#include <evo/bit_array.h>

Detailed Description

template<class TParent>
class evo::BitArraySubsetT< TParent >

A subset of a BitArray.

This references a parent BitArrayT (or is null) and has a similar interface to BitArray
Bits are positioned left-to-right, as if from an array of bools
Modifying bits in this subset actually modifies the parent BitArray
This maintains const-correctness so writes will fail if referencing a const parent
Caution: Resizing, setting, or freeing the parent will invalidate all subsets referencing it

C++11:

Move semantics

Note that this is not a full EvoContainer and doesn't have any iterators.

See BitArrayT notes on performance.
For default parent use BitArraySubset.

Constructors

Read Access

Modifiers

Example

#include <evo/bit_array.h>
#include <evo/io.h>
using namespace evo;
static Console& c = con();
int main() {
    // Create 10-bit array 
    BitArray array(10);
    // Set first and last bits
    array.setbit(0);
    array.setbit(9);
    // Create subset excluding first and last bits
    BitArraySubset subset(array, 1, 8);
    // Set all bits 2-6 in subset, setting bits 3-7 in parent bit array
    subset.setbits(2, 5);
    // Extract and print integer in hex from all 8 bits in subset: 00111110
    uint16 val = subset.extractr<uint16>(0, 8);
    c.out << FmtUInt16(val, fHEX) << NL;
    // Extract and print integer in hex from all 10 bits: 1001111101
    val = array.extractr<uint16>(0, 10);
    c.out << FmtUInt16(val, fHEX) << NL;
    return 0;
}

Output:

3E

27D

Public Types
typedef TParent	Parent
	Parent BitArray type. More...

typedef TParent::Size	Size
	Size integer type. More...

typedef BitArraySubsetT< TParent >	ThisType
	This BitArraySubset type. More...

typedef TParent::Value	Value
	Chunk value type. More...

Public Member Functions
	BitArraySubsetT ()
	Constructor sets as null. More...

	BitArraySubsetT (const Parent &parent)
	Constructor to reference a parent BitArray as read-only. More...

	BitArraySubsetT (Parent &parent)
	Constructor to reference a parent BitArray. More...

	BitArraySubsetT (const Parent &parent, Size pos, Size count=ALL)
	Constructor to reference a subset of parent BitArray as read-only. More...

	BitArraySubsetT (Parent &parent, Size pos, Size count=ALL)
	Constructor to reference a subset of parent BitArray. More...

	BitArraySubsetT (const ThisType &src)
	Copy constructor to reference the same parent and subset. More...

	BitArraySubsetT (ThisType &&src)
	Move constructor (C++11). More...

Size	checkall () const
	Check if all bits are set in subset (const). More...

bool	checkany () const
	Check if any bits are set in subset (const). More...

bool	clearbit (Size pos)
	Clear bit at position in subset. More...

Size	clearbits (Size pos=0, Size count=ALL) const
	Clear count bits at position in subset. More...

Size	countbits (bool value=true) const
	Count number of bits set or cleared in subset (const). More...

bool	empty () const
	Get whether empty. More...

template<class U = ulong>
U	extractl (Size pos=0, Size count=ALL) const
	Extract bits from subset. More...

template<class U = ulong>
U	extractr (Size pos=0, Size count=ALL) const
	Extract bits from subset. More...

template<class U >
bool	format (U &out, int base=fBIN)
	Format bits from subset to stream or string using base. More...

bool	getbit (Size pos) const
	Get bit at position in subset (const). More...

bool	null () const
	Get whether null. More...

Size	offset () const
	Get subset offset position in parent. More...

bool	operator!= (const ThisType &data) const
	Inequality operator. More...

ThisType &	operator= (ThisType &&src)
	Move assignment operator (C++11). More...

ThisType &	operator= (const ThisType &src)
	Assignment operator to copy a subset, referencing the same parent. More...

ThisType &	operator= (const Parent &parent)
	Assignment operator to reference a new parent as read-only. More...

ThisType &	operator= (Parent &parent)
	Assignment operator to reference a new parent. More...

bool	operator== (const ThisType &data) const
	Equality operator. More...

bool	operator[] (Size pos) const
	Get bit at position in subset (const). More...

const Parent *	parent () const
	Get pointer to parent BitArray. More...

Parent *	parent_nonconst ()
	Get non-const pointer to parent BitArray. More...

bool	readonly () const
	Get whether subset is read-only, meaning writes will fail. More...

ThisType &	set ()
	Set as null. More...

ThisType &	set (const ThisType &src, Size pos=0, Size count=ALL)
	Set as subset of another subset. More...

