STD::COLLATE(3cxx)

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Hey bestie 💖 welcome to the std::collate< _CharT > page from the 3cxx manual — yes, that's the C++ header vibes, and we're gonna get into every single member like it's a group chat. No cap, this facet is all about localized string comparison, and the manpage is giving very detailed. Let's go ✨

🌸 NAME 🌸

std::collate< _CharT > — Facet for localized string comparison. Periodt. 💅

🦋 SYNOPSIS 🦋

Okay so first things first, include the locale header:

#include <locale>

Then the family tree tea:

  • Inherits std::locale::facet. 👑
  • Inherited by std::collate_byname< _CharT >. 🧚

✨ Public Types ✨

  • typedef _CharT char_type — Public typedefs. 💖
  • typedef basic_string< _CharT > string_type — Public typedefs. 💖

💖 Public Member Functions 💖

  • collate (__c_locale __cloc, size_t __refs=0) — Internal constructor. Not for general use. 🚨
  • collate (size_t __refs=0) — Constructor performs initialization. ✨
  • int _M_compare (const _CharT *, const _CharT *) const throw () — listed exactly as-is, bestie. 🫶
  • int _M_compare (const char *, const char *) const throw() — listed exactly as-is. 🫶
  • int _M_compare (const wchar_t *, const wchar_t *) const throw() — listed exactly as-is. 🫶
  • size_t _M_transform (_CharT *, const _CharT *, size_t) const throw () — listed exactly as-is. 🫶
  • size_t _M_transform (char *, const char *, size_t) const throw() — listed exactly as-is. 🫶
  • size_t _M_transform (wchar_t *, const wchar_t *, size_t) const throw() — listed exactly as-is. 🫶
  • int compare (const _CharT *__lo1, const _CharT *__hi1, const _CharT *__lo2, const _CharT *__hi2) const — Compare two strings. 💅
  • long hash (const _CharT *__lo, const _CharT *__hi) const — Return hash of a string. 🔥
  • string_type transform (const _CharT *__lo, const _CharT *__hi) const — Transform string to comparable form. 🦋

🌈 Static Public Attributes 🌈

  • static locale::id id — Numpunct facet id. Yes, that's what the manpage says — keeping it exactly. 🫶

🎀 Protected Member Functions 🎀

  • virtual ~collate () — Destructor. 💀
  • virtual int do_compare (const _CharT *__lo1, const _CharT *__hi1, const _CharT *__lo2, const _CharT *__hi2) const — Compare two strings. 💅
  • virtual long do_hash (const _CharT *__lo, const _CharT *__hi) const — Return hash of a string. 🔥
  • virtual string_type do_transform (const _CharT *__lo, const _CharT *__hi) const — Transform string to comparable form. 🦋

🧚 Static Protected Member Functions 🧚

  • static __c_locale _S_clone_c_locale (__c_locale &__cloc) throw () — listed as-is. 🫶
  • static void _S_create_c_locale (__c_locale &__cloc, const char *__s, __c_locale __old=0) — listed as-is. 🫶
  • static void _S_destroy_c_locale (__c_locale &__cloc) — listed as-is. 🫶
  • static __c_locale _S_get_c_locale () — listed as-is. 🫶
  • static const char * _S_get_c_name () throw () — listed as-is. 🫶
  • static __c_locale _S_lc_ctype_c_locale (__c_locale __cloc, const char *__s) — listed as-is. 🫶

🍓 Protected Attributes 🍓

  • __c_locale _M_c_locale_collate — just this one protected attribute, no extra description given. 🫶

💜 Detailed Description 💜

Here's the signature line exactly as the page gives it:

template<typename _CharT>
    class std::collate< _CharT >"Facet for localized string comparison.

This facet encapsulates the code to compare strings in a localized manner. 🫶

The collate template uses protected virtual functions to provide the actual results. The public accessors forward the call to the virtual functions. These virtual functions are hooks for developers to implement the behavior they require from the collate facet. No skipping this, bestie 💅

🎀 Member Typedef Documentation 🎀

🌸 char_type 🌸

template<typename _CharT > typedef _CharT std::collate< _CharT >::char_type

Public typedefs. Simple as that. ✨

🦋 string_type 🦋

template<typename _CharT > typedef basic_string<_CharT> std::collate< _CharT >::string_type

Public typedefs. Again. We love consistency. 💖

🧚 Constructor & Destructor Documentation 🧚

✨ collate (size_t __refs = 0)

template<typename _CharT > std::collate< _CharT >::collate (size_t __refs = 0) [inline],  [explicit]

Constructor performs initialization. This is the constructor provided by the standard. ✨

Parameters

  • __refs — Passed to the base facet class.

