/*
 Formatting library for C++

 Copyright (c) 2012 - 2016, Victor Zverovich
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

 1. Redistributions of source code must retain the above copyright notice, this
    list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "mp/format.h"

#include <string.h>

#include <cctype>
#include <cerrno>
#include <climits>
#include <cmath>
#include <cstdarg>
#include <cstddef>  // for std::ptrdiff_t

#if defined(_WIN32) && defined(__MINGW32__)
# include <cstring>
#endif

#if FMTOLD_USE_WINDOWS_H
# if defined(NOMINMAX) || defined(FMTOLD_WIN_MINMAX)
#  include <windows.h>
# else
#  define NOMINMAX
#  include <windows.h>
#  undef NOMINMAX
# endif
#endif

using fmtold::internal::Arg;

#if FMTOLD_EXCEPTIONS
# define FMTOLD_TRY try
# define FMTOLD_CATCH(x) catch (x)
#else
# define FMTOLD_TRY if (true)
# define FMTOLD_CATCH(x) if (false)
#endif

#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable: 4127)  // conditional expression is constant
# pragma warning(disable: 4702)  // unreachable code
// Disable deprecation warning for strerror. The latter is not called but
// MSVC fails to detect it.
# pragma warning(disable: 4996)
#endif

// Dummy implementations of strerror_r and strerror_s called if corresponding
// system functions are not available.
static inline fmtold::internal::Null<> strerror_r(int, char *, ...) {
  return fmtold::internal::Null<>();
}
static inline fmtold::internal::Null<> strerror_s(char *, std::size_t, ...) {
  return fmtold::internal::Null<>();
}

namespace fmtold {

FMTOLD_FUNC internal::RuntimeError::~RuntimeError() throw() {}
FMTOLD_FUNC FormatError::~FormatError() throw() {}
FMTOLD_FUNC SystemError::~SystemError() throw() {}

namespace {

#ifndef _MSC_VER
# define FMTOLD_SNPRINTF snprintf
#else  // _MSC_VER
inline int fmt_snprintf(char *buffer, size_t size, const char *format, ...) {
  va_list args;
  va_start(args, format);
  int result = vsnprintf_s(buffer, size, _TRUNCATE, format, args);
  va_end(args);
  return result;
}
# define FMTOLD_SNPRINTF fmt_snprintf
#endif  // _MSC_VER

#if defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)
# define FMTOLD_SWPRINTF snwprintf
#else
# define FMTOLD_SWPRINTF swprintf
#endif // defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)

// Checks if a value fits in int - used to avoid warnings about comparing
// signed and unsigned integers.
template <bool IsSigned>
struct IntChecker {
  template <typename T>
  static bool fits_in_int(T value) {
    unsigned max = INT_MAX;
    return value <= max;
  }
  static bool fits_in_int(bool) { return true; }
};

template <>
struct IntChecker<true> {
  template <typename T>
  static bool fits_in_int(T value) {
    return value >= INT_MIN && value <= INT_MAX;
  }
  static bool fits_in_int(int) { return true; }
};

const char RESET_COLOR[] = "\x1b[0m";

typedef void (*FormatFunc)(Writer &, int, StringRef);

// Portable thread-safe version of strerror.
// Sets buffer to point to a string describing the error code.
// This can be either a pointer to a string stored in buffer,
// or a pointer to some static immutable string.
// Returns one of the following values:
//   0      - success
//   ERANGE - buffer is not large enough to store the error message
//   other  - failure
// Buffer should be at least of size 1.
int safe_strerror(
    int error_code, char *&buffer, std::size_t buffer_size) FMTOLD_NOEXCEPT {
  FMTOLD_ASSERT(buffer != 0 && buffer_size != 0, "invalid buffer");

  class StrError {
   private:
    int error_code_;
    char *&buffer_;
    std::size_t buffer_size_;

    // A noop assignment operator to avoid bogus warnings.
    void operator=(const StrError &) {}

