android / platform / prebuilts / python / darwin-x86 / 2.7.5 / refs/tags/android-6.0.1_r17 / . / include / python2.7 / longintrepr.h

#ifndef Py_LONGINTREPR_H | |

#define Py_LONGINTREPR_H | |

#ifdef __cplusplus | |

extern "C" { | |

#endif | |

/* This is published for the benefit of "friend" marshal.c only. */ | |

/* Parameters of the long integer representation. There are two different | |

sets of parameters: one set for 30-bit digits, stored in an unsigned 32-bit | |

integer type, and one set for 15-bit digits with each digit stored in an | |

unsigned short. The value of PYLONG_BITS_IN_DIGIT, defined either at | |

configure time or in pyport.h, is used to decide which digit size to use. | |

Type 'digit' should be able to hold 2*PyLong_BASE-1, and type 'twodigits' | |

should be an unsigned integer type able to hold all integers up to | |

PyLong_BASE*PyLong_BASE-1. x_sub assumes that 'digit' is an unsigned type, | |

and that overflow is handled by taking the result modulo 2**N for some N > | |

PyLong_SHIFT. The majority of the code doesn't care about the precise | |

value of PyLong_SHIFT, but there are some notable exceptions: | |

- long_pow() requires that PyLong_SHIFT be divisible by 5 | |

- PyLong_{As,From}ByteArray require that PyLong_SHIFT be at least 8 | |

- long_hash() requires that PyLong_SHIFT is *strictly* less than the number | |

of bits in an unsigned long, as do the PyLong <-> long (or unsigned long) | |

conversion functions | |

- the long <-> size_t/Py_ssize_t conversion functions expect that | |

PyLong_SHIFT is strictly less than the number of bits in a size_t | |

- the marshal code currently expects that PyLong_SHIFT is a multiple of 15 | |

The values 15 and 30 should fit all of the above requirements, on any | |

platform. | |

*/ | |

#if PYLONG_BITS_IN_DIGIT == 30 | |

#if !(defined HAVE_UINT64_T && defined HAVE_UINT32_T && \ | |

defined HAVE_INT64_T && defined HAVE_INT32_T) | |

#error "30-bit long digits requested, but the necessary types are not available on this platform" | |

#endif | |

typedef PY_UINT32_T digit; | |

typedef PY_INT32_T sdigit; /* signed variant of digit */ | |

typedef PY_UINT64_T twodigits; | |

typedef PY_INT64_T stwodigits; /* signed variant of twodigits */ | |

#define PyLong_SHIFT 30 | |

#define _PyLong_DECIMAL_SHIFT 9 /* max(e such that 10**e fits in a digit) */ | |

#define _PyLong_DECIMAL_BASE ((digit)1000000000) /* 10 ** DECIMAL_SHIFT */ | |

#elif PYLONG_BITS_IN_DIGIT == 15 | |

typedef unsigned short digit; | |

typedef short sdigit; /* signed variant of digit */ | |

typedef unsigned long twodigits; | |

typedef long stwodigits; /* signed variant of twodigits */ | |

#define PyLong_SHIFT 15 | |

#define _PyLong_DECIMAL_SHIFT 4 /* max(e such that 10**e fits in a digit) */ | |

#define _PyLong_DECIMAL_BASE ((digit)10000) /* 10 ** DECIMAL_SHIFT */ | |

#else | |

#error "PYLONG_BITS_IN_DIGIT should be 15 or 30" | |

#endif | |

#define PyLong_BASE ((digit)1 << PyLong_SHIFT) | |

#define PyLong_MASK ((digit)(PyLong_BASE - 1)) | |

/* b/w compatibility with Python 2.5 */ | |

#define SHIFT PyLong_SHIFT | |

#define BASE PyLong_BASE | |

#define MASK PyLong_MASK | |

#if PyLong_SHIFT % 5 != 0 | |

#error "longobject.c requires that PyLong_SHIFT be divisible by 5" | |

#endif | |

/* Long integer representation. | |

The absolute value of a number is equal to | |

SUM(for i=0 through abs(ob_size)-1) ob_digit[i] * 2**(SHIFT*i) | |

Negative numbers are represented with ob_size < 0; | |

zero is represented by ob_size == 0. | |

In a normalized number, ob_digit[abs(ob_size)-1] (the most significant | |

digit) is never zero. Also, in all cases, for all valid i, | |

0 <= ob_digit[i] <= MASK. | |

The allocation function takes care of allocating extra memory | |

so that ob_digit[0] ... ob_digit[abs(ob_size)-1] are actually available. | |

CAUTION: Generic code manipulating subtypes of PyVarObject has to | |

aware that longs abuse ob_size's sign bit. | |

*/ | |

struct _longobject { | |

PyObject_VAR_HEAD | |

digit ob_digit[1]; | |

}; | |

PyAPI_FUNC(PyLongObject *) _PyLong_New(Py_ssize_t); | |

/* Return a copy of src. */ | |

PyAPI_FUNC(PyObject *) _PyLong_Copy(PyLongObject *src); | |

#ifdef __cplusplus | |

} | |

#endif | |

#endif /* !Py_LONGINTREPR_H */ |