整數物件¶
All integers are implemented as "long" integer objects of arbitrary size.
On error, most PyLong_As*
APIs return (return type)-1
which cannot be
distinguished from a number. Use PyErr_Occurred()
to disambiguate.
-
type PyLongObject¶
- 為 受限 API 的一部分 (做為一個不透明結構 (opaque struct)).
This subtype of
PyObject
represents a Python integer object.
-
PyTypeObject PyLong_Type¶
- 為 穩定 ABI 的一部分.
This instance of
PyTypeObject
represents the Python integer type. This is the same object asint
in the Python layer.
-
int PyLong_Check(PyObject *p)¶
Return true if its argument is a
PyLongObject
or a subtype ofPyLongObject
. This function always succeeds.
-
int PyLong_CheckExact(PyObject *p)¶
Return true if its argument is a
PyLongObject
, but not a subtype ofPyLongObject
. This function always succeeds.
-
PyObject *PyLong_FromLong(long v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from v, orNULL
on failure.The current implementation keeps an array of integer objects for all integers between
-5
and256
. When you create an int in that range you actually just get back a reference to the existing object.
-
PyObject *PyLong_FromUnsignedLong(unsigned long v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from a C unsigned long, orNULL
on failure.
-
PyObject *PyLong_FromSsize_t(Py_ssize_t v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from a CPy_ssize_t
, orNULL
on failure.
-
PyObject *PyLong_FromSize_t(size_t v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from a Csize_t
, orNULL
on failure.
-
PyObject *PyLong_FromLongLong(long long v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from a C long long, orNULL
on failure.
-
PyObject *PyLong_FromInt32(int32_t value)¶
-
PyObject *PyLong_FromInt64(int64_t value)¶
- 為 穩定 ABI 的一部分 自 3.14 版本開始.
Return a new
PyLongObject
object from a signed C int32_t or int64_t, orNULL
with an exception set on failure.在 3.14 版被加入.
-
PyObject *PyLong_FromUnsignedLongLong(unsigned long long v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from a C unsigned long long, orNULL
on failure.
-
PyObject *PyLong_FromUInt32(uint32_t value)¶
-
PyObject *PyLong_FromUInt64(uint64_t value)¶
- 為 穩定 ABI 的一部分 自 3.14 版本開始.
Return a new
PyLongObject
object from an unsigned C uint32_t or uint64_t, orNULL
with an exception set on failure.在 3.14 版被加入.
-
PyObject *PyLong_FromDouble(double v)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
object from the integer part of v, orNULL
on failure.
-
PyObject *PyLong_FromString(const char *str, char **pend, int base)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Return a new
PyLongObject
based on the string value in str, which is interpreted according to the radix in base, orNULL
on failure. If pend is non-NULL
, *pend will point to the end of str on success or to the first character that could not be processed on error. If base is0
, str is interpreted using the Integer literals definition; in this case, leading zeros in a non-zero decimal number raises aValueError
. If base is not0
, it must be between2
and36
, inclusive. Leading and trailing whitespace and single underscores after a base specifier and between digits are ignored. If there are no digits or str is not NULL-terminated following the digits and trailing whitespace,ValueError
will be raised.也參考
PyLong_AsNativeBytes()
andPyLong_FromNativeBytes()
functions can be used to convert aPyLongObject
to/from an array of bytes in base256
.
-
PyObject *PyLong_FromUnicodeObject(PyObject *u, int base)¶
- 回傳值:新的參照。
Convert a sequence of Unicode digits in the string u to a Python integer value.
在 3.3 版被加入.
-
PyObject *PyLong_FromVoidPtr(void *p)¶
- 回傳值:新的參照。 為 穩定 ABI 的一部分.
Create a Python integer from the pointer p. The pointer value can be retrieved from the resulting value using
PyLong_AsVoidPtr()
.
-
PyObject *PyLong_FromNativeBytes(const void *buffer, size_t n_bytes, int flags)¶
Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as a two's-complement signed number.
flags are as for
PyLong_AsNativeBytes()
. Passing-1
will select the native endian that CPython was compiled with and assume that the most-significant bit is a sign bit. PassingPy_ASNATIVEBYTES_UNSIGNED_BUFFER
will produce the same result as callingPyLong_FromUnsignedNativeBytes()
. Other flags are ignored.在 3.13 版被加入.
