Unit Class Reference

A unit of measurement, plus conversion to pretty-printed output. More...

#include <Unit.h>

Public Types
enum	UnitType {   UNIT_FS , UNIT_HZ , UNIT_VOLTS , UNIT_AMPS ,   UNIT_OHMS , UNIT_BITRATE , UNIT_PERCENT , UNIT_DB ,   UNIT_DBM , UNIT_COUNTS , UNIT_COUNTS_SCI , UNIT_LOG_BER ,   UNIT_RATIO_SCI , UNIT_SAMPLERATE , UNIT_SAMPLEDEPTH , UNIT_WATTS ,   UNIT_UI , UNIT_DEGREES , UNIT_RPM , UNIT_CELSIUS ,   UNIT_RHO , UNIT_HEXNUM , UNIT_PM , UNIT_MILLIVOLTS ,   UNIT_MICROVOLTS , UNIT_VOLT_SEC , UNIT_BYTES , UNIT_W_M2_NM ,   UNIT_W_M2 , UNIT_MICROAMPS , UNIT_FARADS }

Public Member Functions
	Unit (Unit::UnitType t=UNIT_COUNTS)
	Unit (const std::string &rhs)
std::string	ToString () const
	Converts this unit to a string.
std::string	PrettyPrint (double value, int sigfigs=-1, bool useDisplayLocale=true) const
	Prints a value with SI scaling factors. More...
std::string	PrettyPrintInt64 (int64_t value, int sigfigs=-1, bool useDisplayLocale=true) const
	Prints a value with SI scaling factors. More...
std::string	PrettyPrintRange (double pixelMin, double pixelMax, double rangeMin, double rangeMax) const
	Prints a value with SI scaling factors and unnecessarily significant sub-pixel digits removed. More...
double	ParseString (const std::string &str, bool useDisplayLocale=true)
	Parses a string based on the supplied unit. More...
int64_t	ParseStringInt64 (const std::string &str, bool useDisplayLocale=true)
	Parses a string based on the supplied unit. More...
UnitType	GetType ()
bool	operator== (const Unit &rhs)
bool	operator!= (const Unit &rhs)
bool	operator!= (UnitType rhs)
Unit	operator* (const Unit &rhs)
	Multiplies two units and calculates the resulting unit.
Unit	operator/ (const Unit &rhs)
	Divides two units and calculates the resulting unit.

Static Public Member Functions
static void	SetLocale (const char *locale)

Protected Member Functions
void	GetSIScalingFactor (double num, double &scaleFactor, std::string &prefix) const
	Gets the appropriate SI scaling factor for a number.
void	GetUnitSuffix (UnitType type, double num, double &scaleFactor, std::string &prefix, std::string &numprefix, std::string &suffix) const
	Gets the suffix for a unit. More...

Static Protected Member Functions
static void	SetPrintingLocale ()
	Sets the current locale to the user's selected LC_NUMERIC for printing numbers for display.
static void	SetDefaultLocale ()
	Sets the current locale to "C" for interchange.

Protected Attributes
UnitType	m_type

Static Protected Attributes
static locale_t	m_locale
	The user's requested locale for display.
static locale_t	m_defaultLocale
	Handle to the "C" locale, used for interchange.

Detailed Description

A unit of measurement, plus conversion to pretty-printed output.

TODO: add scale factors too?

Member Function Documentation

GetUnitSuffix()

void Unit::GetUnitSuffix ( UnitType  type, double  num, double &  scaleFactor, std::string &  prefix, std::string &  numprefix, std::string &  suffix  ) const

protected

Gets the suffix for a unit.

Note that this function may modify the SI scale factor and prefix

ParseString()

double Unit::ParseString	(	const std::string &	str,
		bool	useDisplayLocale = true
	)

Parses a string based on the supplied unit.

Parameters

str	The string to parse
useDisplayLocale	True if the string is formatted for display (user's locale) False if the string is formatted for serialization ("C" locale regardless of user pref)

ParseStringInt64()

int64_t Unit::ParseStringInt64	(	const std::string &	str,
		bool	useDisplayLocale = true
	)

Parses a string based on the supplied unit.

Parameters

str	The string to parse
useDisplayLocale	True if the string is formatted for display (user's locale) False if the string is formatted for serialization ("C" locale regardless of user pref)

PrettyPrint()

string Unit::PrettyPrint	(	double	value,
		int	sigfigs = -1,
		bool	useDisplayLocale = true
	)		const

Prints a value with SI scaling factors.

Parameters

value	The value
digits	Number of significant digits to display
useDisplayLocale	True if the string is formatted for display (user's locale) False if the string is formatted for serialization ("C" locale regardless of user pref)

PrettyPrintInt64()

string Unit::PrettyPrintInt64	(	int64_t	value,
		int	sigfigs = -1,
		bool	useDisplayLocale = true
	)		const

Prints a value with SI scaling factors.

Parameters

value	The value
digits	Number of significant digits to display
useDisplayLocale	True if the string is formatted for display (user's locale) False if the string is formatted for serialization ("C" locale regardless of user pref)

PrettyPrintRange()

string Unit::PrettyPrintRange	(	double	pixelMin,
		double	pixelMax,
		double	rangeMin,
		double	rangeMax
	)		const

Prints a value with SI scaling factors and unnecessarily significant sub-pixel digits removed.

The rangeMin/rangeMax values are typically used to ensure all axis labels on a graph use consistent units, for example 0.5V / 1.0V / 1.5V rather than 500 mV / 1.0V / 1.5V.

The pixelMin and pixelMax values are used to determine how many digits are actually significant. Rounding is in the upward direction.

For example, if the pixel covers values 1.3979 to 1.4152, this function will return "1.4".

Parameters

pixelMin	Value at the lowest end of the pixel being labeled
pixelMax	Value at the highest end of the pixel being labeled
rangeMin	Value at the lowest end of the channel range
rangeMax	Value at the highest end of the channel range

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The documentation for this class was generated from the following files:

• lib/scopehal/Unit.h
• lib/scopehal/Unit.cpp