lib/Support/StringExtras.cpp

   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"
  17 using namespace llvm;
  18
  19 /// StrInStrNoCase - Portable version of strcasestr.  Locates the first
  20 /// occurrence of string 's1' in string 's2', ignoring case.  Returns
  21 /// the offset of s2 in s1 or npos if s2 cannot be found.
  22 StringRef::size_type llvm::StrInStrNoCase(StringRef s1, StringRef s2) {
  23   size_t N = s2.size(), M = s1.size();
  24   if (N > M)
  25     return StringRef::npos;
  26   for (size_t i = 0, e = M - N + 1; i != e; ++i)
  27     if (s1.substr(i, N).equals_lower(s2))
  28       return i;
  29   return StringRef::npos;
  30 }
  31
  32 /// getToken - This function extracts one token from source, ignoring any
  33 /// leading characters that appear in the Delimiters string, and ending the
  34 /// token at any of the characters that appear in the Delimiters string.  If
  35 /// there are no tokens in the source string, an empty string is returned.
  36 /// The function returns a pair containing the extracted token and the
  37 /// remaining tail string.
  38 std::pair<StringRef, StringRef> llvm::getToken(StringRef Source,
  39                                                StringRef Delimiters) {
  40   // Figure out where the token starts.
  41   StringRef::size_type Start = Source.find_first_not_of(Delimiters);
  42
  43   // Find the next occurrence of the delimiter.
  44   StringRef::size_type End = Source.find_first_of(Delimiters, Start);
  45
  46   return std::make_pair(Source.slice(Start, End), Source.substr(End));
  47 }
  48
  49 /// SplitString - Split up the specified string according to the specified
  50 /// delimiters, appending the result fragments to the output list.
  51 void llvm::SplitString(StringRef Source,
  52                        SmallVectorImpl<StringRef> &OutFragments,
  53                        StringRef Delimiters) {
  54   StringRef S2, S;
  55   tie(S2, S) = getToken(Source, Delimiters);
  56   while (!S2.empty()) {
  57     OutFragments.push_back(S2);
  58     tie(S2, S) = getToken(S, Delimiters);
  59   }
  60 }
  61
  62 void llvm::StringRef::split(SmallVectorImpl<StringRef> &A,
  63                             StringRef Separators, int MaxSplit,
  64                             bool KeepEmpty) const {
  65   StringRef rest = *this;
  66
  67   // rest.data() is used to distinguish cases like "a," that splits into
  68   // "a" + "" and "a" that splits into "a" + 0.
  69   for (int splits = 0;
  70        rest.data() != NULL && (MaxSplit < 0 || splits < MaxSplit);
  71        ++splits) {
  72     std::pair<llvm::StringRef, llvm::StringRef> p = rest.split(Separators);
  73
  74     if (p.first.size() != 0 || KeepEmpty)
  75       A.push_back(p.first);
  76     rest = p.second;
  77   }
  78   // If we have a tail left, add it.
  79   if (rest.data() != NULL && (rest.size() != 0 || KeepEmpty))
  80     A.push_back(rest);
  81 }