Typedefs | |
using | Word_t = std::uintmax_t |
Functions | |
constexpr std::size_t | MinBufSize (std::size_t count, std::size_t nDstBits) |
Returns the minimum safe size (in bytes) of a buffer that is intended to be used as a destination for PackBits or a source for UnpackBits. | |
void | PackBits (void *dst, const void *src, std::size_t count, std::size_t sizeofSrc, std::size_t nDstBits) |
Tightly packs count items of size sizeofSrc contained in src into dst using nDstBits per item. | |
void | UnpackBits (void *dst, const void *src, std::size_t count, std::size_t sizeofDst, std::size_t nSrcBits) |
Undoes the effect of PackBits . | |
Variables | |
constexpr std::size_t | kBitsPerWord = sizeof(Word_t) * 8 |
using ROOT::Experimental::Internal::BitPacking::Word_t = typedef std::uintmax_t |
Definition at line 32 of file RColumnElement.hxx.
|
constexpr |
Returns the minimum safe size (in bytes) of a buffer that is intended to be used as a destination for PackBits or a source for UnpackBits.
Passing a buffer that's less than this size will cause invalid memory reads and writes.
Definition at line 38 of file RColumnElement.hxx.
void ROOT::Experimental::Internal::BitPacking::PackBits | ( | void * | dst, |
const void * | src, | ||
std::size_t | count, | ||
std::size_t | sizeofSrc, | ||
std::size_t | nDstBits | ||
) |
Tightly packs count
items of size sizeofSrc
contained in src
into dst
using nDstBits
per item.
It must be 0 < sizeofSrc <= 8
and 0 < nDstBits <= sizeofSrc * 8
. The extra least significant bits are dropped (assuming LE ordering of the items in src
). Note that this function doesn't do any byte reordering for you. IMPORTANT: the size of dst
must be at least MinBufSize(count, nBitBits)
Definition at line 183 of file RColumnElement.cxx.
void ROOT::Experimental::Internal::BitPacking::UnpackBits | ( | void * | dst, |
const void * | src, | ||
std::size_t | count, | ||
std::size_t | sizeofDst, | ||
std::size_t | nSrcBits | ||
) |
Undoes the effect of PackBits
.
The bits that were truncated in the packed representation are filled with zeroes. src
must be at least MinBufSize(count, nDstBits)
bytes long. dst
must be at least count * sizeofDst
bytes long.
Definition at line 239 of file RColumnElement.cxx.
|
inlineconstexpr |
Definition at line 33 of file RColumnElement.hxx.