ThisType &	set (const Parent &parent, Size pos=0, Size count=ALL)
	Set as read-only subset of BitArray. More...

ThisType &	set (Parent &parent, Size pos=0, Size count=ALL)
	Set as subset of BitArray. More...

bool	setbit (Size pos, bool value=true)
	Set or clear bit at position in subset. More...

Size	setbits (Size pos=0, Size count=ALL, bool value=true)
	Set or clear count bits at position in subset. More...

Size	size () const
	Get size as number of bits in subset. More...

template<class U >
bool	store (Size pos, Size count, U value)
	Stores bits from value in subset. More...

bool	togglebit (Size pos)
	Toggle bit at position in subset. More...

Size	togglebits (Size pos=0, uint count=ALL)
	Toggle count bits at position in subset. More...

Member Typedef Documentation

◆ Parent

typedef TParent Parent

Parent BitArray type.

◆ Size

typedef TParent::Size Size

Size integer type.

◆ ThisType

typedef BitArraySubsetT<TParent> ThisType

This BitArraySubset type.

◆ Value

typedef TParent::Value Value

Chunk value type.

Constructor & Destructor Documentation

◆ BitArraySubsetT() [1/7]

BitArraySubsetT ( )

inline

Constructor sets as null.

◆ BitArraySubsetT() [2/7]

BitArraySubsetT ( const Parent & parent )

inline

Constructor to reference a parent BitArray as read-only.

Parameters

parent Parent to reference (const)

◆ BitArraySubsetT() [3/7]

BitArraySubsetT ( Parent & parent )

inline

Constructor to reference a parent BitArray.

Parameters

parent Parent to reference

◆ BitArraySubsetT() [4/7]

BitArraySubsetT	(	const Parent &	parent,
		Size	pos,
		Size	count = `ALL`
	)

inline

Constructor to reference a subset of parent BitArray as read-only.

Parameters

parent	Parent to reference (const)
pos	Bit posiiton in parent for subset
count	Number of bits in parent for subset

◆ BitArraySubsetT() [5/7]

BitArraySubsetT	(	Parent &	parent,
		Size	pos,
		Size	count = `ALL`
	)

inline

Constructor to reference a subset of parent BitArray.

Parameters

parent	Parent to reference
pos	Bit posiiton in parent for subset
count	Number of bits in parent for subset

◆ BitArraySubsetT() [6/7]

BitArraySubsetT ( const ThisType & src )

inline

Copy constructor to reference the same parent and subset.

Parameters

src	Subset to copy from

◆ BitArraySubsetT() [7/7]

BitArraySubsetT ( ThisType && src )

inline

Move constructor (C++11).

Parameters

src	Source to move

Member Function Documentation

◆ checkall()

Size checkall ( ) const

inline

Check if all bits are set in subset (const).

This scans and checks that all bits are set in subset, and stops early if a bit isn't set

Returns: Whether all bits are set, true if empty

◆ checkany()

bool checkany ( ) const

inline

Check if any bits are set in subset (const).

This scans and checks that at least 1 bit is set in subset, and stops early if a bit is set

Returns: Whether at least 1 bit is set, false if all bits are cleared or if empty

◆ clearbit()

bool clearbit ( Size pos )

inline

Clear bit at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to clear, 0 for first bit on left, etc

Returns: Whether successful, false if pos out of bounds

See also: clearbits(), setbit(), togglebit(), getbit()

◆ clearbits()

Size clearbits	(	Size	pos = `0`,
		Size	count = `ALL`
	)		const

inline

Clear count bits at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to clear, 0 for first bit on left, etc
count	Number of bits to clear from pos, ALL for all from pos in subset

Returns: Number of bits modified, 0 if out of bounds or count=0

See also: clearbit(), setbits(), togglebits()

◆ countbits()

Size countbits ( bool value = true ) const

inline

Count number of bits set or cleared in subset (const).

This scans through all bits in subset and counts the number of bits set or cleared
For best performace see notes for bits_popcount()

Parameters

value Whether to count bits set, false to count cleared bits (not set)

Returns: Number of bits set or cleared

◆ empty()

bool empty ( ) const

inline

Get whether empty.

Empty when size() is 0

Returns: Whether empty

◆ extractl()

U extractl	(	Size	pos = `0`,
		Size	count = `ALL`
	)		const

inline

Extract bits from subset.

