1//===-- UUID.cpp ----------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Utility/UUID.h"
10
11#include "lldb/Utility/Stream.h"
12#include "llvm/ADT/StringRef.h"
13#include "llvm/Support/Format.h"
14#include "llvm/Support/RandomNumberGenerator.h"
15
16#include <cctype>
17#include <chrono>
18#include <climits>
19#include <cstdint>
20#include <cstdio>
21#include <cstring>
22#include <random>
23
24using namespace lldb_private;
25
26// Whether to put a separator after count uuid bytes.
27// For the first 16 bytes we follow the traditional UUID format. After that, we
28// simply put a dash after every 6 bytes.
29static inline bool separate(size_t count) {
30 if (count >= 10)
31 return (count - 10) % 6 == 0;
32
33 switch (count) {
34 case 4:
35 case 6:
36 case 8:
37 return true;
38 default:
39 return false;
40 }
41}
42
43UUID::UUID(UUID::CvRecordPdb70 debug_info) {
44 llvm::sys::swapByteOrder(Value&: debug_info.Uuid.Data1);
45 llvm::sys::swapByteOrder(Value&: debug_info.Uuid.Data2);
46 llvm::sys::swapByteOrder(Value&: debug_info.Uuid.Data3);
47 llvm::sys::swapByteOrder(Value&: debug_info.Age);
48 if (debug_info.Age)
49 *this = UUID(&debug_info, sizeof(debug_info));
50 else
51 *this = UUID(&debug_info.Uuid, sizeof(debug_info.Uuid));
52}
53
54std::string UUID::GetAsString(llvm::StringRef separator) const {
55 std::string result;
56 llvm::raw_string_ostream os(result);
57
58 for (auto B : llvm::enumerate(First: GetBytes())) {
59 if (separate(count: B.index()))
60 os << separator;
61
62 os << llvm::format_hex_no_prefix(N: B.value(), Width: 2, Upper: true);
63 }
64
65 return result;
66}
67
68void UUID::Dump(Stream &s) const { s.PutCString(cstr: GetAsString()); }
69
70static inline int xdigit_to_int(char ch) {
71 ch = tolower(c: ch);
72 if (ch >= 'a' && ch <= 'f')
73 return 10 + ch - 'a';
74 return ch - '0';
75}
76
77llvm::StringRef
78UUID::DecodeUUIDBytesFromString(llvm::StringRef p,
79 llvm::SmallVectorImpl<uint8_t> &uuid_bytes) {
80 uuid_bytes.clear();
81 while (p.size() >= 2) {
82 if (isxdigit(p[0]) && isxdigit(p[1])) {
83 int hi_nibble = xdigit_to_int(ch: p[0]);
84 int lo_nibble = xdigit_to_int(ch: p[1]);
85 // Translate the two hex nibble characters into a byte
86 uuid_bytes.push_back(Elt: (hi_nibble << 4) + lo_nibble);
87
88 // Skip both hex digits
89 p = p.drop_front(N: 2);
90 } else if (p.front() == '-') {
91 // Skip dashes
92 p = p.drop_front();
93 } else {
94 // UUID values can only consist of hex characters and '-' chars
95 break;
96 }
97 }
98 return p;
99}
100
101bool UUID::SetFromStringRef(llvm::StringRef str) {
102 llvm::StringRef p = str;
103
104 // Skip leading whitespace characters
105 p = p.ltrim();
106
107 llvm::SmallVector<uint8_t, 20> bytes;
108 llvm::StringRef rest = UUID::DecodeUUIDBytesFromString(p, uuid_bytes&: bytes);
109
110 // Return false if we could not consume the entire string or if the parsed
111 // UUID is empty.
112 if (!rest.empty() || bytes.empty())
113 return false;
114
115 *this = UUID(bytes);
116 return true;
117}
118
119UUID UUID::Generate(uint32_t num_bytes) {
120 llvm::SmallVector<uint8_t, 20> bytes(num_bytes);
121 auto ec = llvm::getRandomBytes(Buffer: bytes.data(), Size: bytes.size());
122
123 // If getRandomBytes failed, fall back to a lower entropy source.
124 if (ec) {
125 auto seed = std::chrono::steady_clock::now().time_since_epoch().count();
126 std::independent_bits_engine<std::default_random_engine, CHAR_BIT,
127 unsigned short>
128 engine(seed);
129 std::generate(first: bytes.begin(), last: bytes.end(), gen: std::ref(t&: engine));
130 }
131
132 return UUID(bytes);
133}
134

source code of lldb/source/Utility/UUID.cpp