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 <stdlib.h>
   8 #include <inttypes.h>
   9 #include <wchar.h>
  10 #include <errno.h>
  11
  12 #include "internal.h"
  13
  14 size_t mbsrtowcs(wchar_t *restrict ws, const char **restrict src, size_t wn, mbstate_t *restrict st)
  15 {
  16         unsigned c;
  17         const unsigned char *s = (const void *)*src;
  18         const wchar_t *wsorig = ws;
  19
  20         if (!st) st = (void *)&c, c = 0;
  21         else c = *(unsigned *)st;
  22
  23         if (c) {
  24                 *(unsigned *)st = 0;
  25                 if (!ws) {
  26                         wn = 0;
  27                         goto resume0;
  28                 }
  29                 goto resume;
  30         }
  31
  32         if (!ws) for (wn=0;;) {
  33                 if (*s-SA >= SB-SA) {
  34                         while (((uintptr_t)s&3) && *s-1u<0x7f) s++, wn++;
  35                         while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) s+=4, wn+=4;
  36                         while (*s-1u<0x7f) s++, wn++;
  37                         if (!*s) return wn;
  38                         if (*s-SA >= SB-SA) goto ilseq2;
  39                 }
  40                 c = bittab[*s++-SA];
  41                 do {
  42 resume0:
  43                         if (OOB(c,*s)) goto ilseq2; s++;
  44                         c <<= 6; if (!(c&(1U<<31))) break;
  45                         if (*s++-0x80u >= 0x40) goto ilseq2;
  46                         c <<= 6; if (!(c&(1U<<31))) break;
  47                         if (*s++-0x80u >= 0x40) goto ilseq2;
  48                 } while (0);
  49                 wn++; c = 0;
  50         }
  51
  52         while (wn) {
  53                 if (*s-SA >= SB-SA) {
  54                         if (wn >= 7) {
  55                                 while (((uintptr_t)s&3) && *s-1u<0x7f) {
  56                                         *ws++ = *s++;
  57                                         wn--;
  58                                 }
  59                                 while (wn>=4 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  60                                         *ws++ = *s++;
  61                                         *ws++ = *s++;
  62                                         *ws++ = *s++;
  63                                         *ws++ = *s++;
  64                                         wn -= 4;
  65                                 }
  66                         }
  67                         while (wn && *s-1u<0x7f) {
  68                                 *ws++ = *s++;
  69                                 wn--;
  70                         }
  71                         if (!wn) break;
  72                         if (!*s) {
  73                                 *ws = 0;
  74                                 *src = 0;
  75                                 return ws-wsorig;
  76                         }
  77                         if (*s-SA >= SB-SA) goto ilseq;
  78                 }
  79                 c = bittab[*s++-SA];
  80                 do {
  81 resume:
  82                         if (OOB(c,*s)) goto ilseq;
  83                         c = (c<<6) | *s++-0x80;
  84                         if (!(c&(1U<<31))) break;
  85
  86                         if (*s-0x80u >= 0x40) goto ilseq;
  87                         c = (c<<6) | *s++-0x80;
  88                         if (!(c&(1U<<31))) break;
  89
  90                         if (*s-0x80u >= 0x40) goto ilseq;
  91                         c = (c<<6) | *s++-0x80;
  92                 } while (0);
  93
  94                 *ws++ = c; wn--; c = 0;
  95         }
  96         *src = (const void *)s;
  97         return ws-wsorig;
  98 ilseq:
  99         *src = (const void *)s;
 100 ilseq2:
 101         /* enter permanently failing state */
 102         *(unsigned *)st = FAILSTATE;
 103         errno = EILSEQ;
 104         return -1;
 105 }