py: Support conversion of bignum to bytes.

This gets int.to_bytes working for bignum, and also struct.pack with 'q'
and 'Q' args on 32-bit machines.

Addresses issue #1155.
This commit is contained in:
Damien George 2015-04-25 23:16:39 +01:00
parent 7c8b4c1a8b
commit 271d18eb08
9 changed files with 89 additions and 15 deletions

View File

@ -32,6 +32,7 @@
#include "py/binary.h"
#include "py/smallint.h"
#include "py/objint.h"
// Helpers to work with binary-encoded data
@ -282,10 +283,13 @@ void mp_binary_set_val(char struct_type, char val_type, mp_obj_t val_in, byte **
}
#endif
default:
// we handle large ints here by calling the truncated accessor
#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
if (MP_OBJ_IS_TYPE(val_in, &mp_type_int)) {
val = mp_obj_int_get_truncated(val_in);
} else {
mp_obj_int_to_bytes_impl(val_in, struct_type == '>', size, p);
return;
} else
#endif
{
val = mp_obj_get_int(val_in);
}
}

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@ -1425,6 +1425,40 @@ bool mpz_as_uint_checked(const mpz_t *i, mp_uint_t *value) {
return true;
}
// writes at most len bytes to buf (so buf should be zeroed before calling)
void mpz_as_bytes(const mpz_t *z, bool big_endian, mp_uint_t len, byte *buf) {
byte *b = buf;
if (big_endian) {
b += len;
}
mpz_dig_t *zdig = z->dig;
int bits = 0;
mpz_dbl_dig_t d = 0;
mpz_dbl_dig_t carry = 1;
for (mp_uint_t zlen = z->len; zlen > 0; --zlen) {
bits += DIG_SIZE;
d = (d << DIG_SIZE) | *zdig++;
for (; bits >= 8; bits -= 8, d >>= 8) {
mpz_dig_t val = d;
if (z->neg) {
d = (~d & 0xff) + carry;
carry = d >> 8;
}
if (big_endian) {
*--b = val;
if (b == buf) {
return;
}
} else {
*b++ = val;
if (b == buf + len) {
return;
}
}
}
}
}
#if MICROPY_PY_BUILTINS_FLOAT
mp_float_t mpz_as_float(const mpz_t *i) {
mp_float_t val = 0;

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@ -125,6 +125,7 @@ void mpz_divmod_inpl(mpz_t *dest_quo, mpz_t *dest_rem, const mpz_t *lhs, const m
mp_int_t mpz_hash(const mpz_t *z);
bool mpz_as_int_checked(const mpz_t *z, mp_int_t *value);
bool mpz_as_uint_checked(const mpz_t *z, mp_uint_t *value);
void mpz_as_bytes(const mpz_t *z, bool big_endian, mp_uint_t len, byte *buf);
#if MICROPY_PY_BUILTINS_FLOAT
mp_float_t mpz_as_float(const mpz_t *z);
#endif

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@ -35,6 +35,7 @@
#include "py/objstr.h"
#include "py/runtime0.h"
#include "py/runtime.h"
#include "py/binary.h"
#if MICROPY_PY_BUILTINS_FLOAT
#include <math.h>
@ -398,12 +399,10 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 2, 3, int_fro
STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(int_from_bytes_obj, (const mp_obj_t)&int_from_bytes_fun_obj);
STATIC mp_obj_t int_to_bytes(mp_uint_t n_args, const mp_obj_t *args) {
// TODO: Support long ints
// TODO: Support byteorder param (assumes 'little')
// TODO: Support signed param (assumes signed=False)
(void)n_args;
mp_int_t val = mp_obj_int_get_checked(args[0]);
mp_uint_t len = MP_OBJ_SMALL_INT_VALUE(args[1]);
vstr_t vstr;
@ -411,13 +410,14 @@ STATIC mp_obj_t int_to_bytes(mp_uint_t n_args, const mp_obj_t *args) {
byte *data = (byte*)vstr.buf;
memset(data, 0, len);
if (MP_ENDIANNESS_LITTLE) {
memcpy(data, &val, len < sizeof(mp_int_t) ? len : sizeof(mp_int_t));
} else {
while (len--) {
*data++ = val;
val >>= 8;
}
#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
if (!MP_OBJ_IS_SMALL_INT(args[0])) {
mp_obj_int_to_bytes_impl(args[0], false, len, data);
} else
#endif
{
mp_int_t val = MP_OBJ_SMALL_INT_VALUE(args[0]);
mp_binary_set_int(MIN((size_t)len, sizeof(val)), false, data, val);
}
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);

