keysym: fix locale dependence in xkb_keysym_from_name()

We currently use strcasecmp, which is locale-dependent. In particular,
one well-known surprise even if restricted just ASCII input is found in
the tr_TR (Turkish) locale, see e.g.
https://msdn.microsoft.com/en-us/library/ms973919.aspx#stringsinnet20_topic5

We have known to avoid locale-dependent functions before, but in this
case, we forgot.

Fix it by implementing our own simple ASCII-only strcasecmp/strncasecmp.
Might have been possible to use strcasecmp_l() with the C locale, but
went the easy route.

Side advantage is that even this non-optimized version is faster than
the optimized libc one (__strcasecmp_l_sse42) since it doesn't need to
do the locale stuff. xkb_keysym_from_name(), which uses strcasecmp
heavily, becomes faster, and so for example Compose file parsing, which
uses xkb_keysym_from_name() heavily, becomes ~20% faster.

Resolves https://github.com/xkbcommon/libxkbcommon/issues/42
Signed-off-by: Ran Benita <ran234@gmail.com>
master
Ran Benita 2016-12-02 22:15:19 +02:00
parent 327364d277
commit b5586a6c42
5 changed files with 90 additions and 13 deletions

View File

@ -68,12 +68,6 @@ AS_IF([test ! -f "src/xkbcomp/parser.c" -a "x$YACC_INST" = x], [
]) ])
# Checks for library functions. # Checks for library functions.
AC_CHECK_FUNCS([strcasecmp strncasecmp])
AS_IF([test "x$ac_cv_func_strcasecmp" = xno -o \
"x$ac_cv_func_strncasecmp" = xno], [
AC_MSG_ERROR([C library does not support strcasecmp/strncasecmp])
])
AC_CHECK_FUNCS([eaccess euidaccess mmap]) AC_CHECK_FUNCS([eaccess euidaccess mmap])
AC_CHECK_FUNCS([secure_getenv __secure_getenv]) AC_CHECK_FUNCS([secure_getenv __secure_getenv])

View File

@ -76,7 +76,7 @@ compare_by_name(const void *a, const void *b)
{ {
const char *key = a; const char *key = a;
const struct name_keysym *entry = b; const struct name_keysym *entry = b;
return strcasecmp(key, get_name(entry)); return istrcmp(key, get_name(entry));
} }
XKB_EXPORT int XKB_EXPORT int
@ -109,7 +109,7 @@ xkb_keysym_get_name(xkb_keysym_t ks, char *buffer, size_t size)
/* /*
* Find the correct keysym if one case-insensitive match is given. * Find the correct keysym if one case-insensitive match is given.
* *
* The name_to_keysym table is sorted by strcasecmp(). So bsearch() may return * The name_to_keysym table is sorted by istrcmp(). So bsearch() may return
* _any_ of all possible case-insensitive duplicates. This function searches the * _any_ of all possible case-insensitive duplicates. This function searches the
* returned entry @entry, all previous and all next entries that match by * returned entry @entry, all previous and all next entries that match by
* case-insensitive comparison and returns the exact match to @name. If @icase * case-insensitive comparison and returns the exact match to @name. If @icase
@ -138,7 +138,7 @@ find_sym(const struct name_keysym *entry, const char *name, bool icase)
for (iter = entry - 1; iter >= name_to_keysym; --iter) { for (iter = entry - 1; iter >= name_to_keysym; --iter) {
if (!icase && strcmp(get_name(iter), name) == 0) if (!icase && strcmp(get_name(iter), name) == 0)
return iter; return iter;
if (strcasecmp(get_name(iter), get_name(entry)) != 0) if (istrcmp(get_name(iter), get_name(entry)) != 0)
break; break;
if (icase && xkb_keysym_is_lower(iter->keysym)) if (icase && xkb_keysym_is_lower(iter->keysym))
return iter; return iter;
@ -148,7 +148,7 @@ find_sym(const struct name_keysym *entry, const char *name, bool icase)
for (iter = entry + 1; iter < last; ++iter) { for (iter = entry + 1; iter < last; ++iter) {
if (!icase && strcmp(get_name(iter), name) == 0) if (!icase && strcmp(get_name(iter), name) == 0)
return iter; return iter;
if (strcasecmp(get_name(iter), get_name(entry)) != 0) if (istrcmp(get_name(iter), get_name(entry)) != 0)
break; break;
if (icase && xkb_keysym_is_lower(iter->keysym)) if (icase && xkb_keysym_is_lower(iter->keysym))
return iter; return iter;

