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      1 //===-- StringExtras.cpp - Implement the StringExtras header --------------===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file implements the StringExtras.h header
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #include "llvm/ADT/StringExtras.h"
     14 #include "llvm/ADT/SmallVector.h"
     15 #include "llvm/Support/raw_ostream.h"
     16 #include <cctype>
     17 
     18 using namespace llvm;
     19 
     20 /// StrInStrNoCase - Portable version of strcasestr.  Locates the first
     21 /// occurrence of string 's1' in string 's2', ignoring case.  Returns
     22 /// the offset of s2 in s1 or npos if s2 cannot be found.
     23 StringRef::size_type llvm::StrInStrNoCase(StringRef s1, StringRef s2) {
     24   size_t N = s2.size(), M = s1.size();
     25   if (N > M)
     26     return StringRef::npos;
     27   for (size_t i = 0, e = M - N + 1; i != e; ++i)
     28     if (s1.substr(i, N).equals_lower(s2))
     29       return i;
     30   return StringRef::npos;
     31 }
     32 
     33 /// getToken - This function extracts one token from source, ignoring any
     34 /// leading characters that appear in the Delimiters string, and ending the
     35 /// token at any of the characters that appear in the Delimiters string.  If
     36 /// there are no tokens in the source string, an empty string is returned.
     37 /// The function returns a pair containing the extracted token and the
     38 /// remaining tail string.
     39 std::pair<StringRef, StringRef> llvm::getToken(StringRef Source,
     40                                                StringRef Delimiters) {
     41   // Figure out where the token starts.
     42   StringRef::size_type Start = Source.find_first_not_of(Delimiters);
     43 
     44   // Find the next occurrence of the delimiter.
     45   StringRef::size_type End = Source.find_first_of(Delimiters, Start);
     46 
     47   return std::make_pair(Source.slice(Start, End), Source.substr(End));
     48 }
     49 
     50 /// SplitString - Split up the specified string according to the specified
     51 /// delimiters, appending the result fragments to the output list.
     52 void llvm::SplitString(StringRef Source,
     53                        SmallVectorImpl<StringRef> &OutFragments,
     54                        StringRef Delimiters) {
     55   std::pair<StringRef, StringRef> S = getToken(Source, Delimiters);
     56   while (!S.first.empty()) {
     57     OutFragments.push_back(S.first);
     58     S = getToken(S.second, Delimiters);
     59   }
     60 }
     61 
     62 void llvm::printEscapedString(StringRef Name, raw_ostream &Out) {
     63   for (unsigned i = 0, e = Name.size(); i != e; ++i) {
     64     unsigned char C = Name[i];
     65     if (C == '\\')
     66       Out << '\\' << C;
     67     else if (isPrint(C) && C != '"')
     68       Out << C;
     69     else
     70       Out << '\\' << hexdigit(C >> 4) << hexdigit(C & 0x0F);
     71   }
     72 }
     73 
     74 void llvm::printHTMLEscaped(StringRef String, raw_ostream &Out) {
     75   for (char C : String) {
     76     if (C == '&')
     77       Out << "&amp;";
     78     else if (C == '<')
     79       Out << "&lt;";
     80     else if (C == '>')
     81       Out << "&gt;";
     82     else if (C == '\"')
     83       Out << "&quot;";
     84     else if (C == '\'')
     85       Out << "&apos;";
     86     else
     87       Out << C;
     88   }
     89 }
     90 
     91 void llvm::printLowerCase(StringRef String, raw_ostream &Out) {
     92   for (const char C : String)
     93     Out << toLower(C);
     94 }
     95 
     96 std::string llvm::convertToSnakeFromCamelCase(StringRef input) {
     97   if (input.empty())
     98     return "";
     99 
    100   std::string snakeCase;
    101   snakeCase.reserve(input.size());
    102   for (char c : input) {
    103     if (!std::isupper(c)) {
    104       snakeCase.push_back(c);
    105       continue;
    106     }
    107 
    108     if (!snakeCase.empty() && snakeCase.back() != '_')
    109       snakeCase.push_back('_');
    110     snakeCase.push_back(llvm::toLower(c));
    111   }
    112   return snakeCase;
    113 }
    114 
    115 std::string llvm::convertToCamelFromSnakeCase(StringRef input,
    116                                               bool capitalizeFirst) {
    117   if (input.empty())
    118     return "";
    119 
    120   std::string output;
    121   output.reserve(input.size());
    122 
    123   // Push the first character, capatilizing if necessary.
    124   if (capitalizeFirst && std::islower(input.front()))
    125     output.push_back(llvm::toUpper(input.front()));
    126   else
    127     output.push_back(input.front());
    128 
    129   // Walk the input converting any `*_[a-z]` snake case into `*[A-Z]` camelCase.
    130   for (size_t pos = 1, e = input.size(); pos < e; ++pos) {
    131     if (input[pos] == '_' && pos != (e - 1) && std::islower(input[pos + 1]))
    132       output.push_back(llvm::toUpper(input[++pos]));
    133     else
    134       output.push_back(input[pos]);
    135   }
    136   return output;
    137 }
    138