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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// Make sure the fuzzer eventually finds all possible values of a variable
// within a range.
#include <cassert>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <set>
const size_t N = 1 << 12;
// Define an array of counters that will be understood by libFuzzer
// as extra coverage signal. The array must be:
// * uint8_t
// * in the section named __libfuzzer_extra_counters.
// The target code may declare more than one such array.
// Use either `Counters[Idx] = 1` or `Counters[Idx]++;`
// depending on whether multiple occurrences of the event 'Idx'
// is important to distinguish from one occurrence.
#ifdef __linux__
static uint8_t Counters[N];
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
static std::set<uint16_t> SeenIdx;
if (Size != 4) return 0;
uint32_t Idx;
memcpy(&Idx, Data, 4);
Idx %= N;
assert(Counters[Idx] == 0); // libFuzzer should reset these between the runs.
// Or Counters[Idx]=1 if we don't care how many times this happened.
if (SeenIdx.size() == N) {
fprintf(stderr, "BINGO: found all values\n");
return 0;