    // Handle the result of XSI-compliant version of strerror_r.
    int handle(int result) {
      // glibc versions before 2.13 return result in errno.
      return result == -1 ? errno : result;
    }

    // Handle the result of GNU-specific version of strerror_r.
    int handle(char *message) {
      // If the buffer is full then the message is probably truncated.
      if (message == buffer_ && strlen(buffer_) == buffer_size_ - 1)
        return ERANGE;
      buffer_ = message;
      return 0;
    }

    // Handle the case when strerror_r is not available.
    int handle(internal::Null<>) {
      return fallback(strerror_s(buffer_, buffer_size_, error_code_));
    }

    // Fallback to strerror_s when strerror_r is not available.
    int fallback(int result) {
      // If the buffer is full then the message is probably truncated.
      return result == 0 && strlen(buffer_) == buffer_size_ - 1 ?
            ERANGE : result;
    }

    // Fallback to strerror if strerror_r and strerror_s are not available.
    int fallback(internal::Null<>) {
      errno = 0;
      buffer_ = strerror(error_code_);
      return errno;
    }

   public:
    StrError(int err_code, char *&buf, std::size_t buf_size)
      : error_code_(err_code), buffer_(buf), buffer_size_(buf_size) {}

    int run() {
      strerror_r(0, 0, "");  // Suppress a warning about unused strerror_r.
      return handle(strerror_r(error_code_, buffer_, buffer_size_));
    }
  };
  return StrError(error_code, buffer, buffer_size).run();
}

void format_error_code(Writer &out, int error_code,
                       StringRef message) FMTOLD_NOEXCEPT {
  // Report error code making sure that the output fits into
  // INLINE_BUFFER_SIZE to avoid dynamic memory allocation and potential
  // bad_alloc.
  out.clear();
  static const char SEP[] = ": ";
  static const char ERROR_STR[] = "error ";
  // Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
  std::size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
  typedef internal::IntTraits<int>::MainType MainType;
  MainType abs_value = static_cast<MainType>(error_code);
  if (internal::is_negative(error_code)) {
    abs_value = 0 - abs_value;
    ++error_code_size;
  }
  error_code_size += internal::count_digits(abs_value);
  if (message.size() <= internal::INLINE_BUFFER_SIZE - error_code_size)
    out << message << SEP;
  out << ERROR_STR << error_code;
  assert(out.size() <= internal::INLINE_BUFFER_SIZE);
}

void report_error(FormatFunc func, int error_code,
                  StringRef message) FMTOLD_NOEXCEPT {
  MemoryWriter full_message;
  func(full_message, error_code, message);
  // Use Writer::data instead of Writer::c_str to avoid potential memory
  // allocation.
  std::fwrite(full_message.data(), full_message.size(), 1, stderr);
  std::fputc('\n', stderr);
}

// IsZeroInt::visit(arg) returns true iff arg is a zero integer.
class IsZeroInt : public ArgVisitor<IsZeroInt, bool> {
 public:
  template <typename T>
  bool visit_any_int(T value) { return value == 0; }
};

// Checks if an argument is a valid printf width specifier and sets
// left alignment if it is negative.
class WidthHandler : public ArgVisitor<WidthHandler, unsigned> {
 private:
  FormatSpec &spec_;

  FMTOLD_DISALLOW_COPY_AND_ASSIGN(WidthHandler);

 public:
  explicit WidthHandler(FormatSpec &spec) : spec_(spec) {}

  void report_unhandled_arg() {
    FMTOLD_THROW(FormatError("width is not integer"));
  }

  template <typename T>
  unsigned visit_any_int(T value) {
    typedef typename internal::IntTraits<T>::MainType UnsignedType;
    UnsignedType width = static_cast<UnsignedType>(value);
    if (internal::is_negative(value)) {
      spec_.align_ = ALIGN_LEFT;
      width = 0 - width;
    }
    if (width > INT_MAX)
      FMTOLD_THROW(FormatError("number is too big"));
    return static_cast<unsigned>(width);
  }
};

