Commit 8270e385 authored by Damien George's avatar Damien George
Browse files

py: More robust int conversion and overflow checking.

parent a58a7aef
......@@ -1139,6 +1139,7 @@ mpz_t *mpz_mod(const mpz_t *lhs, const mpz_t *rhs) {
}
#endif
// TODO check that this correctly handles overflow in all cases
machine_int_t mpz_as_int(const mpz_t *i) {
machine_int_t val = 0;
mpz_dig_t *d = i->dig + i->len;
......@@ -1147,11 +1148,13 @@ machine_int_t mpz_as_int(const mpz_t *i) {
machine_int_t oldval = val;
val = (val << DIG_SIZE) | *d;
if (val < oldval) {
// TODO need better handling of conversion overflow
// overflow, return +/- "infinity"
if (i->neg == 0) {
return 0x7fffffff;
// +infinity
return ~WORD_MSBIT_HIGH;
} else {
return 0x80000000;
// -infinity
return WORD_MSBIT_HIGH;
}
}
}
......@@ -1163,6 +1166,28 @@ machine_int_t mpz_as_int(const mpz_t *i) {
return val;
}
// TODO check that this correctly handles overflow in all cases
bool mpz_as_int_checked(const mpz_t *i, machine_int_t *value) {
machine_int_t val = 0;
mpz_dig_t *d = i->dig + i->len;
while (--d >= i->dig) {
machine_int_t oldval = val;
val = (val << DIG_SIZE) | *d;
if (val < oldval) {
// overflow
return false;
}
}
if (i->neg != 0) {
val = -val;
}
*value = val;
return true;
}
#if MICROPY_ENABLE_FLOAT
mp_float_t mpz_as_float(const mpz_t *i) {
mp_float_t val = 0;
......
......@@ -71,6 +71,7 @@ mpz_t *mpz_div(const mpz_t *lhs, const mpz_t *rhs);
mpz_t *mpz_mod(const mpz_t *lhs, const mpz_t *rhs);
machine_int_t mpz_as_int(const mpz_t *z);
bool mpz_as_int_checked(const mpz_t *z, machine_int_t *value);
#if MICROPY_ENABLE_FLOAT
mp_float_t mpz_as_float(const mpz_t *z);
#endif
......
......@@ -203,6 +203,24 @@ machine_int_t mp_obj_get_int(mp_obj_t arg) {
}
}
// returns false if arg is not of integral type
// returns true and sets *value if it is of integral type
// can throw OverflowError if arg is of integral type, but doesn't fit in a machine_int_t
bool mp_obj_get_int_maybe(mp_obj_t arg, machine_int_t *value) {
if (arg == mp_const_false) {
*value = 0;
} else if (arg == mp_const_true) {
*value = 1;
} else if (MP_OBJ_IS_SMALL_INT(arg)) {
*value = MP_OBJ_SMALL_INT_VALUE(arg);
} else if (MP_OBJ_IS_TYPE(arg, &mp_type_int)) {
*value = mp_obj_int_get_checked(arg);
} else {
return false;
}
return true;
}
#if MICROPY_ENABLE_FLOAT
mp_float_t mp_obj_get_float(mp_obj_t arg) {
if (arg == mp_const_false) {
......
......@@ -359,6 +359,7 @@ bool mp_obj_equal(mp_obj_t o1, mp_obj_t o2);
bool mp_obj_less(mp_obj_t o1, mp_obj_t o2);
machine_int_t mp_obj_get_int(mp_obj_t arg);
bool mp_obj_get_int_maybe(mp_obj_t arg, machine_int_t *value);
#if MICROPY_ENABLE_FLOAT
mp_float_t mp_obj_get_float(mp_obj_t self_in);
void mp_obj_get_complex(mp_obj_t self_in, mp_float_t *real, mp_float_t *imag);
......
......@@ -243,8 +243,18 @@ machine_int_t mp_obj_int_get(mp_obj_t self_in) {
}
machine_int_t mp_obj_int_get_checked(mp_obj_t self_in) {
// TODO: Check overflow
return mp_obj_int_get(self_in);
if (MP_OBJ_IS_SMALL_INT(self_in)) {
return MP_OBJ_SMALL_INT_VALUE(self_in);
} else {
mp_obj_int_t *self = self_in;
machine_int_t value;
if (mpz_as_int_checked(&self->mpz, &value)) {
return value;
} else {
// overflow
nlr_jump(mp_obj_new_exception_msg(&mp_type_OverflowError, "overflow converting long int to machine word"));
}
}
}
#if MICROPY_ENABLE_FLOAT
......
......@@ -122,12 +122,11 @@ STATIC mp_obj_t list_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
list_extend(lhs, rhs);
return o;
}
case MP_BINARY_OP_MULTIPLY:
{
if (!MP_OBJ_IS_SMALL_INT(rhs)) {
case MP_BINARY_OP_MULTIPLY: {
machine_int_t n;
if (!mp_obj_get_int_maybe(rhs, &n)) {
return NULL;
}
int n = MP_OBJ_SMALL_INT_VALUE(rhs);
mp_obj_list_t *s = list_new(o->len * n);
mp_seq_multiply(o->items, sizeof(*o->items), o->len, n, s->items);
return s;
......
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