-
PyObject *PyLong_FromUnsignedNativeBytes(const void *buffer, size_t n_bytes, int flags)¶
Create a Python integer from the value contained in the first n_bytes of buffer, interpreted as an unsigned number.
flags are as for
PyLong_AsNativeBytes()
. Passing-1
will select the native endian that CPython was compiled with and assume that the most-significant bit is not a sign bit. Flags other than endian are ignored.在 3.13 版被加入.
-
long PyLong_AsLong(PyObject *obj)¶
- 為 穩定 ABI 的一部分.
Return a C long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.Raise
OverflowError
if the value of obj is out of range for a long.Returns
-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.-
long PyLong_AS_LONG(PyObject *obj)¶
A soft deprecated alias. Exactly equivalent to the preferred
PyLong_AsLong
. In particular, it can fail withOverflowError
or another exception.在 3.14 版之後被棄用: The function is soft deprecated.
-
long PyLong_AS_LONG(PyObject *obj)¶
-
int PyLong_AsInt(PyObject *obj)¶
- 為 穩定 ABI 的一部分 自 3.13 版本開始.
Similar to
PyLong_AsLong()
, but store the result in a C int instead of a C long.在 3.13 版被加入.
-
long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)¶
- 為 穩定 ABI 的一部分.
Return a C long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is greater than
LONG_MAX
or less thanLONG_MIN
, set *overflow to1
or-1
, respectively, and return-1
; otherwise, set *overflow to0
. If any other exception occurs set *overflow to0
and return-1
as usual.Returns
-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.
-
long long PyLong_AsLongLong(PyObject *obj)¶
- 為 穩定 ABI 的一部分.
Return a C long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.Raise
OverflowError
if the value of obj is out of range for a long long.Returns
-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.
-
long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)¶
- 為 穩定 ABI 的一部分.
Return a C long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is greater than
LLONG_MAX
or less thanLLONG_MIN
, set *overflow to1
or-1
, respectively, and return-1
; otherwise, set *overflow to0
. If any other exception occurs set *overflow to0
and return-1
as usual.Returns
-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.2 版被加入.
在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.
-
Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Return a C
Py_ssize_t
representation of pylong. pylong must be an instance ofPyLongObject
.Raise
OverflowError
if the value of pylong is out of range for aPy_ssize_t
.Returns
-1
on error. UsePyErr_Occurred()
to disambiguate.
-
unsigned long PyLong_AsUnsignedLong(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Return a C unsigned long representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for a unsigned long.Returns
(unsigned long)-1
on error. UsePyErr_Occurred()
to disambiguate.
-
size_t PyLong_AsSize_t(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Return a C
size_t
representation of pylong. pylong must be an instance ofPyLongObject
.Raise
OverflowError
if the value of pylong is out of range for asize_t
.Returns
(size_t)-1
on error. UsePyErr_Occurred()
to disambiguate.
-
unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Return a C unsigned long long representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for an unsigned long long.Returns
(unsigned long long)-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.1 版的變更: A negative pylong now raises
OverflowError
, notTypeError
.
-
unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)¶
- 為 穩定 ABI 的一部分.
Return a C unsigned long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is out of range for an unsigned long, return the reduction of that value modulo
ULONG_MAX + 1
.Returns
(unsigned long)-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.
-
unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)¶
- 為 穩定 ABI 的一部分.
Return a C unsigned long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is out of range for an unsigned long long, return the reduction of that value modulo
ULLONG_MAX + 1
.Returns
(unsigned long long)-1
on error. UsePyErr_Occurred()
to disambiguate.在 3.8 版的變更: Use
__index__()
if available.在 3.10 版的變更: This function will no longer use
__int__()
.
-
int PyLong_AsInt32(PyObject *obj, int32_t *value)¶
-
int PyLong_AsInt64(PyObject *obj, int64_t *value)¶
- 為 穩定 ABI 的一部分 自 3.14 版本開始.
Set *value to a signed C int32_t or int64_t representation of obj.
