xref: /llvm-project/llvm/lib/Support/StringExtras.cpp (revision d554e4409278791a30906b5de18c7f539d816c9c)
1 //===-- StringExtras.cpp - Implement the StringExtras header --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the StringExtras.h header
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/ADT/StringExtras.h"
15 #include <cstring>
16 using namespace llvm;
17 
18 /// getToken - This function extracts one token from source, ignoring any
19 /// leading characters that appear in the Delimiters string, and ending the
20 /// token at any of the characters that appear in the Delimiters string.  If
21 /// there are no tokens in the source string, an empty string is returned.
22 /// The Source source string is updated in place to remove the returned string
23 /// and any delimiter prefix from it.
24 std::string llvm::getToken(std::string &Source, const char *Delimiters) {
25   size_t NumDelimiters = std::strlen(Delimiters);
26 
27   // Figure out where the token starts.
28   std::string::size_type Start =
29     Source.find_first_not_of(Delimiters, 0, NumDelimiters);
30   if (Start == std::string::npos) Start = Source.size();
31 
32   // Find the next occurance of the delimiter.
33   std::string::size_type End =
34     Source.find_first_of(Delimiters, Start, NumDelimiters);
35   if (End == std::string::npos) End = Source.size();
36 
37   // Create the return token.
38   std::string Result = std::string(Source.begin()+Start, Source.begin()+End);
39 
40   // Erase the token that we read in.
41   Source.erase(Source.begin(), Source.begin()+End);
42 
43   return Result;
44 }
45 
46 /// SplitString - Split up the specified string according to the specified
47 /// delimiters, appending the result fragments to the output list.
48 void llvm::SplitString(const std::string &Source,
49                        std::vector<std::string> &OutFragments,
50                        const char *Delimiters) {
51   std::string S = Source;
52 
53   std::string S2 = getToken(S, Delimiters);
54   while (!S2.empty()) {
55     OutFragments.push_back(S2);
56     S2 = getToken(S, Delimiters);
57   }
58 }
59 
60 void llvm::StringRef::split(std::vector<StringRef> &A,
61                             StringRef Separators, unsigned MaxSplit,
62                             bool KeepEmpty) const {
63   StringRef rest = *this;
64 
65   for (unsigned splits = 0;
66        rest.size() != 0 && (MaxSplit < 0 || splits < MaxSplit);
67        ++splits) {
68     std::pair<llvm::StringRef, llvm::StringRef> p = rest.split(Separators);
69 
70     if (p.first.size() != 0 || KeepEmpty)
71       A.push_back(p.first);
72     rest = p.second;
73   }
74 
75   if (rest.size() != 0 || KeepEmpty)
76     A.push_back(rest);
77 }
78