memrsh_LE_copy()

void Chusov::Memory::memrsh_LE_copy ( void *restrict  pResult, const void *restrict  pValue, std::size_t  cbValue, std::size_t  nShift  )

noexcept

Bit-shifts a long unsigned integer specified by a vector of bytes in the Little-Endian order to the right and copies the result into a separate output buffer.

Parameters

[out]	pResult	The output buffer receiving the result of the shift. The buffer may not overlap with the input buffer given by pValue.
[in]	pValue	An input buffer containing bytes of the long integer.
	cbValue	A byte size of the data in pValue and the capacity of the output buffer pResult.
	nShift	A value by which the input integer is bit-shifted to the right, that is towards the beginning of the buffer pValue. The value can accept every element of the domain specified by its type size_t. If the value is 0, the result would be a copy of the input. If the value is greater or equal to cbValue * CHAR_BIT, the resulting integer will be zero, and the corresponding buffer pResult is zeroed out by the function.

The function performs a right bit-shift of an unsigned integer (i.e. with zero-propagation) specified as a vector of bytes in the Little-Endian order. That is, given that \(b_i\) and \(b_j\) are bytes in the vector pValue, such that \(i,j\in\mathbb{N}_0\land i < j\), byte \(b_i\) is less significant that \(b_j\). Therefore, the operation shifts the value towards the beginning of the buffer pValue.

For instance, given that \(B\) is a size of a byte in bits, a vector \(\left\{b_0, b_1, b_2, b_3, b_4\right\}\) representing a number \(b_4 B^4 + b_3 B^3 + b_2 B^2 + b_1 B^1 + b_0 B^0 = \overline{b_4 b_3 b_2 b_1 b_0}\), when shifted to the right by \(2B\), results in the value \(\overline{0 0 b_4 b_3 b_2} = 0\cdot B^4 + 0\cdot B^3 + b_4 B^2 + b_3 B^1 + b_2 B^0\) which is represented by the vector \(\left\{b_2, b_3, b_4, 0, 0\right\}\). The bit order within a byte is not taken into account, that is platform-defined bit shift to the right is used.

The buffers pResult and pValue may not overlap. To perform the action within overlapping input and output buffers use the generic memrsh_LE function. To shift inplace one can also use the memrsh_LE_inplace function.

See also

memrsh_LE_inplace;
memrsh_LE;
memlsh_LE_copy;
memlsh_LE_inplace.

Examples

chsvmem\memory_shifts.c.