[pacman-dev] [PATCH 1/2] be_package: be more explicit parsing key/value pairs

[Allan McRae]

On 24/12/11 06:40, Dan McGee wrote:
> This eliminates the need for strtrim() usage completely, instead relying
> on the fact that the only allowed delimiter between key and value is the
> " = " string.
> 
> Signed-off-by: Dan McGee <dan at archlinux.org>
> ---
>  lib/libalpm/be_package.c |   21 ++++++++++++---------
>  1 files changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/libalpm/be_package.c b/lib/libalpm/be_package.c
> index 41ecc75..c602996 100644
> --- a/lib/libalpm/be_package.c
> +++ b/lib/libalpm/be_package.c
> @@ -171,18 +171,21 @@ static int parse_descfile(alpm_handle_t *handle, struct archive *a, alpm_pkg_t *
>  		size_t len = _alpm_strip_newline(buf.line);
>  
>  		linenum++;
> -		if(len == 0 || buf.line[0] == '#') {
> +		key = buf.line;
> +		if(len == 0 || key[0] == '#') {
>  			continue;
>  		}
> -		ptr = buf.line;
> -		key = strsep(&ptr, "=");
> -		if(key == NULL || ptr == NULL) {
> -			_alpm_log(handle, ALPM_LOG_DEBUG, "%s: syntax error in description file line %d\n",
> -								newpkg->name ? newpkg->name : "error", linenum);
> +		/* line is always in this format: "key = value"
> +		 * we can be sure the " = " exists, so look for that */
> +		ptr = memchr(key, ' ', len);
> +		if(!ptr || ptr - key + 2 > len || memcmp(ptr, " = ", 3) != 0) {


be_package.c: In function 'parse_descfile':
be_package.c:181:28: error: comparison between signed and unsigned
integer expressions [-Werror=sign-compare]

ptr - key + 2 is guaranteed to be > 0 so we can cast:

if(!ptr || (size_t)(ptr - key + 2) > len || memcmp(ptr, " = ", 3) != 0) {