1 //===-- UUID.cpp ------------------------------------------------*- C++ -*-===//
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 
15 #include <ctype.h>
16 #include <stdio.h>
17 #include <string.h>
18 
19 using namespace lldb_private;
20 
21 // Whether to put a separator after count uuid bytes.
22 // For the first 16 bytes we follow the traditional UUID format. After that, we
23 // simply put a dash after every 6 bytes.
24 static inline bool separate(size_t count) {
25   if (count >= 10)
26     return (count - 10) % 6 == 0;
27 
28   switch (count) {
29   case 4:
30   case 6:
31   case 8:
32     return true;
33   default:
34     return false;
35   }
36 }
37 
38 std::string UUID::GetAsString(llvm::StringRef separator) const {
39   std::string result;
40   llvm::raw_string_ostream os(result);
41 
42   for (auto B : llvm::enumerate(GetBytes())) {
43     if (separate(B.index()))
44       os << separator;
45 
46     os << llvm::format_hex_no_prefix(B.value(), 2, true);
47   }
48   os.flush();
49 
50   return result;
51 }
52 
53 void UUID::Dump(Stream *s) const { s->PutCString(GetAsString()); }
54 
55 static inline int xdigit_to_int(char ch) {
56   ch = tolower(ch);
57   if (ch >= 'a' && ch <= 'f')
58     return 10 + ch - 'a';
59   return ch - '0';
60 }
61 
62 llvm::StringRef
63 UUID::DecodeUUIDBytesFromString(llvm::StringRef p,
64                                 llvm::SmallVectorImpl<uint8_t> &uuid_bytes,
65                                 uint32_t num_uuid_bytes) {
66   uuid_bytes.clear();
67   while (!p.empty()) {
68     if (isxdigit(p[0]) && isxdigit(p[1])) {
69       int hi_nibble = xdigit_to_int(p[0]);
70       int lo_nibble = xdigit_to_int(p[1]);
71       // Translate the two hex nibble characters into a byte
72       uuid_bytes.push_back((hi_nibble << 4) + lo_nibble);
73 
74       // Skip both hex digits
75       p = p.drop_front(2);
76 
77       // Increment the byte that we are decoding within the UUID value and
78       // break out if we are done
79       if (uuid_bytes.size() == num_uuid_bytes)
80         break;
81     } else if (p.front() == '-') {
82       // Skip dashes
83       p = p.drop_front();
84     } else {
85       // UUID values can only consist of hex characters and '-' chars
86       break;
87     }
88   }
89   return p;
90 }
91 
92 size_t UUID::SetFromStringRef(llvm::StringRef str, uint32_t num_uuid_bytes) {
93   llvm::StringRef p = str;
94 
95   // Skip leading whitespace characters
96   p = p.ltrim();
97 
98   llvm::SmallVector<uint8_t, 20> bytes;
99   llvm::StringRef rest =
100       UUID::DecodeUUIDBytesFromString(p, bytes, num_uuid_bytes);
101 
102   // If we successfully decoded a UUID, return the amount of characters that
103   // were consumed
104   if (bytes.size() == num_uuid_bytes) {
105     *this = fromData(bytes);
106     return str.size() - rest.size();
107   }
108 
109   // Else return zero to indicate we were not able to parse a UUID value
110   return 0;
111 }
112 
113 size_t UUID::SetFromOptionalStringRef(llvm::StringRef str,
114                                       uint32_t num_uuid_bytes) {
115   size_t num_chars_consumed = SetFromStringRef(str, num_uuid_bytes);
116   if (num_chars_consumed) {
117     if (llvm::all_of(m_bytes, [](uint8_t b) { return b == 0; }))
118         Clear();
119   }
120 
121   return num_chars_consumed;
122 }
123 
124