[PATCH] _scanf.c: Implement 'm' modifier for 'c' and '[' conversions.
Will Newton
will.newton at gmail.com
Tue Oct 23 14:12:09 UTC 2012
Ping?
On Tue, Oct 16, 2012 at 12:00 PM, Will Newton <will.newton at gmail.com> wrote:
> The current code implements the 'm' modifier only for 's'
> conversions and would cause a segfault if it was used for 'c'
> or '[' conversions. This patch extends the code to cover these
> cases too.
>
> Signed-off-by: Will Newton <will.newton at imgtec.com>
> ---
> libc/stdio/_scanf.c | 51 ++++++++++++++++++++++++++++++++-------------------
> 1 files changed, 32 insertions(+), 19 deletions(-)
>
> diff --git a/libc/stdio/_scanf.c b/libc/stdio/_scanf.c
> index 952853c..c862afb 100644
> --- a/libc/stdio/_scanf.c
> +++ b/libc/stdio/_scanf.c
> @@ -1355,7 +1355,21 @@ int VFSCANF (FILE *__restrict fp, const Wchar
> *__restrict format, va_list arg)
> (psfs.conv_num >= CONV_c)
> #endif /* __UCLIBC_HAS_WCHAR__ */
> {
> + /* We might have to handle the allocation ourselves */
> + int len;
> + unsigned char **ptr;
> +
> b = (psfs.store ? ((unsigned char *) psfs.cur_ptr) : buf);
> + /* With 'm', we actually got a pointer to a pointer */
> + ptr = (void *)b;
> +
> + i = 0;
> + if (psfs.flags & FLAG_MALLOC) {
> + len = 0;
> + b = NULL;
> + } else
> + len = -1;
> +
> fail = 1;
>
> if (psfs.conv_num == CONV_c) {
> @@ -1363,31 +1377,25 @@ int VFSCANF (FILE *__restrict fp, const Wchar
> *__restrict format, va_list arg)
> sc.width = 1;
> }
>
> + if (psfs.flags & FLAG_MALLOC)
> + b = malloc(sc.width);
> +
> while (__scan_getc(&sc) >= 0) {
> zero_conversions = 0;
> - *b = sc.cc;
> - b += psfs.store;
> + b[i] = sc.cc;
> + i += psfs.store;
> }
> __scan_ungetc(&sc);
> if (sc.width > 0) { /* Failed to read all required. */
> goto DONE;
> }
> + if (psfs.flags & FLAG_MALLOC)
> + *ptr = b;
> psfs.cnt += psfs.store;
> goto NEXT_FMT;
> }
>
> if (psfs.conv_num == CONV_s) {
> - /* We might have to handle the allocation ourselves */
> - int len;
> - /* With 'm', we actually got a pointer to a pointer */
> - unsigned char **ptr = (void *)b;
> -
> - i = 0;
> - if (psfs.flags & FLAG_MALLOC) {
> - len = 0;
> - b = NULL;
> - } else
> - len = -1;
>
> /* Yes, believe it or not, a %s conversion can store nuls. */
> while ((__scan_getc(&sc) >= 0) && !isspace(sc.cc)) {
> @@ -1403,10 +1411,6 @@ int VFSCANF (FILE *__restrict fp, const Wchar
> *__restrict format, va_list arg)
> fail = 0;
> }
>
> - if (psfs.flags & FLAG_MALLOC)
> - *ptr = b;
> - /* The code below takes care of terminating NUL */
> - b += i;
> } else {
> #ifdef __UCLIBC_HAS_WCHAR__
> assert((psfs.conv_num == CONV_LEFTBRACKET) || \
> @@ -1462,8 +1466,14 @@ int VFSCANF (FILE *__restrict fp, const Wchar
> *__restrict format, va_list arg)
> if (!scanset[sc.cc]) {
> break;
> }
> - *b = sc.cc;
> - b += psfs.store;
> + if (i == len) {
> + /* Pick a size that won't trigger a lot of
> + * mallocs early on ... */
> + len += 256;
> + b = realloc(b, len + 1);
> + }
> + b[i] = sc.cc;
> + i += psfs.store;
> fail = 0;
> }
> }
> @@ -1473,6 +1483,9 @@ int VFSCANF (FILE *__restrict fp, const Wchar
> *__restrict format, va_list arg)
> if (fail) { /* nothing stored! */
> goto DONE;
> }
> + if (psfs.flags & FLAG_MALLOC)
> + *ptr = b;
> + b += i;
> *b = 0; /* Nul-terminate string. */
> psfs.cnt += psfs.store;
> goto NEXT_FMT;
> --
> 1.7.1
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