Re: [PATCH 1/5] git-compat-util: add isblank() and isgraph()

["René Scharfe" <l.s.r@web.de>]

Am 10.02.23 um 08:59 schrieb Masahiro Yamada:
> git-compat-util.h implements most of is*() macros.
>
> Add isblank() and isgraph(), which are useful to clean up wildmatch.c
> in a consistent way (in this and later commits).
>
> Use them with care because they are not robust against the pointer
> increment, like isblank(*s++).
>
> The same issue already exists for isspace().
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
>  git-compat-util.h |  4 ++++
>  wildmatch.c       | 14 ++------------
>  2 files changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 4f0028ce60..90b43b2bc9 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -1212,10 +1212,12 @@ extern const unsigned char tolower_trans_tbl[256];
>  /* Sane ctype - no locale, and works with signed chars */
>  #undef isascii
>  #undef isspace
> +#undef isblank
>  #undef isdigit
>  #undef isalpha
>  #undef isalnum
>  #undef isprint
> +#undef isgraph
>  #undef islower
>  #undef isupper
>  #undef tolower
> @@ -1236,10 +1238,12 @@ extern const unsigned char sane_ctype[256];
>  #define sane_istest(x,mask) ((sane_ctype[(unsigned char)(x)] & (mask)) != 0)
>  #define isascii(x) (((x) & ~0x7f) == 0)
>  #define isspace(x) sane_istest(x,GIT_SPACE)
> +#define isblank(x) (isspace(x) || (x) == '\t')

Our isspace() matches \t, \n, \r and space.  A standard implementation
would also match \v (vertical tab) and \f (form feed).  Anyway, your
isblank() here is the same as isspace() because the check for \t is
redundant...

>  #define isdigit(x) sane_istest(x,GIT_DIGIT)
>  #define isalpha(x) sane_istest(x,GIT_ALPHA)
>  #define isalnum(x) sane_istest(x,GIT_ALPHA | GIT_DIGIT)
>  #define isprint(x) ((x) >= 0x20 && (x) <= 0x7e)
> +#define isgraph(x) (isprint(x) && !isspace(x))
>  #define islower(x) sane_iscase(x, 1)
>  #define isupper(x) sane_iscase(x, 0)
>  #define is_glob_special(x) sane_istest(x,GIT_GLOB_SPECIAL)
> diff --git a/wildmatch.c b/wildmatch.c
> index 7e5a7ea1ea..85c4c7f8a7 100644
> --- a/wildmatch.c
> +++ b/wildmatch.c
> @@ -28,18 +28,8 @@ typedef unsigned char uchar;
>  # define ISASCII(c) isascii(c)
>  #endif
>
> -#ifdef isblank
> -# define ISBLANK(c) (ISASCII(c) && isblank(c))
> -#else
> -# define ISBLANK(c) ((c) == ' ' || (c) == '\t')

... and that's not the case for the original code, which only
matches \t and space.

We already use eight bits for the lookup table values in sane_ctype.
Perhaps it's time to move GIT_GLOB_SPECIAL, GIT_REGEX_SPECIAL,
GIT_PATHSPEC_MAGIC and GIT_PUNCT to their own table to make room for
flags for isprint(), isgraph() and isblank().

> -#endif
> -
> -#ifdef isgraph
> -# define ISGRAPH(c) (ISASCII(c) && isgraph(c))
> -#else
> -# define ISGRAPH(c) (ISASCII(c) && isprint(c) && !isspace(c))
> -#endif
> -
> +#define ISBLANK(c) (ISASCII(c) && isblank(c))
> +#define ISGRAPH(c) (ISASCII(c) && isgraph(c))
>  #define ISPRINT(c) (ISASCII(c) && isprint(c))
>  #define ISDIGIT(c) (ISASCII(c) && isdigit(c))
>  #define ISALNUM(c) (ISASCII(c) && isalnum(c))