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construct/ircd/stringops.cc
2019-08-07 00:41:08 -07:00

142 lines
3.2 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 <RB_INC_X86INTRIN_H
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(HAVE_X86INTRIN_H) && 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 __m128i *src_
{
reinterpret_cast<const __m128i *>(begin(in))
};
__m128i *dst
{
reinterpret_cast<__m128i *>(begin(out))
};
while(reinterpret_cast<const char *>(src_) + sizeof(__m128i) < stop)
{
const __m128i lit_A1 { _mm_set1_epi8('A' - 1) };
const __m128i lit_Z1 { _mm_set1_epi8('Z' + 1) };
const __m128i addend { _mm_set1_epi8('a' - 'A') };
const __m128i src { _mm_loadu_si128(src_++) };
const __m128i gte_A { _mm_cmpgt_epi8(src, lit_A1) };
const __m128i lte_Z { _mm_cmplt_epi8(src, lit_Z1) };
const __m128i mask { _mm_and_si128(gte_A, lte_Z) };
const __m128i ctrl_mask { _mm_and_si128(mask, addend) };
const __m128i 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);
});
}