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dhalbertdhalbert
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Implement to_bytes(..., signed=True)
1 parent cabc30e commit c592bd6

4 files changed

Lines changed: 44 additions & 14 deletions

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‎py/objint.c‎

Lines changed: 25 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -490,38 +490,51 @@ STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
490490
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 3, 4, int_from_bytes);
491491
STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(int_from_bytes_obj, MP_ROM_PTR(&int_from_bytes_fun_obj));
492492

493-
STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *args) {
494-
// TODO: Support signed param (assumes signed=False)
495-
(void)n_args;
496-
497-
mp_int_t len = mp_obj_get_int(args[1]);
493+
STATIC mp_obj_t int_to_bytes(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
494+
enum { ARG_length, ARG_byteorder, ARG_signed };
495+
static const mp_arg_t allowed_args[] = {
496+
{ MP_QSTR_length, MP_ARG_REQUIRED | MP_ARG_INT },
497+
{ MP_QSTR_byteorder, MP_ARG_REQUIRED | MP_ARG_OBJ },
498+
{ MP_QSTR_signed, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
499+
};
500+
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
501+
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
502+
503+
mp_int_t len = args[ARG_length].u_int;
498504
if (len < 0) {
499505
mp_raise_ValueError(NULL);
500506
}
501-
bool big_endian = args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little);
507+
508+
mp_obj_t self = pos_args[0];
509+
bool big_endian = args[ARG_byteorder].u_obj != MP_OBJ_NEW_QSTR(MP_QSTR_little);
510+
bool signed_ = args[ARG_signed].u_bool;
502511

503512
vstr_t vstr;
504513
vstr_init_len(&vstr, len);
505514
byte *data = (byte*)vstr.buf;
506515
memset(data, 0, len);
507516

508517
#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
509-
if (!MP_OBJ_IS_SMALL_INT(args[0])) {
510-
mp_obj_int_buffer_overflow_check(args[0], len, false);
511-
mp_obj_int_to_bytes_impl(args[0], big_endian, len, data);
518+
if (!MP_OBJ_IS_SMALL_INT(self)) {
519+
mp_obj_int_buffer_overflow_check(self, len, signed_);
520+
mp_obj_int_to_bytes_impl(self, big_endian, len, data);
512521
} else
513522
#endif
514523
{
515-
mp_int_t val = MP_OBJ_SMALL_INT_VALUE(args[0]);
524+
mp_int_t val = MP_OBJ_SMALL_INT_VALUE(self);
516525
// Small int checking is separate, to be fast.
517-
mp_small_int_buffer_overflow_check(val, len, false);
526+
mp_small_int_buffer_overflow_check(val, len, signed_);
518527
size_t l = MIN((size_t)len, sizeof(val));
528+
if (val < 0) {
529+
// Sign extend negative numbers.
530+
memset(data, -1, len);
531+
}
519532
mp_binary_set_int(l, big_endian, data + (big_endian ? (len - l) : 0), val);
520533
}
521534

522535
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
523536
}
524-
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_to_bytes_obj, 3, 4, int_to_bytes);
537+
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(int_to_bytes_obj, 3, int_to_bytes);
525538

526539
STATIC const mp_rom_map_elem_t int_locals_dict_table[] = {
527540
{ MP_ROM_QSTR(MP_QSTR_from_bytes), MP_ROM_PTR(&int_from_bytes_obj) },

‎tests/basics/int_bytes.py‎

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,16 +1,21 @@
11
print((10).to_bytes(1, "little"))
2+
print((-10).to_bytes(1, "little", signed=True))
23
# Test fitting in length that's not a power of two.
34
print((0x10000).to_bytes(3, 'little'))
45
print((111111).to_bytes(4, "little"))
6+
print((-111111).to_bytes(4, "little", signed=True))
57
print((100).to_bytes(10, "little"))
8+
print((-100).to_bytes(10, "little", signed=True))
69

710
# check that extra zero bytes don't change the internal int value
811
print(int.from_bytes(bytes(20), "little") == 0)
912
print(int.from_bytes(b"\x01" + bytes(20), "little") == 1)
1013

1114
# big-endian conversion
1215
print((10).to_bytes(1, "big"))
16+
print((-10).to_bytes(1, "big", signed=True))
1317
print((100).to_bytes(10, "big"))
18+
print((-100).to_bytes(10, "big", signed=True))
1419
print(int.from_bytes(b"\0\0\0\0\0\0\0\0\0\x01", "big"))
1520
print(int.from_bytes(b"\x01\0", "big"))
1621

@@ -26,8 +31,13 @@
2631
except OverflowError:
2732
print("OverflowError")
2833

29-
# negative numbers should raise an error
34+
# negative numbers should raise an error if signed=False
3035
try:
3136
(-256).to_bytes(2, "little")
3237
except OverflowError:
3338
print("OverflowError")
39+
40+
try:
41+
(-256).to_bytes(2, "little", signed=False)
42+
except OverflowError:
43+
print("OverflowError")

‎tests/basics/int_bytes_intbig.py‎

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,9 @@
22
skip_if.no_bigint()
33

44
print((2**64).to_bytes(9, "little"))
5+
print((-2**64).to_bytes(9, "little", signed=True))
56
print((2**64).to_bytes(9, "big"))
7+
print((-2**64).to_bytes(9, "big", signed=True))
68

79
b = bytes(range(20))
810

@@ -22,8 +24,12 @@
2224
except OverflowError:
2325
print("OverflowError")
2426

25-
# negative numbers should raise an error
27+
# negative numbers should raise an error if signed=False
2628
try:
2729
(-2**64).to_bytes(9, "little")
2830
except OverflowError:
2931
print("OverflowError")
32+
try:
33+
(-2**64).to_bytes(9, "little", signed=False)
34+
except OverflowError:
35+
print("OverflowError")

‎tests/basics/int_longint_bytes.py‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,7 @@
33
skip_if.no_bigint()
44

55
print((2**64).to_bytes(9, "little"))
6+
print((-2**64).to_bytes(9, "little", signed=True))
67
print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))
78
print(int.from_bytes(b"\x01\0\0\0\0\0\0\0", "little"))
89
print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))

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