Detailed Description

template<typename HighType>
class stxxl::uint_pair< HighType >

Construct an 40-bit or 48-bit unsigned integer stored in five or six bytes.

The purpose of this class is to provide integers with smaller data storage footprints when more than 32-bit, but less than 64-bit indexes are needed. This is commonly the case for storing file offsets and indexes. Here smaller types currently suffice for files < 1 TiB or < 16 TiB.

The class combines a 32-bit integer with a HighType (either 8-bit or 16-bit) to get a larger type. Only unsigned values are supported, which fits the general application of file offsets.

Calculation in uint_pair are generally done by transforming everything to 64-bit data type, so that 64-bit register arithmetic can be used. The exception here is increment and decrement, which is done directly on the lower/higher part. Not all arithmetic operations are supported, patches welcome if you really need the operations.

Definition at line 52 of file uint_types.h.

Public Types
typedef HighType	high_type
	higher part type, currently either 8-bit or 16-bit More...

typedef uint32	low_type
	lower part type, always 32-bit More...

Public Member Functions
	uint_pair ()
	empty constructor, does not even initialize to zero! More...

	uint_pair (const low_type &l, const high_type &h)
	construct unit pair from lower and higher parts. More...

	uint_pair (const uint_pair &a)
	copy constructor More...

	uint_pair (const uint32 &a)
	const from a simple 32-bit unsigned integer More...

	uint_pair (const int32 &a)
	const from a simple 32-bit signed integer More...

	uint_pair (const uint64 &a)
	construct from an uint64 (unsigned long long) More...

	operator uint64 () const
	implicit cast to an unsigned long long More...

bool	operator!= (const uint_pair &b) const
	inequality checking operator More...

uint_pair &	operator++ ()
	prefix increment operator (directly manipulates the integer parts) More...

uint_pair &	operator+= (const uint_pair &b)
	addition operator (uses 64-bit arithmetic) More...

uint_pair &	operator-- ()
	prefix decrement operator (directly manipulates the integer parts) More...

bool	operator< (const uint_pair &b) const
	less-than comparison operator More...

bool	operator<= (const uint_pair &b) const
	less-or-equal comparison operator More...

bool	operator== (const uint_pair &b) const
	equality checking operator More...

bool	operator> (const uint_pair &b) const
	greater comparison operator More...

bool	operator>= (const uint_pair &b) const
	greater-or-equal comparison operator More...

uint64	u64 () const
	return the number as a uint64 More...

uint64	ull () const
	return the number as an uint64 (unsigned long long) More...

Static Public Member Functions
static uint_pair	max ()
	return an uint_pair instance containing the largest value possible More...

static uint_pair	min ()
	return an uint_pair instance containing the smallest value possible More...

Static Public Attributes
static const size_t	bytes = sizeof(low_type) + sizeof(high_type)
	number of bytes in uint_pair More...

static const size_t	digits = low_bits + high_bits
	number of binary digits (bits) in uint_pair More...

Static Private Member Functions
static unsigned_type	high_max ()
	return highest value storable in higher part, also used as a mask. More...

static unsigned_type	low_max ()
	return highest value storable in lower part, also used as a mask. More...

Private Attributes
high_type	high
	member containing higher significant integer value More...

low_type	low
	member containing lower significant integer value More...

Static Private Attributes
static const size_t	high_bits = 8 * sizeof(high_type)
	number of bits in the higher integer part, used a bit shift value. More...

static const size_t	low_bits = 8 * sizeof(low_type)
	number of bits in the lower integer part, used a bit shift value. More...

Friends
std::ostream &	operator<< (std::ostream &os, const uint_pair &a)
	make a uint_pair outputtable via iostreams, using unsigned long long. More...

Member Typedef Documentation

template<typename HighType >

typedef HighType stxxl::uint_pair< HighType >::high_type

higher part type, currently either 8-bit or 16-bit

Definition at line 58 of file uint_types.h.

template<typename HighType >

typedef uint32 stxxl::uint_pair< HighType >::low_type

lower part type, always 32-bit

Definition at line 56 of file uint_types.h.

Constructor & Destructor Documentation

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair ( )

inline

empty constructor, does not even initialize to zero!

Definition at line 92 of file uint_types.h.

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair	(	const low_type &	l,
		const high_type &	h
	)

inline

construct unit pair from lower and higher parts.

Definition at line 104 of file uint_types.h.

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair ( const uint_pair< HighType > & a )

inline

copy constructor

Definition at line 109 of file uint_types.h.

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair ( const uint32 & a )

inline

const from a simple 32-bit unsigned integer

Definition at line 114 of file uint_types.h.

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair ( const int32 & a )

inline

const from a simple 32-bit signed integer

Definition at line 119 of file uint_types.h.

template<typename HighType >

stxxl::uint_pair< HighType >::uint_pair ( const uint64 & a )

inline

construct from an uint64 (unsigned long long)

Definition at line 129 of file uint_types.h.

References high_bits, and low_bits.

Member Function Documentation

template<typename HighType >

static unsigned_type stxxl::uint_pair< HighType >::high_max ( )

inlinestaticprivate

return highest value storable in higher part, also used as a mask.

Definition at line 76 of file uint_types.h.

