Files
nearby/internal/platform/byte_utils.cc
T
hai007 e458d6afaa This fixes a discrepancy between the C++ and Java version of the ToFourDigitString() function, given byte array inputs that include negative signed byte values.
Added a unit test to verify that the output with negative signed bytes in the input will result in the same output as the Java version.

PiperOrigin-RevId: 712709020
2025-01-06 17:58:35 -08:00

41 lines
1.3 KiB
C++

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "internal/platform/byte_utils.h"
#include <cstdint>
#include <cstdlib>
#include <string>
#include "absl/strings/str_format.h"
#include "internal/platform/base_input_stream.h"
#include "internal/platform/byte_array.h"
namespace nearby {
std::string ByteUtils::ToFourDigitString(ByteArray& bytes) {
int multiplier = 1;
int hashCode = 0;
BaseInputStream base_input_stream{bytes};
while (base_input_stream.IsAvailable(1)) {
auto byte = static_cast<int8_t>(base_input_stream.ReadUint8());
hashCode = (hashCode + byte * multiplier) % kHashBasePrime;
multiplier = multiplier * kHashBaseMultiplier % kHashBasePrime;
}
return absl::StrFormat("%04d", abs(hashCode));
}
} // namespace nearby