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 #ifdef __GNUC__
  42                 typedef uint32_t __attribute__((__may_alias__)) w32;
  43                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  44                         while (!(( *(w32*)s | *(w32*)s-0x01010101) & 0x80808080)) {
  45                                 s += 4;
  46                                 wn -= 4;
  47                         }
  48                 }
  49 #endif
  50                 if (*s-1u < 0x7f) {
  51                         s++;
  52                         wn--;
  53                         continue;
  54                 }
  55                 if (*s-SA > SB-SA) break;
  56                 c = bittab[*s++-SA];
  57 resume0:
  58                 if (OOB(c,*s)) { s--; break; }
  59                 s++;
  60                 if (c&(1U<<25)) {
  61                         if (*s-0x80u >= 0x40) { s-=2; break; }
  62                         s++;
  63                         if (c&(1U<<19)) {
  64                                 if (*s-0x80u >= 0x40) { s-=3; break; }
  65                                 s++;
  66                         }
  67                 }
  68                 wn--;
  69                 c = 0;
  70         } else for (;;) {
  71                 if (!wn) {
  72                         *src = (const void *)s;
  73                         return wn0;
  74                 }
  75 #ifdef __GNUC__
  76                 typedef uint32_t __attribute__((__may_alias__)) w32;
  77                 if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
  78                         while (wn>=5 && !(( *(w32*)s | *(w32*)s-0x01010101) & 0x80808080)) {
  79                                 *ws++ = *s++;
  80                                 *ws++ = *s++;
  81                                 *ws++ = *s++;
  82                                 *ws++ = *s++;
  83                                 wn -= 4;
  84                         }
  85                 }
  86 #endif
  87                 if (*s-1u < 0x7f) {
  88                         *ws++ = *s++;
  89                         wn--;
  90                         continue;
  91                 }
  92                 if (*s-SA > SB-SA) break;
  93                 c = bittab[*s++-SA];
  94 resume:
  95                 if (OOB(c,*s)) { s--; break; }
  96                 c = (c<<6) | *s++-0x80;
  97                 if (c&(1U<<31)) {
  98                         if (*s-0x80u >= 0x40) { s-=2; break; }
  99                         c = (c<<6) | *s++-0x80;
 100                         if (c&(1U<<31)) {
 101                                 if (*s-0x80u >= 0x40) { s-=3; break; }
 102                                 c = (c<<6) | *s++-0x80;
 103                         }
 104                 }
 105                 *ws++ = c;
 106                 wn--;
 107                 c = 0;
 108         }
 109
 110         if (!c && !*s) {
 111                 if (ws) {
 112                         *ws = 0;
 113                         *src = 0;
 114                 }
 115                 return wn0-wn;
 116         }
 117         errno = EILSEQ;
 118         if (ws) *src = (const void *)s;
 119         return -1;
 120 }