| // Copyright 2016 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/lib/uuid/uuid.h" |
| |
| #include <src/lib/fxl/strings/string_printf.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <zircon/syscalls.h> |
| |
| #include <string> |
| |
| namespace uuid { |
| namespace { |
| |
| inline bool IsHexDigit(char c) { |
| return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f'); |
| } |
| |
| inline bool IsLowerHexDigit(char c) { return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f'); } |
| |
| bool IsValidInternal(const std::string& guid, bool strict) { |
| constexpr size_t kUUIDLength = 36U; |
| if (guid.length() != kUUIDLength) |
| return false; |
| for (size_t i = 0; i < guid.length(); ++i) { |
| char current = guid[i]; |
| if (i == 8 || i == 13 || i == 18 || i == 23) { |
| if (current != '-') |
| return false; |
| } else { |
| if ((strict && !IsLowerHexDigit(current)) || !IsHexDigit(current)) |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| } // namespace |
| |
| std::string Generate() { |
| uint64_t bytes[2]; |
| zx_cprng_draw(bytes, sizeof(bytes)); |
| |
| // Set the UUID to version 4 as described in RFC 4122, section 4.4. |
| // The format of UUID version 4 must be xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, |
| // where y is one of [8, 9, A, B]. |
| // Clear the version bits and set the version to 4: |
| bytes[0] &= 0xffffffffffff0fffULL; |
| bytes[0] |= 0x0000000000004000ULL; |
| |
| // Set the two most significant bits (bits 6 and 7) of the |
| // clock_seq_hi_and_reserved to zero and one, respectively: |
| bytes[1] &= 0x3fffffffffffffffULL; |
| bytes[1] |= 0x8000000000000000ULL; |
| |
| return fxl::StringPrintf("%08x-%04x-%04x-%04x-%012llx", static_cast<unsigned int>(bytes[0] >> 32), |
| static_cast<unsigned int>((bytes[0] >> 16) & 0x0000ffff), |
| static_cast<unsigned int>(bytes[0] & 0x0000ffff), |
| static_cast<unsigned int>(bytes[1] >> 48), |
| bytes[1] & 0x0000ffffffffffffULL); |
| } |
| |
| bool IsValid(const std::string& guid) { return IsValidInternal(guid, false /* strict */); } |
| |
| bool IsValidOutputString(const std::string& guid) { |
| return IsValidInternal(guid, true /* strict */); |
| } |
| |
| } // namespace uuid |