[apparmor] [patch 4/5] parser: convert var expansion to use alternations

[Seth Arnold]

On Mon, Dec 09, 2013 at 12:37:13PM -0800, Steve Beattie wrote:

It's too late to make it through expand_by_alternations(), so just a quick
thought on these first two functions...

> +static void trim_trailing_slash(std::string& str)
> +{
> +	for (std::string::reverse_iterator rit = str.rbegin();
> +			rit != str.rend() && *rit == '/'; ++rit) {
> +		/* yuck, reverse_iterators are ugly */
> +		str.erase(--rit.base());
> +	}
> +}
> +
> +static void write_replacement(const char separator, const char* value,
> +			     std::string& replacement, bool filter_leading_slash,
> +			     bool filter_trailing_slash)
> +{
> +	const char *p = value;
> +
> +	replacement.append(1, separator);
> +
> +	if (filter_leading_slash)
> +		while (*p == '/')
> +			p++;
> +
> +	replacement.append(p);
> +	if (filter_trailing_slash)
> +		trim_trailing_slash(replacement);
> +}

Yuck, reverse iterators _are_ ugly. :)

While trying to come up with something better using substr, I stumbled
over find_last_not_of() and find_first_not_of():
http://www.cplusplus.com/reference/string/string/find_first_not_of/
http://www.cplusplus.com/reference/string/string/find_last_not_of/

I think these two functions would make it easier to snip the results
(substr() maybe?) down to something less ugly than modifying a string in
the middle of a reverse iterator.

Thanks
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