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// Copyright (c) The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <span.h>
#include <test/fuzz/util.h>
#include <test/util/xoroshiro128plusplus.h>
#include <util/bitset.h>
#include <bitset>
#include <vector>
namespace {
/** Pop the first byte from a Span<const uint8_t>, and return it. */
uint8_t ReadByte(Span<const uint8_t>& buffer)
{
if (buffer.empty()) return 0;
uint8_t ret = buffer.front();
buffer = buffer.subspan(1);
return ret;
}
/** Perform a simulation fuzz test on BitSet type S. */
template<typename S>
void TestType(Span<const uint8_t> buffer)
{
/** This fuzz test's design is based on the assumption that the actual bits stored in the
* bitsets and their simulations do not matter for the purpose of detecting edge cases, thus
* these are taken from a deterministically-seeded RNG instead. To provide some level of
* variation however, pick the seed based on the buffer size and size of the chosen bitset. */
XoRoShiRo128PlusPlus rng(buffer.size() + 0x10000 * S::Size());
using Sim = std::bitset<S::Size()>;
// Up to 4 real BitSets (initially 2).
std::vector<S> real(2);
// Up to 4 std::bitsets with the same corresponding contents.
std::vector<Sim> sim(2);
/* Compare sim[idx] with real[idx], using all inspector operations. */
auto compare_fn = [&](unsigned idx) {
/* iterators and operator[] */
auto it = real[idx].begin();
unsigned first = S::Size();
unsigned last = S::Size();
for (unsigned i = 0; i < S::Size(); ++i) {
bool match = (it != real[idx].end()) && *it == i;
assert(sim[idx][i] == real[idx][i]);
assert(match == real[idx][i]);
assert((it == real[idx].end()) != (it != real[idx].end()));
if (match) {
++it;
if (first == S::Size()) first = i;
last = i;
}
}
assert(it == real[idx].end());
assert(!(it != real[idx].end()));
/* Any / None */
assert(sim[idx].any() == real[idx].Any());
assert(sim[idx].none() == real[idx].None());
/* First / Last */
if (sim[idx].any()) {
assert(first == real[idx].First());
assert(last == real[idx].Last());
}
/* Count */
assert(sim[idx].count() == real[idx].Count());
};
LIMITED_WHILE(buffer.size() > 0, 1000) {
// Read one byte to determine which operation to execute on the BitSets.
int command = ReadByte(buffer) % 64;
// Read another byte that determines which bitsets will be involved.
unsigned args = ReadByte(buffer);
unsigned dest = ((args & 7) * sim.size()) >> 3;
unsigned src = (((args >> 3) & 7) * sim.size()) >> 3;
unsigned aux = (((args >> 6) & 3) * sim.size()) >> 2;
// Args are in range for non-empty sim, or sim is completely empty and will be grown
assert((sim.empty() && dest == 0 && src == 0 && aux == 0) ||
(!sim.empty() && dest < sim.size() && src < sim.size() && aux < sim.size()));
// Pick one operation based on value of command. Not all operations are always applicable.
// Loop through the applicable ones until command reaches 0 (which avoids the need to
// compute the number of applicable commands ahead of time).