class PrecisionHandler : public ArgVisitor<PrecisionHandler, int> {
 public:
  void report_unhandled_arg() {
    FMTOLD_THROW(FormatError("precision is not integer"));
  }

  template <typename T>
  int visit_any_int(T value) {
    if (!IntChecker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
      FMTOLD_THROW(FormatError("number is too big"));
    return static_cast<int>(value);
  }
};

template <typename T, typename U>
struct is_same {
  enum { value = 0 };
};

template <typename T>
struct is_same<T, T> {
  enum { value = 1 };
};

// An argument visitor that converts an integer argument to T for printf,
// if T is an integral type. If T is void, the argument is converted to
// corresponding signed or unsigned type depending on the type specifier:
// 'd' and 'i' - signed, other - unsigned)
template <typename T = void>
class ArgConverter : public ArgVisitor<ArgConverter<T>, void> {
 private:
  internal::Arg &arg_;
  wchar_t type_;

  FMTOLD_DISALLOW_COPY_AND_ASSIGN(ArgConverter);

 public:
  ArgConverter(internal::Arg &arg, wchar_t type)
    : arg_(arg), type_(type) {}

  void visit_bool(bool value) {
    if (type_ != 's')
      visit_any_int(value);
  }

  template <typename U>
  void visit_any_int(U value) {
    bool is_signed = type_ == 'd' || type_ == 'i';
    using internal::Arg;
    typedef typename internal::Conditional<
        is_same<T, void>::value, U, T>::type TargetType;
    if (sizeof(TargetType) <= sizeof(int)) {
      // Extra casts are used to silence warnings.
      if (is_signed) {
        arg_.type = Arg::INT;
        arg_.int_value = static_cast<int>(static_cast<TargetType>(value));
      } else {
        arg_.type = Arg::UINT;
        typedef typename internal::MakeUnsigned<TargetType>::Type Unsigned;
        arg_.uint_value = static_cast<unsigned>(static_cast<Unsigned>(value));
      }
    } else {
      if (is_signed) {
        arg_.type = Arg::LONG_LONG;
        // glibc's printf doesn't sign extend arguments of smaller types:
        //   std::printf("%lld", -42);  // prints "4294967254"
        // but we don't have to do the same because it's a UB.
        arg_.long_long_value = static_cast<LongLong>(value);
      } else {
        arg_.type = Arg::ULONG_LONG;
        arg_.ulong_long_value =
            static_cast<typename internal::MakeUnsigned<U>::Type>(value);
      }
    }
  }
};

// Converts an integer argument to char for printf.
class CharConverter : public ArgVisitor<CharConverter, void> {
 private:
  internal::Arg &arg_;

  FMTOLD_DISALLOW_COPY_AND_ASSIGN(CharConverter);

 public:
  explicit CharConverter(internal::Arg &arg) : arg_(arg) {}

  template <typename T>
  void visit_any_int(T value) {
    arg_.type = internal::Arg::CHAR;
    arg_.int_value = static_cast<char>(value);
  }
};
}  // namespace

namespace internal {

template <typename Char>
class PrintfArgFormatter :
    public ArgFormatterBase<PrintfArgFormatter<Char>, Char> {

  void write_null_pointer() {
    this->spec().type_ = 0;
    this->write("(nil)");
  }

  typedef ArgFormatterBase<PrintfArgFormatter<Char>, Char> Base;

 public:
  PrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
  : ArgFormatterBase<PrintfArgFormatter<Char>, Char>(w, s) {}

  void visit_bool(bool value) {
    FormatSpec &fmt_spec = this->spec();
    if (fmt_spec.type_ != 's')
      return this->visit_any_int(value);
    fmt_spec.type_ = 0;
    this->write(value);
  }

