text: /*
   * Copyright 2017 WebAssembly Community Group participants
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #ifndef wasm_support_string_h
  #define wasm_support_string_h
  
  #include <cstring>
  
  #include "emscripten-optimizer/istring.h"
  
  namespace wasm {
  
  // We use a Name for all of the identifiers. These are IStrings, so they are
  // all interned - comparisons etc are just pointer comparisons, so there is no
  // perf loss. Having names everywhere makes using the AST much nicer (for
  // example, block names are strings and not offsets, which makes composition
  // - adding blocks, removing blocks - easy). One exception is local variables,
  // where we do use indices, as they are a large proportion of the AST,
  // perf matters a lot there, and compositionality is not a problem.
  // TODO: as an optimization, IString values < some threshold could be considered
  //       numerical indices directly.
  
  struct Name : public cashew::IString {
    Name() : cashew::IString() {}
    Name(const char* str) : cashew::IString(str, false) {}
    Name(cashew::IString str) : cashew::IString(str) {}
    Name(const std::string& str) : cashew::IString(str.c_str(), false) {}
  
    friend std::ostream& operator<<(std::ostream& o, Name name) {
      assert(name.str);
      return o << '$' << name.str; // reference interpreter requires we prefix all names
    }
  
    static Name fromInt(size_t i) {
      return cashew::IString(std::to_string(i).c_str(), false);
    }
  
    bool hasSubstring(cashew::IString substring) {
      return strstr(c_str(), substring.c_str()) != nullptr;
    }
  };
  
  } // namespace wasm
  
  namespace std {
  
  template <> struct hash<wasm::Name> : hash<cashew::IString> {};
  
  } // namespace std
  
  
  #endif // wasm_support_string_h
  