Objets Integer¶
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¶
- Part of the Limited API (as an opaque struct).
This subtype of
PyObject
represents a Python integer object.
-
PyTypeObject PyLong_Type¶
- Part of the Stable ABI.
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)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
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)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
Return a new
PyLongObject
object from a C unsigned long, orNULL
on failure.
-
PyObject *PyLong_FromSsize_t(Py_ssize_t v)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
Return a new
PyLongObject
object from a CPy_ssize_t
, orNULL
on failure.
-
PyObject *PyLong_FromSize_t(size_t v)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
Return a new
PyLongObject
object from a Csize_t
, orNULL
on failure.
-
PyObject *PyLong_FromLongLong(long long v)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
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)¶
- Part of the Stable ABI since version 3.14.
Return a new
PyLongObject
object from a signed C int32_t or int64_t, orNULL
with an exception set on failure.Ajouté dans la version 3.14.
-
PyObject *PyLong_FromUnsignedLongLong(unsigned long long v)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
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)¶
- Part of the Stable ABI since version 3.14.
Return a new
PyLongObject
object from an unsigned C uint32_t or uint64_t, orNULL
with an exception set on failure.Ajouté dans la version 3.14.
-
PyObject *PyLong_FromDouble(double v)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
Return a new
PyLongObject
object from the integer part of v, orNULL
on failure.
-
PyObject *PyLong_FromString(const char *str, char **pend, int base)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
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 Entiers littéraux 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.Voir aussi
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)¶
- Valeur de retour : nouvelle référence.
Convert a sequence of Unicode digits in the string u to a Python integer value.
Ajouté dans la version 3.3.
-
PyObject *PyLong_FromVoidPtr(void *p)¶
- Valeur de retour : nouvelle référence. Part of the Stable ABI.
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.Ajouté dans la version 3.13.
-
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.Ajouté dans la version 3.13.
-
long PyLong_AsLong(PyObject *obj)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: 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.Obsolète depuis la version 3.14: The function is soft deprecated.
-
long PyLong_AS_LONG(PyObject *obj)¶
-
int PyLong_AsInt(PyObject *obj)¶
- Part of the Stable ABI since version 3.13.
Similar to
PyLong_AsLong()
, but store the result in a C int instead of a C long.Ajouté dans la version 3.13.
-
long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: This function will no longer use
__int__()
.
-
long long PyLong_AsLongLong(PyObject *obj)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: This function will no longer use
__int__()
.
-
long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)¶
- Part of the Stable ABI.
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.Ajouté dans la version 3.2.
Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: This function will no longer use
__int__()
.
-
Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)¶
- Part of the Stable ABI.
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)¶
- Part of the Stable ABI.
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)¶
- Part of the Stable ABI.
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)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.1: A negative pylong now raises
OverflowError
, notTypeError
.
-
unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: This function will no longer use
__int__()
.
-
unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)¶
- Part of the Stable ABI.
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.Modifié dans la version 3.8: Use
__index__()
if available.Modifié dans la version 3.10: This function will no longer use
__int__()
.
-
int PyLong_AsInt32(PyObject *obj, int32_t *value)¶
-
int PyLong_AsInt64(PyObject *obj, int64_t *value)¶
- Part of the Stable ABI since version 3.14.
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
.Ajouté dans la version 3.14.
-
int PyLong_AsUInt32(PyObject *obj, uint32_t *value)¶
-
int PyLong_AsUInt64(PyObject *obj, uint64_t *value)¶
- Part of the Stable ABI since version 3.14.
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
.Ajouté dans la version 3.14.
-
double PyLong_AsDouble(PyObject *pylong)¶
- Part of the Stable ABI.
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)¶
- Part of the Stable ABI.
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.
Note
Overflow is not considered an error. If the returned value is larger than n_bytes, most significant bits were discarded.
0
will never be returned.Values are always copied as two's-complement.
Usage example:
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
.Note
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
.Flag
Value
-
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
.Note
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.Ajouté dans la version 3.13.
-
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.Ajouté dans la version 3.14.
-
PyObject *PyLong_GetInfo(void)¶
- Part of the Stable ABI.
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.On failure, return
NULL
with an exception set.Ajouté dans la version 3.1.
-
int PyUnstable_Long_IsCompact(const PyLongObject *op)¶
- This is Unstable API. It may change without warning in minor releases.
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.
Ajouté dans la version 3.12.
-
Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject *op)¶
- This is Unstable API. It may change without warning in minor releases.
If op is compact, as determined by
PyUnstable_Long_IsCompact()
, return its value.Otherwise, the return value is undefined.
Ajouté dans la version 3.12.