#include <sponge_processing.h>

Public Member Functions
word_t	masked_assignment (word_t state_word, word_t partial_input_word) const
word_t	read_from (BufferSlicer &slicer) const
void	write_into (BufferStuffer &stuffer, word_t partial_word) const

Public Attributes
size_t	length
size_t	offset

Detailed Description

template<SpongeLike SpongeT>
class Botan::detail::PartialWordBounds< SpongeT >

Represents the bounds of partial byte-oriented data within a word of the sponge state. Downstream algorithms can use this to conveniently modify the passed in partial state word with data written or read from an input or output byte buffer.

Definition at line 45 of file sponge_processing.h.

Member Function Documentation

◆ masked_assignment()

template<SpongeLike SpongeT>

word_t Botan::detail::PartialWordBounds< SpongeT >::masked_assignment	(	word_t	state_word,
		word_t	partial_input_word ) const

inline

Assigns the bits in 'partial_input_word' to their corresponding bits in 'state_word' at the specified '.offset' and '.length' while leaving all other bits in 'state_word' unchanged.

Definition at line 79 of file sponge_processing.h.

                                                                                   {
         BOTAN_DEBUG_ASSERT(length > 0);
         const auto mask = ((word_t(0) - 1) >> ((word_bytes - length) * 8)) << (offset * 8);
         return (state_word & ~mask) | (partial_input_word & mask);
      }

References BOTAN_DEBUG_ASSERT, length, and offset.

◆ read_from()

template<SpongeLike SpongeT>

word_t Botan::detail::PartialWordBounds< SpongeT >::read_from ( BufferSlicer & slicer ) const

inline

Reads '.length' bytes from the provided slicer and places them within a word at the specified '.offset' in little-endian order.

Definition at line 59 of file sponge_processing.h.

                                                   {
         std::array<uint8_t, word_bytes> partial_word_bytes{};
         slicer.copy_into(std::span{partial_word_bytes}.subspan(offset, length));
         return load_le(partial_word_bytes);
      }

References Botan::BufferSlicer::copy_into(), length, Botan::load_le(), and offset.

◆ write_into()

template<SpongeLike SpongeT>

void Botan::detail::PartialWordBounds< SpongeT >::write_into	(	BufferStuffer &	stuffer,
		word_t	partial_word ) const

inline

Writes '.length' bytes from the provided word at the specified '.offset' into the provided stuffer in little-endian order.

Definition at line 69 of file sponge_processing.h.

                                                                         {
         const auto partial_word_bytes = store_le(partial_word);
         stuffer.append(std::span{partial_word_bytes}.subspan(offset, length));
      }