Integer Operations

Typedefs
typedef int8_t	elm::t::int8
typedef uint8_t	elm::t::uint8
typedef int16_t	elm::t::int16
typedef uint16_t	elm::t::uint16
typedef int32_t	elm::t::int32
typedef uint32_t	elm::t::uint32
typedef int64_t	elm::t::int64
typedef uint64_t	elm::t::uint64
typedef uint32	elm::t::size
typedef uint32	elm::t::offset
typedef uint32	elm::t::uint
typedef uint32	elm::t::intptr

Functions
int	elm::msb (t::uint32 i)
int	elm::msb (t::uint64 i)
int	elm::ones (t::uint8 i)
t::uint32	elm::leastUpperPowerOf2 (t::uint32 v)
t::uint64	elm::leastUpperPowerOf2 (t::uint64 v)
t::uint32	elm::mult (t::uint32 a, t::uint32, bool &over)
t::uint64	elm::mult (t::uint64 a, t::uint64, bool &over)
t::uint32	elm::roundup (t::uint32 v, t::uint32 m)
t::uint32	elm::rounddown (t::uint32 v, t::uint32 m)
int	elm::ones (t::uint16 i)
int	elm::ones (t::uint64 i)

Detailed Description

This module provides several facilities to work with integers. To use, one has to include <elm/int.h>.

This module provides reliable and OS-independent types to represent integers together with a list of efficiently-implemented functions to process them. These types are stored in the elm::t sub-namespace and, if you are using the elm namespace, are quickly accessed by syntax t::type .

#include <elm/int.h>
using namespace elm;
...
t::uint32 my_variable;

Typedef Documentation

elm::t::int16

Signed 16-bit integer type.

elm::t::int32

Signed 32-bit integer type.

elm::t::int64

Signed 64-bit integer type.

elm::t::int8

Signed 8-bit integer type.

elm::t::intptr

Integer sufficiently big to store a pointer (according to the system configuration).

elm::t::offset

Integer type to represent memory offset (according to the system configuration).

elm::t::size

Integer type to represent memory size (according to the system configuration).

elm::t::uint

Default size unsigned integer type.

elm::t::uint16

Unsigned 16-bit integer type.

elm::t::uint32

Unsigned 32-bit integer type.

elm::t::uint64

Unsigned 64-bit integer type.

elm::t::uint8

Unsigned 8-bit integer type.

Function Documentation

t::uint32 elm::leastUpperPowerOf2

(

t::uint32

v

)

Get the least upper power of 2 for the given value. If the value is a power of two, return it else compute the least greater power.

Parameters

v	Value to process.

Returns

Least upper power of two.

References elm::msb().

Referenced by elm::stree::Builder< K, T, C >::allocate().

t::uint64 elm::leastUpperPowerOf2

(

t::uint64

v

)

Get the least upper power of 2 for the given value. If the value is a power of two, return it else compute the least greater power.

Parameters

v	Value to process.

Returns

Least upper power of two.

References elm::msb().

int elm::msb

(

t::uint32

i

)

Compute the position of the left-most bit to one.

Parameters

i	Integer to test.

Returns

Position of left-most bit to one or -1 if the integer is 0.

Referenced by elm::leastUpperPowerOf2(), and elm::msb().

int elm::msb

(

t::uint64

i

)

Compute the position of the left-most bit to one.

Parameters

i	Integer to test.

Returns

Position of left-most bit to one or -1 if the integer is 0.

References elm::msb().

t::uint32 elm::mult	(	t::uint32	a,
		t::uint32	b,
		bool &	over
	)

Perform multiplication on unsigned integer 32-bits.

Parameters

a	First number to multiply.
b	Second number to multiply.
over	Set to true if overflow occurs.

Returns

Result of multiplication (only valide if over is false).

t::uint64 elm::mult	(	t::uint64	a,
		t::uint64	b,
		bool &	over
	)

Perform multiplication on unsigned integer 64-bits.

Parameters

a	First number to multiply.
b	Second number to multiply.
over	Set to true if overflow occurs.

Returns

Result of multiplication (only valide if over is false).

int elm::ones

(

t::uint8

i

)

Count the number of ones in the given byte.

Parameters

i	Byte to count ones in.

Returns

Number of ones in the byte.

Referenced by elm::WAHVector::countOnes(), elm::BitVector::countOnes(), and elm::ones().

int elm::ones

(

t::uint16

i

)

Count the number of ones in the given half-word.

Parameters

i	Half-word to count ones in.

Returns

Number of ones in the half-word.

References elm::ones().

int elm::ones

(

t::uint64

i

)

Count the number of ones in the given double-word.

Parameters

i	Double-word to count ones in.

Returns

Number of ones in the double-word.

References elm::ones().

t::uint32 elm::rounddown	(	t::uint32	v,
		t::uint32	m
	)

Round upto upper multiple integer

Parameters

v	Value to round.
m	Multiple to round with.

Returns

Value round upto the upper multiple integer.

t::uint32 elm::roundup	(	t::uint32	v,
		t::uint32	m
	)

Round upto upper multiple integer

Parameters

v	Value to round.
m	Multiple to round with.

Returns

Value round upto the upper multiple integer.