Chris@87
|
1 #ifndef Py_LONGINTREPR_H
|
Chris@87
|
2 #define Py_LONGINTREPR_H
|
Chris@87
|
3 #ifdef __cplusplus
|
Chris@87
|
4 extern "C" {
|
Chris@87
|
5 #endif
|
Chris@87
|
6
|
Chris@87
|
7
|
Chris@87
|
8 /* This is published for the benefit of "friend" marshal.c only. */
|
Chris@87
|
9
|
Chris@87
|
10 /* Parameters of the long integer representation. There are two different
|
Chris@87
|
11 sets of parameters: one set for 30-bit digits, stored in an unsigned 32-bit
|
Chris@87
|
12 integer type, and one set for 15-bit digits with each digit stored in an
|
Chris@87
|
13 unsigned short. The value of PYLONG_BITS_IN_DIGIT, defined either at
|
Chris@87
|
14 configure time or in pyport.h, is used to decide which digit size to use.
|
Chris@87
|
15
|
Chris@87
|
16 Type 'digit' should be able to hold 2*PyLong_BASE-1, and type 'twodigits'
|
Chris@87
|
17 should be an unsigned integer type able to hold all integers up to
|
Chris@87
|
18 PyLong_BASE*PyLong_BASE-1. x_sub assumes that 'digit' is an unsigned type,
|
Chris@87
|
19 and that overflow is handled by taking the result modulo 2**N for some N >
|
Chris@87
|
20 PyLong_SHIFT. The majority of the code doesn't care about the precise
|
Chris@87
|
21 value of PyLong_SHIFT, but there are some notable exceptions:
|
Chris@87
|
22
|
Chris@87
|
23 - long_pow() requires that PyLong_SHIFT be divisible by 5
|
Chris@87
|
24
|
Chris@87
|
25 - PyLong_{As,From}ByteArray require that PyLong_SHIFT be at least 8
|
Chris@87
|
26
|
Chris@87
|
27 - long_hash() requires that PyLong_SHIFT is *strictly* less than the number
|
Chris@87
|
28 of bits in an unsigned long, as do the PyLong <-> long (or unsigned long)
|
Chris@87
|
29 conversion functions
|
Chris@87
|
30
|
Chris@87
|
31 - the long <-> size_t/Py_ssize_t conversion functions expect that
|
Chris@87
|
32 PyLong_SHIFT is strictly less than the number of bits in a size_t
|
Chris@87
|
33
|
Chris@87
|
34 - the marshal code currently expects that PyLong_SHIFT is a multiple of 15
|
Chris@87
|
35
|
Chris@87
|
36 The values 15 and 30 should fit all of the above requirements, on any
|
Chris@87
|
37 platform.
|
Chris@87
|
38 */
|
Chris@87
|
39
|
Chris@87
|
40 #if PYLONG_BITS_IN_DIGIT == 30
|
Chris@87
|
41 #if !(defined HAVE_UINT64_T && defined HAVE_UINT32_T && \
|
Chris@87
|
42 defined HAVE_INT64_T && defined HAVE_INT32_T)
|
Chris@87
|
43 #error "30-bit long digits requested, but the necessary types are not available on this platform"
|
Chris@87
|
44 #endif
|
Chris@87
|
45 typedef PY_UINT32_T digit;
|
Chris@87
|
46 typedef PY_INT32_T sdigit; /* signed variant of digit */
|
Chris@87
|
47 typedef PY_UINT64_T twodigits;
|
Chris@87
|
48 typedef PY_INT64_T stwodigits; /* signed variant of twodigits */
|
Chris@87
|
49 #define PyLong_SHIFT 30
|
Chris@87
|
50 #define _PyLong_DECIMAL_SHIFT 9 /* max(e such that 10**e fits in a digit) */
|
Chris@87
|
51 #define _PyLong_DECIMAL_BASE ((digit)1000000000) /* 10 ** DECIMAL_SHIFT */
|
Chris@87
|
52 #elif PYLONG_BITS_IN_DIGIT == 15
|
Chris@87
|
53 typedef unsigned short digit;
|
Chris@87
|
54 typedef short sdigit; /* signed variant of digit */
|
Chris@87
|
55 typedef unsigned long twodigits;
|
Chris@87
|
56 typedef long stwodigits; /* signed variant of twodigits */
|
Chris@87
|
57 #define PyLong_SHIFT 15
|
Chris@87
|
58 #define _PyLong_DECIMAL_SHIFT 4 /* max(e such that 10**e fits in a digit) */
|
Chris@87
|
59 #define _PyLong_DECIMAL_BASE ((digit)10000) /* 10 ** DECIMAL_SHIFT */
|
Chris@87
|
60 #else
|
Chris@87
|
61 #error "PYLONG_BITS_IN_DIGIT should be 15 or 30"
|
Chris@87
|
62 #endif
|
Chris@87
|
63 #define PyLong_BASE ((digit)1 << PyLong_SHIFT)
|
Chris@87
|
64 #define PyLong_MASK ((digit)(PyLong_BASE - 1))
|
Chris@87
|
65
|
Chris@87
|
66 /* b/w compatibility with Python 2.5 */
|
Chris@87
|
67 #define SHIFT PyLong_SHIFT
|
Chris@87
|
68 #define BASE PyLong_BASE
|
Chris@87
|
69 #define MASK PyLong_MASK
|
Chris@87
|
70
|
Chris@87
|
71 #if PyLong_SHIFT % 5 != 0
|
Chris@87
|
72 #error "longobject.c requires that PyLong_SHIFT be divisible by 5"
|
Chris@87
|
73 #endif
|
Chris@87
|
74
|
Chris@87
|
75 /* Long integer representation.
|
Chris@87
|
76 The absolute value of a number is equal to
|
Chris@87
|
77 SUM(for i=0 through abs(ob_size)-1) ob_digit[i] * 2**(SHIFT*i)
|
Chris@87
|
78 Negative numbers are represented with ob_size < 0;
|
Chris@87
|
79 zero is represented by ob_size == 0.
|
Chris@87
|
80 In a normalized number, ob_digit[abs(ob_size)-1] (the most significant
|
Chris@87
|
81 digit) is never zero. Also, in all cases, for all valid i,
|
Chris@87
|
82 0 <= ob_digit[i] <= MASK.
|
Chris@87
|
83 The allocation function takes care of allocating extra memory
|
Chris@87
|
84 so that ob_digit[0] ... ob_digit[abs(ob_size)-1] are actually available.
|
Chris@87
|
85
|
Chris@87
|
86 CAUTION: Generic code manipulating subtypes of PyVarObject has to
|
Chris@87
|
87 aware that longs abuse ob_size's sign bit.
|
Chris@87
|
88 */
|
Chris@87
|
89
|
Chris@87
|
90 struct _longobject {
|
Chris@87
|
91 PyObject_VAR_HEAD
|
Chris@87
|
92 digit ob_digit[1];
|
Chris@87
|
93 };
|
Chris@87
|
94
|
Chris@87
|
95 PyAPI_FUNC(PyLongObject *) _PyLong_New(Py_ssize_t);
|
Chris@87
|
96
|
Chris@87
|
97 /* Return a copy of src. */
|
Chris@87
|
98 PyAPI_FUNC(PyObject *) _PyLong_Copy(PyLongObject *src);
|
Chris@87
|
99
|
Chris@87
|
100 #ifdef __cplusplus
|
Chris@87
|
101 }
|
Chris@87
|
102 #endif
|
Chris@87
|
103 #endif /* !Py_LONGINTREPR_H */
|