  void visit_char(int value) {
    const FormatSpec &fmt_spec = this->spec();
    BasicWriter<Char> &w = this->writer();
    if (fmt_spec.type_ && fmt_spec.type_ != 'c')
      w.write_int(value, fmt_spec);
    typedef typename BasicWriter<Char>::CharPtr CharPtr;
    CharPtr out = CharPtr();
    if (fmt_spec.width_ > 1) {
      Char fill = ' ';
      out = w.grow_buffer(fmt_spec.width_);
      if (fmt_spec.align_ != ALIGN_LEFT) {
        std::fill_n(out, fmt_spec.width_ - 1, fill);
        out += fmt_spec.width_ - 1;
      } else {
        std::fill_n(out + 1, fmt_spec.width_ - 1, fill);
      }
    } else {
      out = w.grow_buffer(1);
    }
    *out = static_cast<Char>(value);
  }

  void visit_cstring(const char *value) {
    if (value)
      Base::visit_cstring(value);
    else if (this->spec().type_ == 'p')
      write_null_pointer();
    else
      this->write("(null)");
  }

  void visit_pointer(const void *value) {
    if (value)
      return Base::visit_pointer(value);
    this->spec().type_ = 0;
    write_null_pointer();
  }

  void visit_custom(Arg::CustomValue c) {
    BasicFormatter<Char> formatter(ArgList(), this->writer());
    const Char format_str[] = {'}', 0};
    const Char *format = format_str;
    c.format(&formatter, c.value, &format);
  }
};
}  // namespace internal
}  // namespace fmtold

FMTOLD_FUNC void fmtold::SystemError::init(
    int err_code, CStringRef format_str, ArgList args) {
  error_code_ = err_code;
  MemoryWriter w;
  internal::format_system_error(w, err_code, format(format_str, args));
  std::runtime_error &base = *this;
  base = std::runtime_error(w.str());
}

template <typename T>
int fmtold::internal::CharTraits<char>::format_float(
    char *buffer, std::size_t size, const char *format,
    unsigned width, int precision, T value) {
  if (width == 0) {
    return precision < 0 ?
        FMTOLD_SNPRINTF(buffer, size, format, value) :
        FMTOLD_SNPRINTF(buffer, size, format, precision, value);
  }
  return precision < 0 ?
      FMTOLD_SNPRINTF(buffer, size, format, width, value) :
      FMTOLD_SNPRINTF(buffer, size, format, width, precision, value);
}

template <typename T>
int fmtold::internal::CharTraits<wchar_t>::format_float(
    wchar_t *buffer, std::size_t size, const wchar_t *format,
    unsigned width, int precision, T value) {
  if (width == 0) {
    return precision < 0 ?
        FMTOLD_SWPRINTF(buffer, size, format, value) :
        FMTOLD_SWPRINTF(buffer, size, format, precision, value);
  }
  return precision < 0 ?
      FMTOLD_SWPRINTF(buffer, size, format, width, value) :
      FMTOLD_SWPRINTF(buffer, size, format, width, precision, value);
}

template <typename T>
const char fmtold::internal::BasicData<T>::DIGITS[] =
    "0001020304050607080910111213141516171819"
    "2021222324252627282930313233343536373839"
    "4041424344454647484950515253545556575859"
    "6061626364656667686970717273747576777879"
    "8081828384858687888990919293949596979899";

#define FMTOLD_POWERS_OF_10(factor) \
  factor * 10, \
  factor * 100, \
  factor * 1000, \
  factor * 10000, \
  factor * 100000, \
  factor * 1000000, \
  factor * 10000000, \
  factor * 100000000, \
  factor * 1000000000

template <typename T>
const uint32_t fmtold::internal::BasicData<T>::POWERS_OF_10_32[] = {
  0, FMTOLD_POWERS_OF_10(1)
};

template <typename T>
const uint64_t fmtold::internal::BasicData<T>::POWERS_OF_10_64[] = {
  0,
  FMTOLD_POWERS_OF_10(1),
  FMTOLD_POWERS_OF_10(fmtold::ULongLong(1000000000)),
  // Multiply several constants instead of using a single long long constant
  // to avoid warnings about C++98 not supporting long long.
  fmtold::ULongLong(1000000000) * fmtold::ULongLong(1000000000) * 10
};