View File

@ -108,3 +108,56 @@ unmap_file(char *str, size_t size)
} }
#endif #endif
// ASCII lower-case map.
static const unsigned char lower_map[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58,
59, 60, 61, 62, 63, 64, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122,
91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122,
123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137,
138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152,
153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,
168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182,
183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197,
198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212,
213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227,
228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242,
243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255
};
// ASCII tolower (to avoid locale issues).
char
to_lower(char c)
{
return (char) lower_map[(unsigned char) c];
}
// ASCII strcasecmp (to avoid locale issues).
int
istrcmp(const char *a, const char *b)
{
for (size_t i = 0; ; i++) {
if (to_lower(a[i]) != to_lower(b[i]))
return (int) to_lower(a[i]) - (int) to_lower(b[i]);
if (!a[i])
break;
}
return 0;
}
// ASCII strncasecmp (to avoid locale issues).
int
istrncmp(const char *a, const char *b, size_t n)
{
for (size_t i = 0; i < n; i++) {
if (to_lower(a[i]) != to_lower(b[i]))
return (int) to_lower(a[i]) - (int) to_lower(b[i]);
if (!a[i])
break;
}
return 0;
}

View File

@ -29,7 +29,6 @@
#include <stdbool.h> #include <stdbool.h>
#include <stdio.h> #include <stdio.h>
#include <string.h> #include <string.h>
#include <strings.h>
#include "darray.h" #include "darray.h"
@ -44,6 +43,15 @@
switch (0) { case 0: case (expr): ; } \ switch (0) { case 0: case (expr): ; } \
} while (0) } while (0)
char
to_lower(char c);
int
istrcmp(const char *a, const char *b);
int
istrncmp(const char *a, const char *b, size_t n);
static inline bool static inline bool
streq(const char *s1, const char *s2) streq(const char *s1, const char *s2)
{ {
@ -61,13 +69,13 @@ streq_not_null(const char *s1, const char *s2)
static inline bool static inline bool
istreq(const char *s1, const char *s2) istreq(const char *s1, const char *s2)
{ {
return strcasecmp(s1, s2) == 0; return istrcmp(s1, s2) == 0;
} }
static inline bool static inline bool
istreq_prefix(const char *s1, const char *s2) istreq_prefix(const char *s1, const char *s2)
{ {
return strncasecmp(s1, s2, strlen(s1)) == 0; return istrncmp(s1, s2, strlen(s1)) == 0;
} }
static inline char * static inline char *

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@ -20,6 +20,7 @@
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE. * DEALINGS IN THE SOFTWARE.
*/ */
#include <locale.h>
#include "test.h" #include "test.h"
#include "keysym.h" /* For unexported is_lower/upper/keypad() */ #include "keysym.h" /* For unexported is_lower/upper/keypad() */
@ -81,6 +82,25 @@ test_utf8(xkb_keysym_t keysym, const char *expected)
return streq(s, expected); return streq(s, expected);
} }
static void
test_github_issue_42(void)
{
// Verify we are not dependent on locale, Turkish-i problem in particular.
if (setlocale(LC_CTYPE, "tr_TR.UTF-8") == NULL) {
// The locale is not available, probably; skip.
return;
}
assert(test_string("i", XKB_KEY_i));
assert(test_string("I", XKB_KEY_I));
assert(test_casestring("i", XKB_KEY_i));
assert(test_casestring("I", XKB_KEY_i));
assert(xkb_keysym_to_upper(XKB_KEY_i) == XKB_KEY_I);
assert(xkb_keysym_to_lower(XKB_KEY_I) == XKB_KEY_i);
setlocale(LC_CTYPE, "C");
}
int int
main(void) main(void)
{ {
@ -196,5 +216,7 @@ main(void)
assert(xkb_keysym_to_upper(XKB_KEY_eacute) == XKB_KEY_Eacute); assert(xkb_keysym_to_upper(XKB_KEY_eacute) == XKB_KEY_Eacute);
assert(xkb_keysym_to_lower(XKB_KEY_Eacute) == XKB_KEY_eacute); assert(xkb_keysym_to_lower(XKB_KEY_Eacute) == XKB_KEY_eacute);
test_github_issue_42();
return 0; return 0;
} }