🎀 collate (__c_locale __cloc, size_t __refs = 0)

template<typename _CharT > std::collate< _CharT >::collate (__c_locale __cloc, size_t __refs = 0) [inline],  [explicit]

Internal constructor. Not for general use. This is a constructor for use by the library itself to set up new locales. 🚨

Parameters

  • __cloc — The C locale.
  • __refs — Passed to the base facet class.

💀 ~collate ()

template<typename _CharT > virtual std::collate< _CharT >::~collate () [inline],  [protected],  [virtual]

Destructor. 💀

💖 Member Function Documentation 💖

💅 compare

template<typename _CharT > int std::collate< _CharT >::compare (const _CharT * __lo1, const _CharT * __hi1, const _CharT * __lo2, const _CharT * __hi2) const [inline]

Compare two strings. This function compares two strings and returns the result by calling collate::do_compare(). 💅

Parameters

  • __lo1 — Start of string 1.
  • __hi1 — End of string 1.
  • __lo2 — Start of string 2.
  • __hi2 — End of string 2.

Returns

1 if string1 > string2, -1 if string1 < string2, else 0.

🦋 do_compare

template<typename _CharT > int std::collate< _CharT >::do_compare (const _CharT * __lo1, const _CharT * __hi1, const _CharT * __lo2, const _CharT * __hi2) const [protected],  [virtual]

Compare two strings. This function is a hook for derived classes to change the value returned. 🫶

See also: compare().

Parameters

  • __lo1 — Start of string 1.
  • __hi1 — End of string 1.
  • __lo2 — Start of string 2.
  • __hi2 — End of string 2.

Returns

1 if string1 > string2, -1 if string1 < string2, else 0.

References: std::basic_string< _CharT, _Traits, _Alloc >::c_str(), std::basic_string< _CharT, _Traits, _Alloc >::data(), and std::basic_string< _CharT, _Traits, _Alloc >::length().

🔥 do_hash

template<typename _CharT > long std::collate< _CharT >::do_hash (const _CharT * __lo, const _CharT * __hi) const [protected],  [virtual]

Return hash of a string. This function computes and returns a hash on the input string. This function is a hook for derived classes to change the value returned. 🔥

Parameters

  • __lo — Start of string.
  • __hi — End of string.

Returns

Hash value.

🧚 do_transform

template<typename _CharT > collate< _CharT >::string_type std::collate< _CharT >::do_transform (const _CharT * __lo, const _CharT * __hi) const [protected],  [virtual]

Transform string to comparable form. This function is a hook for derived classes to change the value returned. 🦋

Parameters

  • __lo — Start.
  • __hi — End.

Returns

transformed string.

References: std::basic_string< _CharT, _Traits, _Alloc >::append(), std::basic_string< _CharT, _Traits, _Alloc >::c_str(), std::basic_string< _CharT, _Traits, _Alloc >::data(), std::basic_string< _CharT, _Traits, _Alloc >::length(), and std::basic_string< _CharT, _Traits, _Alloc >::push_back().

⭐ hash

template<typename _CharT > long std::collate< _CharT >::hash (const _CharT * __lo, const _CharT * __hi) const [inline]

Return hash of a string. This function computes and returns a hash on the input string. It does so by returning collate::do_hash(). ⭐

Parameters

  • __lo — Start of string.
  • __hi — End of string.

Returns

Hash value.

🌈 transform

template<typename _CharT > string_type std::collate< _CharT >::transform (const _CharT * __lo, const _CharT * __hi) const [inline]

Transform string to comparable form. This function is a wrapper for strxfrm functionality. It takes the input string and returns a modified string that can be directly compared to other transformed strings. In the C locale, this function just returns a copy of the input string. In some other locales, it may replace two chars with one, change a char for another, etc. It does so by returning collate::do_transform(). 🌈

Parameters

  • __lo — Start of string.
  • __hi — End of string.

Returns

Transformed string_type.

👑 Member Data Documentation 👑

id

template<typename _CharT > locale::id std::collate< _CharT >::id [static]

Numpunct facet id. 👑

😭 Author 😭

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