mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-14 14:46:12 -04:00
210 lines
6.6 KiB
C++
210 lines
6.6 KiB
C++
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "internal/platform/uuid.h"
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#include <array>
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#include <cstdint>
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#include <iomanip>
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#include <ios>
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#include <optional>
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#include <ostream>
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#include <sstream>
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#include <string>
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#include <vector>
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#include "absl/strings/numbers.h"
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#include "absl/strings/str_cat.h"
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#include "absl/strings/str_split.h"
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#include "absl/strings/string_view.h"
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#include "internal/platform/byte_array.h"
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#include <openssl/base.h>
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#include <openssl/digest.h>
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namespace nearby {
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namespace {
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// The most significant bits and the least significant bits or Bluetooth Base
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// UUID.
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// See Bluetooth Core Specification 6.0 Vol.3, Part B, Section 2.5.1
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const std::uint64_t kBluetoothBaseUuidMsb = 0x0000000000001000;
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const std::uint64_t kBluetoothBaseUuidLsb = 0x800000805F9B34FB;
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// Mask for UUID16 bits.
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const std::uint64_t kBluetoothBaseUuid16MsbMask = 0x0000FFFF00000000;
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std::ostream& write_hex(std::ostream& os, absl::string_view data) {
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for (const auto b : data) {
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os << std::setfill('0') << std::setw(2) << std::hex << std::uppercase
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<< (static_cast<unsigned int>(b) & 0x0ff);
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}
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return os;
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}
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ByteArray Hash(absl::string_view input, const EVP_MD* algo) {
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unsigned int md_out_size = EVP_MAX_MD_SIZE;
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uint8_t digest_buffer[EVP_MAX_MD_SIZE];
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if (input.empty()) return {};
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if (!EVP_Digest(input.data(), input.size(), digest_buffer, &md_out_size, algo,
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nullptr))
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return {};
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return ByteArray{reinterpret_cast<char*>(digest_buffer), md_out_size};
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}
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ByteArray Md5(absl::string_view input) { return Hash(input, EVP_md5()); }
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} // namespace
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// Based on the Java implementation
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// http://androidxref.com/8.0.0_r4/xref/libcore/ojluni/src/main/java/java/util/UUID.java#191
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std::optional<Uuid> Uuid::FromString(absl::string_view data) {
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std::vector<std::string> components = absl::StrSplit(data, '-');
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if (components.size() != 5) {
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return std::nullopt;
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}
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for (std::string& component : components) {
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component = absl::StrCat("0x", component);
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}
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int64_t most_sig_bits = 0L;
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int64_t least_sig_bits = 0L;
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int64_t temp;
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if (!absl::SimpleHexAtoi(components[0], &temp)) {
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return std::nullopt;
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}
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most_sig_bits = temp;
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most_sig_bits <<= 16;
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if (!absl::SimpleHexAtoi(components[1], &temp)) {
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return std::nullopt;
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}
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most_sig_bits |= temp;
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most_sig_bits <<= 16;
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if (!absl::SimpleHexAtoi(components[2], &temp)) {
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return std::nullopt;
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}
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most_sig_bits |= temp;
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if (!absl::SimpleHexAtoi(components[3], &temp)) {
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return std::nullopt;
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}
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least_sig_bits = temp;
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least_sig_bits <<= 48;
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if (!absl::SimpleHexAtoi(components[4], &temp)) {
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return std::nullopt;
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}
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least_sig_bits |= temp;
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return Uuid(most_sig_bits, least_sig_bits);
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}
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Uuid::Uuid(absl::string_view data) {
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// Based on the Java counterpart at
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// http://androidxref.com/8.0.0_r4/xref/libcore/ojluni/src/main/java/java/util/UUID.java#162.
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std::string md5_data(Md5(data));
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md5_data[6] &= 0x0f; // Clear version.
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md5_data[6] |= 0x30; // Set to version 3.
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md5_data[8] &= 0x3f; // Clear variant.
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md5_data[8] |= 0x80; // Set to IETF variant.