FMTOLD_FUNC void fmtold::internal::report_unknown_type(char code, const char *type) {
  (void)type;
  if (std::isprint(static_cast<unsigned char>(code))) {
    FMTOLD_THROW(fmtold::FormatError(
        fmtold::format("unknown format code '{}' for {}", code, type)));
  }
  FMTOLD_THROW(fmtold::FormatError(
      fmtold::format("unknown format code '\\x{:02x}' for {}",
        static_cast<unsigned>(code), type)));
}

#if FMTOLD_USE_WINDOWS_H

FMTOLD_FUNC fmtold::internal::UTF8ToUTF16::UTF8ToUTF16(fmtold::StringRef s) {
  static const char ERROR_MSG[] = "cannot convert string from UTF-8 to UTF-16";
  if (s.size() > INT_MAX)
    FMTOLD_THROW(WindowsError(ERROR_INVALID_PARAMETER, ERROR_MSG));
  int s_size = static_cast<int>(s.size());
  int length = MultiByteToWideChar(
      CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size, 0, 0);
  if (length == 0)
    FMTOLD_THROW(WindowsError(GetLastError(), ERROR_MSG));
  buffer_.resize(length + 1);
  length = MultiByteToWideChar(
    CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size, &buffer_[0], length);
  if (length == 0)
    FMTOLD_THROW(WindowsError(GetLastError(), ERROR_MSG));
  buffer_[length] = 0;
}

FMTOLD_FUNC fmtold::internal::UTF16ToUTF8::UTF16ToUTF8(fmtold::WStringRef s) {
  if (int error_code = convert(s)) {
    FMTOLD_THROW(WindowsError(error_code,
        "cannot convert string from UTF-16 to UTF-8"));
  }
}

FMTOLD_FUNC int fmtold::internal::UTF16ToUTF8::convert(fmtold::WStringRef s) {
  if (s.size() > INT_MAX)
    return ERROR_INVALID_PARAMETER;
  int s_size = static_cast<int>(s.size());
  int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, 0, 0, 0, 0);
  if (length == 0)
    return GetLastError();
  buffer_.resize(length + 1);
  length = WideCharToMultiByte(
    CP_UTF8, 0, s.data(), s_size, &buffer_[0], length, 0, 0);
  if (length == 0)
    return GetLastError();
  buffer_[length] = 0;
  return 0;
}

FMTOLD_FUNC void fmtold::WindowsError::init(
    int err_code, CStringRef format_str, ArgList args) {
  error_code_ = err_code;
  MemoryWriter w;
  internal::format_windows_error(w, err_code, format(format_str, args));
  std::runtime_error &base = *this;
  base = std::runtime_error(w.str());
}

FMTOLD_FUNC void fmtold::internal::format_windows_error(
    fmtold::Writer &out, int error_code,
    fmtold::StringRef message) FMTOLD_NOEXCEPT {
  FMTOLD_TRY {
    MemoryBuffer<wchar_t, INLINE_BUFFER_SIZE> buffer;
    buffer.resize(INLINE_BUFFER_SIZE);
    for (;;) {
      wchar_t *system_message = &buffer[0];
      int result = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                                  0, error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                                  system_message, static_cast<uint32_t>(buffer.size()), 0);
      if (result != 0) {
        UTF16ToUTF8 utf8_message;
        if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
          out << message << ": " << utf8_message;
          return;
        }
        break;
      }
      if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
        break;  // Can't get error message, report error code instead.
      buffer.resize(buffer.size() * 2);
    }
  } FMTOLD_CATCH(...) {}
  fmtold::format_error_code(out, error_code, message);  // 'fmtold::' is for bcc32.
}

