cosmopolitan/libc/x/utf8to32.c
2024-08-24 17:53:30 -07:00

94 lines
3.9 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2021 Justine Alexandra Roberts Tunney │
│ │
│ 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 appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/mem/mem.h"
#include "libc/str/str.h"
#include "libc/str/thompike.h"
#include "libc/str/utf16.h"
#include "libc/x/x.h"
#include "third_party/intel/emmintrin.internal.h"
/**
* Transcodes UTF-8 to UTF-32.
*
* @param p is input value
* @param n if -1 implies strlen
* @param z if non-NULL receives output length
*/
wchar_t *utf8to32(const char *p, size_t n, size_t *z) {
size_t i;
unsigned m, j;
wint_t x, a, b;
wchar_t *r, *q;
if (z)
*z = 0;
if (n == -1)
n = p ? strlen(p) : 0;
if ((q = r = malloc(n * sizeof(wchar_t) + sizeof(wchar_t)))) {
for (i = 0; i < n;) {
#ifdef __x86_64__
if (!((uintptr_t)(p + i) & 15) && i + 16 < n) {
do {
__m128i v1, v2, v3, v4;
v1 = _mm_loadu_si128((__m128i *)(p + i));
v2 = _mm_cmpgt_epi8(v1, _mm_setzero_si128());
if (_mm_movemask_epi8(v2) != 0xFFFF)
break;
v3 = _mm_unpacklo_epi8(v1, _mm_setzero_si128());
v1 = _mm_unpackhi_epi8(v1, _mm_setzero_si128());
v4 = _mm_unpacklo_epi16(v3, _mm_setzero_si128());
v3 = _mm_unpackhi_epi16(v3, _mm_setzero_si128());
v2 = _mm_unpacklo_epi16(v1, _mm_setzero_si128());
v1 = _mm_unpackhi_epi16(v1, _mm_setzero_si128());
_mm_storeu_si128((__m128i *)(q + 0), v4);
_mm_storeu_si128((__m128i *)(q + 4), v3);
_mm_storeu_si128((__m128i *)(q + 8), v2);
_mm_storeu_si128((__m128i *)(q + 12), v1);
i += 16;
q += 16;
} while (i + 16 < n);
}
#endif
x = p[i++] & 0xff;
if (x >= 0300) {
a = ThomPikeByte(x);
m = ThomPikeLen(x) - 1;
if (i + m <= n) {
for (j = 0;;) {
b = p[i + j] & 0xff;
if (!ThomPikeCont(b))
break;
a = ThomPikeMerge(a, b);
if (++j == m) {
x = a;
i += j;
break;
}
}
}
}
*q++ = x;
}
if (z)
*z = q - r;
*q++ = '\0';
if ((q = realloc(r, (q - r) * sizeof(wchar_t))))
r = q;
}
return r;
}