Bits are stored in chunks but are extracted left-to-right, as if from an array of bools
- This works the same regardless of chunk size, or system endianness
Extracted bits are left-aligned in the return value, and the left-most bit is the "first" bit (as if from an array of bools)
- Example with 3 extracted bits 111 returned as uint8: 11100000

Template Parameters

U	Return type for extracted bits, must be unsigned (uint, ulong, uint32, etc) – defaults to `ulong` in C++11 or newer

Parameters

pos	Bit position to extract from, 0 for first bit on left, etc
count	Number of bits to extract, truncated if larger than bitsize or return value

Returns: Extracted bits, aligned to the left

See also: extractr(), get(), store()

◆ extractr()

U extractr	(	Size	pos = `0`,
		Size	count = `ALL`
	)		const

inline

Extract bits from subset.

Bits are stored in chunks but are extracted left-to-right, as if from an array of bools
- This works the same regardless of chunk size, or system endianness
Extracted bits returned are right-aligned so the result is an integer
- Example with 3 extracted bits 111 returned as uint8: 00000111 or 7 in decimal
A count larger than bits in return type will be truncated – this should be avoided as it may not be easy to tell how many bits were truncated
- For example, if you pass count=9 with return type uint8 then this uses count=8
Otherwise count may go out of bit array bounds without truncation – bits from out of bounds are set to 0 and still are right-aligned according to count

Template Parameters

U	Return type for extracted bits, must be unsigned (uint, ulong, uint32, etc) – defaults to `ulong` in C++11 or newer

Parameters

pos	Bit position to extract from, 0 for first bit on left, etc
count	Number of bits to extract, ALL for num bits in return type, truncated if larger than bits in return type

Returns: Extracted bits, aligned to the right

See also: extractl(), get(), store()

◆ format()

bool format	(	U &	out,
		int	base = `fBIN`
	)

inline

Format bits from subset to stream or string using base.

If there aren't enough bits for the last digit then zero-bits are padded on the right to finish, ex: 1 set bit formatted as hex is 8, or 5 set bits formatted as hex is F8
- Bits are ordered left-to-right, as if from an array of bools, so this padding is added at the end

Template Parameters

U	Output string/stream type, deduced from arguments

Parameters

out	Output string or stream (or associated Format object) to format to
base	Base to format as, must be a power of 2 between 2-32 (inclusive), add 100 for lowercase letters, or use enum: fBIN for binary fOCT for octal fHEX for hexidecimal fHEXL for lowercase hexadecimal

Returns: Whether successful, false on stream error or if base is invalid

◆ getbit()

bool getbit ( Size pos ) const

inline

Get bit at position in subset (const).

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to get, 0 for first bit on left, etc

Returns: Bit value, false if pos is out of bounds

See also: setbit(), clearbit(), togglebit()

◆ null()

bool null ( ) const

inline

Get whether null.

Always empty when null

Returns: Whether null

◆ offset()

Size offset ( ) const

inline

Get subset offset position in parent.

Returns: Offset position

◆ operator!=()

bool operator!= ( const ThisType & data ) const

inline

Inequality operator.

Parameters

data	Subset to compare to

Returns: Whether inequal

◆ operator=() [1/4]

ThisType& operator= ( ThisType && src )

inline

Move assignment operator (C++11).

Parameters

src	Source to move

Returns: This

◆ operator=() [2/4]

ThisType& operator= ( const ThisType & src )

inline

Assignment operator to copy a subset, referencing the same parent.

Parameters

src	Subset to copy from

Returns: This

◆ operator=() [3/4]

ThisType& operator= ( const Parent & parent )

inline

Assignment operator to reference a new parent as read-only.

Parameters

parent Parent to reference (const)

Returns: This

◆ operator=() [4/4]

ThisType& operator= ( Parent & parent )

inline

Assignment operator to reference a new parent.

Parameters

parent Parent to reference

Returns: This

◆ operator==()

bool operator== ( const ThisType & data ) const

inline

Equality operator.

Parameters

data	Subset to compare to

Returns: Whether equal

◆ operator[]()

bool operator[] ( Size pos ) const

inline

Get bit at position in subset (const).

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to get, 0 for first bit on left, etc

Returns: Bit value, false if pos is out of subset bounds

See also: getbit(), setbit()

◆ parent()

const Parent* parent ( ) const

inline

Get pointer to parent BitArray.

Returns: Parent pointer, NULL if null

◆ parent_nonconst()

Parent* parent_nonconst ( )

inline

Get non-const pointer to parent BitArray.

Returns: Parent pointer, NULL if read-only or null

◆ readonly()

bool readonly ( ) const

inline

Get whether subset is read-only, meaning writes will fail.

Null is also considered read-only

Returns: Whether read-only

◆ set() [1/4]

ThisType& set ( )

inline

Set as null.

Returns: This

◆ set() [2/4]

ThisType& set	(	const ThisType &	src,
		Size	pos = `0`,
		Size	count = `ALL`
	)

inline

Set as subset of another subset.

