Messages in this thread | | | Subject | Re: [PATCH 1/1] sscanf: implement basic character sets | From | Andy Shevchenko <> | Date | Mon, 22 Feb 2016 12:13:41 +0200 |
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On Fri, 2016-02-19 at 20:22 -0500, Jessica Yu wrote: > Implement basic character sets for the '%[]' conversion specifier. > > The '%[]' conversion specifier matches a nonempty sequence of > characters > from the specified set of accepted (or with '^', rejected) characters > between the brackets. The substring matched is to be made up of > characters > in (or not in) the set. This implementation differs from its glibc > counterpart in that it does not support character ranges (e.g., 'a-z' > or > '0-9'), the hyphen '-' is *not* a special character, and the brackets > themselves cannot be matched. > > Signed-off-by: Jessica Yu <jeyu@redhat.com> > --- > lib/vsprintf.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 525c8e1..6ee3e7f 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -2714,6 +2714,41 @@ int vsscanf(const char *buf, const char *fmt, > va_list args) > num++; > } > continue; > + case '[': > + { > + char *s = (char *)va_arg(args, char *); > + char set[U8_MAX] = { 0 };
Hmm... 255 on stack, not the best idea.
> + size_t (*op)(const char *str, const char > *set); > + size_t len = 0; > + bool negate = (*(fmt) == '^'); > + > + if (field_width == -1) > + field_width = SHRT_MAX; > + > + op = negate ? &strcspn : &strspn; > + if (negate) > + fmt++; > + > + len = strcspn(fmt, "]"); > + /* invalid format; stop here */ > + if (!len) > + return num; > + > + strncpy(set, fmt, len);
Perhaps here you may allocate memory on heap and copy the given set. IIRC kstrndup() does this.
> + /* advance fmt past ']' */ > + fmt += len + 1; > + > + len = (*op)(str, set); > + /* no matches */ > + if (!len) > + return num; > + > + while (*str && len-- && field_width--) > + *s++ = *str++; > + *s = '\0'; > + num++; > + } > + continue; > case 'o': > base = 8; > break;
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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