#endif  // FMTOLD_USE_WINDOWS_H

FMTOLD_FUNC void fmtold::internal::format_system_error(
    fmtold::Writer &out, int error_code,
    fmtold::StringRef message) FMTOLD_NOEXCEPT {
  FMTOLD_TRY {
    MemoryBuffer<char, INLINE_BUFFER_SIZE> buffer;
    buffer.resize(INLINE_BUFFER_SIZE);
    for (;;) {
      char *system_message = &buffer[0];
      int result = safe_strerror(error_code, system_message, buffer.size());
      if (result == 0) {
        out << message << ": " << system_message;
        return;
      }
      if (result != ERANGE)
        break;  // Can't get error message, report error code instead.
      buffer.resize(buffer.size() * 2);
    }
  } FMTOLD_CATCH(...) {}
  fmtold::format_error_code(out, error_code, message);  // 'fmtold::' is for bcc32.
}

template <typename Char>
void fmtold::internal::ArgMap<Char>::init(const ArgList &args) {
  if (!map_.empty())
    return;
  typedef internal::NamedArg<Char> NamedArg;
  const NamedArg *named_arg = 0;
  bool use_values =
      args.type(ArgList::MAX_PACKED_ARGS - 1) == internal::Arg::NONE;
  if (use_values) {
    for (unsigned i = 0;/*nothing*/; ++i) {
      internal::Arg::Type arg_type = args.type(i);
      switch (arg_type) {
      case internal::Arg::NONE:
        return;
      case internal::Arg::NAMED_ARG:
        named_arg = static_cast<const NamedArg*>(args.values_[i].pointer);
        map_.push_back(Pair(named_arg->name, *named_arg));
        break;
      default:
        /*nothing*/;
      }
    }
    return;
  }
  for (unsigned i = 0; i != ArgList::MAX_PACKED_ARGS; ++i) {
    internal::Arg::Type arg_type = args.type(i);
    if (arg_type == internal::Arg::NAMED_ARG) {
      named_arg = static_cast<const NamedArg*>(args.args_[i].pointer);
      map_.push_back(Pair(named_arg->name, *named_arg));
    }
  }
  for (unsigned i = ArgList::MAX_PACKED_ARGS;/*nothing*/; ++i) {
    switch (args.args_[i].type) {
    case internal::Arg::NONE:
      return;
    case internal::Arg::NAMED_ARG:
      named_arg = static_cast<const NamedArg*>(args.args_[i].pointer);
      map_.push_back(Pair(named_arg->name, *named_arg));
      break;
    default:
      /*nothing*/;
    }
  }
}

template <typename Char>
void fmtold::internal::FixedBuffer<Char>::grow(std::size_t) {
  FMTOLD_THROW(std::runtime_error("buffer overflow"));
}

FMTOLD_FUNC Arg fmtold::internal::FormatterBase::do_get_arg(
    unsigned arg_index, const char *&error) {
  Arg arg = args_[arg_index];
  switch (arg.type) {
  case Arg::NONE:
    error = "argument index out of range";
    break;
  case Arg::NAMED_ARG:
    arg = *static_cast<const internal::Arg*>(arg.pointer);
    break;
  default:
    /*nothing*/;
  }
  return arg;
}

template <typename Char>
void fmtold::internal::PrintfFormatter<Char>::parse_flags(
    FormatSpec &spec, const Char *&s) {
  for (;;) {
    switch (*s++) {
      case '-':
        spec.align_ = ALIGN_LEFT;
        break;
      case '+':
        spec.flags_ |= SIGN_FLAG | PLUS_FLAG;
        break;
      case '0':
        spec.fill_ = '0';
        break;
      case ' ':
        spec.flags_ |= SIGN_FLAG;
        break;
      case '#':
        spec.flags_ |= HASH_FLAG;
        break;
      default:
        --s;
        return;
    }
  }
}

