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 *ws, const char **src, size_t wn, mbstate_t *st)
  15 {
  16         unsigned c;
  17         const unsigned char *s = *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 ((unsigned)*s-SA >= SB-SA) {
  34                         while (((unsigned)s&3) && (unsigned)*s-1<0x7f) s++, wn++;
  35                         while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) s+=4, wn+=4;
  36                         while ((unsigned)*s-1<0x7f) s++, wn++;
  37                         if (!*s) return wn;
  38                         if ((unsigned)*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 #ifdef I_FAILED_TO_RTFM_RFC3629
  46                         if ((unsigned)*s++-0x80 >= 0x40) goto ilseq2;
  47                         c <<= 6; if (!(c&(1U<<31))) break;
  48                         if ((unsigned)*s++-0x80 >= 0x40) goto ilseq2;
  49                         c <<= 6; if (!(c&(1U<<31))) break;
  50 #endif
  51                         if ((unsigned)*s++-0x80 >= 0x40) goto ilseq2;
  52                         c <<= 6; if (!(c&(1U<<31))) break;
  53                         if ((unsigned)*s++-0x80 >= 0x40) goto ilseq2;
  54                 } while (0);
  55                 wn++; c = 0;
  56         }
  57
  58         while (wn) {
  59                 if ((unsigned)*s-SA >= SB-SA) {
  60                         if (wn >= 7) {
  61                                 while (((unsigned)s&3) && (unsigned)*s-1<0x7f) {
  62                                         *ws++ = *s++;
  63                                         wn--;
  64                                 }
  65                                 while (wn>=4 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  66                                         *ws++ = *s++;
  67                                         *ws++ = *s++;
  68                                         *ws++ = *s++;
  69                                         *ws++ = *s++;
  70                                         wn -= 4;
  71                                 }
  72                         }
  73                         while (wn && (unsigned)*s-1<0x7f) {
  74                                 *ws++ = *s++;
  75                                 wn--;
  76                         }
  77                         if (!wn) break;
  78                         if (!*s) {
  79                                 *ws = 0;
  80                                 *src = 0;
  81                                 return ws-wsorig;
  82                         }
  83                         if ((unsigned)*s-SA >= SB-SA) goto ilseq;
  84                 }
  85                 c = bittab[*s++-SA];
  86                 do {
  87 resume:
  88                         if (OOB(c,*s)) goto ilseq;
  89                         c = (c<<6) | *s++-0x80;
  90                         if (!(c&(1U<<31))) break;
  91
  92 #ifdef I_FAILED_TO_RTFM_RFC3629
  93                         if ((unsigned)*s-0x80 >= 0x40) goto ilseq;
  94                         c = (c<<6) | *s++-0x80;
  95                         if (!(c&(1U<<31))) break;
  96
  97                         if ((unsigned)*s-0x80 >= 0x40) goto ilseq;
  98                         c = (c<<6) | *s++-0x80;
  99                         if (!(c&(1U<<31))) break;
 100 #endif
 101
 102                         if ((unsigned)*s-0x80 >= 0x40) goto ilseq;
 103                         c = (c<<6) | *s++-0x80;
 104                         if (!(c&(1U<<31))) break;
 105
 106                         if ((unsigned)*s-0x80 >= 0x40) goto ilseq;
 107                         c = (c<<6) | *s++-0x80;
 108                 } while (0);
 109
 110                 *ws++ = c; wn--; c = 0;
 111         }
 112         *src = s;
 113         return ws-wsorig;
 114 ilseq:
 115         *src = s;
 116 ilseq2:
 117         /* enter permanently failing state */
 118         *(unsigned *)st = FAILSTATE;
 119         errno = EILSEQ;
 120         return -1;
 121 }