diff options
Diffstat (limited to 'py/objint.c')
| -rw-r--r-- | py/objint.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/py/objint.c b/py/objint.c index fd746d331..80f6dfe55 100644 --- a/py/objint.c +++ b/py/objint.c @@ -300,6 +300,38 @@ char *mp_obj_int_formatted(char **buf, size_t *buf_size, size_t *fmt_size, mp_co return b; } +void mp_obj_int_buffer_overflow_check(mp_obj_t self_in, size_t nbytes, bool is_signed) +{ + if (is_signed) { + // self must be < 2**(bits - 1) + mp_obj_t edge = mp_binary_op(MP_BINARY_OP_INPLACE_LSHIFT, + mp_obj_new_int(1), + mp_obj_new_int(nbytes * 8 - 1)); + + if (mp_binary_op(MP_BINARY_OP_LESS, self_in, edge) == mp_const_true) { + // and >= -2**(bits - 1) + edge = mp_unary_op(MP_UNARY_OP_NEGATIVE, edge); + if (mp_binary_op(MP_BINARY_OP_MORE_EQUAL, self_in, edge) == mp_const_true) { + return; + } + } + } else { + // self must be >= 0 + if (mp_obj_int_sign(self_in) >= 0) { + // and < 2**(bits) + mp_obj_t edge = mp_binary_op(MP_BINARY_OP_INPLACE_LSHIFT, + mp_obj_new_int(1), + mp_obj_new_int(nbytes * 8)); + + if (mp_binary_op(MP_BINARY_OP_LESS, self_in, edge) == mp_const_true) { + return; + } + } + } + + mp_raise_OverflowError_varg(translate("value would overflow a %d byte buffer"), nbytes); +} + #if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE int mp_obj_int_sign(mp_obj_t self_in) { @@ -435,6 +467,8 @@ STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *args) { byte *data = (byte*)vstr.buf; memset(data, 0, len); + mp_obj_int_buffer_overflow_check(args[0], len, false); + #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE if (!MP_OBJ_IS_SMALL_INT(args[0])) { mp_obj_int_to_bytes_impl(args[0], big_endian, len, data); |