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py: Fix check of small-int overflow when parsing ints.

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Also unifies use of SMALL_INT_FITS macro across parser and runtime.
This commit is contained in:
Damien George
2014-05-28 14:51:12 +01:00
parent 813ed3bda6
commit d1e355ea8e
11 changed files with 37 additions and 34 deletions
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17
py/parsenum.c
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@@ -34,6 +34,7 @@
#include "obj.h"
#include "parsenumbase.h"
#include "parsenum.h"
#include "smallint.h"
#if MICROPY_ENABLE_FLOAT
#include <math.h>
@@ -70,16 +71,16 @@ mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base) {
machine_int_t int_val = 0;
const char *restrict str_val_start = str;
for (; str < top; str++) {
machine_int_t old_val = int_val;
// get next digit as a value
int dig = *str;
if (unichar_isdigit(dig) && dig - '0' < base) {
// 0-9 digit
int_val = base * int_val + dig - '0';
dig = dig - '0';
} else if (base == 16) {
dig |= 0x20;
if ('a' <= dig && dig <= 'f') {
// a-f hex digit
int_val = base * int_val + dig - 'a' + 10;
dig = dig - 'a' + 10;
} else {
// unknown character
break;
@@ -88,11 +89,13 @@ mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base) {
// unknown character
break;
}
if (int_val < old_val) {
// If new value became less than previous, it's overflow
// add next digi and check for overflow
if (mp_small_int_mul_overflow(int_val, base)) {
goto overflow;
} else if ((old_val ^ int_val) & WORD_MSBIT_HIGH) {
// If signed number changed sign - it's overflow
}
int_val = int_val * base + dig;
if (!MP_SMALL_INT_FITS(int_val)) {
goto overflow;
}
}