rust-node: handling binary Node prefix
Parallel to the inner signatures of the nodetree functions in
revlog.c, we'll have to handle prefixes of `Node` in binary
form.
Another motivation is that it allows to convert from full Node
references to `NodePrefixRef` without copy. This is expected to
be by far the most common case in practice.
There's a slight complication due to the fact that we'll be sometimes
interested in prefixes with an odd number of hexadecimal digits,
which translates in binary form by a last byte in which only the
highest weight 4 bits are considered. This is totally transparent for
callers and could be revised once we have proper means to measure
performance.
The C implementation does the same, passing the length in nybbles as
function arguments. Because Rust byte slices already have a length, we carry
the even/odd informaton as a boolean, to avoid introducing logical
redundancies and the related potential inconsistency bugs.
There are a few candidates for inlining here, but we refrain from
such premature optimizations, letting the compiler decide.
Differential Revision: https://phab.mercurial-scm.org/D7790
/*
* 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"