If the obj value is out of range, raise an
OverflowError
.Set *value and return
0
on success. Set an exception and return-1
on error.value must not be
NULL
.在 3.14 版被加入.
-
int PyLong_AsUInt32(PyObject *obj, uint32_t *value)¶
-
int PyLong_AsUInt64(PyObject *obj, uint64_t *value)¶
- 為 穩定 ABI 的一部分 自 3.14 版本開始.
Set *value to an unsigned C uint32_t or uint64_t representation of obj.
If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If obj is negative, raise a
ValueError
.If the obj value is out of range, raise an
OverflowError
.
Set *value and return
0
on success. Set an exception and return-1
on error.value must not be
NULL
.在 3.14 版被加入.
-
double PyLong_AsDouble(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Return a C double representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for a double.Returns
-1.0
on error. UsePyErr_Occurred()
to disambiguate.
-
void *PyLong_AsVoidPtr(PyObject *pylong)¶
- 為 穩定 ABI 的一部分.
Convert a Python integer pylong to a C void pointer. If pylong cannot be converted, an
OverflowError
will be raised. This is only assured to produce a usable void pointer for values created withPyLong_FromVoidPtr()
.Returns
NULL
on error. UsePyErr_Occurred()
to disambiguate.
-
Py_ssize_t PyLong_AsNativeBytes(PyObject *pylong, void *buffer, Py_ssize_t n_bytes, int flags)¶
Copy the Python integer value pylong to a native buffer of size n_bytes. The flags can be set to
-1
to behave similarly to a C cast, or to values documented below to control the behavior.Returns
-1
with an exception raised on error. This may happen if pylong cannot be interpreted as an integer, or if pylong was negative and thePy_ASNATIVEBYTES_REJECT_NEGATIVE
flag was set.Otherwise, returns the number of bytes required to store the value. If this is equal to or less than n_bytes, the entire value was copied. All n_bytes of the buffer are written: large buffers are padded with zeroes.
If the returned value is greater than than n_bytes, the value was truncated: as many of the lowest bits of the value as could fit are written, and the higher bits are ignored. This matches the typical behavior of a C-style downcast.
備註
Overflow is not considered an error. If the returned value is larger than n_bytes, most significant bits were discarded.
0
將永不被回傳。Values are always copied as two's-complement.
使用範例:
int32_t value; Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, &value, sizeof(value), -1); if (bytes < 0) { // Failed. A Python exception was set with the reason. return NULL; } else if (bytes <= (Py_ssize_t)sizeof(value)) { // Success! } else { // Overflow occurred, but 'value' contains the truncated // lowest bits of pylong. }
Passing zero to n_bytes will return the size of a buffer that would be large enough to hold the value. This may be larger than technically necessary, but not unreasonably so. If n_bytes=0, buffer may be
NULL
.備註
Passing n_bytes=0 to this function is not an accurate way to determine the bit length of the value.
To get at the entire Python value of an unknown size, the function can be called twice: first to determine the buffer size, then to fill it:
// Ask how much space we need. Py_ssize_t expected = PyLong_AsNativeBytes(pylong, NULL, 0, -1); if (expected < 0) { // Failed. A Python exception was set with the reason. return NULL; } assert(expected != 0); // Impossible per the API definition. uint8_t *bignum = malloc(expected); if (!bignum) { PyErr_SetString(PyExc_MemoryError, "bignum malloc failed."); return NULL; } // Safely get the entire value. Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, bignum, expected, -1); if (bytes < 0) { // Exception has been set. free(bignum); return NULL; } else if (bytes > expected) { // This should not be possible. PyErr_SetString(PyExc_RuntimeError, "Unexpected bignum truncation after a size check."); free(bignum); return NULL; } // The expected success given the above pre-check. // ... use bignum ... free(bignum);
flags is either
-1
(Py_ASNATIVEBYTES_DEFAULTS
) to select defaults that behave most like a C cast, or a combination of the other flags in the table below. Note that-1
cannot be combined with other flags.Currently,
-1
corresponds toPy_ASNATIVEBYTES_NATIVE_ENDIAN | Py_ASNATIVEBYTES_UNSIGNED_BUFFER
.旗標
數值
-
Py_ASNATIVEBYTES_DEFAULTS¶
-1
-
Py_ASNATIVEBYTES_BIG_ENDIAN¶
0
-
Py_ASNATIVEBYTES_LITTLE_ENDIAN¶
1
-
Py_ASNATIVEBYTES_NATIVE_ENDIAN¶
3
-
Py_ASNATIVEBYTES_UNSIGNED_BUFFER¶
4
-
Py_ASNATIVEBYTES_REJECT_NEGATIVE¶
8
-
Py_ASNATIVEBYTES_ALLOW_INDEX¶
16
Specifying
Py_ASNATIVEBYTES_NATIVE_ENDIAN
will override any other endian flags. Passing2
is reserved.By default, sufficient buffer will be requested to include a sign bit. For example, when converting 128 with n_bytes=1, the function will return 2 (or more) in order to store a zero sign bit.
If
Py_ASNATIVEBYTES_UNSIGNED_BUFFER
is specified, a zero sign bit will be omitted from size calculations. This allows, for example, 128 to fit in a single-byte buffer. If the destination buffer is later treated as signed, a positive input value may become negative. Note that the flag does not affect handling of negative values: for those, space for a sign bit is always requested.Specifying
Py_ASNATIVEBYTES_REJECT_NEGATIVE
causes an exception to be set if pylong is negative. Without this flag, negative values will be copied provided there is enough space for at least one sign bit, regardless of whetherPy_ASNATIVEBYTES_UNSIGNED_BUFFER
was specified.If
Py_ASNATIVEBYTES_ALLOW_INDEX
is specified and a non-integer value is passed, its__index__()
method will be called first. This may result in Python code executing and other threads being allowed to run, which could cause changes to other objects or values in use. When flags is-1
, this option is not set, and non-integer values will raiseTypeError
.備註
With the default flags (
-1
, or UNSIGNED_BUFFER without REJECT_NEGATIVE), multiple Python integers can map to a single value without overflow. For example, both255
and-1
fit a single-byte buffer and set all its bits. This matches typical C cast behavior.在 3.13 版被加入.
-
Py_ASNATIVEBYTES_DEFAULTS¶
-
int PyLong_GetSign(PyObject *obj, int *sign)¶
Get the sign of the integer object obj.
On success, set *sign to the integer sign (0, -1 or +1 for zero, negative or positive integer, respectively) and return 0.
On failure, return -1 with an exception set. This function always succeeds if obj is a
PyLongObject
or its subtype.在 3.14 版被加入.
-
int PyLong_IsPositive(PyObject *obj)¶
Check if the integer object obj is positive (
obj > 0
).If obj is an instance of
PyLongObject
or its subtype, return1
when it's positive and0
otherwise. Else set an exception and return-1
.在 3.14 版被加入.
-
int PyLong_IsNegative(PyObject *obj)¶
Check if the integer object obj is negative (
obj < 0
).If obj is an instance of
PyLongObject
or its subtype, return1
when it's negative and0
otherwise. Else set an exception and return-1
.在 3.14 版被加入.
-
int PyLong_IsZero(PyObject *obj)¶
Check if the integer object obj is zero.
If obj is an instance of
PyLongObject
or its subtype, return1
when it's zero and0
otherwise. Else set an exception and return-1
.在 3.14 版被加入.
-
PyObject *PyLong_GetInfo(void)¶
- 為 穩定 ABI 的一部分.
On success, return a read only named tuple, that holds information about Python's internal representation of integers. See
sys.int_info
for description of individual fields.在失敗時,會回傳
NULL
並設定例外。在 3.1 版被加入.
-
int PyUnstable_Long_IsCompact(const PyLongObject *op)¶
- 這是 不穩定 API,它可能在小版本發布中沒有任何警告地被變更。
Return 1 if op is compact, 0 otherwise.
This function makes it possible for performance-critical code to implement a “fast path” for small integers. For compact values use
PyUnstable_Long_CompactValue()
; for others fall back to aPyLong_As*
function orPyLong_AsNativeBytes()
.The speedup is expected to be negligible for most users.
Exactly what values are considered compact is an implementation detail and is subject to change.
