Green shading in the line number column means the source is part of the translation unit, red means it is conditionally excluded. Highlighted line numbers link to the translation unit page. Highlighted macros link to the macro page.
1: #ifndef Py_LIMITED_API 2: #ifndef Py_LONGINTREPR_H 3: #define Py_LONGINTREPR_H 4: #ifdef __cplusplus 5: extern "C" { 6: #endif 7: 8: 9: /* This is published for the benefit of "friends" marshal.c and _decimal.c. */ 10: 11: /* Parameters of the integer representation. There are two different 12: sets of parameters: one set for 30-bit digits, stored in an unsigned 32-bit 13: integer type, and one set for 15-bit digits with each digit stored in an 14: unsigned short. The value of PYLONG_BITS_IN_DIGIT, defined either at 15: configure time or in pyport.h, is used to decide which digit size to use. 16: 17: Type 'digit' should be able to hold 2*PyLong_BASE-1, and type 'twodigits' 18: should be an unsigned integer type able to hold all integers up to 19: PyLong_BASE*PyLong_BASE-1. x_sub assumes that 'digit' is an unsigned type, 20: and that overflow is handled by taking the result modulo 2**N for some N > 21: PyLong_SHIFT. The majority of the code doesn't care about the precise 22: value of PyLong_SHIFT, but there are some notable exceptions: 23: 24: - long_pow() requires that PyLong_SHIFT be divisible by 5 25: 26: - PyLong_{As,From}ByteArray require that PyLong_SHIFT be at least 8 27: 28: - long_hash() requires that PyLong_SHIFT is *strictly* less than the number 29: of bits in an unsigned long, as do the PyLong <-> long (or unsigned long) 30: conversion functions 31: 32: - the Python int <-> size_t/Py_ssize_t conversion functions expect that 33: PyLong_SHIFT is strictly less than the number of bits in a size_t 34: 35: - the marshal code currently expects that PyLong_SHIFT is a multiple of 15 36: 37: - NSMALLNEGINTS and NSMALLPOSINTS should be small enough to fit in a single 38: digit; with the current values this forces PyLong_SHIFT >= 9 39: 40: The values 15 and 30 should fit all of the above requirements, on any 41: platform. 42: */ 43: 44: #if PYLONG_BITS_IN_DIGIT == 30 45: typedef uint32_t digit; 46: typedef int32_t sdigit; /* signed variant of digit */ 47: typedef uint64_t twodigits; 48: typedef int64_t stwodigits; /* signed variant of twodigits */ 49: #define PyLong_SHIFT 30 50: #define _PyLong_DECIMAL_SHIFT 9 /* max(e such that 10**e fits in a digit) */ 51: #define _PyLong_DECIMAL_BASE ((digit)1000000000) /* 10 ** DECIMAL_SHIFT */ 52: #elif PYLONG_BITS_IN_DIGIT == 15 53: typedef unsigned short digit; 54: typedef short sdigit; /* signed variant of digit */ 55: typedef unsigned long twodigits; 56: typedef long stwodigits; /* signed variant of twodigits */ 57: #define PyLong_SHIFT 15 58: #define _PyLong_DECIMAL_SHIFT 4 /* max(e such that 10**e fits in a digit) */ 59: #define _PyLong_DECIMAL_BASE ((digit)10000) /* 10 ** DECIMAL_SHIFT */ 60: #else 61: #error "PYLONG_BITS_IN_DIGIT should be 15 or 30" 62: #endif 63: #define PyLong_BASE ((digit)1 << PyLong_SHIFT) 64: #define PyLong_MASK ((digit)(PyLong_BASE - 1)) 65: 66: #if PyLong_SHIFT % 5 != 0 67: #error "longobject.c requires that PyLong_SHIFT be divisible by 5" 68: #endif 69: 70: /* Long integer representation. 71: The absolute value of a number is equal to 72: SUM(for i=0 through abs(ob_size)-1) ob_digit[i] * 2**(SHIFT*i) 73: Negative numbers are represented with ob_size < 0; 74: zero is represented by ob_size == 0. 75: In a normalized number, ob_digit[abs(ob_size)-1] (the most significant 76: digit) is never zero. Also, in all cases, for all valid i, 77: 0 <= ob_digit[i] <= MASK. 78: The allocation function takes care of allocating extra memory 79: so that ob_digit[0] ... ob_digit[abs(ob_size)-1] are actually available. 80: 81: CAUTION: Generic code manipulating subtypes of PyVarObject has to 82: aware that ints abuse ob_size's sign bit. 83: */ 84: 85: struct _longobject { 86: PyObject_VAR_HEAD 87: digit ob_digit[1]; 88: }; 89: 90: PyAPI_FUNC(PyLongObject *) _PyLong_New(Py_ssize_t); 91: 92: /* Return a copy of src. */ 93: PyAPI_FUNC(PyObject *) _PyLong_Copy(PyLongObject *src); 94: 95: #ifdef __cplusplus 96: } 97: #endif 98: #endif /* !Py_LONGINTREPR_H */ 99: #endif /* Py_LIMITED_API */ 100: