diff options
Diffstat (limited to 'src/multibyte/mbsnrtowcs.c')
-rw-r--r-- | src/multibyte/mbsnrtowcs.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/src/multibyte/mbsnrtowcs.c b/src/multibyte/mbsnrtowcs.c new file mode 100644 index 00000000..c6f0207f --- /dev/null +++ b/src/multibyte/mbsnrtowcs.c @@ -0,0 +1,61 @@ +/* + * This code was written by Rich Felker in 2010; no copyright is claimed. + * This code is in the public domain. Attribution is appreciated but + * unnecessary. + */ + +#include <stdlib.h> +#include <inttypes.h> +#include <wchar.h> +#include <errno.h> +#include <stdio.h> + +#include "internal.h" + +size_t mbsnrtowcs(wchar_t *wcs, const char **src, size_t n, size_t wn, mbstate_t *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; + } + /* 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; +} |