在 3.12 版被加入.
-
Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject *op)¶
- 這是 不穩定 API,它可能在小版本發布中沒有任何警告地被變更。
If op is compact, as determined by
PyUnstable_Long_IsCompact()
, return its value.Otherwise, the return value is undefined.
在 3.12 版被加入.
Export API¶
在 3.14 版被加入.
-
struct PyLongLayout¶
Layout of an array of "digits" ("limbs" in the GMP terminology), used to represent absolute value for arbitrary precision integers.
Use
PyLong_GetNativeLayout()
to get the native layout of Pythonint
objects, used internally for integers with "big enough" absolute value.See also
sys.int_info
which exposes similar information in Python.-
uint8_t bits_per_digit¶
Bits per digit. For example, a 15 bit digit means that bits 0-14 contain meaningful information.
-
uint8_t digit_size¶
Digit size in bytes. For example, a 15 bit digit will require at least 2 bytes.
-
int8_t digits_order¶
Digits order:
1
for most significant digit first-1
for least significant digit first
-
int8_t digit_endianness¶
Digit endianness:
1
for most significant byte first (big endian)-1
for least significant byte first (little endian)
-
uint8_t bits_per_digit¶
-
const PyLongLayout *PyLong_GetNativeLayout(void)¶
Get the native layout of Python
int
objects.See the
PyLongLayout
structure.The function must not be called before Python initialization nor after Python finalization. The returned layout is valid until Python is finalized. The layout is the same for all Python sub-interpreters in a process, and so it can be cached.
-
struct PyLongExport¶
Export of a Python
int
object.There are two cases:
-
Py_ssize_t ndigits¶
Number of digits in
digits
array. Only valid ifdigits
is notNULL
.
-
const void *digits¶
Read-only array of unsigned digits. Can be
NULL
.
-
Py_ssize_t ndigits¶
-
int PyLong_Export(PyObject *obj, PyLongExport *export_long)¶
Export a Python
int
object.export_long must point to a
PyLongExport
structure allocated by the caller. It must not beNULL
.On success, fill in *export_long and return
0
. On error, set an exception and return-1
.PyLong_FreeExport()
must be called when the export is no longer needed.CPython 實作細節: This function always succeeds if obj is a Python
int
object or a subclass.
-
void PyLong_FreeExport(PyLongExport *export_long)¶
Release the export export_long created by
PyLong_Export()
.CPython 實作細節: Calling
PyLong_FreeExport()
is optional if export_long->digits isNULL
.
PyLongWriter API¶
The PyLongWriter
API can be used to import an integer.
在 3.14 版被加入.
-
struct PyLongWriter¶
A Python
int
writer instance.The instance must be destroyed by
PyLongWriter_Finish()
orPyLongWriter_Discard()
.
-
PyLongWriter *PyLongWriter_Create(int negative, Py_ssize_t ndigits, void **digits)¶
Create a
PyLongWriter
.On success, allocate *digits and return a writer. On error, set an exception and return
NULL
.negative is
1
if the number is negative, or0
otherwise.ndigits is the number of digits in the digits array. It must be greater than 0.
digits must not be NULL.
After a successful call to this function, the caller should fill in the array of digits digits and then call
PyLongWriter_Finish()
to get a Pythonint
. The layout of digits is described byPyLong_GetNativeLayout()
.Digits must be in the range [
0
;(1 << bits_per_digit) - 1
] (where thebits_per_digit
is the number of bits per digit). Any unused most significant digits must be set to0
.Alternately, call
PyLongWriter_Discard()
to destroy the writer instance without creating anint
object.
-
PyObject *PyLongWriter_Finish(PyLongWriter *writer)¶
- 回傳值:新的參照。
Finish a
PyLongWriter
created byPyLongWriter_Create()
.On success, return a Python
int
object. On error, set an exception and returnNULL
.The function takes care of normalizing the digits and converts the object to a compact integer if needed.
The writer instance and the digits array are invalid after the call.
-
void PyLongWriter_Discard(PyLongWriter *writer)¶
Discard a
PyLongWriter
created byPyLongWriter_Create()
.writer must not be
NULL
.The writer instance and the digits array are invalid after the call.