HeartLinked commented on code in PR #242: URL: https://github.com/apache/iceberg-cpp/pull/242#discussion_r2371255523
########## src/iceberg/util/uuid_util.cc: ########## @@ -0,0 +1,207 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 + * + * http://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 "iceberg/util/uuid_util.h" + +#include <chrono> +#include <cstdint> +#include <cstring> +#include <random> +#include <string> + +#include "iceberg/result.h" +#include "iceberg/util/int128.h" +#include "iceberg/util/macros.h" + +namespace iceberg { + +std::array<uint8_t, 16> UUIDUtils::GenerateUuidV4() { + static std::random_device rd; + static std::mt19937 gen(rd()); + static std::uniform_int_distribution<uint64_t> distrib( + std::numeric_limits<uint64_t>::min(), std::numeric_limits<uint64_t>::max()); + std::array<uint8_t, 16> uuid; + + // Generate two random 64-bit integers + uint64_t high_bits = distrib(gen); + uint64_t low_bits = distrib(gen); + + // Combine them into a uint128_t + uint128_t random_128_bit_number = (static_cast<uint128_t>(high_bits) << 64) | low_bits; + + // Copy the bytes into the uuid array + std::memcpy(uuid.data(), &random_128_bit_number, 16); + + // Set magic numbers for a "version 4" (pseudorandom) UUID and variant, + // see https://datatracker.ietf.org/doc/html/rfc9562#name-uuid-version-4 + uuid[6] = (uuid[6] & 0x0F) | 0x40; + // Set variant field, top two bits are 1, 0 + uuid[8] = (uuid[8] & 0x3F) | 0x80; + + return uuid; +} + +std::array<uint8_t, 16> UUIDUtils::GenerateUuidV7() { + // Get the current time in milliseconds since the Unix epoch + auto now = std::chrono::system_clock::now(); + auto duration_since_epoch = now.time_since_epoch(); + auto unix_ts_ms = + std::chrono::duration_cast<std::chrono::milliseconds>(duration_since_epoch).count(); + + return GenerateUuidV7(static_cast<uint64_t>(unix_ts_ms)); +} + +std::array<uint8_t, 16> UUIDUtils::GenerateUuidV7(uint64_t unix_ts_ms) { + std::array<uint8_t, 16> uuid = {}; + + // Set the timestamp (in milliseconds since Unix epoch) + uuid[0] = (unix_ts_ms >> 40) & 0xFF; + uuid[1] = (unix_ts_ms >> 32) & 0xFF; + uuid[2] = (unix_ts_ms >> 24) & 0xFF; + uuid[3] = (unix_ts_ms >> 16) & 0xFF; + uuid[4] = (unix_ts_ms >> 8) & 0xFF; + uuid[5] = unix_ts_ms & 0xFF; + + // Generate random bytes for the remaining fields + static std::random_device rd; + static std::mt19937 gen(rd()); + static std::uniform_int_distribution<uint16_t> distrib( + std::numeric_limits<uint16_t>::min(), std::numeric_limits<uint16_t>::max()); + + // Note: uint8_t is invalid for uniform_int_distribution on Windows + for (size_t i = 6; i < 16; i += 2) { + auto rand = static_cast<uint16_t>(distrib(gen)); + uuid[i] = (rand >> 8) & 0xFF; + uuid[i + 1] = rand & 0xFF; + } + + // Set magic numbers for a "version 7" (pseudorandom) UUID and variant, + // see https://www.rfc-editor.org/rfc/rfc9562#name-version-field + uuid[6] = (uuid[6] & 0x0F) | 0x70; + // set variant field, top two bits are 1, 0 + uuid[8] = (uuid[8] & 0x3F) | 0x80; + + return uuid; +} + +namespace { + +constexpr std::array<uint8_t, 256> BuildHexTable() { + std::array<uint8_t, 256> buf{}; + for (int i = 0; i < 256; i++) { + if (i >= '0' && i <= '9') { + buf[i] = static_cast<uint8_t>(i - '0'); + } else if (i >= 'a' && i <= 'f') { + buf[i] = static_cast<uint8_t>(i - 'a' + 10); + } else if (i >= 'A' && i <= 'F') { + buf[i] = static_cast<uint8_t>(i - 'A' + 10); + } else { + buf[i] = 0xff; + } + } + return buf; +} + +constexpr std::array<uint8_t, 256> BuildShl4Table() { + std::array<uint8_t, 256> buf{}; + for (int i = 0; i < 256; i++) { + buf[i] = static_cast<uint8_t>(i << 4); + } + return buf; +} + +constexpr auto HEX_TABLE = BuildHexTable(); +constexpr auto SHL4_TABLE = BuildShl4Table(); + +// Parse a UUID string without dashes, e.g. "67e5504410b1426f9247bb680e5fe0c8" +inline Result<std::array<uint8_t, 16>> ParseSimple(std::string_view s) { + ICEBERG_DCHECK(s.size() == 32, "s must be 32 characters long"); + + std::array<uint8_t, 16> buf{}; + for (size_t i = 0; i < 16; i++) { + uint8_t h1 = HEX_TABLE[static_cast<uint8_t>(s[i * 2])]; + uint8_t h2 = HEX_TABLE[static_cast<uint8_t>(s[i * 2 + 1])]; + + if ((h1 | h2) == 0xff) { + return InvalidArgument("Invalid UUID string: {}", s); + } + + buf[i] = static_cast<uint8_t>(SHL4_TABLE[h1] | h2); + } + return buf; +} + +// Parse a UUID string with dashes, e.g. "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" +inline Result<std::array<uint8_t, 16>> ParseHyphenated(std::string_view s) { + ICEBERG_DCHECK(s.size() == 36, "s must be 36 characters long"); + + // Check that dashes are in the right places + if (!(s[8] == '-' && s[13] == '-' && s[18] == '-' && s[23] == '-')) { + return InvalidArgument("Invalid UUID string: {}", s); + } + + constexpr std::array<size_t, 8> positions = {0, 4, 9, 14, 19, 24, 28, 32}; + std::array<uint8_t, 16> buf{}; + + for (size_t j = 0; j < 8; j++) { + size_t i = positions[j]; + uint8_t h1 = HEX_TABLE[static_cast<uint8_t>(s[i])]; + uint8_t h2 = HEX_TABLE[static_cast<uint8_t>(s[i + 1])]; + uint8_t h3 = HEX_TABLE[static_cast<uint8_t>(s[i + 2])]; + uint8_t h4 = HEX_TABLE[static_cast<uint8_t>(s[i + 3])]; + + if ((h1 | h2 | h3 | h4) == 0xff) { + return InvalidArgument("Invalid UUID string: {}", s); + } + + buf[j * 2] = static_cast<uint8_t>(SHL4_TABLE[h1] | h2); + buf[j * 2 + 1] = static_cast<uint8_t>(SHL4_TABLE[h3] | h4); + } + + return buf; +} + +} // namespace + +Result<std::array<uint8_t, 16>> UUIDUtils::FromString(std::string_view str) { + if (str.size() == 32) { + return ParseSimple(str); + } else if (str.size() == 36) { + return ParseHyphenated(str); + } else { + return InvalidArgument("Invalid UUID string: {}", str); + } +} + +std::string UUIDUtils::ToString(std::span<uint8_t> uuid) { + static const char* hex_chars = "0123456789abcdef"; + ICEBERG_DCHECK(uuid.size() == 16, "uuid must be 16 bytes long"); + std::string str(36, '-'); + + for (size_t i = 0; i < 16; i++) { Review Comment: This can be simplified using std::format? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
