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#ifndef Py_INTERNAL_LONG_H
#define Py_INTERNAL_LONG_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
#include "pycore_global_objects.h" // _PY_NSMALLNEGINTS
#include "pycore_runtime.h" // _PyRuntime
/*
* Default int base conversion size limitation: Denial of Service prevention.
*
* Chosen such that this isn't wildly slow on modern hardware and so that
* everyone's existing deployed numpy test suite passes before
* https://github.com/numpy/numpy/issues/22098 is widely available.
*
* $ python -m timeit -s 's = "1"*4300' 'int(s)'
* 2000 loops, best of 5: 125 usec per loop
* $ python -m timeit -s 's = "1"*4300; v = int(s)' 'str(v)'
* 1000 loops, best of 5: 311 usec per loop
* (zen2 cloud VM)
*
* 4300 decimal digits fits a ~14284 bit number.
*/
#define _PY_LONG_DEFAULT_MAX_STR_DIGITS 4300
/*
* Threshold for max digits check. For performance reasons int() and
* int.__str__() don't checks values that are smaller than this
* threshold. Acts as a guaranteed minimum size limit for bignums that
* applications can expect from CPython.
*
* % python -m timeit -s 's = "1"*640; v = int(s)' 'str(int(s))'
* 20000 loops, best of 5: 12 usec per loop
*
* "640 digits should be enough for anyone." - gps
* fits a ~2126 bit decimal number.
*/
#define _PY_LONG_MAX_STR_DIGITS_THRESHOLD 640
#if ((_PY_LONG_DEFAULT_MAX_STR_DIGITS != 0) && \
(_PY_LONG_DEFAULT_MAX_STR_DIGITS < _PY_LONG_MAX_STR_DIGITS_THRESHOLD))
# error "_PY_LONG_DEFAULT_MAX_STR_DIGITS smaller than threshold."
#endif
/* runtime lifecycle */
extern PyStatus _PyLong_InitTypes(PyInterpreterState *);
extern void _PyLong_FiniTypes(PyInterpreterState *interp);
/* other API */
#define _PyLong_SMALL_INTS _Py_SINGLETON(small_ints)
// _PyLong_GetZero() and _PyLong_GetOne() must always be available
// _PyLong_FromUnsignedChar must always be available
#if _PY_NSMALLPOSINTS < 257
# error "_PY_NSMALLPOSINTS must be greater than or equal to 257"
#endif
// Return a borrowed reference to the zero singleton.
// The function cannot return NULL.
static inline PyObject* _PyLong_GetZero(void)
{ return (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS]; }
// Return a borrowed reference to the one singleton.
// The function cannot return NULL.
static inline PyObject* _PyLong_GetOne(void)
{ return (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS+1]; }
static inline PyObject* _PyLong_FromUnsignedChar(unsigned char i)
{
return Py_NewRef((PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS+i]);
}
PyObject *_PyLong_Add(PyLongObject *left, PyLongObject *right);
PyObject *_PyLong_Multiply(PyLongObject *left, PyLongObject *right);
PyObject *_PyLong_Subtract(PyLongObject *left, PyLongObject *right);
/* Used by Python/mystrtoul.c, _PyBytes_FromHex(),
_PyBytes_DecodeEscape(), etc. */
PyAPI_DATA(unsigned char) _PyLong_DigitValue[256];
/* Format the object based on the format_spec, as defined in PEP 3101
(Advanced String Formatting). */
PyAPI_FUNC(int) _PyLong_FormatAdvancedWriter(
_PyUnicodeWriter *writer,
PyObject *obj,
PyObject *format_spec,
Py_ssize_t start,
Py_ssize_t end);
PyAPI_FUNC(int) _PyLong_FormatWriter(
_PyUnicodeWriter *writer,
PyObject *obj,
int base,
int alternate);
PyAPI_FUNC(char*) _PyLong_FormatBytesWriter(
_PyBytesWriter *writer,
char *str,
PyObject *obj,
int base,
int alternate);
/* Long value tag bits:
* 0-1: Sign bits value = (1-sign), ie. negative=2, positive=0, zero=1.
* 2: Reserved for immortality bit
* 3+ Unsigned digit count
*/
#define SIGN_MASK 3
#define SIGN_ZERO 1
#define SIGN_NEGATIVE 2
#define NON_SIZE_BITS 3
/* The functions _PyLong_IsCompact and _PyLong_CompactValue are defined
* in Include/cpython/longobject.h, since they need to be inline.
*
* "Compact" values have at least one bit to spare,
* so that addition and subtraction can be performed on the values
* without risk of overflow.
*
* The inline functions need tag bits.
