contrib/fuzz/bdiff.cc

rust-dirstatemap: add unit tests

These were missing and have already proven valuable since they have found
two bugs (fixed in previous patches).

There may be other behavior to test, but this gives us a decent coverage.

Differential Revision: https://phab.mercurial-scm.org/D12524

/*
 * bdiff.cc - fuzzer harness for bdiff.c
 *
 * Copyright 2018, Google Inc.
 *
 * This software may be used and distributed according to the terms of
 * the GNU General Public License, incorporated herein by reference.
 */
#include <memory>
#include <stdlib.h>

#include "FuzzedDataProvider.h"

extern "C" {
#include "bdiff.h"

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
	return 0;
}

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
	FuzzedDataProvider provider(Data, Size);
	std::string left = provider.ConsumeRandomLengthString(Size);
	std::string right = provider.ConsumeRemainingBytesAsString();

	struct bdiff_line *a, *b;
	int an = bdiff_splitlines(left.c_str(), left.size(), &a);
	int bn = bdiff_splitlines(right.c_str(), right.size(), &b);
	struct bdiff_hunk l;
	bdiff_diff(a, an, b, bn, &l);
	free(a);
	free(b);
	bdiff_freehunks(l.next);
	return 0; // Non-zero return values are reserved for future use.
}

} // extern "C"