etl/docs/strings/string_stream.md

title
string_stream

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Streaming types

string_stream
wstring_stream
u16string_stream
u32string_stream

Classes to build strings using a streaming API. Uses etl::basic_format_spec to define the required formatting.

The documentation below is for etl::string_stream. The other streams have a similar API, though using w, u8, u16 or u32 types.

Member functions

explicit string_stream(etl::istring& str)

Description
Construct, using the supplied string as a buffer. Uses the default format_spec.

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string_stream(etl::istring& str, const etl::format_spec& spec)

Description
Construct, using the supplied string as a buffer. Initialised with the supplied format_spec.

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void set_format(const etl::format_spec& spec_)

Description
Sets a new format_spec to use.

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const etl::format_spec& get_format() const

Description
Gets the current format_spec.

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etl::istring& str()

Description
Gets a reference to the internal string.

const etl::istring& str() const

Description
Gets a const reference to the internal string.

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void str(const etl::istring::const_pointer p)

Description
Resets the internal string to the text pointed to by p.

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void str(const etl::istring& text)

Description
Resets the internal string to text.

Streaming operators

string_stream& operator <<(string_stream& ss, T value)

Description
Where T may be one of the following:-

Any fundamental type.
etl::format_spec
etl::setb0ase(n)
etl::bin
etl::oct
etl::dec
etl::hex
etl::setfill(c)
etl::setw(n)
etl::setprecision(n)
etl::left
etl::right
etl::boolalpha
etl::noboolalpha
etl::uppercase
etl::nouppercase
etl::showbase
etl::noshowbase
etl::string
etl::istring
etl::string_view
const char*

See etl::format_spec

Custom user types may be streamed by overloading the streaming operator.

Examples

Using format_spec

etl::format_spec   format1 = etl::format_spec().hex().width(8).fill('0');
etl::format_spec   format2;
etl::format_spec   format3 = etl::format_spec().width(6).fill('#').precision(3);
etl::string<50>    text;
etl::string_stream stream(text);

stream << format1 << 1193046 << format2 << " " << format3 << 3.1415;
const etl::istring& result = stream.str();

text is set to "00123456 #3.142".

Using stream manipulators

etl::string<50>    text;
etl::string_stream stream(text);

stream << etl::hex << etl::setw(8) << etl::setfill('0') << 1193046 
       << etl::setw(0) << " " 
       << etl::setw(6) << etl::setfill('#') << etl::setprecision(3) << 3.1415;
const etl::istring& result = stream.str();

text is set to "00123456 #3.142".