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hush: speed up ${var:+ARG} for literal ARGs

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function                                             old     new   delta
first_special_char_in_vararg                           -      52     +52
expand_one_var                                      2248    2296     +48
encode_then_expand_vararg                            357     336     -21
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 100/-21)            Total: 79 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-07-31 10:36:29 +02:00
parent a5db1d7354
commit 54fdabda3b
1 changed files with 31 additions and 27 deletions
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58
shell/hush.c
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@ -5913,6 +5913,26 @@ static char *encode_then_expand_string(const char *str)
return exp_str;
}
static const char *first_special_char_in_vararg(const char *cp)
{
for (;;) {
if (!*cp) return NULL; /* string has no special chars */
if (*cp == '$') return cp;
if (*cp == '\\') return cp;
if (*cp == '\'') return cp;
if (*cp == '"') return cp;
#if ENABLE_HUSH_TICK
if (*cp == '`') return cp;
#endif
/* dquoted "${x:+ARG}" should not glob, therefore
* '*' et al require some non-literal processing: */
if (*cp == '*') return cp;
if (*cp == '?') return cp;
if (*cp == '[') return cp;
cp++;
}
}
/* Expanding ARG in ${var#ARG}, ${var%ARG}, or ${var/ARG/ARG}.
* These can contain single- and double-quoted strings,
* and treated as if the ARG string is initially unquoted. IOW:
@ -5932,19 +5952,10 @@ static char *encode_then_expand_vararg(const char *str, int handle_squotes, int
char *exp_str;
struct in_str input;
o_string dest = NULL_O_STRING;
const char *cp;
cp = str;
for (;;) {
if (!*cp) return NULL; /* string has no special chars */
if (*cp == '$') break;
if (*cp == '\\') break;
if (*cp == '\'') break;
if (*cp == '"') break;
#if ENABLE_HUSH_TICK
if (*cp == '`') break;
#endif
cp++;
if (!first_special_char_in_vararg(str)) {
/* string has no special chars */
return NULL;
}
setup_string_in_str(&input, str);
@ -6025,26 +6036,19 @@ static char *encode_then_expand_vararg(const char *str, int handle_squotes, int
/* Expanding ARG in ${var+ARG}, ${var-ARG}
*/
static int encode_then_append_var_plusminus(o_string *output, int n,
const char *str, int dquoted)
char *str, int dquoted)
{
struct in_str input;
o_string dest = NULL_O_STRING;
#if 0 //todo?
const char *cp;
cp = str;
for (;;) {
if (!*cp) return NULL; /* string has no special chars */
if (*cp == '$') break;
if (*cp == '\\') break;
if (*cp == '\'') break;
if (*cp == '"') break;
#if ENABLE_HUSH_TICK
if (*cp == '`') break;
#endif
cp++;
if (!first_special_char_in_vararg(str)
&& '\0' == str[strcspn(str, G.ifs)]
) {
/* string has no special chars
* && string has no $IFS chars
*/
return expand_vars_to_list(output, n, str);
}
#endif
setup_string_in_str(&input, str);