std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::from_bytes
From cppreference.com
< cpp | locale | wstring convert
Defined in header <locale>
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wide_string from_bytes( char byte ); |
(1) | |
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wide_string from_bytes( const char* ptr );
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(2) | |
wide_string from_bytes( const byte_string& str ); |
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wide_string from_bytes(
const
char
* first, const
char
* last )
;
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(4) | |
Converts a byte sequence to a wide string using the facet pointed to by cvtptr .
1) The byte sequence only consists of one element byte.
2) The byte sequence is the null-terminated sequence beginning at ptr.
3) The byte sequence is the sequence contained in str.
4) The byte sequence is the range
[first, last)
Before the conversion begins, if *this was not constructed with constructor overload (3), cvtstate
The number of input elements successfully converted will be stored in cvtcount .
Return value
If the conversion succeeds, returns the conversion result. Otherwise, if *this is constructed with constructor overload (4), returns wide_err_string
Exceptions
If the conversion fails and *this was not constructed with constructor overload (4), throws std::range_error
Example
Run this code
#include <codecvt> #include <cstdint> #include <iostream> #include <locale> #include <string> int main() { std::string utf8 = "z\u00df\u6c34\U0001d10b"; // or u8"zß水𝄋" // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b"; // the UTF-8 / UTF-16 standard conversion facet std::u16string utf16 = std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>{}.from_bytes(utf8.data()); std::cout << "UTF-16 conversion produced " << utf16.size() << " code units: " << std::showbase; for (char16_t c : utf16) std::cout << std::hex << static_cast<std::uint16_t>(c) << ' '; // the UTF-8 / UTF-32 standard conversion facet std::u32string utf32 = std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t>{}.from_bytes(utf8); std::cout << "\nUTF-32 conversion produced " << std::dec << utf32.size() << " code units: "; for (char32_t c : utf32) std::cout << std::hex << static_cast<std::uint32_t>(c) << ' '; std::cout << '\n'; }
Output:
UTF-16 conversion produced 5 code units: 0x7a 0xdf 0x6c34 0xd834 0xdd0b UTF-32 conversion produced 4 code units: 0x7a 0xdf 0x6c34 0x1d10b
See also
| converts a wide string into a byte string (public member function) |
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| converts a narrow multibyte character string to wide string, given state (function) |
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[virtual]
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converts a string from ExternT to InternT, such as when reading from file (virtual protected member function of std::codecvt<InternT,ExternT,StateT>) |