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std::pair<const char32_t *, char *>
lsx_convert_utf32_to_utf8(const char32_t *buf, size_t len, char *utf8_out) {
uint8_t *utf8_output = reinterpret_cast<uint8_t *>(utf8_out);
const char32_t *end = buf + len;
__m128i v_c080 = __lsx_vreplgr2vr_h(uint16_t(0xC080));
__m128i v_07ff = __lsx_vreplgr2vr_h(uint16_t(0x7FF));
__m128i v_dfff = __lsx_vreplgr2vr_h(uint16_t(0xDFFF));
__m128i v_d800 = __lsx_vldi(-2600); /*0xD800*/
__m128i forbidden_bytemask = __lsx_vldi(0x0);
const size_t safety_margin =
12; // to avoid overruns, see issue
// https://github.com/simdutf/simdutf/issues/92
while (buf + 16 + safety_margin < end) {
__m128i in = __lsx_vld(reinterpret_cast<const uint32_t *>(buf), 0);
__m128i nextin = __lsx_vld(reinterpret_cast<const uint32_t *>(buf), 16);
// Check if no bits set above 16th
if (__lsx_bz_v(__lsx_vpickod_h(in, nextin))) {
// Pack UTF-32 to UTF-16 safely (without surrogate pairs)
// Apply UTF-16 => UTF-8 routine (lsx_convert_utf16_to_utf8.cpp)
__m128i utf16_packed = __lsx_vpickev_h(nextin, in);
if (__lsx_bz_v(__lsx_vslt_hu(__lsx_vrepli_h(0x7F),
utf16_packed))) { // ASCII fast path!!!!
// 1. pack the bytes
// obviously suboptimal.
__m128i utf8_packed = __lsx_vpickev_b(utf16_packed, utf16_packed);
// 2. store (8 bytes)
__lsx_vst(utf8_packed, utf8_output, 0);
// 3. adjust pointers
buf += 8;
utf8_output += 8;
continue; // we are done for this round!
}
__m128i zero = __lsx_vldi(0);
if (__lsx_bz_v(__lsx_vslt_hu(v_07ff, utf16_packed))) {
// 1. prepare 2-byte values
// input 16-bit word : [0000|0aaa|aabb|bbbb] x 8
// expected output : [110a|aaaa|10bb|bbbb] x 8
// t0 = [000a|aaaa|bbbb|bb00]
const __m128i t0 = __lsx_vslli_h(utf16_packed, 2);
// t1 = [000a|aaaa|0000|0000]
const __m128i t1 = __lsx_vand_v(t0, __lsx_vldi(-2785 /*0x1f00*/));
// t2 = [0000|0000|00bb|bbbb]
const __m128i t2 = __lsx_vand_v(utf16_packed, __lsx_vrepli_h(0x3f));
// t3 = [000a|aaaa|00bb|bbbb]
const __m128i t3 = __lsx_vor_v(t1, t2);
// t4 = [110a|aaaa|10bb|bbbb]
const __m128i t4 = __lsx_vor_v(t3, v_c080);
// 2. merge ASCII and 2-byte codewords
__m128i one_byte_bytemask =
__lsx_vsle_hu(utf16_packed, __lsx_vrepli_h(0x7F /*0x007F*/));
__m128i utf8_unpacked =
__lsx_vbitsel_v(t4, utf16_packed, one_byte_bytemask);
// 3. prepare bitmask for 8-bit lookup
uint32_t m2 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(one_byte_bytemask), 0);
// 4. pack the bytes
const uint8_t *row =
&simdutf::tables::utf16_to_utf8::pack_1_2_utf8_bytes
[lsx_1_2_utf8_bytes_mask[m2]][0];
__m128i shuffle = __lsx_vld(row, 1);
__m128i utf8_packed = __lsx_vshuf_b(zero, utf8_unpacked, shuffle);
// 5. store bytes
__lsx_vst(utf8_packed, utf8_output, 0);
// 6. adjust pointers
buf += 8;
utf8_output += row[0];
continue;
} else {
// case: code units from register produce either 1, 2 or 3 UTF-8 bytes
forbidden_bytemask = __lsx_vor_v(
__lsx_vand_v(
__lsx_vsle_h(utf16_packed, v_dfff), // utf16_packed <= 0xdfff
__lsx_vsle_h(v_d800, utf16_packed)), // utf16_packed >= 0xd800
forbidden_bytemask);
/* In this branch we handle three cases:
1. [0000|0000|0ccc|cccc] => [0ccc|cccc] - single
UFT-8 byte
2. [0000|0bbb|bbcc|cccc] => [110b|bbbb], [10cc|cccc] - two
UTF-8 bytes
3. [aaaa|bbbb|bbcc|cccc] => [1110|aaaa], [10bb|bbbb], [10cc|cccc] - three
UTF-8 bytes
We expand the input word (16-bit) into two code units (32-bit), thus
we have room for four bytes. However, we need five distinct bit
layouts. Note that the last byte in cases #2 and #3 is the same.
