[git commit master] *: use better isspace implementation

Denys Vlasenko vda.linux at googlemail.com
Thu Oct 22 17:42:26 UTC 2009


commit: http://git.busybox.net/busybox/commit/?id=f125b6d341b06fda5412b82d23e486100e107eaa
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
asciifile                                             90     106     +16
expand                                               653     658      +5
skip_non_whitespace                                   21      25      +4
bb_iswspace                                           25      28      +3
readcmd                                             1071    1072      +1
find_range                                           496     497      +1
singlemount                                          772     771      -1
ifupdown_main                                       2134    2133      -1
edir                                                 370     369      -1
volume_id_set_label_string                            82      79      -3
trim                                                  85      82      -3
rtc_adjtime_is_utc                                   141     138      -3
rewrite                                             1039    1036      -3
do_cmd                                              4465    4462      -3
bb_dump_add                                          358     355      -3
awk_split                                            553     550      -3
fbset_main                                          1273    1268      -5
skip_thing                                           259     253      -6
get_trimmed_slice                                     46      39      -7
bb__parsegrent                                       245     238      -7
parse_file_cmd                                       116     108      -8
check                                               1532    1523      -9
bb__pgsreader                                        198     188     -10
dot_skip_over_ws                                      61      46     -15
colon                                               3032    3012     -20
if_readlist_proc                                     655     634     -21
normalize                                            193     165     -28
add_cmd                                             1162    1133     -29
get_key                                              528     476     -52
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 6/23 up/down: 30/-241)         Total: -211 bytes

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 include/libbb.h         |   11 ++++++++++-
 libbb/skip_whitespace.c |   13 ++++++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/include/libbb.h b/include/libbb.h
index 97dbe86..fb7296f 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1576,7 +1576,6 @@ extern const char bb_default_login_shell[];
 #undef islower
 #undef isprint
 #undef ispunct
-#undef isspace
 #undef isupper
 #undef isxdigit
 
@@ -1584,6 +1583,16 @@ extern const char bb_default_login_shell[];
 #undef isdigit
 #define isdigit(a) ((unsigned)((a) - '0') <= 9)
 
+/* This one is more efficient too! ~200 bytes */
+/* In POSIX/C locale (the only locale we care about: do we REALLY want
+ * to allow Unicode whitespace in, say, .conf files? nuts!)
+ * isspace is only these chars: "\t\n\v\f\r" and space.
+ * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
+ * Use that.
+ */
+#undef isspace
+#define isspace(a) ({ unsigned char bb__isspace = (a) - 9; bb__isspace == (' ' - 9) || bb__isspace <= (13 - 9); })
+
 #define ARRAY_SIZE(x) ((unsigned)(sizeof(x) / sizeof((x)[0])))
 
 
diff --git a/libbb/skip_whitespace.c b/libbb/skip_whitespace.c
index e85f385..7b12326 100644
--- a/libbb/skip_whitespace.c
+++ b/libbb/skip_whitespace.c
@@ -11,15 +11,22 @@
 
 char* FAST_FUNC skip_whitespace(const char *s)
 {
-	/* NB: isspace('\0') returns 0 */
-	while (isspace(*s)) ++s;
+	/* In POSIX/C locale (the only locale we care about: do we REALLY want
+	 * to allow Unicode whitespace in, say, .conf files? nuts!)
+	 * isspace is only these chars: "\t\n\v\f\r" and space.
+	 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
+	 * Use that.
+	 */
+	while (*s == ' ' || (unsigned char)(*s - 9) <= (13 - 9))
+		s++;
 
 	return (char *) s;
 }
 
 char* FAST_FUNC skip_non_whitespace(const char *s)
 {
-	while (*s && !isspace(*s)) ++s;
+	while (*s != '\0' && *s != ' ' && (unsigned char)(*s - 9) > (13 - 9))
+		s++;
 
 	return (char *) s;
 }
-- 
1.6.3.3



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