py/modbuiltins: Add support for rounding integers.

As per CPython semantics.  This feature is controlled by
MICROPY_PY_BUILTINS_ROUND_INT which is disabled by default.
This commit is contained in:
Jan Klusacek 2018-01-09 22:47:35 +01:00 committed by Damien George
parent f2ec792554
commit b318ebf101
4 changed files with 70 additions and 1 deletions

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@ -445,7 +445,36 @@ MP_DEFINE_CONST_FUN_OBJ_1(mp_builtin_repr_obj, mp_builtin_repr);
STATIC mp_obj_t mp_builtin_round(size_t n_args, const mp_obj_t *args) {
mp_obj_t o_in = args[0];
if (MP_OBJ_IS_INT(o_in)) {
return o_in;
if (n_args <= 1) {
return o_in;
}
#if !MICROPY_PY_BUILTINS_ROUND_INT
mp_raise_NotImplementedError(NULL);
#else
mp_int_t num_dig = mp_obj_get_int(args[1]);
if (num_dig >= 0) {
return o_in;
}
mp_obj_t mult = mp_binary_op(MP_BINARY_OP_POWER, MP_OBJ_NEW_SMALL_INT(10), MP_OBJ_NEW_SMALL_INT(-num_dig));
mp_obj_t half_mult = mp_binary_op(MP_BINARY_OP_FLOOR_DIVIDE, mult, MP_OBJ_NEW_SMALL_INT(2));
mp_obj_t modulo = mp_binary_op(MP_BINARY_OP_MODULO, o_in, mult);
mp_obj_t rounded = mp_binary_op(MP_BINARY_OP_SUBTRACT, o_in, modulo);
if (mp_obj_is_true(mp_binary_op(MP_BINARY_OP_MORE, half_mult, modulo))) {
return rounded;
} else if (mp_obj_is_true(mp_binary_op(MP_BINARY_OP_MORE, modulo, half_mult))) {
return mp_binary_op(MP_BINARY_OP_ADD, rounded, mult);
} else {
// round to even number
mp_obj_t floor = mp_binary_op(MP_BINARY_OP_FLOOR_DIVIDE, o_in, mult);
if (mp_obj_is_true(mp_binary_op(MP_BINARY_OP_AND, floor, MP_OBJ_NEW_SMALL_INT(1)))) {
return mp_binary_op(MP_BINARY_OP_ADD, rounded, mult);
} else {
return rounded;
}
}
#endif
}
#if MICROPY_PY_BUILTINS_FLOAT
mp_float_t val = mp_obj_get_float(o_in);

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@ -802,6 +802,11 @@ typedef double mp_float_t;
#define MICROPY_PY_BUILTINS_RANGE_BINOP (0)
#endif
// Whether to support rounding of integers (incl bignum); eg round(123,-1)=120
#ifndef MICROPY_PY_BUILTINS_ROUND_INT
#define MICROPY_PY_BUILTINS_ROUND_INT (0)
#endif
// Whether to support timeout exceptions (like socket.timeout)
#ifndef MICROPY_PY_BUILTINS_TIMEOUTERROR
#define MICROPY_PY_BUILTINS_TIMEOUTERROR (0)

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@ -0,0 +1,18 @@
# test round() with integer values and second arg
# rounding integers is an optional feature so test for it
try:
round(1, -1)
except NotImplementedError:
print('SKIP')
raise SystemExit
tests = [
(1, False), (1, True),
(124, -1), (125, -1), (126, -1),
(5, -1), (15, -1), (25, -1),
(12345, 0), (12345, -1), (12345, 1),
(-1234, 0), (-1234, -1), (-1234, 1),
]
for t in tests:
print(round(*t))

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@ -0,0 +1,17 @@
# test round() with large integer values and second arg
# rounding integers is an optional feature so test for it
try:
round(1, -1)
except NotImplementedError:
print('SKIP')
raise SystemExit
i = 2**70
tests = [
(i, 0), (i, -1), (i, -10), (i, 1),
(-i, 0), (-i, -1), (-i, -10), (-i, 1),
]
for t in tests:
print(round(*t))