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std::uint64_t msb = 0;
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std::uint64_t lsb = 0;
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for (int i = 0; i < 8; i++) {
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msb = (msb << 8) | (md5_data[i] & 0xff);
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}
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for (int i = 8; i < 16; i++) {
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lsb = (lsb << 8) | (md5_data[i] & 0xff);
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}
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most_sig_bits_ = msb;
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least_sig_bits_ = lsb;
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}
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Uuid::operator std::string() const { return ToCanonicalString(data()); }
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std::string Uuid::Get16BitAsString() const {
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std::ostringstream sixteen_bit_string;
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char data = static_cast<char>((most_sig_bits_ >> 40) & 0x0ff);
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write_hex(sixteen_bit_string, absl::string_view(&data, 1));
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data = static_cast<char>((most_sig_bits_ >> 32) & 0x0ff);
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write_hex(sixteen_bit_string, absl::string_view(&data, 1));
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return sixteen_bit_string.str();
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}
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std::optional<uint16_t> Uuid::GetBtUuid16() const {
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// Verify that the UUID is in valid range.
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if ((GetMostSigBits() & ~kBluetoothBaseUuid16MsbMask) !=
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kBluetoothBaseUuidMsb ||
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GetLeastSigBits() != kBluetoothBaseUuidLsb) {
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return std::nullopt;
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}
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return (GetMostSigBits() & kBluetoothBaseUuid16MsbMask) >> 32;
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}
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std::array<char, 16> Uuid::data() const {
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std::array<char, 16> data;
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data[0] = (most_sig_bits_ >> 56) & 0x0ff;
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data[1] = (most_sig_bits_ >> 48) & 0x0ff;
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data[2] = (most_sig_bits_ >> 40) & 0x0ff;
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data[3] = (most_sig_bits_ >> 32) & 0x0ff;
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data[4] = (most_sig_bits_ >> 24) & 0x0ff;
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data[5] = (most_sig_bits_ >> 16) & 0x0ff;
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data[6] = (most_sig_bits_ >> 8) & 0x0ff;
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data[7] = (most_sig_bits_ >> 0) & 0x0ff;
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data[8] = (least_sig_bits_ >> 56) & 0x0ff;
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data[9] = (least_sig_bits_ >> 48) & 0x0ff;
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data[10] = (least_sig_bits_ >> 40) & 0x0ff;
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data[11] = (least_sig_bits_ >> 32) & 0x0ff;
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data[12] = (least_sig_bits_ >> 24) & 0x0ff;
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data[13] = (least_sig_bits_ >> 16) & 0x0ff;
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data[14] = (least_sig_bits_ >> 8) & 0x0ff;
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data[15] = (least_sig_bits_ >> 0) & 0x0ff;
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return data;
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}
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std::string Uuid::ToCanonicalString(const std::array<char, 16>& data) const {
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// Based on the Java counterpart at
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// http://androidxref.com/8.0.0_r4/xref/libcore/ojluni/src/main/java/java/util/UUID.java#375.
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std::ostringstream md5_hex;
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std::string uuid_string(data.data(), data.size());
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write_hex(md5_hex, absl::string_view(&uuid_string[0], 4));
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md5_hex << "-";
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write_hex(md5_hex, absl::string_view(&uuid_string[4], 2));
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md5_hex << "-";
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write_hex(md5_hex, absl::string_view(&uuid_string[6], 2));
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md5_hex << "-";
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write_hex(md5_hex, absl::string_view(&uuid_string[8], 2));
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md5_hex << "-";
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write_hex(md5_hex, absl::string_view(&uuid_string[10], 6));
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return md5_hex.str();
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}
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bool Uuid::operator<(const Uuid& rhs) const {
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return GetMostSigBits() == rhs.GetMostSigBits()
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? GetLeastSigBits() < rhs.GetLeastSigBits()
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: GetMostSigBits() < rhs.GetLeastSigBits();
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}
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bool Uuid::operator==(const Uuid& rhs) const {
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return GetMostSigBits() == rhs.GetMostSigBits() &&
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GetLeastSigBits() == rhs.GetLeastSigBits();
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}
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bool Uuid::operator!=(const Uuid& rhs) const { return !(*this == rhs); }
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} // namespace nearby
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