x20001);
filter->add(&one);
MOZ_ASSERT(filter->mightContain(&one),
"Filter should contain 'one'");
MOZ_ASSERT(!filter->mightContain(&multiple),
"Filter claims to contain 'multiple' when it should not");
MOZ_ASSERT(filter->mightContain(&many),
"Filter should contain 'many' (false positive)");
filter->add(&two);
MOZ_ASSERT(filter->mightContain(&multiple),
"Filter should contain 'multiple' (false positive)");
// Test basic removals
filter->remove(&two);
MOZ_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_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_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_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_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_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_ASSERT(!filter->mightContain(&one),
"Filter should not contain 'one', because we didn't overflow its "
"bucket");
filter->clear();
MOZ_ASSERT(!filter->mightContain(&multiple),
"clear() failed to work");
return 0;
}