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@ -56,6 +56,7 @@ char *mp_obj_int_formatted(char **buf, mp_uint_t *buf_size, mp_uint_t *fmt_size,
char *mp_obj_int_formatted_impl(char **buf, mp_uint_t *buf_size, mp_uint_t *fmt_size, mp_const_obj_t self_in,
int base, const char *prefix, char base_char, char comma);
mp_int_t mp_obj_int_hash(mp_obj_t self_in);
void mp_obj_int_to_bytes_impl(mp_obj_t self_in, bool big_endian, mp_uint_t len, byte *buf);
bool mp_obj_int_is_positive(mp_obj_t self_in);
mp_obj_t mp_obj_int_abs(mp_obj_t self_in);
mp_obj_t mp_obj_int_unary_op(mp_uint_t op, mp_obj_t o_in);

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@ -63,6 +63,24 @@ mp_int_t mp_obj_int_hash(mp_obj_t self_in) {
return self->val;
}
void mp_obj_int_to_bytes_impl(mp_obj_t self_in, bool big_endian, mp_uint_t len, byte *buf) {
assert(MP_OBJ_IS_TYPE(self_in, &mp_type_int));
mp_obj_int_t *self = self_in;
long long val = self->val;
if (big_endian) {
byte *b = buf + len;
while (b > buf) {
*--b = val;
val >>= 8;
}
} else {
for (; len > 0; --len) {
*buf++ = val;
val >>= 8;
}
}
}
bool mp_obj_int_is_positive(mp_obj_t self_in) {
if (MP_OBJ_IS_SMALL_INT(self_in)) {
return MP_OBJ_SMALL_INT_VALUE(self_in) >= 0;

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@ -104,6 +104,12 @@ mp_int_t mp_obj_int_hash(mp_obj_t self_in) {
return mpz_hash(&self->mpz);
}
void mp_obj_int_to_bytes_impl(mp_obj_t self_in, bool big_endian, mp_uint_t len, byte *buf) {
assert(MP_OBJ_IS_TYPE(self_in, &mp_type_int));
mp_obj_int_t *self = self_in;
mpz_as_bytes(&self->mpz, big_endian, len, buf);
}
bool mp_obj_int_is_positive(mp_obj_t self_in) {
if (MP_OBJ_IS_SMALL_INT(self_in)) {
return MP_OBJ_SMALL_INT_VALUE(self_in) >= 0;

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@ -1,6 +1,7 @@
print((10).to_bytes(1, "little"))
print((111111).to_bytes(4, "little"))
print((100).to_bytes(10, "little"))
print((2**64).to_bytes(9, "little"))
print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))
print(int.from_bytes(b"\x01\0\0\0\0\0\0\0", "little"))
print(int.from_bytes(b"\x00\x01\0\0\0\0\0\0", "little"))

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@ -30,9 +30,18 @@ print(v == (10, 100, 200, 300))
print(struct.pack("<I", 2**32 - 1))
print(struct.pack("<I", 0xffffffff))
# fails on 32-bit machine
#print(struct.pack("<Q", 2**64 - 1))
#print(struct.pack("<Q", 0xffffffffffffffff))
# long long ints
print(struct.pack("<Q", 2**64 - 1))
print(struct.pack("<Q", 0xffffffffffffffff))
print(struct.pack("<q", -1))
print(struct.pack("<Q", 1234567890123456789))
print(struct.pack("<q", -1234567890123456789))
print(struct.pack(">Q", 1234567890123456789))
print(struct.pack(">q", -1234567890123456789))
print(struct.unpack("<Q", b"\x12\x34\x56\x78\x90\x12\x34\x56"))
print(struct.unpack(">Q", b"\x12\x34\x56\x78\x90\x12\x34\x56"))
print(struct.unpack("<q", b"\x12\x34\x56\x78\x90\x12\x34\xf6"))
print(struct.unpack(">q", b"\xf2\x34\x56\x78\x90\x12\x34\x56"))
# check maximum unpack
print(struct.unpack("<I", b"\xff\xff\xff\xff"))