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construct/include/ircd/simd/tokens.h

130 lines
3.2 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_SIMD_TOKENS_H
namespace ircd::simd
{
template<class token_block_t,
class input_block_t>
using tokens_prototype = u64x2 (token_block_t &, input_block_t, input_block_t mask);
template<class input_t,
class block_t,
class lambda>
u64x2 tokens(block_t *, const char *, const u64x2, lambda&&) noexcept;
}
/// Tokenize a character string input into fixed-width elements of the output
/// array.
///
/// The input streams variably with character (byte) resolution; the return
/// value for the input side of the closure advances the input one or more
/// bytes for the next iteration.
///
/// The output streams variably with element (lane) resolution; the return
/// value for the output side of the closure advances the output zero or more
/// tokens at a time. Note iff the token type is u8 this value is a byte incr.
///
/// The closure performs the transformation for as many tokens as the block
/// size allows for at a time. Closure returns the number of tokens written
/// to the output block, and number of characters to consume off the input
/// block for the next iteration.
///
template<class input_t,
class block_t,
class lambda>
inline ircd::u64x2
ircd::simd::tokens(block_t *const __restrict__ out_,
const char *const __restrict__ in,
const u64x2 max,
lambda&& closure)
noexcept
{
using input_t_u = unaligned<input_t>;
using block_t_u = unaligned<block_t>;
using token_t = lane_type<block_t>;
u64x2 count
{
0, // total token count (one for each lane populated in block_t's)
0, // input pos (bytes)
};
const auto out
{
reinterpret_cast<token_t *>(out_)
};
// primary broadband loop
while(count[1] + sizeof(input_t) <= max[1] && count[0] + lanes<block_t>() <= max[0])
{
const auto mask
{
mask_full<input_t>()
};
const auto di
{
reinterpret_cast<block_t_u *>(out + count[0])
};
const auto si
{
reinterpret_cast<const input_t_u *>(in + count[1])
};
const input_t input
(
*si
);
block_t output;
const auto consume
{
closure(output, input, mask)
};
*di = output;
count += consume;
}
// trailing narrowband loop
while(count[0] < max[0] && count[1] < max[1])
{
block_t output;
input_t input {0}, mask {0};
for(size_t i(0); count[1] + i < max[1] && i < sizeof(input_t); ++i)
{
input[i] = in[count[1] + i];
mask[i] = 0xff;
}
const auto consume
{
closure(output, input, mask)
};
assert(consume[0] < sizeof(block_t));
for(size_t i(0); i < consume[0] && count[0] + i < max[0]; ++i)
out[count[0] + i] = output[i];
count += consume;
}
const u64x2 ret
{
std::min(count[0], max[0]),
std::min(count[1], max[1]),
};
return ret;
}