Re: [Patch v3b 3/9] util: add string-util.[ch]

[Mark Walters <markwalters1009@gmail.com>]

On Fri, 07 Dec 2012, david@tethera.net wrote:
> From: David Bremner <bremner@debian.org>
>
> This is to give a home to strtok_len. It's a bit silly to add a header
> for one routine, but it needs to be shared between several compilation
> units (or at least that's the most natural design).
> ---
>  util/Makefile.local |    3 ++-
>  util/string-util.c  |   34 ++++++++++++++++++++++++++++++++++
>  util/string-util.h  |   19 +++++++++++++++++++
>  3 files changed, 55 insertions(+), 1 deletion(-)
>  create mode 100644 util/string-util.c
>  create mode 100644 util/string-util.h
>
> diff --git a/util/Makefile.local b/util/Makefile.local
> index 3ca623e..a11e35b 100644
> --- a/util/Makefile.local
> +++ b/util/Makefile.local
> @@ -3,7 +3,8 @@
>  dir := util
>  extra_cflags += -I$(srcdir)/$(dir)
>  
> -libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c
> +libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c \
> +		  $(dir)/string-util.c
>  
>  libutil_modules := $(libutil_c_srcs:.c=.o)
>  
> diff --git a/util/string-util.c b/util/string-util.c
> new file mode 100644
> index 0000000..44f8cd3
> --- /dev/null
> +++ b/util/string-util.c
> @@ -0,0 +1,34 @@
> +/* string-util.c -  Extra or enhanced routines for null terminated strings.
> + *
> + * Copyright (c) 2012 Jani Nikula
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 3 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see http://www.gnu.org/licenses/ .
> + *
> + * Author: Jani Nikula <jani@nikula.org>
> + */
> +
> +
> +#include "string-util.h"
> +
> +char *
> +strtok_len (char *s, const char *delim, size_t *len)
> +{
> +    /* skip initial delims */
> +    s += strspn (s, delim);
> +
> +    /* length of token */
> +    *len = strcspn (s, delim);
> +
> +    return *len ? s : NULL;
> +}
> diff --git a/util/string-util.h b/util/string-util.h
> new file mode 100644
> index 0000000..696da40
> --- /dev/null
> +++ b/util/string-util.h
> @@ -0,0 +1,19 @@
> +#ifndef _STRING_UTIL_H
> +#define _STRING_UTIL_H
> +
> +#include <string.h>
> +
> +/* like strtok(3), but without state, and doesn't modify s. usage pattern:
> + *
> + * const char *tok = input;
> + * const char *delim = " \t";
> + * size_t tok_len = 0;
> + *
> + * while ((tok = strtok_len (tok + tok_len, delim, &tok_len)) != NULL) {
> + *     // do stuff with string tok of length tok_len
> + * }

Hi

Some possibly silly comments on the comment. strtok(3) seems to return a
null terminated string and this does not. Might be worth including in
the comment? Secondly every time I read this I read "..modify s. usage
pattern" as one ongoing sentence with s. an abbreviation. Perhaps a
capital u? and maybe str or string rather than s?

Best wishes

Mark

> + */
> +
> +char *strtok_len (char *s, const char *delim, size_t *len);
> +
> +#endif
> -- 
> 1.7.10.4
>
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