We precompute byte 1 for case #1 and the common byte for cases #2 & #3
in register t2.
We precompute byte 1 for case #3 and -- **conditionally** -- precompute
either byte 1 for case #2 or byte 2 for case #3. Note that they
differ by exactly one bit.
Finally from these two code units we build proper UTF-8 sequence, taking
into account the case (i.e, the number of bytes to write).
*/
/**
* Given [aaaa|bbbb|bbcc|cccc] our goal is to produce:
* t2 => [0ccc|cccc] [10cc|cccc]
* s4 => [1110|aaaa] ([110b|bbbb] OR [10bb|bbbb])
*/
// [aaaa|bbbb|bbcc|cccc] => [bbcc|cccc|bbcc|cccc]
__m128i t0 = __lsx_vpickev_b(utf16_packed, utf16_packed);
t0 = __lsx_vilvl_b(t0, t0);
// [bbcc|cccc|bbcc|cccc] => [00cc|cccc|0bcc|cccc]
__m128i v_3f7f = __lsx_vreplgr2vr_h(uint16_t(0x3F7F));
__m128i t1 = __lsx_vand_v(t0, v_3f7f);
// [00cc|cccc|0bcc|cccc] => [10cc|cccc|0bcc|cccc]
__m128i t2 = __lsx_vor_v(t1, __lsx_vldi(-2688 /*0x8000*/));
// s0: [aaaa|bbbb|bbcc|cccc] => [0000|0000|0000|aaaa]
__m128i s0 = __lsx_vsrli_h(utf16_packed, 12);
// s1: [aaaa|bbbb|bbcc|cccc] => [0000|bbbb|bb00|0000]
__m128i s1 = __lsx_vslli_h(utf16_packed, 2);
// [0000|bbbb|bb00|0000] => [00bb|bbbb|0000|0000]
s1 = __lsx_vand_v(s1, __lsx_vldi(-2753 /*0x3F00*/));
// [00bb|bbbb|0000|aaaa]
__m128i s2 = __lsx_vor_v(s0, s1);
// s3: [00bb|bbbb|0000|aaaa] => [11bb|bbbb|1110|aaaa]
__m128i v_c0e0 = __lsx_vreplgr2vr_h(uint16_t(0xC0E0));
__m128i s3 = __lsx_vor_v(s2, v_c0e0);
// __m128i v_07ff = vmovq_n_u16((uint16_t)0x07FF);
__m128i one_or_two_bytes_bytemask = __lsx_vsle_hu(utf16_packed, v_07ff);
__m128i m0 = __lsx_vandn_v(one_or_two_bytes_bytemask,
__lsx_vldi(-2752 /*0x4000*/));
__m128i s4 = __lsx_vxor_v(s3, m0);
// 4. expand code units 16-bit => 32-bit
__m128i out0 = __lsx_vilvl_h(s4, t2);
__m128i out1 = __lsx_vilvh_h(s4, t2);
// 5. compress 32-bit code units into 1, 2 or 3 bytes -- 2 x shuffle
__m128i one_byte_bytemask =
__lsx_vsle_hu(utf16_packed, __lsx_vrepli_h(0x7F));
__m128i one_or_two_bytes_bytemask_u16_to_u32_low =
__lsx_vilvl_h(one_or_two_bytes_bytemask, zero);
__m128i one_or_two_bytes_bytemask_u16_to_u32_high =
__lsx_vilvh_h(one_or_two_bytes_bytemask, zero);
__m128i one_byte_bytemask_u16_to_u32_low =
__lsx_vilvl_h(one_byte_bytemask, one_byte_bytemask);
__m128i one_byte_bytemask_u16_to_u32_high =
__lsx_vilvh_h(one_byte_bytemask, one_byte_bytemask);
const uint32_t mask0 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(__lsx_vor_v(
one_or_two_bytes_bytemask_u16_to_u32_low,
one_byte_bytemask_u16_to_u32_low)),
0);
const uint32_t mask1 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(__lsx_vor_v(
one_or_two_bytes_bytemask_u16_to_u32_high,
one_byte_bytemask_u16_to_u32_high)),
0);
const uint8_t *row0 =
&simdutf::tables::utf16_to_utf8::pack_1_2_3_utf8_bytes[mask0][0];
