storageutil: move metadata parsing and packing from revlog (API)
Parsing and writing of revision text metadata is likely identical
across storage backends. Let's move the code out of revlog so we
don't need to import the revlog module in order to use it.
Differential Revision: https://phab.mercurial-scm.org/D4754
#include "fuzzutil.h"
#include <cstring>
#include <utility>
contrib::optional<two_inputs> SplitInputs(const uint8_t *Data, size_t Size)
{
if (!Size) {
return contrib::nullopt;
}
// figure out a random point in [0, Size] to split our input.
size_t left_size = (Data[0] / 255.0) * (Size - 1);
// Copy inputs to new allocations so if bdiff over-reads
// AddressSanitizer can detect it.
std::unique_ptr<char[]> left(new char[left_size]);
std::memcpy(left.get(), Data + 1, left_size);
// right starts at the next byte after left ends
size_t right_size = Size - (left_size + 1);
std::unique_ptr<char[]> right(new char[right_size]);
std::memcpy(right.get(), Data + 1 + left_size, right_size);
LOG(2) << "inputs are " << left_size << " and " << right_size
<< " bytes" << std::endl;
two_inputs result = {std::move(right), right_size, std::move(left),
left_size};
return result;
}