#ifndef Py_LONGINTREPR_H

[0] Fix | Delete

#define Py_LONGINTREPR_H

[1] Fix | Delete

#ifdef __cplusplus

[2] Fix | Delete

extern "C" {

[3] Fix | Delete

#endif

[4] Fix | Delete

[5] Fix | Delete

[6] Fix | Delete

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

[7] Fix | Delete

[8] Fix | Delete

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

[9] Fix | Delete

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

[10] Fix | Delete

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

[11] Fix | Delete

unsigned short. The value of PYLONG_BITS_IN_DIGIT, defined either at

[12] Fix | Delete

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

[13] Fix | Delete

[14] Fix | Delete

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

[15] Fix | Delete

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

[16] Fix | Delete

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

[17] Fix | Delete

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

[18] Fix | Delete

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

[19] Fix | Delete

value of PyLong_SHIFT, but there are some notable exceptions:

[20] Fix | Delete

[21] Fix | Delete

- long_pow() requires that PyLong_SHIFT be divisible by 5

[22] Fix | Delete

[23] Fix | Delete

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

[24] Fix | Delete

[25] Fix | Delete

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

[26] Fix | Delete

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

[27] Fix | Delete

conversion functions

[28] Fix | Delete

[29] Fix | Delete

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

[30] Fix | Delete

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

[31] Fix | Delete

[32] Fix | Delete

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

[33] Fix | Delete

[34] Fix | Delete

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

[35] Fix | Delete

platform.

[36] Fix | Delete

*/

[37] Fix | Delete

[38] Fix | Delete

#if PYLONG_BITS_IN_DIGIT == 30

[39] Fix | Delete

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

[40] Fix | Delete

defined HAVE_INT64_T && defined HAVE_INT32_T)

[41] Fix | Delete

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

[42] Fix | Delete

#endif

[43] Fix | Delete

typedef PY_UINT32_T digit;

[44] Fix | Delete

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

[45] Fix | Delete

typedef PY_UINT64_T twodigits;

[46] Fix | Delete

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

[47] Fix | Delete

#define PyLong_SHIFT 30

[48] Fix | Delete

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

[49] Fix | Delete

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

[50] Fix | Delete

#elif PYLONG_BITS_IN_DIGIT == 15

[51] Fix | Delete

typedef unsigned short digit;

[52] Fix | Delete

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

[53] Fix | Delete

typedef unsigned long twodigits;

[54] Fix | Delete

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

[55] Fix | Delete

#define PyLong_SHIFT 15

[56] Fix | Delete

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

[57] Fix | Delete

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

[58] Fix | Delete

#else

[59] Fix | Delete

#error "PYLONG_BITS_IN_DIGIT should be 15 or 30"

[60] Fix | Delete

#endif

[61] Fix | Delete

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

[62] Fix | Delete

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

[63] Fix | Delete

[64] Fix | Delete

/* b/w compatibility with Python 2.5 */

[65] Fix | Delete

#define SHIFT PyLong_SHIFT

[66] Fix | Delete

#define BASE PyLong_BASE

[67] Fix | Delete

#define MASK PyLong_MASK

[68] Fix | Delete

[69] Fix | Delete

#if PyLong_SHIFT % 5 != 0

[70] Fix | Delete

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

[71] Fix | Delete

#endif

[72] Fix | Delete

[73] Fix | Delete

/* Long integer representation.

[74] Fix | Delete

The absolute value of a number is equal to

[75] Fix | Delete

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

[76] Fix | Delete

Negative numbers are represented with ob_size < 0;

[77] Fix | Delete

zero is represented by ob_size == 0.

[78] Fix | Delete

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

[79] Fix | Delete

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

[80] Fix | Delete

0 <= ob_digit[i] <= MASK.

[81] Fix | Delete

The allocation function takes care of allocating extra memory

[82] Fix | Delete

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

[83] Fix | Delete

[84] Fix | Delete

CAUTION: Generic code manipulating subtypes of PyVarObject has to

[85] Fix | Delete

aware that longs abuse ob_size's sign bit.

[86] Fix | Delete

*/

[87] Fix | Delete

[88] Fix | Delete

struct _longobject {

[89] Fix | Delete

PyObject_VAR_HEAD

[90] Fix | Delete

digit ob_digit[1];

[91] Fix | Delete

};

[92] Fix | Delete

[93] Fix | Delete

PyAPI_FUNC(PyLongObject *) _PyLong_New(Py_ssize_t);

[94] Fix | Delete

[95] Fix | Delete

/* Return a copy of src. */

[96] Fix | Delete

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

[97] Fix | Delete

[98] Fix | Delete

#ifdef __cplusplus

[99] Fix | Delete

}

[100] Fix | Delete

#endif

[101] Fix | Delete

#endif /* !Py_LONGINTREPR_H */

[102] Fix | Delete

[103] Fix | Delete