Parameters

src	Subset to copy from
pos	Bit position for subset of subset
count	Number of bits for subset of subset

Returns: This

◆ set() [3/4]

ThisType& set	(	const Parent &	parent,
		Size	pos = `0`,
		Size	count = `ALL`
	)

inline

Set as read-only subset of BitArray.

Parameters

parent	Parent to reference (const)
pos	Bit posiiton in parent for subset
count	Number of bits in parent for subset

◆ set() [4/4]

ThisType& set	(	Parent &	parent,
		Size	pos = `0`,
		Size	count = `ALL`
	)

inline

Set as subset of BitArray.

Parameters

parent	Parent to reference
pos	Bit posiiton in parent for subset
count	Number of bits in parent for subset

◆ setbit()

bool setbit	(	Size	pos,
		bool	value = `true`
	)

inline

Set or clear bit at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to set, 0 for first bit on left, etc
value	Bit value to set, true to set bit, false to clear bit

Returns: Whether successful, false if pos out of bounds

See also: setbits(), clearbit(), togglebit(), getbit()

◆ setbits()

Size setbits	(	Size	pos = `0`,
		Size	count = `ALL`,
		bool	value = `true`
	)

inline

Set or clear count bits at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to set, 0 for first bit on left, etc
count	Number of bits to set from pos, ALL for all from pos in subset
value	Bit value to set, true to set bits, false to clear bits

Returns: Number of bits modified, 0 if out of bounds or count=0

See also: setbit(), clearbits(), togglebits()

◆ size()

Size size ( ) const

inline

Get size as number of bits in subset.

Returns: Subset size, 0 if empty

◆ store()

bool store	(	Size	pos,
		Size	count,
		U	value
	)

inline

Stores bits from value in subset.

Bits are stored in chunks but are positioned left-to-right, as if in an array of bools
This works the same regardless of chunk size, or system endianness
Value bits are taken from the right so integers can be stored
Example value 00000111 with count=3 would store 111 (3 right-most bits) or 7 in decimal
Bits stored after end of subset are truncated and lost
Caution: If count exceeds value size, count is capped at that size – only bits from value are stored

Template Parameters

U	Value type to store, signed value is treated as unsigned – inferred from `value` param

Parameters

pos	Bit position in subset to store at, 0 for first bit on left, etc
count	Number of bits to store from value
value	Value to store (`count` right-most bits are stored)

Returns: Whether successful, false if pos is out of bounds

See also: setbit(), extractl(), extractr()

◆ togglebit()

bool togglebit ( Size pos )

inline

Toggle bit at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to toggle, 0 for first bit on left, etc

Returns: Whether successful, false if pos out of bounds

See also: togglebits(), setbit(), getbit()

◆ togglebits()

Size togglebits	(	Size	pos = `0`,
		uint	count = `ALL`
	)

inline

Toggle count bits at position in subset.

Bits are counted left-to-right, as if from an array of bools

Parameters

pos	Bit position in subset to toggle, 0 for first bit on left, etc
count	Number of bits to toggle from pos, ALL for all from pos in subset

Returns: Number of bits modified, 0 if out of bounds or count=0

See also: togglebit(), setbits()

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

evo/bit_array.h

Detailed Description

template<class TParent> class evo::BitArraySubsetT< TParent >

Public Types

Public Member Functions

Member Typedef Documentation

◆ Parent

◆ Size

◆ ThisType

◆ Value

Constructor & Destructor Documentation

◆ BitArraySubsetT() [1/7]

◆ BitArraySubsetT() [2/7]

◆ BitArraySubsetT() [3/7]

◆ BitArraySubsetT() [4/7]

◆ BitArraySubsetT() [5/7]

◆ BitArraySubsetT() [6/7]

◆ BitArraySubsetT() [7/7]

Member Function Documentation

◆ checkall()

◆ checkany()

◆ clearbit()

◆ clearbits()

◆ countbits()

◆ empty()

◆ extractl()

◆ extractr()

◆ format()

◆ getbit()

◆ null()

◆ offset()

◆ operator!=()

◆ operator=() [1/4]

◆ operator=() [2/4]

◆ operator=() [3/4]

◆ operator=() [4/4]

◆ operator==()

◆ operator[]()

◆ parent()

◆ parent_nonconst()

◆ readonly()

◆ set() [1/4]

◆ set() [2/4]

◆ set() [3/4]

◆ set() [4/4]

◆ setbit()

◆ setbits()

◆ size()

◆ store()

◆ togglebit()

◆ togglebits()

template<class TParent>
class evo::BitArraySubsetT< TParent >