template <typename Char>
Arg fmtold::internal::PrintfFormatter<Char>::get_arg(
    const Char *s, unsigned arg_index) {
  (void)s;
  const char *error = 0;
  Arg arg = arg_index == UINT_MAX ?
    next_arg(error) : FormatterBase::get_arg(arg_index - 1, error);
  if (error)
    FMTOLD_THROW(FormatError(!*s ? "invalid format string" : error));
  return arg;
}

template <typename Char>
unsigned fmtold::internal::PrintfFormatter<Char>::parse_header(
  const Char *&s, FormatSpec &spec) {
  unsigned arg_index = UINT_MAX;
  Char c = *s;
  if (c >= '0' && c <= '9') {
    // Parse an argument index (if followed by '$') or a width possibly
    // preceded with '0' flag(s).
    unsigned value = parse_nonnegative_int(s);
    if (*s == '$') {  // value is an argument index
      ++s;
      arg_index = value;
    } else {
      if (c == '0')
        spec.fill_ = '0';
      if (value != 0) {
        // Nonzero value means that we parsed width and don't need to
        // parse it or flags again, so return now.
        spec.width_ = value;
        return arg_index;
      }
    }
  }
  parse_flags(spec, s);
  // Parse width.
  if (*s >= '0' && *s <= '9') {
    spec.width_ = parse_nonnegative_int(s);
  } else if (*s == '*') {
    ++s;
    spec.width_ = WidthHandler(spec).visit(get_arg(s));
  }
  return arg_index;
}

template <typename Char>
void fmtold::internal::PrintfFormatter<Char>::format(
    BasicWriter<Char> &writer, BasicCStringRef<Char> format_str) {
  const Char *start = format_str.c_str();
  const Char *s = start;
  while (*s) {
    Char c = *s++;
    if (c != '%') continue;
    if (*s == c) {
      write(writer, start, s);
      start = ++s;
      continue;
    }
    write(writer, start, s - 1);

    FormatSpec spec;
    spec.align_ = ALIGN_RIGHT;

    // Parse argument index, flags and width.
    unsigned arg_index = parse_header(s, spec);

    // Parse precision.
    if (*s == '.') {
      ++s;
      if ('0' <= *s && *s <= '9') {
        spec.precision_ = static_cast<int>(parse_nonnegative_int(s));
      } else if (*s == '*') {
        ++s;
        spec.precision_ = PrecisionHandler().visit(get_arg(s));
      }
    }

    Arg arg = get_arg(s, arg_index);
    if (spec.flag(HASH_FLAG) && IsZeroInt().visit(arg))
      spec.flags_ &= ~to_unsigned<int>(HASH_FLAG);
    if (spec.fill_ == '0') {
      if (arg.type <= Arg::LAST_NUMERIC_TYPE)
        spec.align_ = ALIGN_NUMERIC;
      else
        spec.fill_ = ' ';  // Ignore '0' flag for non-numeric types.
    }

    // Parse length and convert the argument to the required type.
    switch (*s++) {
    case 'h':
      if (*s == 'h')
        ArgConverter<signed char>(arg, *++s).visit(arg);
      else
        ArgConverter<short>(arg, *s).visit(arg);
      break;
    case 'l':
      if (*s == 'l')
        ArgConverter<fmtold::LongLong>(arg, *++s).visit(arg);
      else
        ArgConverter<long>(arg, *s).visit(arg);
      break;
    case 'j':
      ArgConverter<intmax_t>(arg, *s).visit(arg);
      break;
    case 'z':
      ArgConverter<std::size_t>(arg, *s).visit(arg);
      break;
    case 't':
      ArgConverter<std::ptrdiff_t>(arg, *s).visit(arg);
      break;
    case 'L':
      // printf produces garbage when 'L' is omitted for long double, no
      // need to do the same.
      break;
    default:
      --s;
      ArgConverter<void>(arg, *s).visit(arg);
    }

