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implement support for parameter substitution via #/% operators

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This commit is contained in:
Mike Frysinger
2009-04-07 06:03:22 +00:00
parent 6c9be7f451
commit a4f331d3c3
6 changed files with 242 additions and 24 deletions
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63
shell/hush.c
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@@ -43,7 +43,6 @@
* Here Documents ( << word )
* Functions
* Tilde Expansion
* Parameter Expansion for substring processing ${var#word} ${var%word}
*
* Bash stuff (maybe optionally enable?):
* &> and >& redirection of stdout+stderr
@@ -76,6 +75,7 @@
#include <fnmatch.h>
#endif
#include "math.h"
#include "match.h"
#ifdef WANT_TO_TEST_NOMMU
# undef BB_MMU
@@ -1667,8 +1667,9 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
char first_ch, ored_ch;
int i;
const char *val;
char *p;
char *dyn_val, *p;
dyn_val = NULL;
ored_ch = 0;
debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
@@ -1844,7 +1845,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
++var;
} else {
/* maybe handle parameter expansion */
exp_off = strcspn(var, ":-=+?");
exp_off = strcspn(var, ":-=+?%#");
if (!var[exp_off])
exp_off = 0;
if (exp_off) {
@@ -1873,29 +1874,45 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
val = utoa(val ? strlen(val) : 0);
debug_printf_expand("%s\n", val);
} else if (exp_off) {
/* we need to do an expansion */
int exp_test = (!val || (exp_null && !val[0]));
if (exp_op == '+')
exp_test = !exp_test;
debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
exp_null ? "true" : "false", exp_test);
if (exp_test) {
if (exp_op == '?')
maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
if (exp_op == '%' || exp_op == '#') {
/* we need to do a pattern match */
bool zero;
char *loc;
scan_t scan = pick_scan(exp_op, *exp_word, &zero);
if (exp_op == *exp_word) /* ## or %% */
++exp_word;
val = dyn_val = xstrdup(val);
loc = scan(dyn_val, exp_word, zero);
if (zero)
val = loc;
else
val = exp_word;
*loc = '\0';
} else {
/* we need to do an expansion */
int exp_test = (!val || (exp_null && !val[0]));
if (exp_op == '+')
exp_test = !exp_test;
debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
exp_null ? "true" : "false", exp_test);
if (exp_test) {
if (exp_op == '?')
maybe_die(var, *exp_word ? exp_word : "parameter null or not set");
else
val = exp_word;
if (exp_op == '=') {
if (isdigit(var[0]) || var[0] == '#') {
maybe_die(var, "special vars cannot assign in this way");
val = NULL;
} else {
char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
sprintf(new_var, "%s=%s", var, val);
set_local_var(new_var, -1, 0);
if (exp_op == '=') {
if (isdigit(var[0]) || var[0] == '#') {
maybe_die(var, "special vars cannot assign in this way");
val = NULL;
} else {
char *new_var = xmalloc(strlen(var) + strlen(val) + 2);
sprintf(new_var, "%s=%s", var, val);
set_local_var(new_var, -1, 0);
}
}
}
}
var[exp_off] = exp_save;
}
@@ -1921,6 +1938,8 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
if (val) {
o_addQstr(output, val, strlen(val));
}
free(dyn_val);
dyn_val = NULL;
/* Do the check to avoid writing to a const string */
if (*p != SPECIAL_VAR_SYMBOL)
*p = SPECIAL_VAR_SYMBOL;
@@ -4428,7 +4447,6 @@ static int handle_dollar(o_string *as_string,
break;
}
goto case_default;
#if 0 /* not implemented yet :( */
case '#': /* remove prefix */
case '%': /* remove suffix */
if (expansion == 0) {
@@ -4437,7 +4455,6 @@ static int handle_dollar(o_string *as_string,
break;
}
goto case_default;
#endif
case '-': /* default value */
case '=': /* assign default */
case '+': /* alternative */