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std::codecvt_utf8

提供: cppreference.com
< cpp‎ | locale

 
 
 
ヘッダ <codecvt> で定義
template<

    class Elem,
    unsigned long Maxcode = 0x10ffff,
    std::codecvt_mode Mode = (std::codecvt_mode)0

> class codecvt_utf8 : public std::codecvt<Elem, char, std::mbstate_t>;
std::codecvt_utf8UTF-8でエンコードされたバイト列とUCS2またはUCS4の文字列(std::codecvtの種類によって異なります)との間の変換をカプセル化Elemファセットです。このcodecvtファセットは、テキストとバイナリの両方をUTF-8のファイルを読み書きするために使用することができます.
Original:
std::codecvt_utf8 is a std::codecvt facet which encapsulates conversion between a UTF-8 encoded byte string and UCS2 or UCS4 character string (depending on the type of Elem). This codecvt facet can be used to read and write UTF-8 files, both text and binary.
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目次

[編集] テンプレートパラメータ

Elem -
どちらchar16_tchar32_t、またはwchar_t
Original:
either char16_t, char32_t, or wchar_t
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Maxcode -
このファセットはエラーなしで読み取りまたは書き込みすることElemの最大値
Original:
the largest value of Elem that this facet will read or write without error
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Mode -
タイプstd::codecvt_modeの定数
Original:
a constant of type std::codecvt_mode
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std::codecvt から継承

Member types

メンバー·タイプ
Original:
Member type
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Definition
intern_type internT
extern_type externT
state_type stateT

Member objects

メンバー名
Original:
Member name
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Type
id (静的) std::locale::id

Member functions

do_outを呼び出します
Original:
invokes do_out
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(std::codecvtのパブリックメンバ関数) [edit]
do_inを呼び出します
Original:
invokes do_in
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(std::codecvtのパブリックメンバ関数) [edit]
do_unshiftを呼び出します
Original:
invokes do_unshift
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(std::codecvtのパブリックメンバ関数) [edit]
do_encodingを呼び出します
Original:
invokes do_encoding
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(std::codecvtのパブリックメンバ関数) [edit]
do_always_noconvを呼び出します
Original:
invokes do_always_noconv
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(std::codecvtのパブリックメンバ関数) [edit]
do_lengthを呼び出します
Original:
invokes do_length
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(std::codecvtのパブリックメンバ関数) [edit]
do_max_lengthを呼び出します
Original:
invokes do_max_length
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(std::codecvtのパブリックメンバ関数) [edit]

Protected member functions

[仮想]
そのようなファイルに書き込むときのように、internTからexternTに文字列を変換します
Original:
converts a string from internT to externT, such as when writing to file
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
[仮想]
そのようなファイルからの読み込みの場合のように、externTからinternTに文字列を変換します
Original:
converts a string from externT to internT, such as when reading from file
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
[仮想]
不完全な変換のためexternT文字の終端文字列を生成する
Original:
generates the termination character sequence of externT characters for incomplete conversion
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
[仮想]
一定の場合には、1 internT文字を生成するのに必要なexternT文字の数を返します
Original:
returns the number of externT characters necessary to produce one internT character, if constant
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
ファセットかどうかをテストし、すべての有効な引数値の恒等変換をエンコードします
Original:
tests if the facet encodes an identity conversion for all valid argument values
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
[仮想]
与えられたinternTバッファに変換することによって消費されるexternT文字列の長さを計算します
Original:
calculates the length of the externT string that would be consumed by conversion into given internT buffer
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]
シングルinternT文字に変換することができるexternT文字の最大数を返します
Original:
returns the maximum number of externT characters that could be converted into a single internT character
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(std::codecvtの仮想プロテクテッドメンバ関数) [edit]


std::codecvt_base から継承

メンバー·タイプ
Original:
Member type
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Definition
enum result { ok, partial, error, noconv };
対象範囲外の列挙型
Original:
Unscoped enumeration type
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列挙定数
Original:
Enumeration constant
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Definition
ok
変換はエラーなしで完了しました
Original:
conversion was completed with no error
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partial
ていないすべてのソースの文字が変換されました
Original:
not all source characters were converted
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error
無効な文字を検出しました
Original:
encountered an invalid character
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noconv
変換が必要なく、入力と出力の種類が同じものはありません
Original:
no conversion required, input and output types are the same
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[編集]

次の例では、UCS2/UTF-8とUTF-16/UTF-8変換と変換の間の違いを示しています:文字列の3番目の文字は有効なのUCS2文字ではありません.
Original:
The following example demonstrates the difference between UCS2/UTF-8 and UTF-16/UTF-8 conversions: the third character in the string is not a valid UCS2 character.
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#include <iostream>
#include <string>
#include <locale>
#include <codecvt>
int main()
{
    // UTF-8 data. The character U+1d10b, musical sign segno, does not fit in UCS2
    std::string utf8 = u8"z\u6c34\U0001d10b";
 
    // the UTF-8 / UTF-16 standard conversion facet
    std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> utf16conv;
    std::u16string utf16 = utf16conv.from_bytes(utf8);
    std::cout << "UTF16 conversion produced " << utf16.size() << " code points:\n";
    for(char16_t c : utf16)
        std::cout << std::hex << std::showbase << c << '\n';
 
    // the UTF-8 / UCS2 standard conversion facet
    std::wstring_convert<std::codecvt_utf8<char16_t>, char16_t> ucs2conv;
    try {
        std::u16string ucs2 = ucs2conv.from_bytes(utf8);
    } catch(const std::range_error& e) {
        std::u16string ucs2 = ucs2conv.from_bytes(utf8.substr(0, ucs2conv.converted()));
        std::cout << "UCS2 failed after producing " << std::dec << ucs2.size()<<" characters:\n";
        for(char16_t c : ucs2)
            std::cout << std::hex << std::showbase << c << '\n';
    }
}

出力:

UTF16 conversion produced 4 code points:
0x7a
0x6c34
0xd834
0xdd0b
UCS2 failed after producing 2 characters:
0x7a
0x6c34

[編集] 参照

Character
conversions
narrow multibyte
(char)
UTF-8
(char)
UTF-16
(char16_t)
UTF-16 mbrtoc16 / c16rtomb codecvt<char16_t, char, mbstate_t>
codecvt_utf8_utf16<char16_t>
codecvt_utf8_utf16<char32_t>
codecvt_utf8_utf16<wchar_t>
N/A
UCS2 No codecvt_utf8<char16_t> codecvt_utf16<char16_t>
UTF-32/UCS4
(char32_t)
mbrtoc32 / c32rtomb codecvt<char32_t, char, mbstate_t>
codecvt_utf8<char32_t>
codecvt_utf16<char32_t>
UCS2/UCS4
(wchar_t)
No codecvt_utf8<wchar_t> codecvt_utf16<wchar_t>
wide
(wchar_t)
codecvt<wchar_t, char, mbstate_t>
mbsrtowcs / wcsrtombs
No No
UTF-8, UTF-16, UTF-32 を含む文字エンコーディング間の変換を行います
(クラステンプレート) [edit]
(C++11)(deprecated in C++17)
標準の codecvt ファセットの動作を変更するためのタグ
(列挙) [edit]
(C++11)(deprecated in C++17)
UTF-16 と UCS2/UCS4 の間で変換を行います
(クラステンプレート) [edit]
(C++11)(deprecated in C++17)
UTF-8 と UTF-16 の間で変換を行います
(クラステンプレート) [edit]