nsz Git - musl/blob - src/multibyte/mbsrtowcs.c

   1 /*
   2  * This code was written by Rich Felker in 2010; no copyright is claimed.
   3  * This code is in the public domain. Attribution is appreciated but
   4  * unnecessary.
   5  */
   6
   7 #include <stdint.h>
   8 #include <wchar.h>
   9 #include <errno.h>
  10 #include "internal.h"
  11
  12 size_t mbsrtowcs(wchar_t *restrict ws, const char **restrict src, size_t wn, mbstate_t *restrict st)
  13 {
  14         const unsigned char *s = (const void *)*src;
  15         size_t wn0 = wn;
  16         unsigned c = 0;
  17
  18         if (st && (c = *(unsigned *)st)) {
  19                 if (ws) {
  20                         *(unsigned *)st = 0;
  21                         goto resume;
  22                 } else {
  23                         goto resume0;
  24                 }
  25         }
  26
  27         if (!ws) for (;;) {
  28                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  29                         while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  30                                 s += 4;
  31                                 wn -= 4;
  32                         }
  33                 }
  34                 if (*s-1u < 0x7f) {
  35                         s++;
  36                         wn--;
  37                         continue;
  38                 }
  39                 if (*s-SA > SB-SA) break;
  40                 c = bittab[*s++-SA];
  41 resume0:
  42                 if (OOB(c,*s)) { s--; break; }
  43                 s++;
  44                 if (c&(1U<<25)) {
  45                         if (*s-0x80u >= 0x40) { s-=2; break; }
  46                         s++;
  47                         if (c&(1U<<19)) {
  48                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  49                                 s++;
  50                         }
  51                 }
  52                 wn--;
  53                 c = 0;
  54         } else for (;;) {
  55                 if (!wn) {
  56                         *src = (const void *)s;
  57                         return wn0;
  58                 }
  59                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  60                         while (wn>=5 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  61                                 *ws++ = *s++;
  62                                 *ws++ = *s++;
  63                                 *ws++ = *s++;
  64                                 *ws++ = *s++;
  65                                 wn -= 4;
  66                         }
  67                 }
  68                 if (*s-1u < 0x7f) {
  69                         *ws++ = *s++;
  70                         wn--;
  71                         continue;
  72                 }
  73                 if (*s-SA > SB-SA) break;
  74                 c = bittab[*s++-SA];
  75 resume:
  76                 if (OOB(c,*s)) { s--; break; }
  77                 c = (c<<6) | *s++-0x80;
  78                 if (c&(1U<<31)) {
  79                         if (*s-0x80u >= 0x40) { s-=2; break; }
  80                         c = (c<<6) | *s++-0x80;
  81                         if (c&(1U<<31)) {
  82                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  83                                 c = (c<<6) | *s++-0x80;
  84                         }
  85                 }
  86                 *ws++ = c;
  87                 wn--;
  88                 c = 0;
  89         }
  90
  91         if (!c && !*s) {
  92                 if (ws) {
  93                         *ws = 0;
  94                         *src = 0;
  95                 }
  96                 return wn0-wn;
  97         }
  98         errno = EILSEQ;
  99         if (ws) *src = (const void *)s;
 100         return -1;
 101 }