Re: [PATCH v2 1/5] git-compat-util: add isblank() and isgraph()
flat view
From: René Scharfe <hidden>
Date: 2023-02-26 18:45:34
Am 26.02.23 um 12:50 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). In the previous submission, I just moved isblank() and isgraph() as implemented in wildmatch.c. I knew they were not robust against the pointer increment like isblank(*s++), but I thought it was the same pattern as isprint(), which has the same issue. Unfortunately, it was more controversial than I had expected...
Not sure we need that story in the commit message, but it gave me an idea: To go back to the isprint() version from 1c149ab2dd (ctype: support iscntrl, ispunct, isxdigit and isprint, 2012-10-15), which evaluates its argument only once: #define isprint(x) (sane_istest(x, GIT_ALPHA | GIT_DIGIT | GIT_SPACE | \ GIT_PUNCT | GIT_REGEX_SPECIAL | GIT_GLOB_SPECIAL | \ GIT_PATHSPEC_MAGIC)) But then I realized that it wrongly classifies \t, \r and \n as being printing characters; 567342fc77 (test-ctype: test iscntrl, ispunct, isxdigit and isprint, 2023-02-13) shows it. So it's not so easy, however, ...
This version implements them as inline functions because we ran out all bits in the sane_ctype[] table. This is the same pattern as islower() and isupper().
... if you remove GIT_SPACE from the definition above you get a macro version of isgraph() that uses a single table lookup.
Once we refactor ctype.c to create more room in sane_ctype[], isblank() and isgraph() will be able to use sane_istest(). Probably so will islower() and isupper(). The ctype in Linux kernel (lib/ctype.c) has the LOWER and UPPER bits separately.
If we're out of bits then isblank() is a good choice to implement without a table lookup, as this class only contains two characters and two comparisons should be quite fast. Stepping back a bit: Is using the unlocalized is* macros in wildmatch() safe, i.e. do we get the same results as before regardless of locale? Junio's remark in https://lore.kernel.org/git/xmqq3579crsd.fsf@gitster.g/ (local) sounds convincing to me if we don't care about single-byte code pages and require plain ASCII or UTF-8. I think it's a good idea to address that point in the commit message. And adding tests to t/helper/test-ctype.c would be nice.
quoted hunk ↗ jump to hunk
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Changes in v2: - Use inline functions git-compat-util.h | 14 ++++++++++++++ wildmatch.c | 14 ++------------ 2 files changed, 16 insertions(+), 12 deletions(-)diff --git a/git-compat-util.h b/git-compat-util.h index 4f0028ce60..b29c238f02 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) sane_isblank(x) #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) sane_isgraph(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)@@ -1270,6 +1274,16 @@ static inline int sane_iscase(int x, int is_lower) return (x & 0x20) == 0; } +static inline int sane_isblank(int c) +{ + return c == ' ' || c == '\t'; +} + +static inline int sane_isgraph(int c) +{ + return isprint(c) && !isspace(c); +} + /* * Like skip_prefix, but compare case-insensitively. Note that the comparison * is done via tolower(), so it is strictly ASCII (no multi-byte characters ordiff --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') -#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))