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hush: support ${VAR:N:-M}

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function                                             old     new   delta
expand_one_var                                      1602    1615     +13
builtin_type                                         114     116      +2

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2017-07-17 16:46:57 +02:00
parent 203fd7bc66
commit e32b6503e7
3 changed files with 74 additions and 25 deletions
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52
shell/hush.c
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@@ -5723,32 +5723,34 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha
if (errmsg)
goto arith_err;
debug_printf_varexp("len:'%s'=%lld\n", exp_word, (long long)len);
if (len >= 0) {
if (beg < 0) {
/* negative beg counts from the end */
beg = (arith_t)strlen(val) + beg;
if (beg < 0) /* ${v: -999999} is "" */
beg = len = 0;
}
debug_printf_varexp("from val:'%s'\n", val);
if (len == 0 || !val || beg >= strlen(val)) {
arith_err:
val = NULL;
} else {
/* Paranoia. What if user entered 9999999999999
* which fits in arith_t but not int? */
if (len >= INT_MAX)
len = INT_MAX;
val = to_be_freed = xstrndup(val + beg, len);
}
debug_printf_varexp("val:'%s'\n", val);
} else
//TODO: in bash, len=-n means strlen()-n
#endif /* HUSH_SUBSTR_EXPANSION && FEATURE_SH_MATH */
{
die_if_script("malformed ${%s:...}", var);
val = NULL;
if (beg < 0) {
/* negative beg counts from the end */
beg = (arith_t)strlen(val) + beg;
if (beg < 0) /* ${v: -999999} is "" */
beg = len = 0;
}
debug_printf_varexp("from val:'%s'\n", val);
if (len < 0) {
/* in bash, len=-n means strlen()-n */
len = (arith_t)strlen(val) - beg + len;
if (len < 0) /* bash compat */
die_if_script("%s: substring expression < 0", var);
}
if (len == 0 || !val || beg >= strlen(val)) {
arith_err:
val = NULL;
} else {
/* Paranoia. What if user entered 9999999999999
* which fits in arith_t but not int? */
if (len >= INT_MAX)
len = INT_MAX;
val = to_be_freed = xstrndup(val + beg, len);
}
debug_printf_varexp("val:'%s'\n", val);
#else /* not (HUSH_SUBSTR_EXPANSION && FEATURE_SH_MATH) */
die_if_script("malformed ${%s:...}", var);
val = NULL;
#endif
} else { /* one of "-=+?" */
/* Standard-mandated substitution ops:
* ${var?word} - indicate error if unset