* For readability, rather than do `#define SIGN_MASK _PyLong_SIGN_MASK`
* we define them to the numbers in both places and then assert that
* they're the same.
*/
static_assert(SIGN_MASK == _PyLong_SIGN_MASK, "SIGN_MASK does not match _PyLong_SIGN_MASK");
static_assert(NON_SIZE_BITS == _PyLong_NON_SIZE_BITS, "NON_SIZE_BITS does not match _PyLong_NON_SIZE_BITS");
/* All *compact" values are guaranteed to fit into
* a Py_ssize_t with at least one bit to spare.
* In other words, for 64 bit machines, compact
* will be signed 63 (or fewer) bit values
*/
/* Return 1 if the argument is compact int */
static inline int
_PyLong_IsNonNegativeCompact(const PyLongObject* op) {
assert(PyLong_Check(op));
return op->long_value.lv_tag <= (1 << NON_SIZE_BITS);
}
static inline int
_PyLong_BothAreCompact(const PyLongObject* a, const PyLongObject* b) {
assert(PyLong_Check(a));
assert(PyLong_Check(b));
return (a->long_value.lv_tag | b->long_value.lv_tag) < (2 << NON_SIZE_BITS);
}
static inline bool
_PyLong_IsZero(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == SIGN_ZERO;
}
static inline bool
_PyLong_IsNegative(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == SIGN_NEGATIVE;
}
static inline bool
_PyLong_IsPositive(const PyLongObject *op)
{
return (op->long_value.lv_tag & SIGN_MASK) == 0;
}
static inline Py_ssize_t
_PyLong_DigitCount(const PyLongObject *op)
{
assert(PyLong_Check(op));
return op->long_value.lv_tag >> NON_SIZE_BITS;
}
/* Equivalent to _PyLong_DigitCount(op) * _PyLong_NonCompactSign(op) */
static inline Py_ssize_t
_PyLong_SignedDigitCount(const PyLongObject *op)
{
assert(PyLong_Check(op));
Py_ssize_t sign = 1 - (op->long_value.lv_tag & SIGN_MASK);
return sign * (Py_ssize_t)(op->long_value.lv_tag >> NON_SIZE_BITS);
}
static inline int
_PyLong_CompactSign(const PyLongObject *op)
{
assert(PyLong_Check(op));
assert(_PyLong_IsCompact(op));
return 1 - (op->long_value.lv_tag & SIGN_MASK);
}
static inline int
_PyLong_NonCompactSign(const PyLongObject *op)
{
assert(PyLong_Check(op));
assert(!_PyLong_IsCompact(op));
return 1 - (op->long_value.lv_tag & SIGN_MASK);
}
/* Do a and b have the same sign? */
static inline int
_PyLong_SameSign(const PyLongObject *a, const PyLongObject *b)
{
return (a->long_value.lv_tag & SIGN_MASK) == (b->long_value.lv_tag & SIGN_MASK);
}
#define TAG_FROM_SIGN_AND_SIZE(sign, size) ((1 - (sign)) | ((size) << NON_SIZE_BITS))
static inline void
_PyLong_SetSignAndDigitCount(PyLongObject *op, int sign, Py_ssize_t size)
{
assert(size >= 0);
assert(-1 <= sign && sign <= 1);
assert(sign != 0 || size == 0);
op->long_value.lv_tag = TAG_FROM_SIGN_AND_SIZE(sign, (size_t)size);
}
static inline void
_PyLong_SetDigitCount(PyLongObject *op, Py_ssize_t size)
{
assert(size >= 0);
op->long_value.lv_tag = (((size_t)size) << NON_SIZE_BITS) | (op->long_value.lv_tag & SIGN_MASK);
}
#define NON_SIZE_MASK ~((1 << NON_SIZE_BITS) - 1)
static inline void
_PyLong_FlipSign(PyLongObject *op) {
unsigned int flipped_sign = 2 - (op->long_value.lv_tag & SIGN_MASK);
op->long_value.lv_tag &= NON_SIZE_MASK;
op->long_value.lv_tag |= flipped_sign;
}
#define _PyLong_DIGIT_INIT(val) \
{ \
.ob_base = _PyObject_HEAD_INIT(&PyLong_Type) \
.long_value = { \
.lv_tag = TAG_FROM_SIGN_AND_SIZE( \
(val) == 0 ? 0 : ((val) < 0 ? -1 : 1), \
(val) == 0 ? 0 : 1), \
{ ((val) >= 0 ? (val) : -(val)) }, \
} \
}
#define _PyLong_FALSE_TAG TAG_FROM_SIGN_AND_SIZE(0, 0)
#define _PyLong_TRUE_TAG TAG_FROM_SIGN_AND_SIZE(1, 1)
#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_LONG_H */
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