QStringEncoder 类

QStringEncoder 类提供用于文本基于状态的编码器。更多...

头：	#include <QStringEncoder>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake:	QT += core
继承：	QStringConverter

所有成员列表，包括继承成员

注意： 此类的所有函数可重入 .

公共函数

	QStringEncoder ()
	QStringEncoder (QStringConverter::Encoding encoding , QStringConverter::Flags flags = Flag::Default)
	QStringEncoder (const char * name , QStringConverter::Flags flags = Flag::Default)
char *	appendToBuffer (char * out , QStringView in )
DecodedData<const QString &>	encode (const QString & in )
DecodedData<QStringView>	encode (QStringView in )
qsizetype	requiredSpace (qsizetype inputLength ) const
DecodedData<const QString &>	operator() (const QString & in )
DecodedData<QStringView>	operator() (QStringView in )

详细描述

A text encoder converts text from Qt's internal representation into an encoded text format using a specific encoding.

Converting a string from Unicode to the local encoding can be achieved using the following code:

QString string = "...";
auto fromUtf16 = QStringEncoder(QStringEncoder::Utf8);
QByteArray encodedString = fromUtf16(string);

The encoder remembers any state that is required between calls, so converting data received in chunks, for example, when receiving it over a network, is just as easy, by calling the encoder whenever new data is available:

auto fromUtf16 = QStringEncoder(QStringEncoder::Utf8);
QByteArray encoded;
while (new_data_available()) {
    QString chunk = get_new_data();
    encoded += fromUtf16(chunk);
}

The QStringEncoder object maintains state between chunks and therefore works correctly even if a UTF-16 surrogate character is split between chunks.

QStringEncoder objects can't be copied because of their internal state, but can be moved.

另请参阅 QStringConverter and QStringDecoder .

成员函数文档编制

DecodedData < QStringView > QStringEncoder:: encode ( QStringView in )

DecodedData < QStringView > QStringEncoder:: operator() ( QStringView in )

DecodedData <const QString &> QStringEncoder:: encode (const QString & in )

DecodedData <const QString &> QStringEncoder:: operator() (const QString & in )

转换 in and returns a struct that is implicitly convertible to QByteArray .

QString string = "...";
auto fromUtf16 = QStringEncoder(QStringEncoder::Utf8);
auto data = fromUtf16(string); // data's type is QStringEncoder::DecodedData<const QString &>
QByteArray encodedString = fromUtf16(string); // Implicit conversion to QByteArray
// Here you have to cast "data" to QByteArray
auto func = [&]() { return !fromUtf16.hasError() ? QByteArray(data) : "foo"_ba; }

`[constexpr noexcept]` QStringEncoder:: QStringEncoder ()

Default constructs an encoder. The default encoder is not valid, and can't be used for converting text.

`[explicit constexpr]` QStringEncoder:: QStringEncoder ( QStringConverter::Encoding encoding , QStringConverter::Flags flags = Flag::Default)

Creates an encoder object using encoding and flags .

`[explicit]` QStringEncoder:: QStringEncoder (const char * name , QStringConverter::Flags flags = Flag::Default)

Creates an encoder object using name and flags 。若 name is not the name of a known encoding an invalid converter will get created.

另请参阅 isValid ().

char QStringEncoder:: appendToBuffer ( char out , QStringView in )

Encodes in and writes the encoded result into the buffer starting at out . Returns a pointer to the end of the data written.

注意： out must be large enough to be able to hold all the decoded data. Use requiredSpace () to determine the maximum size requirement to be able to encode in .

另请参阅 requiredSpace ().

qsizetype QStringEncoder:: requiredSpace ( qsizetype inputLength ) const

Returns the maximum amount of characters required to be able to process inputLength decoded data.

另请参阅 appendToBuffer ().