Template Struct ChaChaState

• Defined in File chacha_simd.hpp

Struct Documentation

template<class Arch, std::uint8_t R>
struct ChaChaState

SIMD state for the ChaCha generator. Contains the matrix state, SIMD block cache, and all generation logic.

Template Parameters:

• Arch – The xsimd architecture type.

• R – Number of ChaCha rounds.

Public Types

using input_word = std::uint64_t

using matrix_word = std::uint32_t

using matrix_type = std::array<matrix_word, MATRIX_WORDCOUNT>

using simd_type = xsimd::batch<matrix_word, Arch>

using working_state_type = std::array<simd_type, MATRIX_WORDCOUNT>

using cache_block_type = std::array<simd_type, BLOCK_SEGMENTCOUNT>

using cache_batch_type = std::array<cache_block_type, SIMD_WIDTH>

Public Functions

inline explicit ChaChaState(const std::array<matrix_word, KEY_WORDCOUNT> key, const input_word counter, const input_word nonce)

inline matrix_type getState(bool prev) const noexcept

inline matrix_type next_block() noexcept

Public Members

matrix_type m_state

std::array<cache_batch_type, CACHE_BATCHCOUNT> m_cache

std::uint8_t m_cache_index = CACHE_BLOCKCOUNT

Public Static Functions

static inline constexpr std::uint8_t cache_batchcount() noexcept

Public Static Attributes

static constexpr auto MATRIX_WORDCOUNT = std::uint8_t{16}

static constexpr auto KEY_WORDCOUNT = std::uint8_t{8}

static constexpr std::uint8_t SIMD_WIDTH = std::uint8_t{simd_type::size}

static constexpr std::uint8_t SIMD_WIDTH_SHIFT = SIMD_WIDTH > 0 ? static_cast<std::uint8_t>(std::countr_zero(static_cast<unsigned int>(SIMD_WIDTH))) : 0

static constexpr std::uint8_t SIMD_WIDTH_MASK = SIMD_WIDTH > 0 ? std::uint8_t(SIMD_WIDTH - 1) : 0

static constexpr std::uint8_t BLOCK_SEGMENTCOUNT = SIMD_WIDTH > 0 ? static_cast<std::uint8_t>(MATRIX_WORDCOUNT / SIMD_WIDTH) : 0

static constexpr auto CACHE_BATCHCOUNT = cache_batchcount()

static constexpr auto CACHE_BLOCKCOUNT = std::uint8_t{CACHE_BATCHCOUNT * SIMD_WIDTH}