std::collate< _CharT >

Section: C Library Functions (3)
Updated: Wed Apr 17 2019
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NAME

std::collate< _CharT > - Facet for localized string comparison.

SYNOPSIS

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 (size_t __refs=0)
Constructor performs initialization.
collate (__c_locale __cloc, size_t __refs=0)
Internal constructor. Not for general use.
int _M_compare (const _CharT *, const _CharT *) const throw ()

template<> int _M_compare (const char *, const char *) const throw()

template<> int _M_compare (const wchar_t *, const wchar_t *) const throw()

size_t _M_transform (_CharT *, const _CharT *, size_t) const throw ()

template<> size_t _M_transform (char *, const char *, size_t) const throw()

template<> size_t _M_transform (wchar_t *, const wchar_t *, size_t) const throw()

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.

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 ()

static void _S_create_c_locale (__c_locale &__cloc, const char *__s, __c_locale __old=0)

static void _S_destroy_c_locale (__c_locale &__cloc)

static __c_locale _S_get_c_locale ()

static const char * _S_get_c_name () throw ()

static __c_locale _S_lc_ctype_c_locale (__c_locale __cloc, const char *__s)

Protected Attributes

__c_locale _M_c_locale_collate

Detailed Description

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.

Definition at line 642 of file locale_classes.h.

Member Typedef Documentation

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

Public typedefs.

Definition at line 648 of file locale_classes.h.

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

Public typedefs.

Definition at line 649 of file locale_classes.h.

Constructor & Destructor Documentation

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.

Definition at line 669 of file locale_classes.h.

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.

Definition at line 683 of file locale_classes.h.

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

Destructor.

Definition at line 746 of file locale_classes.h.

Member Function Documentation

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.

Definition at line 700 of file locale_classes.h.

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.

Definition at line 161 of file locale_classes.tcc.

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

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.

Definition at line 256 of file locale_classes.tcc.

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.

Definition at line 200 of file locale_classes.tcc.

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

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.

Definition at line 733 of file locale_classes.h.

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.

Definition at line 719 of file locale_classes.h.

Member Data Documentation

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

Numpunct facet id.

Definition at line 659 of file locale_classes.h.

Author

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