basic_format_spec

format_spec

wformat_spec

u16format_spec

u32format_spec

A template class and four typedefs that allow a specification for string formatting functions and streams.

It defines specifications for strings, bool, integrals, floating point and pointers.

Used in conjunction with etl::to_string and string streams

The class stores the following specifications:

base The number base. Predefined settings for binary, octal, decimal and hex.

width The total minimum field width for the value's text representation.

precision The total number of decimal places.

upper_case If true then numerical digits for bases >10 are in upper case.

left_justified If true then the text representation is left justified with padding up to the field width on the right.

boolalpha If true then Boolean values are rendered as "true" and "false".

showbase If true then binary, octal and hex values are prefixed with the base tag.

fill Determines the character used for the padding for width.

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basic_format_spec

template <typename TString>

class basic_format_spec

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basic_format_spec()

The default constructor.

Sets:-

base : 10

width : 0

precision : 0

upper case : false

left justified : false

boolalpha : false

show base

fill : ' '

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basic_format_spec& base(const uint32_t b)

Sets the base to b.

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basic_format_spec& binary()

Sets the base to binary.

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basic_format_spec& octal()

Sets the base to octal.

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basic_format_spec& hex()

Sets the base to hexadecimal.

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basic_format_spec& octal()

Sets the base to octal.

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uint32_t get_base() const

Returns the current setting for base.

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basic_format_spec& width(const uint32_t w)

Sets the width to w.

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uint32_t get_width() const

Returns the current width value.

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basic_format_spec& precision(const uint32_t p)

Sets the precision to p.

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uint32_t get_precision() const

Returns the current precision value.

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basic_format_spec& upper_case(const bool b)

Sets the upper case flag to b.

Only affects numerical output such as hexadecimal.

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bool is_upper_case() const

Returns true if the upper case flag is set.

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basic_format_spec& show_base(const bool b)

Sets the showbase flag to b.

Only affects binary and hexadecimal output.

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bool is_show_base() const

Returns true if the showbase flag is set.

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basic_format_spec& fill(const typename TString::value_type c)

Sets the fill character to c.

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typename TString::value_type get_fill() const

Returns the fill character.

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basic_format_spec& left()

Sets the left justified flag to true.

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bool is_left() const

Returns true if the left justified flag is set.

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basic_format_spec& right()

Sets the left justified flag to false.

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bool is_right() const

Returns true if the left justified flag is clear.

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basic_format_spec& boolalpha(bool b)

Sets the bool alpha flag to b.

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bool is_boolalpha() const

Returns true if the bool alpha flag is set.

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Typedefs

typedef etl::basic_format_spec<etl::istring> format_spec;

typedef etl::basic_format_spec<etl::iwstring> wformat_spec;

typedef etl::basic_format_spec<etl::iu16string> u16format_spec;

typedef etl::basic_format_spec<etl::iu32string> u32format_spec;

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Stream manipulators

These manipulators are used in conjunction with the ETL's string streams.

Streams may also use a format spec as a manipulator.

setbase(uint32_t base)

Sets the base for numerical output to base.

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setw(uint32_t width)

Sets the format width to width.

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template <typename TChar>

setfill(TChar fill)

Sets the fill character to fill.

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setprecision(uint32_t precision)

Sets the number of decimal places to precision.

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bin

Sets the base for numerical output to binary.

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oct

Sets the base for numerical output to octal.

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dec

Sets the base for numerical output to decimal.

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hex

Sets the base for numerical output to hexadecimal.

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left

Sets the alignment to left.

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right

Sets the alignment to right.

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boolalpha

Sets the boolalpha flag to true.

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noboolalpha

Sets the boolalpha flag to false.

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uppercase

Sets the uppercase flag to true.

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nouppercase

Sets the uppercase flag to false.

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showbase

Sets the showbase flag to true.

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noshowbase

Sets the showbase flag to false.

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Example (to_string)

etl::format_spec format;

// Format as a hex character, minimum fill width of 8, fill with zeros.

format.hex().width(8).fill('0');

etl::string<8> text;

// 'text' is set to "00123456"

etl::to_string(1193046, text, format);

// Format minimum fill width of 8, fill with space and three decimal digits.

format.width(8).fill(' ').precision(3);

// 'text' is set to " 3.142"

etl::to_string(3.1415, text, format);

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Example (string_stream)

etl::string<20> buffer;

etl::string_stream stream(buffer);

// Manipulators

stream << etl::showbase

<< etl::bin << 123456 << " "

<< etl::oct << 123456 << " "

<< etl::dec << 123456 << " "

<< etl::hex << 123456;

The generated string:-

0b11110001001000000 0361100 123456 0x1e240

// Format spec

etl::format_spec format;

format.show_base(true).hex();

stream << format << 123456;

The generated string:-

0x1e240

format_spec.h