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

   1 #include <stdint.h>
   2 #include <wchar.h>
   3 #include <errno.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include "internal.h"
   7
   8 size_t mbsrtowcs(wchar_t *restrict ws, const char **restrict src, size_t wn, mbstate_t *restrict st)
   9 {
  10         const unsigned char *s = (const void *)*src;
  11         size_t wn0 = wn;
  12         unsigned c = 0;
  13
  14         if (st && (c = *(unsigned *)st)) {
  15                 if (ws) {
  16                         *(unsigned *)st = 0;
  17                         goto resume;
  18                 } else {
  19                         goto resume0;
  20                 }
  21         }
  22
  23         if (MB_CUR_MAX==1) {
  24                 if (!ws) return strlen((const char *)s);
  25                 for (;;) {
  26                         if (!wn) {
  27                                 *src = (const void *)s;
  28                                 return wn0;
  29                         }
  30                         if (!*s) break;
  31                         c = *s++;
  32                         *ws++ = CODEUNIT(c);
  33                         wn--;
  34                 }
  35                 *ws = 0;
  36                 *src = 0;
  37                 return wn0-wn;
  38         }
  39
  40         if (!ws) for (;;) {
  41                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  42                         while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  43                                 s += 4;
  44                                 wn -= 4;
  45                         }
  46                 }
  47                 if (*s-1u < 0x7f) {
  48                         s++;
  49                         wn--;
  50                         continue;
  51                 }
  52                 if (*s-SA > SB-SA) break;
  53                 c = bittab[*s++-SA];
  54 resume0:
  55                 if (OOB(c,*s)) { s--; break; }
  56                 s++;
  57                 if (c&(1U<<25)) {
  58                         if (*s-0x80u >= 0x40) { s-=2; break; }
  59                         s++;
  60                         if (c&(1U<<19)) {
  61                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  62                                 s++;
  63                         }
  64                 }
  65                 wn--;
  66                 c = 0;
  67         } else for (;;) {
  68                 if (!wn) {
  69                         *src = (const void *)s;
  70                         return wn0;
  71                 }
  72                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  73                         while (wn>=5 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
  74                                 *ws++ = *s++;
  75                                 *ws++ = *s++;
  76                                 *ws++ = *s++;
  77                                 *ws++ = *s++;
  78                                 wn -= 4;
  79                         }
  80                 }
  81                 if (*s-1u < 0x7f) {
  82                         *ws++ = *s++;
  83                         wn--;
  84                         continue;
  85                 }
  86                 if (*s-SA > SB-SA) break;
  87                 c = bittab[*s++-SA];
  88 resume:
  89                 if (OOB(c,*s)) { s--; break; }
  90                 c = (c<<6) | *s++-0x80;
  91                 if (c&(1U<<31)) {
  92                         if (*s-0x80u >= 0x40) { s-=2; break; }
  93                         c = (c<<6) | *s++-0x80;
  94                         if (c&(1U<<31)) {
  95                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  96                                 c = (c<<6) | *s++-0x80;
  97                         }
  98                 }
  99                 *ws++ = c;
 100                 wn--;
 101                 c = 0;
 102         }
 103
 104         if (!c && !*s) {
 105                 if (ws) {
 106                         *ws = 0;
 107                         *src = 0;
 108                 }
 109                 return wn0-wn;
 110         }
 111         errno = EILSEQ;
 112         if (ws) *src = (const void *)s;
 113         return -1;
 114 }