cosmopolitan/libc/str/tprecode16to8.c
2024-08-24 17:53:30 -07:00

117 lines
4.2 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 2020 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/dce.h"
#include "libc/fmt/conv.h"
#include "libc/str/str.h"
#include "libc/str/utf16.h"
#include "third_party/aarch64/arm_neon.internal.h"
#include "third_party/intel/emmintrin.internal.h"
#if !IsModeDbg()
#if defined(__x86_64__)
static axdx_t tprecode16to8_sse2(char *dst, size_t dstsize, const char16_t *src,
axdx_t r) {
__m128i v1, v2, v3, vz;
vz = _mm_setzero_si128();
while (r.ax + 8 < dstsize) {
v1 = _mm_loadu_si128((__m128i *)(src + r.dx));
v2 = _mm_cmpgt_epi16(v1, vz);
v3 = _mm_cmpgt_epi16(v1, _mm_set1_epi16(0x7F));
v2 = _mm_andnot_si128(v3, v2);
if (_mm_movemask_epi8(v2) != 0xFFFF)
break;
v1 = _mm_packs_epi16(v1, v1);
_mm_storel_epi64((__m128i *)(dst + r.ax), v1);
r.ax += 8;
r.dx += 8;
}
return r;
}
#elif defined(__aarch64__)
static axdx_t tprecode16to8_neon(char *dst, size_t dstsize, const char16_t *src,
axdx_t r) {
uint16x8_t v1, v2, v3;
while (r.ax + 8 < dstsize) {
v1 = vld1q_u16((const uint16_t *)(src + r.dx));
v2 = vcgtq_u16(v1, vdupq_n_u16(0));
v3 = vcgtq_u16(v1, vdupq_n_u16(0x7F));
v2 = vbicq_u16(v2, v3);
if (vaddvq_u16(v2) != 8 * 0xFFFF)
break;
vst1_u8((uint8_t *)(dst + r.ax), vqmovn_u16(v1));
r.ax += 8;
r.dx += 8;
}
return r;
}
#endif
#endif
/**
* Transcodes UTF-16 to UTF-8.
*
* This is a low-level function intended for the core runtime. Use
* utf16to8() for a much better API that uses malloc().
*
* @param dst is output buffer
* @param dstsize is bytes in dst
* @param src is NUL-terminated UTF-16 input string
* @return ax bytes written excluding nul
* @return dx index of character after nul word in src
*/
axdx_t tprecode16to8(char *dst, size_t dstsize, const char16_t *src) {
axdx_t r;
uint64_t w;
wint_t x, y;
r.ax = 0;
r.dx = 0;
for (;;) {
#if !IsModeDbg()
#if defined(__x86_64__)
if (!((uintptr_t)(src + r.dx) & 15))
r = tprecode16to8_sse2(dst, dstsize, src, r);
#elif defined(__aarch64__)
if (!((uintptr_t)(src + r.dx) & 15))
r = tprecode16to8_neon(dst, dstsize, src, r);
#endif
#endif
if (!(x = src[r.dx++]))
break;
if (IsUtf16Cont(x))
continue;
if (!IsUcs2(x)) {
if (!(y = src[r.dx++]))
break;
x = MergeUtf16(x, y);
}
w = tpenc(x);
while (w && r.ax + 1 < dstsize) {
dst[r.ax++] = w & 0xFF;
w >>= 8;
}
}
if (r.ax < dstsize) {
dst[r.ax] = 0;
}
return r;
}