__m128i shuffle0 = __lsx_vld(row0, 1);
__m128i utf8_0 = __lsx_vshuf_b(zero, out0, shuffle0);
const uint8_t *row1 =
&simdutf::tables::utf16_to_utf8::pack_1_2_3_utf8_bytes[mask1][0];
__m128i shuffle1 = __lsx_vld(row1, 1);
__m128i utf8_1 = __lsx_vshuf_b(zero, out1, shuffle1);
__lsx_vst(utf8_0, utf8_output, 0);
utf8_output += row0[0];
__lsx_vst(utf8_1, utf8_output, 0);
utf8_output += row1[0];
buf += 8;
}
// At least one 32-bit word will produce a surrogate pair in UTF-16 <=>
// will produce four UTF-8 bytes.
} else {
// Let us do a scalar fallback.
// It may seem wasteful to use scalar code, but being efficient with SIMD
// in the presence of surrogate pairs may require non-trivial tables.
size_t forward = 15;
size_t k = 0;
if (size_t(end - buf) < forward + 1) {
forward = size_t(end - buf - 1);
}
for (; k < forward; k++) {
uint32_t word = buf[k];
if ((word & 0xFFFFFF80) == 0) {
*utf8_output++ = char(word);
} else if ((word & 0xFFFFF800) == 0) {
*utf8_output++ = char((word >> 6) | 0b11000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
} else if ((word & 0xFFFF0000) == 0) {
if (word >= 0xD800 && word <= 0xDFFF) {
return std::make_pair(nullptr,
reinterpret_cast<char *>(utf8_output));
}
*utf8_output++ = char((word >> 12) | 0b11100000);
*utf8_output++ = char(((word >> 6) & 0b111111) | 0b10000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
} else {
if (word > 0x10FFFF) {
return std::make_pair(nullptr,
reinterpret_cast<char *>(utf8_output));
}
*utf8_output++ = char((word >> 18) | 0b11110000);
*utf8_output++ = char(((word >> 12) & 0b111111) | 0b10000000);
*utf8_output++ = char(((word >> 6) & 0b111111) | 0b10000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
}
}
buf += k;
}
} // while
// check for invalid input
if (__lsx_bnz_v(forbidden_bytemask)) {
return std::make_pair(nullptr, reinterpret_cast<char *>(utf8_output));
}
return std::make_pair(buf, reinterpret_cast<char *>(utf8_output));
}
std::pair<result, char *>
lsx_convert_utf32_to_utf8_with_errors(const char32_t *buf, size_t len,
char *utf8_out) {
uint8_t *utf8_output = reinterpret_cast<uint8_t *>(utf8_out);
const char32_t *start = buf;
const char32_t *end = buf + len;
__m128i v_c080 = __lsx_vreplgr2vr_h(uint16_t(0xC080));
__m128i v_07ff = __lsx_vreplgr2vr_h(uint16_t(0x7FF));
__m128i v_dfff = __lsx_vreplgr2vr_h(uint16_t(0xDFFF));
__m128i v_d800 = __lsx_vldi(-2600); /*0xD800*/
__m128i forbidden_bytemask = __lsx_vldi(0x0);
const size_t safety_margin =
12; // to avoid overruns, see issue
// https://github.com/simdutf/simdutf/issues/92
while (buf + 16 + safety_margin < end) {
__m128i in = __lsx_vld(reinterpret_cast<const uint32_t *>(buf), 0);
__m128i nextin = __lsx_vld(reinterpret_cast<const uint32_t *>(buf), 16);
// Check if no bits set above 16th