while (true) {
if (dest < sim.size() && command-- == 0) {
/* Set() (true) */
unsigned val = ReadByte(buffer) % S::Size();
assert(sim[dest][val] == real[dest][val]);
sim[dest].set(val);
real[dest].Set(val);
break;
} else if (dest < sim.size() && command-- == 0) {
/* Reset() */
unsigned val = ReadByte(buffer) % S::Size();
assert(sim[dest][val] == real[dest][val]);
sim[dest].reset(val);
real[dest].Reset(val);
break;
} else if (dest < sim.size() && command-- == 0) {
/* Set() (conditional) */
unsigned val = ReadByte(buffer) % S::Size();
assert(sim[dest][val] == real[dest][val]);
sim[dest].set(val, args >> 7);
real[dest].Set(val, args >> 7);
break;
} else if (sim.size() < 4 && command-- == 0) {
/* Construct empty. */
sim.resize(sim.size() + 1);
real.resize(real.size() + 1);
break;
} else if (sim.size() < 4 && command-- == 0) {
/* Construct singleton. */
unsigned val = ReadByte(buffer) % S::Size();
std::bitset<S::Size()> newset;
newset[val] = true;
sim.push_back(newset);
real.push_back(S::Singleton(val));
break;
} else if (dest < sim.size() && command-- == 0) {
/* Make random. */
compare_fn(dest);
sim[dest].reset();
real[dest] = S{};
for (unsigned i = 0; i < S::Size(); ++i) {
if (rng() & 1) {
sim[dest][i] = true;
real[dest].Set(i);
}
}
break;
} else if (dest < sim.size() && command-- == 0) {
/* Assign initializer list. */
unsigned r1 = rng() % S::Size();
unsigned r2 = rng() % S::Size();
unsigned r3 = rng() % S::Size();
compare_fn(dest);
sim[dest].reset();
real[dest] = {r1, r2, r3};
sim[dest].set(r1);
sim[dest].set(r2);
sim[dest].set(r3);
break;
} else if (!sim.empty() && command-- == 0) {
/* Destruct. */
compare_fn(sim.size() - 1);
sim.pop_back();
real.pop_back();
break;
} else if (sim.size() < 4 && src < sim.size() && command-- == 0) {
/* Copy construct. */
sim.emplace_back(sim[src]);
real.emplace_back(real[src]);
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* Copy assign. */
compare_fn(dest);
sim[dest] = sim[src];
real[dest] = real[src];
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* swap() function. */
swap(sim[dest], sim[src]);
swap(real[dest], real[src]);
break;
} else if (sim.size() < 4 && command-- == 0) {
/* Construct with initializer list. */
unsigned r1 = rng() % S::Size();
unsigned r2 = rng() % S::Size();
sim.emplace_back();
sim.back().set(r1);
sim.back().set(r2);
real.push_back(S{r1, r2});
break;
} else if (dest < sim.size() && command-- == 0) {
/* Fill() + copy assign. */
unsigned len = ReadByte(buffer) % S::Size();
compare_fn(dest);
sim[dest].reset();
for (unsigned i = 0; i < len; ++i) sim[dest][i] = true;
real[dest] = S::Fill(len);
break;
} else if (src < sim.size() && command-- == 0) {
/* Iterator copy based compare. */
unsigned val = ReadByte(buffer) % S::Size();
/* In a first loop, compare begin..end, and copy to it_copy at some point. */
auto it = real[src].begin(), it_copy = it;
for (unsigned i = 0; i < S::Size(); ++i) {
if (i == val) it_copy = it;
bool match = (it != real[src].end()) && *it == i;
assert(match == sim[src][i]);
if (match) ++it;
}
assert(it == real[src].end());
/* Then compare from the copied point again to end. */
for (unsigned i = val; i < S::Size(); ++i) {
bool match = (it_copy != real[src].end()) && *it_copy == i;
assert(match == sim[src][i]);
if (match) ++it_copy;
}
assert(it_copy == real[src].end());
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* operator|= */
compare_fn(dest);
sim[dest] |= sim[src];
real[dest] |= real[src];
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* operator&= */
