Bits.h File Reference

#include "Stroika/Foundation/StroikaPreComp.h"
#include <memory>
#include "Stroika/Foundation/Common/Common.h"
#include "Bits.inl"

Go to the source code of this file.

Namespaces
namespace	Stroika::Foundation

Functions
template<integral INT_TYPE = unsigned int>
constexpr INT_TYPE	Stroika::Foundation::Memory::Bit (unsigned int bitNumber)
template<integral INT_TYPE>
constexpr INT_TYPE	Stroika::Foundation::Memory::BitSubstring (INT_TYPE bitField, unsigned int startOffset, unsigned int endOffset)

Function Documentation

Bit()

template<integral INT_TYPE = unsigned int>

constexpr INT_TYPE Stroika::Foundation::Memory::Bit ( unsigned int  bitNumber )

constexpr

bitNumber's start with 0, not 1.

Example Usage

EXPECT_EQ (Bit (0), 0x1u);
EXPECT_EQ (Bit (1), 0x2u);
EXPECT_EQ (Bit (3), 0x8u);
EXPECT_EQ (Bit (15), 0x8000u);
EXPECT_EQ (Bit<int> (1, 2), 6);
EXPECT_EQ (Bit<int> (1, 2, 15), 0x8006);

Definition at line 16 of file Bits.inl.

BitSubstring()

template<integral INT_TYPE>

constexpr INT_TYPE Stroika::Foundation::Memory::BitSubstring ( INT_TYPE  bitField, unsigned int  startOffset, unsigned int  endOffset  )

constexpr

Capture the bits from 'bitField' - starting at bit 'startOffset' (zero-based), extending to endOffset (also zero based - not inclusive). The number of bits captured is endOffset-startOffset, so:

Precondition

startOffset <= endOffset

the result is zero-filled with bits, so if zero bits are captured, the return value will be zero.

Example Usage

EXPECT_EQ (BitSubstring (0x3, 0, 1), 1);
EXPECT_EQ (BitSubstring (0x3, 1, 2), 1);
EXPECT_EQ (BitSubstring (0x3, 2, 3), 0);
EXPECT_EQ (BitSubstring (0x3, 0, 3), 0x3);
EXPECT_EQ (BitSubstring (0xff, 0, 8), 0xff);
EXPECT_EQ (BitSubstring (0xff, 8, 16), 0x0);
EXPECT_EQ (BitSubstring (0b10101010, 0, 1), 0x0);  // low# bit on right
EXPECT_EQ (BitSubstring (0b10101010, 7, 8), 0x1);  // high# bit on left

Note

The startOffset/endOffset pattern matches that with STL iterators (not including the last item)

This was previously named TakeNBitsFrom()

Definition at line 33 of file Bits.inl.