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hush: optimization: do not glob words "[" and "[["

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function                                             old     new   delta
glob_needed                                           71      86     +15

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2025-08-07 00:00:03 +02:00
parent 8f5d890071
commit 558ef4962d
1 changed files with 40 additions and 0 deletions
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40
shell/hush.c
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@ -115,6 +115,11 @@
//config:# It's only needed to get "nice" menuconfig indenting.
//config:if SHELL_HUSH || HUSH || SH_IS_HUSH || BASH_IS_HUSH
//config:
//config:config HUSH_NEED_FOR_SPEED
//config: bool "Faster, but larger code"
//config: default y
//config: depends on SHELL_HUSH
//config:
//config:config HUSH_BASH_COMPAT
//config: bool "bash-compatible extensions"
//config: default y
@ -3381,6 +3386,24 @@ static int o_get_last_ptr(o_string *o, int n)
/* Helper */
static int glob_needed(const char *s)
{
# if ENABLE_HUSH_NEED_FOR_SPEED
char c = *s;
if (c == '[' /*|| c == '{'*/) {
/* Special-case words consisting entirely of [.
* Optimization to avoid glob()
* on "[ COND ]" and "[[ COND ]]":
* strace hush -c 'i=0; while [ $((++i)) != 50000 ]; do :; done'
* shouldn't be doing 50000 stat("[").
* (Can do it for "{" too, but it's not a common case).
*/
const char *p = s;
while (*++p == c)
continue;
if (*p == '\0')
return 0;
}
# endif
while (*s) {
if (*s == '\\') {
if (!s[1])
@ -3572,6 +3595,23 @@ static int perform_glob(o_string *o, int n)
/* Helper */
static int glob_needed(const char *s)
{
# if ENABLE_HUSH_NEED_FOR_SPEED
char c = *s;
if (c == '[') {
/* Special-case words consisting entirely of [.
* Optimization to avoid glob()
* on "[ COND ]" and "[[ COND ]]":
* strace hush -c 'i=0; while [ $((++i)) != 50000 ]; do :; done'
* shouldn't be doing 50000 stat("[").
*/
const char *p = s;
while (*++p == c)
continue;
if (*p == '\0')
return 0;
}
# endif
while (*s) {
if (*s == '\\') {
if (!s[1])