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construct/ircd/stringops.cc
Jason Volk 8c33f21f95 ircd::stringops: Add noexcept to indexof().
ircd::stringops: Minor simplifications.

ircd::stringops: Fix return value.
2020-04-03 14:37:14 -07:00

217 lines
4.6 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 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.
#include <ircd/simd.h>
namespace ircd
{
template<class i8xN,
size_t N>
static size_t indexof(const string_view &, const string_view *const &) noexcept;
}
size_t
ircd::indexof(const string_view &s,
const string_views &tab)
noexcept
{
#if defined(__AVX__)
static const size_t N {32};
using i8xN = i8x32;
#elif defined(__SSE__)
static const size_t N {16};
using i8xN = i8x16;
#else
static const size_t N {1};
using i8xN = char __attribute__((vector_size(1)));
#endif
string_view a[N];
size_t i, j, ret;
for(i = 0; i < tab.size() / N; ++i)
{
for(j = 0; j < N; ++j)
a[j] = tab[i * N + j];
if((ret = indexof<i8xN, N>(s, a)) != N)
return i * N + ret;
}
for(j = 0; j < tab.size() % N; ++j)
a[j] = tab[i * N + j];
for(; j < N; ++j)
a[j] = string_view{};
ret = i * N + indexof<i8xN, N>(s, a);
return std::min(ret, tab.size());
}
template<class i8xN,
size_t N>
size_t
ircd::indexof(const string_view &s,
const string_view *const &st)
noexcept
{
i8xN ct, res;
size_t i, j, k;
for(i = 0; i < N; ++i)
res[i] = true;
const size_t max(s.size());
for(i = 0, j = 0; i < max; i = (j < N)? i + 1 : max)
{
#pragma clang loop unroll (disable)
for(k = 0; k < N; ++k)
{
res[k] &= size(st[k]) > i;
ct[k] = res[k]? st[k][i]: 0;
}
res &= ct == s[i];
while(j < N && !res[j])
++j;
}
for(i = 0; i < N && !res[i]; ++i);
return i;
}
ircd::string_view
ircd::toupper(const mutable_buffer &out,
const string_view &in)
noexcept
{
const auto stop
{
std::next(begin(in), std::min(size(in), size(out)))
};
const auto end
{
std::transform(begin(in), stop, begin(out), []
(auto&& c)
{
return std::toupper(c);
})
};
assert(intptr_t(begin(out)) <= intptr_t(end));
return string_view
{
data(out), size_t(std::distance(begin(out), end))
};
}
#if defined(IRCD_SIMD) && defined(__SSE2__)
ircd::string_view
ircd::tolower(const mutable_buffer &out,
const string_view &in)
noexcept
{
const auto stop
{
std::next(begin(in), std::min(size(in), size(out)))
};
const u128x1 *src_
{
reinterpret_cast<const u128x1 *>(begin(in))
};
u128x1 *dst
{
reinterpret_cast<u128x1 *>(begin(out))
};
while(intptr_t(src_) < intptr_t(stop) - ssize_t(sizeof(u128x1)))
{
const u128x1 lit_A1 { _mm_set1_epi8('A' - 1) };
const u128x1 lit_Z1 { _mm_set1_epi8('Z' + 1) };
const u128x1 addend { _mm_set1_epi8('a' - 'A') };
const u128x1 src { _mm_loadu_si128(src_++) };
const u128x1 gte_A { _mm_cmpgt_epi8(src, lit_A1) };
const u128x1 lte_Z { _mm_cmplt_epi8(src, lit_Z1) };
const u128x1 mask { _mm_and_si128(gte_A, lte_Z) };
const u128x1 ctrl_mask { _mm_and_si128(mask, addend) };
const u128x1 result { _mm_add_epi8(src, ctrl_mask) };
_mm_storeu_si128(dst++, result);
}
const auto end{std::transform
(
reinterpret_cast<const char *>(src_),
stop,
reinterpret_cast<char *>(dst),
::tolower
)};
assert(intptr_t(begin(out)) <= intptr_t(end));
return string_view{begin(out), end};
}
#else
ircd::string_view
ircd::tolower(const mutable_buffer &out,
const string_view &in)
noexcept
{
const auto stop
{
std::next(begin(in), std::min(size(in), size(out)))
};
const auto end
{
std::transform(begin(in), stop, begin(out), ::tolower)
};
assert(intptr_t(begin(out)) <= intptr_t(end));
return string_view
{
data(out), size_t(std::distance(begin(out), end))
};
}
#endif
std::string
ircd::replace(const string_view &s,
const char &before,
const string_view &after)
{
const uint32_t occurs
(
std::count(begin(s), end(s), before)
);
const size_t size
{
occurs? s.size() + (occurs * after.size()):
s.size() - occurs
};
return string(size, [&s, &before, &after]
(const mutable_buffer &buf)
{
char *p{begin(buf)};
std::for_each(begin(s), end(s), [&before, &after, &p]
(const char &c)
{
if(c == before)
{
memcpy(p, after.data(), after.size());
p += after.size();
}
else *p++ = c;
});
return std::distance(begin(buf), p);
});
}