if (__lsx_bz_v(__lsx_vpickod_h(in, nextin))) {
// Pack UTF-32 to UTF-16 safely (without surrogate pairs)
// Apply UTF-16 => UTF-8 routine (lsx_convert_utf16_to_utf8.cpp)
__m128i utf16_packed = __lsx_vpickev_h(nextin, in);
if (__lsx_bz_v(__lsx_vslt_hu(__lsx_vrepli_h(0x7F),
utf16_packed))) { // ASCII fast path!!!!
// 1. pack the bytes
// obviously suboptimal.
__m128i utf8_packed = __lsx_vpickev_b(utf16_packed, utf16_packed);
// 2. store (8 bytes)
__lsx_vst(utf8_packed, utf8_output, 0);
// 3. adjust pointers
buf += 8;
utf8_output += 8;
continue; // we are done for this round!
}
__m128i zero = __lsx_vldi(0);
if (__lsx_bz_v(__lsx_vslt_hu(v_07ff, utf16_packed))) {
// 1. prepare 2-byte values
// input 16-bit word : [0000|0aaa|aabb|bbbb] x 8
// expected output : [110a|aaaa|10bb|bbbb] x 8
// t0 = [000a|aaaa|bbbb|bb00]
const __m128i t0 = __lsx_vslli_h(utf16_packed, 2);
// t1 = [000a|aaaa|0000|0000]
const __m128i t1 = __lsx_vand_v(t0, __lsx_vldi(-2785 /*0x1f00*/));
// t2 = [0000|0000|00bb|bbbb]
const __m128i t2 = __lsx_vand_v(utf16_packed, __lsx_vrepli_h(0x3f));
// t3 = [000a|aaaa|00bb|bbbb]
const __m128i t3 = __lsx_vor_v(t1, t2);
// t4 = [110a|aaaa|10bb|bbbb]
const __m128i t4 = __lsx_vor_v(t3, v_c080);
// 2. merge ASCII and 2-byte codewords
__m128i one_byte_bytemask =
__lsx_vsle_hu(utf16_packed, __lsx_vrepli_h(0x7F /*0x007F*/));
__m128i utf8_unpacked =
__lsx_vbitsel_v(t4, utf16_packed, one_byte_bytemask);
// 3. prepare bitmask for 8-bit lookup
uint32_t m2 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(one_byte_bytemask), 0);
// 4. pack the bytes
const uint8_t *row =
&simdutf::tables::utf16_to_utf8::pack_1_2_utf8_bytes
[lsx_1_2_utf8_bytes_mask[m2]][0];
__m128i shuffle = __lsx_vld(row, 1);
__m128i utf8_packed = __lsx_vshuf_b(zero, utf8_unpacked, shuffle);
// 5. store bytes
__lsx_vst(utf8_packed, utf8_output, 0);
// 6. adjust pointers
buf += 8;
utf8_output += row[0];
continue;
} else {
// case: code units from register produce either 1, 2 or 3 UTF-8 bytes
forbidden_bytemask = __lsx_vor_v(
__lsx_vand_v(
__lsx_vsle_h(utf16_packed, v_dfff), // utf16_packed <= 0xdfff
__lsx_vsle_h(v_d800, utf16_packed)), // utf16_packed >= 0xd800
forbidden_bytemask);
if (__lsx_bnz_v(forbidden_bytemask)) {
return std::make_pair(result(error_code::SURROGATE, buf - start),
reinterpret_cast<char *>(utf8_output));
}
/* In this branch we handle three cases:
1. [0000|0000|0ccc|cccc] => [0ccc|cccc] - single
UFT-8 byte
2. [0000|0bbb|bbcc|cccc] => [110b|bbbb], [10cc|cccc] - two
UTF-8 bytes
3. [aaaa|bbbb|bbcc|cccc] => [1110|aaaa], [10bb|bbbb], [10cc|cccc] - three
UTF-8 bytes
We expand the input word (16-bit) into two code units (32-bit), thus
we have room for four bytes. However, we need five distinct bit
layouts. Note that the last byte in cases #2 and #3 is the same.
