llvm-6502/lib/Support/StringExtras.cpp
Chris Lattner d5b58c239e Add a helper function
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31981 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-28 22:32:35 +00:00

109 lines
3.8 KiB
C++

//===-- StringExtras.cpp - Implement the StringExtras header --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and 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/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 Source source string is updated in place to remove the returned string
/// and any delimiter prefix from it.
std::string llvm::getToken(std::string &Source, const char *Delimiters) {
unsigned NumDelimiters = std::strlen(Delimiters);
// Figure out where the token starts.
std::string::size_type Start =
Source.find_first_not_of(Delimiters, 0, NumDelimiters);
if (Start == std::string::npos) Start = Source.size();
// Find the next occurance of the delimiter.
std::string::size_type End =
Source.find_first_of(Delimiters, Start, NumDelimiters);
if (End == std::string::npos) End = Source.size();
// Create the return token.
std::string Result = std::string(Source.begin()+Start, Source.begin()+End);
// Erase the token that we read in.
Source.erase(Source.begin(), Source.begin()+End);
return Result;
}
/// SplitString - Split up the specified string according to the specified
/// delimiters, appending the result fragments to the output list.
void llvm::SplitString(const std::string &Source,
std::vector<std::string> &OutFragments,
const char *Delimiters) {
std::string S = Source;
std::string S2 = getToken(S, Delimiters);
while (!S2.empty()) {
OutFragments.push_back(S2);
S2 = getToken(S, Delimiters);
}
}
/// UnescapeString - Modify the argument string, turning two character sequences
/// like '\\' 'n' into '\n'. This handles: \e \a \b \f \n \r \t \v \' \\ and
/// \num (where num is a 1-3 byte octal value).
void llvm::UnescapeString(std::string &Str) {
for (unsigned i = 0; i != Str.size(); ++i) {
if (Str[i] == '\\' && i != Str.size()-1) {
switch (Str[i+1]) {
default: continue; // Don't execute the code after the switch.
case 'a': Str[i] = '\a'; break;
case 'b': Str[i] = '\b'; break;
case 'e': Str[i] = 27; break;
case 'f': Str[i] = '\f'; break;
case 'n': Str[i] = '\n'; break;
case 'r': Str[i] = '\r'; break;
case 't': Str[i] = '\t'; break;
case 'v': Str[i] = '\v'; break;
case '\'': Str[i] = '\''; break;
case '\\': Str[i] = '\\'; break;
}
// Nuke the second character.
Str.erase(Str.begin()+i+1);
}
}
}
/// EscapeString - Modify the argument string, turning '\\' and anything that
/// doesn't satisfy std::isprint into an escape sequence.
void llvm::EscapeString(std::string &Str) {
for (unsigned i = 0; i != Str.size(); ++i) {
if (Str[i] == '\\') {
++i;
Str.insert(Str.begin()+i, '\\');
} else if (Str[i] == '\t') {
Str[i++] = '\\';
Str.insert(Str.begin()+i, 't');
} else if (Str[i] == '\n') {
Str[i++] = '\\';
Str.insert(Str.begin()+i, 'n');
} else if (!std::isprint(Str[i])) {
// Always expand to a 3-digit octal escape.
unsigned Char = Str[i];
Str[i++] = '\\';
Str.insert(Str.begin()+i++, '0'+((Char/64) & 7));
Str.insert(Str.begin()+i++, '0'+((Char/8) & 7));
Str.insert(Str.begin()+i , '0'+( Char & 7));
}
}
}