stream.hh

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#pragma once

#include <iostream> // cin
#include <memory> // shared_ptr
#include <sstream>
#include <stdexcept>

#include <vcsn/misc/escape.hh>
#include <vcsn/misc/export.hh>
#include <vcsn/misc/raise.hh>
#include <vcsn/misc/to-string.hh>

namespace vcsn LIBVCSN_API
{
  extern std::ostream cnull;

  extern std::wostream wcnull;

  std::string
  bracketed(std::istream& i, char lbracket, char rbracket);

  template <typename ValueSet, typename... Args>
  auto
  conv(const ValueSet& vs, const std::string& str, Args&&... args)
    -> decltype(vs.conv(std::declval<std::istream&>(),
                        std::forward<Args>(args)...))
  {
    std::istringstream i{str};
    try
      {
        const auto res = vs.conv(i, std::forward<Args>(args)...);
        VCSN_REQUIRE(i.peek() == EOF,
                     vs, ": unexpected trailing characters: ", i);
        return res;
      }
    catch (const std::runtime_error& e)
      {
        raise(e, "  while reading: ", str_quote(str));
      }
  }

  char eat(std::istream& is, char c);

  const std::string& eat(std::istream& is, const std::string& s);

  bool
  equal_files(const std::string& fn1, const std::string& fn2);

  // http://stackoverflow.com/questions/4891006.
  std::string expand_tilda(const std::string& res);

  template <typename... Args>
  ATTRIBUTE_NORETURN
  void fail_reading(std::istream& is, Args&&... args)
  {
    is.clear();
    std::string buf;
    std::getline(is, buf, '\n');
    if (!is.good())
      // This shouldn't really happen; however it's best to fail cleanly.
      is.clear();
    if (buf.empty())
      raise(std::forward<Args>(args)...);
    else
      raise(std::forward<Args>(args)..., ": ", str_quote(buf));
  }

  char get_char(std::istream& i);

  std::string get_file_contents(const std::string& file);

  std::shared_ptr<std::istream> open_input_file(const std::string& file);

  std::shared_ptr<std::ostream> open_output_file(const std::string& file);

  void skip_space(std::istream& is);

  std::string
  xgetenv(const std::string& var, const std::string& val = "");
}