bitcoin/src/test/fuzz/util.h

// Copyright (c) 2009-2019 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_TEST_FUZZ_UTIL_H
#define BITCOIN_TEST_FUZZ_UTIL_H

#include <amount.h>
#include <attributes.h>
#include <optional.h>
#include <script/script.h>
#include <serialize.h>
#include <streams.h>
#include <test/fuzz/FuzzedDataProvider.h>
#include <test/fuzz/fuzz.h>
#include <version.h>

#include <cstdint>
#include <string>
#include <vector>

NODISCARD inline std::vector<uint8_t> ConsumeRandomLengthByteVector(FuzzedDataProvider& fuzzed_data_provider, size_t max_length = 4096) noexcept
{
    const std::string s = fuzzed_data_provider.ConsumeRandomLengthString(max_length);
    return {s.begin(), s.end()};
}

template <typename T>
NODISCARD inline Optional<T> ConsumeDeserializable(FuzzedDataProvider& fuzzed_data_provider, size_t max_length = 4096) noexcept
{
    const std::vector<uint8_t> buffer = ConsumeRandomLengthByteVector(fuzzed_data_provider, max_length);
    CDataStream ds{buffer, SER_NETWORK, INIT_PROTO_VERSION};
    T obj;
    try {
        ds >> obj;
    } catch (const std::ios_base::failure&) {
        return nullopt;
    }
    return obj;
}

NODISCARD inline opcodetype ConsumeOpcodeType(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
    return static_cast<opcodetype>(fuzzed_data_provider.ConsumeIntegralInRange<uint32_t>(0, MAX_OPCODE));
}

NODISCARD inline CAmount ConsumeMoney(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
    return fuzzed_data_provider.ConsumeIntegralInRange<CAmount>(0, MAX_MONEY);
}

NODISCARD inline CScript ConsumeScript(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
    const std::vector<uint8_t> b = ConsumeRandomLengthByteVector(fuzzed_data_provider);
    return {b.begin(), b.end()};
}

NODISCARD inline CScriptNum ConsumeScriptNum(FuzzedDataProvider& fuzzed_data_provider) noexcept
{
    return CScriptNum{fuzzed_data_provider.ConsumeIntegral<int64_t>()};
}

template <typename T>
bool MultiplicationOverflow(T i, T j)
{
    static_assert(std::is_integral<T>::value, "Integral required.");
    if (std::numeric_limits<T>::is_signed) {
        if (i > 0) {
            if (j > 0) {
                return i > (std::numeric_limits<T>::max() / j);
            } else {
                return j < (std::numeric_limits<T>::min() / i);
            }
        } else {
            if (j > 0) {
                return i < (std::numeric_limits<T>::min() / j);
            } else {
                return i != 0 && (j < (std::numeric_limits<T>::max() / i));
            }
        }
    } else {
        return j != 0 && i > std::numeric_limits<T>::max() / j;
    }
}

#endif // BITCOIN_TEST_FUZZ_UTIL_H