e3be7842b
Denys Vlasenko
2010-05-20
Subject
hush: shrink variable expansion code
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shell/hush.c+19 -20
| @@ -2568,35 +2568,33 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| #endif | |
| default: /* <SPECIAL_VAR_SYMBOL>varname<SPECIAL_VAR_SYMBOL> */ | |
| case_default: { | |
| - | bool exp_len = false; |
| - | bool exp_null = false; |
| char *var = arg; | |
| + | bool exp_len; |
| + | char exp_op; |
| char exp_save = exp_save; /* for compiler */ | |
| - | char exp_op = exp_op; /* for compiler */ |
| + | char *exp_saveptr = exp_saveptr; /* points to expansion operator */ |
| char *exp_word = exp_word; /* for compiler */ | |
| - | size_t exp_off = 0; |
| *p = '\0'; | |
| arg[0] = first_ch & 0x7f; | |
| /* prepare for expansions */ | |
| + | exp_len = false; |
| + | exp_op = 0; |
| if (var[0] == '#') { | |
| /* handle length expansion ${#var} */ | |
| exp_len = true; | |
| ++var; | |
| } else { | |
| /* maybe handle parameter expansion */ | |
| - | exp_off = strcspn(var, ":-=+?%#"); |
| - | if (!var[exp_off]) |
| - | exp_off = 0; |
| - | if (exp_off) { |
| - | exp_save = var[exp_off]; |
| - | exp_null = exp_save == ':'; |
| - | exp_word = var + exp_off; |
| - | if (exp_null) |
| - | ++exp_word; |
| + | exp_saveptr = var + strcspn(var, ":-=+?%#"); |
| + | exp_save = *exp_saveptr; |
| + | if (exp_save) { |
| + | exp_word = exp_saveptr; |
| + | if (exp_save == ':') |
| + | exp_word++; |
| exp_op = *exp_word++; | |
| - | var[exp_off] = '\0'; |
| + | *exp_saveptr = '\0'; |
| } | |
| } | |
| @@ -2615,7 +2613,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| debug_printf_expand("expand: length of '%s' = ", val); | |
| val = utoa(val ? strlen(val) : 0); | |
| debug_printf_expand("%s\n", val); | |
| - | } else if (exp_off) { |
| + | } else if (exp_op) { |
| if (exp_op == '%' || exp_op == '#') { | |
| if (val) { | |
| /* we need to do a pattern match */ | |
| @@ -2623,7 +2621,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| char *loc; | |
| scan_t scan = pick_scan(exp_op, *exp_word, &match_at_left); | |
| if (exp_op == *exp_word) /* ## or %% */ | |
| - | ++exp_word; |
| + | exp_word++; |
| val = dyn_val = xstrdup(val); | |
| loc = scan(dyn_val, exp_word, match_at_left); | |
| if (match_at_left) /* # or ## */ | |
| @@ -2631,13 +2629,14 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| else if (loc) /* % or %% and match was found */ | |
| *loc = '\0'; | |
| } | |
| - | } else { |
| + | } else { /* one of :-=+? */ |
| + | //TODO: handle ${VAR:N[:M]} here. N, M can be expressions similar to $((EXPR)): 2+2, 2+var etc |
| /* we need to do an expansion */ | |
| - | int exp_test = (!val || (exp_null && !val[0])); |
| + | int exp_test = (!val || ((exp_save == ':') && !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); |
| + | (exp_save == ':') ? "true" : "false", exp_test); |
| if (exp_test) { | |
| if (exp_op == '?') { | |
| //TODO: how interactive bash aborts expansion mid-command? | |
| @@ -2666,7 +2665,7 @@ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char | |
| } | |
| } | |
| - | var[exp_off] = exp_save; |
| + | *exp_saveptr = exp_save; |
| } | |
| arg[0] = first_ch; | |