compare_fn(dest);
sim[dest] &= sim[src];
real[dest] &= real[src];
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* operator-= */
compare_fn(dest);
sim[dest] &= ~sim[src];
real[dest] -= real[src];
break;
} else if (src < sim.size() && dest < sim.size() && command-- == 0) {
/* operator^= */
compare_fn(dest);
sim[dest] ^= sim[src];
real[dest] ^= real[src];
break;
} else if (src < sim.size() && dest < sim.size() && aux < sim.size() && command-- == 0) {
/* operator| */
compare_fn(dest);
sim[dest] = sim[src] | sim[aux];
real[dest] = real[src] | real[aux];
break;
} else if (src < sim.size() && dest < sim.size() && aux < sim.size() && command-- == 0) {
/* operator& */
compare_fn(dest);
sim[dest] = sim[src] & sim[aux];
real[dest] = real[src] & real[aux];
break;
} else if (src < sim.size() && dest < sim.size() && aux < sim.size() && command-- == 0) {
/* operator- */
compare_fn(dest);
sim[dest] = sim[src] & ~sim[aux];
real[dest] = real[src] - real[aux];
break;
} else if (src < sim.size() && dest < sim.size() && aux < sim.size() && command-- == 0) {
/* operator^ */
compare_fn(dest);
sim[dest] = sim[src] ^ sim[aux];
real[dest] = real[src] ^ real[aux];
break;
} else if (src < sim.size() && aux < sim.size() && command-- == 0) {
/* IsSupersetOf() and IsSubsetOf() */
bool is_superset = (sim[aux] & ~sim[src]).none();
bool is_subset = (sim[src] & ~sim[aux]).none();
assert(real[src].IsSupersetOf(real[aux]) == is_superset);
assert(real[src].IsSubsetOf(real[aux]) == is_subset);
assert(real[aux].IsSupersetOf(real[src]) == is_subset);
assert(real[aux].IsSubsetOf(real[src]) == is_superset);
break;
} else if (src < sim.size() && aux < sim.size() && command-- == 0) {
/* operator== and operator!= */
assert((sim[src] == sim[aux]) == (real[src] == real[aux]));
assert((sim[src] != sim[aux]) == (real[src] != real[aux]));
break;
} else if (src < sim.size() && aux < sim.size() && command-- == 0) {
/* Overlaps() */
assert((sim[src] & sim[aux]).any() == real[src].Overlaps(real[aux]));
assert((sim[src] & sim[aux]).any() == real[aux].Overlaps(real[src]));
break;
}
}
}
/* Fully compare the final state. */
for (unsigned i = 0; i < sim.size(); ++i) {
compare_fn(i);
}
}
} // namespace
FUZZ_TARGET(bitset)
{
unsigned typdat = ReadByte(buffer) % 8;
if (typdat == 0) {
/* 16 bits */
TestType<bitset_detail::IntBitSet<uint16_t>>(buffer);
TestType<bitset_detail::MultiIntBitSet<uint16_t, 1>>(buffer);
} else if (typdat == 1) {
/* 32 bits */
TestType<bitset_detail::MultiIntBitSet<uint16_t, 2>>(buffer);
TestType<bitset_detail::IntBitSet<uint32_t>>(buffer);
} else if (typdat == 2) {
/* 48 bits */
TestType<bitset_detail::MultiIntBitSet<uint16_t, 3>>(buffer);
} else if (typdat == 3) {
/* 64 bits */
TestType<bitset_detail::IntBitSet<uint64_t>>(buffer);
TestType<bitset_detail::MultiIntBitSet<uint64_t, 1>>(buffer);
TestType<bitset_detail::MultiIntBitSet<uint32_t, 2>>(buffer);
TestType<bitset_detail::MultiIntBitSet<uint16_t, 4>>(buffer);
} else if (typdat == 4) {
/* 96 bits */
TestType<bitset_detail::MultiIntBitSet<uint32_t, 3>>(buffer);
} else if (typdat == 5) {
/* 128 bits */
TestType<bitset_detail::MultiIntBitSet<uint64_t, 2>>(buffer);
TestType<bitset_detail::MultiIntBitSet<uint32_t, 4>>(buffer);
} else if (typdat == 6) {
/* 192 bits */
TestType<bitset_detail::MultiIntBitSet<uint64_t, 3>>(buffer);
} else if (typdat == 7) {
/* 256 bits */
TestType<bitset_detail::MultiIntBitSet<uint64_t, 4>>(buffer);
}
}
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