StringFlt< T, PADDING > Struct Template Reference

#include <evo/string.h>

Inheritance diagram for StringFlt< T, PADDING >:

Detailed Description

template<class T = double, int PADDING = 1>
struct evo::StringFlt< T, PADDING >

String fixed-size buffer for formatting a floating point number.

• This is used for efficiently formatting a floating point number to a string buffer, without allocating memory
• Useful for setting up a terminated string pointer to pass to a low-level function

Template Parameters

T	Floating point type
PADDING	Additional padding for buffer, defaults to 1 for terminator

Example

This example uses printf() as a function that requires a terminated string.

#include <evo/string.h>
#include <stdio.h>
using namespace evo;

int main() {
    StringFlt<double> str1(1.23);
    printf("%s\n", str1.data());

    StringFlt<double> str2;
    printf("%s\n", str2.set(66.77));

    return 0;
}

Output:

1.23
66.77

Classes
struct	NumInfo
	Advanced: Special structure used to avoid automatically allocating memory when a bigger buffer is needed. More...

Public Types
typedef ListBase< char, StrSizeT >	ListBaseType
	List base type (this) More...
typedef StrSizeT	Size
	Size type. More...
typedef StringFlt< T, PADDING >	ThisType
	This type. More...

Public Member Functions
	StringFlt ()
	Constructor intializes to null. More...
	StringFlt (T num, int precision=fPREC_AUTO, bool terminated=true)
	Constructor intializes with set(). More...
	~StringFlt ()
	Destructor. More...
char *	data ()
	Get formatted string pointer. More...
ThisType &	set ()
	Set as null. More...
char *	set (T num, int precision=fPREC_AUTO, bool terminated=true, NumInfo *info=NULL)
	Set floating point number and format to string. More...
Size	size () const
	Get formatting string size. More...

Public Attributes
char	buffer [BUF_SIZE]
	String buffer More...
char *	data_
	Data pointer, NULL if null. More...
StrSizeT	size_
	Data size as item count, 0 if empty or null. More...

Static Public Attributes
static const int	BUF_SIZE = FloatT<T>::MAXDIGITS_AUTO + PADDING
	Buffer size. More...

Member Typedef Documentation

ListBaseType

typedef ListBase<char ,StrSizeT > ListBaseType

inherited

List base type (this)

Size

typedef StrSizeT Size

Size type.

ThisType

typedef StringFlt<T,PADDING> ThisType

This type.

Constructor & Destructor Documentation

StringFlt() [1/2]

StringFlt ( )

inline

Constructor intializes to null.

StringFlt() [2/2]

StringFlt ( T  num, int  precision = fPREC_AUTO, bool  terminated = true  )

inline

Constructor intializes with set().

• For special cases where stack buffer isn't big enough, this allocates the needed memory internally (which is freed by destructor)

Parameters

num	Number to set/format
precision	Formatting precision (number of fractional digits), 0 for none, fPREC_AUTO for automatic
terminated	Whether to add terminator after number

~StringFlt()

~StringFlt ( )

inline

Destructor.

Member Function Documentation

data()

char* data ( )

inline

Get formatted string pointer.

• This is null until set(T,int,bool,uint) is called

Returns

String pointer, NULL if null

set() [1/2]

ThisType& set ( )

inline

Set as null.

Returns

This

set() [2/2]

char* set ( T  num, int  precision = fPREC_AUTO, bool  terminated = true, NumInfo *  info = NULL  )

inline

Set floating point number and format to string.

• For optimizing a special case where more memory is needed:
  • 1. Pass info=NULL (the default): this allocates the needed memory internally (which is freed by destructor) and formatting always succeeds
  • 2. Advanced: Pass an object pointer for info: this populates the info object and returns NULL, call info->format() to finish formatting with your own buffer
    • This allows optimization with your own buffer to minimize memory allocs
  • These cases don't apply when precision=fPREC_AUTO as the stack buffer is always big enough for automatic precision formatting (which uses scientific notation if needed)

Parameters

num	Number to set/format
precision	Formatting precision (number of fractional digits), 0 for none, fPREC_AUTO for automatic
info	Used when more memory is needed: NULL to alloc internally and free in destructor, otherwise this is populated and NULL is returned
terminated	Whether to add terminator after number
info	NULL by default, otherwise a non-NULL value enables optimization for a special case (see above)

Returns

Pointer to formatted string in buffer, NULL if info != NULL and a buffer alloc is needed (see above)

size()

Size size ( ) const

inline

Get formatting string size.

• Padding is not included in size

Returns

string size in bytes, 0 if null

Member Data Documentation

BUF_SIZE

const int BUF_SIZE = FloatT<T>::MAXDIGITS_AUTO + PADDING

static

Buffer size.

buffer

char buffer[BUF_SIZE]

String buffer

data_

char * data_

inherited

Data pointer, NULL if null.

size_

StrSizeT size_

inherited

Data size as item count, 0 if empty or null.

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The documentation for this struct was generated from the following file:

• evo/string.h