| #include <wchar.h> |
| |
| size_t mbsnrtowcs(wchar_t* restrict wcs, const char** restrict src, size_t n, size_t wn, |
| mbstate_t* restrict st) { |
| size_t l, cnt = 0, n2; |
| wchar_t *ws, wbuf[256]; |
| const char* s = *src; |
| |
| if (!wcs) |
| ws = wbuf, wn = sizeof wbuf / sizeof *wbuf; |
| else |
| ws = wcs; |
| |
| /* making sure output buffer size is at most n/4 will ensure |
| * that mbsrtowcs never reads more than n input bytes. thus |
| * we can use mbsrtowcs as long as it's practical.. */ |
| |
| while (s && wn && ((n2 = n / 4) >= wn || n2 > 32)) { |
| if (n2 >= wn) |
| n2 = wn; |
| n -= n2; |
| l = mbsrtowcs(ws, &s, n2, st); |
| if (!(l + 1)) { |
| cnt = l; |
| wn = 0; |
| break; |
| } |
| if (ws != wbuf) { |
| ws += l; |
| wn -= l; |
| } |
| cnt += l; |
| } |
| if (s) |
| while (wn && n) { |
| l = mbrtowc(ws, s, n, st); |
| if (l + 2 <= 2) { |
| if (!(l + 1)) { |
| cnt = l; |
| break; |
| } |
| if (!l) { |
| s = 0; |
| break; |
| } |
| /* have to roll back partial character */ |
| *(unsigned*)st = 0; |
| break; |
| } |
| s += l; |
| n -= l; |
| /* safe - this loop runs fewer than sizeof(wbuf)/8 times */ |
| ws++; |
| wn--; |
| cnt++; |
| } |
| if (wcs) |
| *src = s; |
| return cnt; |
| } |
