| #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_interp.h" // PyInterpreterState.small_ints |
| #include "pycore_pystate.h" // _PyThreadState_GET() |
| |
| /* |
| * 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 |
| |
| // Don't call this function but _PyLong_GetZero() and _PyLong_GetOne() |
| static inline PyObject* __PyLong_GetSmallInt_internal(int value) |
| { |
| PyInterpreterState *interp = _PyInterpreterState_GET(); |
| assert(-_PY_NSMALLNEGINTS <= value && value < _PY_NSMALLPOSINTS); |
| size_t index = _PY_NSMALLNEGINTS + value; |
| PyObject *obj = (PyObject*)interp->small_ints[index]; |
| // _PyLong_GetZero(), _PyLong_GetOne() and get_small_int() must not be |
| // called before _PyLong_Init() nor after _PyLong_Fini(). |
| assert(obj != NULL); |
| return obj; |
| } |
| |
| // Return a borrowed reference to the zero singleton. |
| // The function cannot return NULL. |
| static inline PyObject* _PyLong_GetZero(void) |
| { return __PyLong_GetSmallInt_internal(0); } |
| |
| // Return a borrowed reference to the one singleton. |
| // The function cannot return NULL. |
| static inline PyObject* _PyLong_GetOne(void) |
| { return __PyLong_GetSmallInt_internal(1); } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| #endif /* !Py_INTERNAL_LONG_H */ |