We precompute byte 1 for case #1 and the common byte for cases #2 & #3
in register t2.
We precompute byte 1 for case #3 and -- **conditionally** -- precompute
either byte 1 for case #2 or byte 2 for case #3. Note that they
differ by exactly one bit.
Finally from these two code units we build proper UTF-8 sequence, taking
into account the case (i.e, the number of bytes to write).
*/
/**
* Given [aaaa|bbbb|bbcc|cccc] our goal is to produce:
* t2 => [0ccc|cccc] [10cc|cccc]
* s4 => [1110|aaaa] ([110b|bbbb] OR [10bb|bbbb])
*/
// [aaaa|bbbb|bbcc|cccc] => [bbcc|cccc|bbcc|cccc]
__m128i t0 = __lsx_vpickev_b(utf16_packed, utf16_packed);
t0 = __lsx_vilvl_b(t0, t0);
// [bbcc|cccc|bbcc|cccc] => [00cc|cccc|0bcc|cccc]
__m128i v_3f7f = __lsx_vreplgr2vr_h(uint16_t(0x3F7F));
__m128i t1 = __lsx_vand_v(t0, v_3f7f);
// [00cc|cccc|0bcc|cccc] => [10cc|cccc|0bcc|cccc]
__m128i t2 = __lsx_vor_v(t1, __lsx_vldi(-2688 /*0x8000*/));
// s0: [aaaa|bbbb|bbcc|cccc] => [0000|0000|0000|aaaa]
__m128i s0 = __lsx_vsrli_h(utf16_packed, 12);
// s1: [aaaa|bbbb|bbcc|cccc] => [0000|bbbb|bb00|0000]
__m128i s1 = __lsx_vslli_h(utf16_packed, 2);
// [0000|bbbb|bb00|0000] => [00bb|bbbb|0000|0000]
s1 = __lsx_vand_v(s1, __lsx_vldi(-2753 /*0x3F00*/));
// [00bb|bbbb|0000|aaaa]
__m128i s2 = __lsx_vor_v(s0, s1);
// s3: [00bb|bbbb|0000|aaaa] => [11bb|bbbb|1110|aaaa]
__m128i v_c0e0 = __lsx_vreplgr2vr_h(uint16_t(0xC0E0));
__m128i s3 = __lsx_vor_v(s2, v_c0e0);
// __m128i v_07ff = vmovq_n_u16((uint16_t)0x07FF);
__m128i one_or_two_bytes_bytemask = __lsx_vsle_hu(utf16_packed, v_07ff);
__m128i m0 = __lsx_vandn_v(one_or_two_bytes_bytemask,
__lsx_vldi(-2752 /*0x4000*/));
__m128i s4 = __lsx_vxor_v(s3, m0);
// 4. expand code units 16-bit => 32-bit
__m128i out0 = __lsx_vilvl_h(s4, t2);
__m128i out1 = __lsx_vilvh_h(s4, t2);
// 5. compress 32-bit code units into 1, 2 or 3 bytes -- 2 x shuffle
__m128i one_byte_bytemask =
__lsx_vsle_hu(utf16_packed, __lsx_vrepli_h(0x7F));
__m128i one_or_two_bytes_bytemask_u16_to_u32_low =
__lsx_vilvl_h(one_or_two_bytes_bytemask, zero);
__m128i one_or_two_bytes_bytemask_u16_to_u32_high =
__lsx_vilvh_h(one_or_two_bytes_bytemask, zero);
__m128i one_byte_bytemask_u16_to_u32_low =
__lsx_vilvl_h(one_byte_bytemask, one_byte_bytemask);
__m128i one_byte_bytemask_u16_to_u32_high =
__lsx_vilvh_h(one_byte_bytemask, one_byte_bytemask);
const uint32_t mask0 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(__lsx_vor_v(
