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shell: fix arithmentic evaluation of "++7" and such (it is + + 7, i.e. 7)

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function                                             old     new   delta
evaluate_string                                      945     988     +43

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2021-09-25 22:04:45 +02:00
parent 627821e42b
commit d84a604830
9 changed files with 65 additions and 46 deletions
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23
shell/math.c
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@@ -668,19 +668,26 @@ evaluate_string(arith_state_t *math_state, const char *expr)
/* Should be an operator */
/* Special case: NUM-- and NUM++ are not recognized if NUM
* is a literal number, not a variable. IOW:
/* Special case: XYZ--, XYZ++, --XYZ, ++XYZ are recognized
* only if XYZ is a variable name, not a number or EXPR. IOW:
* "a+++v" is a++ + v.
* "7+++v" is 7 + ++v, not 7++ + v.
* "--7" is - - 7, not --7.
* "++++a" is + + ++a, not ++ ++ a.
* (we still mishandle "(a)+++7", should be treated as (a) + + + 7, but we do increment a)
*/
if (lasttok == TOK_NUM && !numstackptr[-1].var /* number literal */
&& (expr[0] == '+' || expr[0] == '-')
if ((expr[0] == '+' || expr[0] == '-')
&& (expr[1] == expr[0])
) {
//bb_error_msg("special %c%c", expr[0], expr[0]);
op = (expr[0] == '+' ? TOK_ADD : TOK_SUB);
expr += 1;
goto tok_found1;
if (numstackptr == numstack || !numstackptr[-1].var) { /* not a VAR++ */
char next = skip_whitespace(expr + 2)[0];
if (!(isalpha(next) || next == '_')) { /* not a ++VAR */
//bb_error_msg("special %c%c", expr[0], expr[0]);
op = (expr[0] == '+' ? TOK_ADD : TOK_SUB);
expr++;
goto tok_found1;
}
}
}
p = op_tokens;