StringExtras.cpp revision d4f195999a7774611e5f9e457a86f14d5e257324 
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/SmallVector.h"
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/StringExtras.h"
17using namespace llvm;
18
19/// getToken - This function extracts one token from source, ignoring any
20/// leading characters that appear in the Delimiters string, and ending the
21/// token at any of the characters that appear in the Delimiters string.  If
22/// there are no tokens in the source string, an empty string is returned.
23/// The function returns a pair containing the extracted token and the
24/// remaining tail string.
25std::pair<StringRef, StringRef> llvm::getToken(StringRef Source,
26                                               StringRef Delimiters) {
27  // Figure out where the token starts.
28  StringRef::size_type Start = Source.find_first_not_of(Delimiters);
29  if (Start == StringRef::npos) Start = Source.size();
30
31  // Find the next occurrence of the delimiter.
32  StringRef::size_type End = Source.find_first_of(Delimiters, Start);
33  if (End == StringRef::npos) End = Source.size();
34
35  return std::make_pair(Source.substr(Start, End), Source.substr(End));
36}
37
38/// SplitString - Split up the specified string according to the specified
39/// delimiters, appending the result fragments to the output list.
40void llvm::SplitString(StringRef Source,
41                       SmallVectorImpl<StringRef> &OutFragments,
42                       StringRef Delimiters) {
43  StringRef S2, S;
44  tie(S2, S) = getToken(Source, Delimiters);
45  while (!S2.empty()) {
46    OutFragments.push_back(S2);
47    tie(S2, S) = getToken(S, Delimiters);
48  }
49}
50
51void llvm::StringRef::split(SmallVectorImpl<StringRef> &A,
52                            StringRef Separators, int MaxSplit,
53                            bool KeepEmpty) const {
54  StringRef rest = *this;
55
56  // rest.data() is used to distinguish cases like "a," that splits into
57  // "a" + "" and "a" that splits into "a" + 0.
58  for (int splits = 0;
59       rest.data() != NULL && (MaxSplit < 0 || splits < MaxSplit);
60       ++splits) {
61    std::pair<llvm::StringRef, llvm::StringRef> p = rest.split(Separators);
62
63    if (p.first.size() != 0 || KeepEmpty)
64      A.push_back(p.first);
65    rest = p.second;
66  }
67  // If we have a tail left, add it.
68  if (rest.data() != NULL && (rest.size() != 0 || KeepEmpty))
69    A.push_back(rest);
70}
71