llvm/lib/Support/StringExtras.cpp
Benjamin Kramer d4f195999a Reimplement getToken and SplitString as "StringRef helper functions"
- getToken is modeled after StringRef::split but it can split on multiple
  separator chars and skips leading seperators.
- SplitString is a StringRef::split variant for more than 2 elements with the
  same behaviour as getToken.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93161 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-11 18:03:24 +00:00

71 lines
2.7 KiB
C++

//===-- StringExtras.cpp - Implement the StringExtras header --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the StringExtras.h header
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
/// getToken - This function extracts one token from source, ignoring any
/// leading characters that appear in the Delimiters string, and ending the
/// token at any of the characters that appear in the Delimiters string. If
/// there are no tokens in the source string, an empty string is returned.
/// The function returns a pair containing the extracted token and the
/// remaining tail string.
std::pair<StringRef, StringRef> llvm::getToken(StringRef Source,
StringRef Delimiters) {
// Figure out where the token starts.
StringRef::size_type Start = Source.find_first_not_of(Delimiters);
if (Start == StringRef::npos) Start = Source.size();
// Find the next occurrence of the delimiter.
StringRef::size_type End = Source.find_first_of(Delimiters, Start);
if (End == StringRef::npos) End = Source.size();
return std::make_pair(Source.substr(Start, End), Source.substr(End));
}
/// SplitString - Split up the specified string according to the specified
/// delimiters, appending the result fragments to the output list.
void llvm::SplitString(StringRef Source,
SmallVectorImpl<StringRef> &OutFragments,
StringRef Delimiters) {
StringRef S2, S;
tie(S2, S) = getToken(Source, Delimiters);
while (!S2.empty()) {
OutFragments.push_back(S2);
tie(S2, S) = getToken(S, Delimiters);
}
}
void llvm::StringRef::split(SmallVectorImpl<StringRef> &A,
StringRef Separators, int MaxSplit,
bool KeepEmpty) const {
StringRef rest = *this;
// rest.data() is used to distinguish cases like "a," that splits into
// "a" + "" and "a" that splits into "a" + 0.
for (int splits = 0;
rest.data() != NULL && (MaxSplit < 0 || splits < MaxSplit);
++splits) {
std::pair<llvm::StringRef, llvm::StringRef> p = rest.split(Separators);
if (p.first.size() != 0 || KeepEmpty)
A.push_back(p.first);
rest = p.second;
}
// If we have a tail left, add it.
if (rest.data() != NULL && (rest.size() != 0 || KeepEmpty))
A.push_back(rest);
}