References max().

template<typename HighType >

static unsigned_type stxxl::uint_pair< HighType >::low_max ( )

inlinestaticprivate

return highest value storable in lower part, also used as a mask.

Definition at line 67 of file uint_types.h.

template<typename HighType >

static uint_pair stxxl::uint_pair< HighType >::max ( )

inlinestatic

return an uint_pair instance containing the largest value possible

Definition at line 234 of file uint_types.h.

Referenced by std::numeric_limits< stxxl::uint_pair< HighType > >::max().

template<typename HighType >

static uint_pair stxxl::uint_pair< HighType >::min ( )

inlinestatic

return an uint_pair instance containing the smallest value possible

Definition at line 227 of file uint_types.h.

Referenced by std::numeric_limits< stxxl::uint_pair< HighType > >::min().

template<typename HighType >

stxxl::uint_pair< HighType >::operator uint64 ( ) const

inline

implicit cast to an unsigned long long

Definition at line 144 of file uint_types.h.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator!= ( const uint_pair< HighType > & b ) const

inline

inequality checking operator

Definition at line 191 of file uint_types.h.

template<typename HighType >

uint_pair& stxxl::uint_pair< HighType >::operator++ ( )

inline

prefix increment operator (directly manipulates the integer parts)

Definition at line 156 of file uint_types.h.

template<typename HighType >

uint_pair& stxxl::uint_pair< HighType >::operator+= ( const uint_pair< HighType > & b )

inline

addition operator (uses 64-bit arithmetic)

Definition at line 176 of file uint_types.h.

References stxxl::uint_pair< HighType >::high, high, high_max(), stxxl::uint_pair< HighType >::low, low, low_bits, and low_max().

template<typename HighType >

uint_pair& stxxl::uint_pair< HighType >::operator-- ( )

inline

prefix decrement operator (directly manipulates the integer parts)

Definition at line 166 of file uint_types.h.

References high, low, low_max(), and UNLIKELY.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator< ( const uint_pair< HighType > & b ) const

inline

less-than comparison operator

Definition at line 197 of file uint_types.h.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator<= ( const uint_pair< HighType > & b ) const

inline

less-or-equal comparison operator

Definition at line 203 of file uint_types.h.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator== ( const uint_pair< HighType > & b ) const

inline

equality checking operator

Definition at line 185 of file uint_types.h.

References stxxl::uint_pair< HighType >::high, high, stxxl::uint_pair< HighType >::low, and low.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator> ( const uint_pair< HighType > & b ) const

inline

greater comparison operator

Definition at line 209 of file uint_types.h.

template<typename HighType >

bool stxxl::uint_pair< HighType >::operator>= ( const uint_pair< HighType > & b ) const

inline

greater-or-equal comparison operator

Definition at line 215 of file uint_types.h.

template<typename HighType >

uint64 stxxl::uint_pair< HighType >::u64 ( ) const

inline

return the number as a uint64

Definition at line 150 of file uint_types.h.

template<typename HighType >

uint64 stxxl::uint_pair< HighType >::ull ( ) const

inline

return the number as an uint64 (unsigned long long)

Definition at line 138 of file uint_types.h.

References high, low, and low_bits.

Referenced by operator>=().

Friends And Related Function Documentation

template<typename HighType >

std::ostream& operator<<	(	std::ostream &	os,
		const uint_pair< HighType > &	a
	)

friend

make a uint_pair outputtable via iostreams, using unsigned long long.

Definition at line 221 of file uint_types.h.

Member Data Documentation

template<typename HighType >

const size_t stxxl::uint_pair< HighType >::bytes = sizeof(low_type) + sizeof(high_type)

static

number of bytes in uint_pair

Definition at line 89 of file uint_types.h.

template<typename HighType >

const size_t stxxl::uint_pair< HighType >::digits = low_bits + high_bits

static

number of binary digits (bits) in uint_pair

Definition at line 86 of file uint_types.h.

template<typename HighType >

high_type stxxl::uint_pair< HighType >::high

private

member containing higher significant integer value

Definition at line 64 of file uint_types.h.

Referenced by operator!=(), stxxl::uint_pair< HighType >::operator+=(), operator<(), operator<=(), stxxl::uint_pair< HighType >::operator==(), operator==(), and operator>().

template<typename HighType >

const size_t stxxl::uint_pair< HighType >::high_bits = 8 * sizeof(high_type)

staticprivate

number of bits in the higher integer part, used a bit shift value.

Definition at line 82 of file uint_types.h.

template<typename HighType >

low_type stxxl::uint_pair< HighType >::low

private

member containing lower significant integer value

Definition at line 62 of file uint_types.h.

Referenced by operator!=(), stxxl::uint_pair< HighType >::operator+=(), operator<(), operator<=(), stxxl::uint_pair< HighType >::operator==(), operator==(), and operator>().

template<typename HighType >

const size_t stxxl::uint_pair< HighType >::low_bits = 8 * sizeof(low_type)

staticprivate

number of bits in the lower integer part, used a bit shift value.

Definition at line 73 of file uint_types.h.

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

include/stxxl/bits/common/uint_types.h

Detailed Description

template<typename HighType> class stxxl::uint_pair< HighType >

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Static Private Member Functions

Private Attributes

Static Private Attributes

Friends

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

template<typename HighType>
class stxxl::uint_pair< HighType >