    // Parse type.
    if (!*s)
      FMTOLD_THROW(FormatError("invalid format string"));
    spec.type_ = static_cast<char>(*s++);
    if (arg.type <= Arg::LAST_INTEGER_TYPE) {
      // Normalize type.
      switch (spec.type_) {
      case 'i': case 'u':
        spec.type_ = 'd';
        break;
      case 'c':
        // TODO: handle wchar_t
        CharConverter(arg).visit(arg);
        break;
      }
    }

    start = s;

    // Format argument.
    internal::PrintfArgFormatter<Char>(writer, spec).visit(arg);
  }
  write(writer, start, s);
}

FMTOLD_FUNC void fmtold::report_system_error(
    int error_code, fmtold::StringRef message) FMTOLD_NOEXCEPT {
  // 'fmtold::' is for bcc32.
  fmtold::report_error(internal::format_system_error, error_code, message);
}

#if FMTOLD_USE_WINDOWS_H
FMTOLD_FUNC void fmtold::report_windows_error(
    int error_code, fmtold::StringRef message) FMTOLD_NOEXCEPT {
  // 'fmtold::' is for bcc32.
  fmtold::report_error(internal::format_windows_error, error_code, message);
}
#endif

FMTOLD_FUNC void fmtold::print(std::FILE *f, CStringRef format_str, ArgList args) {
  MemoryWriter w;
  w.write(format_str, args);
  std::fwrite(w.data(), 1, w.size(), f);
}

FMTOLD_FUNC void fmtold::print(CStringRef format_str, ArgList args) {
  print(stdout, format_str, args);
}

FMTOLD_FUNC void fmtold::print_colored(Color c, CStringRef format, ArgList args) {
  char escape[] = "\x1b[30m";
  escape[3] = static_cast<char>('0' + c);
  std::fputs(escape, stdout);
  print(format, args);
  std::fputs(RESET_COLOR, stdout);
}

FMTOLD_FUNC int fmtold::fprintf(std::FILE *f, CStringRef format, ArgList args) {
  MemoryWriter w;
  printf(w, format, args);
  std::size_t size = w.size();
  return std::fwrite(w.data(), 1, size, f) < size ? -1 : static_cast<int>(size);
}

#ifndef FMTOLD_HEADER_ONLY

template struct fmtold::internal::BasicData<void>;

// Explicit instantiations for char.

template void fmtold::internal::FixedBuffer<char>::grow(std::size_t);

template void fmtold::internal::ArgMap<char>::init(const fmtold::ArgList &args);

template void fmtold::internal::PrintfFormatter<char>::format(
  BasicWriter<char> &writer, CStringRef format);

template int fmtold::internal::CharTraits<char>::format_float(
    char *buffer, std::size_t size, const char *format,
    unsigned width, int precision, double value);

template int fmtold::internal::CharTraits<char>::format_float(
    char *buffer, std::size_t size, const char *format,
    unsigned width, int precision, long double value);

// Explicit instantiations for wchar_t.

template void fmtold::internal::FixedBuffer<wchar_t>::grow(std::size_t);

template void fmtold::internal::ArgMap<wchar_t>::init(const fmtold::ArgList &args);

template void fmtold::internal::PrintfFormatter<wchar_t>::format(
    BasicWriter<wchar_t> &writer, WCStringRef format);

template int fmtold::internal::CharTraits<wchar_t>::format_float(
    wchar_t *buffer, std::size_t size, const wchar_t *format,
    unsigned width, int precision, double value);

template int fmtold::internal::CharTraits<wchar_t>::format_float(
    wchar_t *buffer, std::size_t size, const wchar_t *format,
    unsigned width, int precision, long double value);

#endif  // FMTOLD_HEADER_ONLY

#ifdef _MSC_VER
# pragma warning(pop)
#endif