one_or_two_bytes_bytemask_u16_to_u32_low,
one_byte_bytemask_u16_to_u32_low)),
0);
const uint32_t mask1 =
__lsx_vpickve2gr_bu(__lsx_vmskltz_h(__lsx_vor_v(
one_or_two_bytes_bytemask_u16_to_u32_high,
one_byte_bytemask_u16_to_u32_high)),
0);
const uint8_t *row0 =
&simdutf::tables::utf16_to_utf8::pack_1_2_3_utf8_bytes[mask0][0];
__m128i shuffle0 = __lsx_vld(row0, 1);
__m128i utf8_0 = __lsx_vshuf_b(zero, out0, shuffle0);
const uint8_t *row1 =
&simdutf::tables::utf16_to_utf8::pack_1_2_3_utf8_bytes[mask1][0];
__m128i shuffle1 = __lsx_vld(row1, 1);
__m128i utf8_1 = __lsx_vshuf_b(zero, out1, shuffle1);
__lsx_vst(utf8_0, utf8_output, 0);
utf8_output += row0[0];
__lsx_vst(utf8_1, utf8_output, 0);
utf8_output += row1[0];
buf += 8;
}
// At least one 32-bit word will produce a surrogate pair in UTF-16 <=>
// will produce four UTF-8 bytes.
} else {
// Let us do a scalar fallback.
// It may seem wasteful to use scalar code, but being efficient with SIMD
// in the presence of surrogate pairs may require non-trivial tables.
size_t forward = 15;
size_t k = 0;
if (size_t(end - buf) < forward + 1) {
forward = size_t(end - buf - 1);
}
for (; k < forward; k++) {
uint32_t word = buf[k];
if ((word & 0xFFFFFF80) == 0) {
*utf8_output++ = char(word);
} else if ((word & 0xFFFFF800) == 0) {
*utf8_output++ = char((word >> 6) | 0b11000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
} else if ((word & 0xFFFF0000) == 0) {
if (word >= 0xD800 && word <= 0xDFFF) {
return std::make_pair(
result(error_code::SURROGATE, buf - start + k),
reinterpret_cast<char *>(utf8_output));
}
*utf8_output++ = char((word >> 12) | 0b11100000);
*utf8_output++ = char(((word >> 6) & 0b111111) | 0b10000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
} else {
if (word > 0x10FFFF) {
return std::make_pair(
result(error_code::TOO_LARGE, buf - start + k),
reinterpret_cast<char *>(utf8_output));
}
*utf8_output++ = char((word >> 18) | 0b11110000);
*utf8_output++ = char(((word >> 12) & 0b111111) | 0b10000000);
*utf8_output++ = char(((word >> 6) & 0b111111) | 0b10000000);
*utf8_output++ = char((word & 0b111111) | 0b10000000);
}
}
buf += k;
}
} // while
return std::make_pair(result(error_code::SUCCESS, buf - start),
reinterpret_cast<char *>(utf8_output));
}
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