Home
About
Blog
Products
Forum
Support
Contact
Sunbelt Computer Software
PL/B Language Development and Support
Home
About
Blog
Products
Forum
Support
Contact
cpython/Include/cpython/longintrepr.h at main · python/cpython · GitHub
Skip to content
Navigation Menu
Sign in
Appearance settings
Platform
AI CODE CREATION
GitHub Copilot
Write better code with AI
GitHub Copilot app
Direct agents from issue to merge
MCP Registry
Integrate external tools
DEVELOPER WORKFLOWS
Actions
Automate any workflow
Codespaces
Instant dev environments
Issues
Plan and track work
Code Review
Manage code changes
Code Quality
Enforce quality at merge
APPLICATION SECURITY
GitHub Advanced Security
Find and fix vulnerabilities
Code security
Secure your code as you build
Secret protection
Stop leaks before they start
EXPLORE
Why GitHub
Documentation
Blog
Changelog
Marketplace
View all features
Solutions
BY COMPANY SIZE
Enterprises
Small and medium teams
Startups
Nonprofits
BY USE CASE
App Modernization
DevSecOps
DevOps
CI/CD
View all use cases
BY INDUSTRY
Healthcare
Financial services
Manufacturing
Government
View all industries
View all solutions
Resources
EXPLORE BY TOPIC
AI
Software Development
DevOps
Security
View all topics
EXPLORE BY TYPE
Customer stories
Events & webinars
Ebooks & reports
Business insights
GitHub Skills
SUPPORT & SERVICES
Documentation
Customer support
Community forum
Trust center
Partners
View all resources
Open Source
COMMUNITY
GitHub Sponsors
Fund open source developers
PROGRAMS
Security Lab
Maintainer Community
GitHub Stars
Archive Program
REPOSITORIES
Topics
Trending
Collections
Enterprise
ENTERPRISE SOLUTIONS
Enterprise platform
AI-powered developer platform
AVAILABLE ADD-ONS
GitHub Advanced Security
Enterprise-grade security features
Copilot for Business
Enterprise-grade AI features
Premium Support
Enterprise-grade 24/7 support
Pricing
Search
/
Sign in
Sign up
Appearance settings
You signed in with another tab or window.
Reload
to refresh your session.
You signed out in another tab or window.
Reload
to refresh your session.
You switched accounts on another tab or window.
Reload
to refresh your session.
Dismiss alert
{{ message }}
Uh oh!
There was an error while loading.
Please reload this page
.
python
/
cpython
Public
Uh oh!
There was an error while loading.
Please reload this page
.
Notifications
You must be signed in to change notification settings
Fork
35.4k
Star
77.1k
Code
Issues
5k+
Pull requests
2.6k
Actions
Projects
Security and quality
0
Insights
Additional navigation options
Code
Issues
Pull requests
Actions
Projects
Security and quality
Insights
Files
Expand file tree
main
Breadcrumbs
cpython
/
Include
/
cpython
/
longintrepr.h
Copy path
Blame
More file actions
Blame
More file actions
Latest commit
History
History
History
150 lines (117 loc) · 5.19 KB
main
Breadcrumbs
cpython
/
Include
/
cpython
/
longintrepr.h
Copy path
Top
File metadata and controls
Code
Blame
150 lines (117 loc) · 5.19 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
#ifndef
Py_LIMITED_API
#ifndef
Py_LONGINTREPR_H
#define
Py_LONGINTREPR_H
#ifdef
__cplusplus
extern
"C"
{
#endif
/* This is published for the benefit of "friends" marshal.c and _decimal.c. */
/* Parameters of the 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:
- 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 Python int <-> 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
- NSMALLNEGINTS and NSMALLPOSINTS should be small enough to fit in a single
digit; with the current values this forces PyLong_SHIFT >= 9
The values 15 and 30 should fit all of the above requirements, on any
platform.
*/
#if
PYLONG_BITS_IN_DIGIT
==
30
typedef
uint32_t
digit
;
typedef
int32_t
sdigit
;
/* signed variant of digit */
typedef
uint64_t
twodigits
;
typedef
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))
/* Long integer representation.
Long integers are made up of a number of 30- or 15-bit digits, depending on
the platform. The number of digits (ndigits) is stored in the high bits of
the lv_tag field (lvtag >> _PyLong_NON_SIZE_BITS).
The absolute value of a number is equal to
SUM(for i=0 through ndigits-1) ob_digit[i] * 2**(PyLong_SHIFT*i)
The sign of the value is stored in the lower 2 bits of lv_tag.
- 0: Positive
- 1: Zero
- 2: Negative
The third lowest bit of lv_tag is
set to 1 for the small ints.
In a normalized number, ob_digit[ndigits-1] (the most significant
digit) is never zero. Also, in all cases, for all valid i,
0 <= ob_digit[i] <= PyLong_MASK.
The allocation function takes care of allocating extra memory
so that ob_digit[0] ... ob_digit[ndigits-1] are actually available.
We always allocate memory for at least one digit, so accessing ob_digit[0]
is always safe. However, in the case ndigits == 0, the contents of
ob_digit[0] may be undefined.
*/
typedef
struct
_PyLongValue
{
uintptr_t
lv_tag
;
/* Number of digits, sign and flags */
digit
ob_digit
[
1
];
}
_PyLongValue
;
struct
_longobject
{
PyObject_HEAD
_PyLongValue
long_value
;
};
Py_DEPRECATED
(
3.14
)
PyAPI_FUNC
(
PyLongObject
*
)
_PyLong_New
(
Py_ssize_t
);
// Return a copy of src.
PyAPI_FUNC
(
PyObject
*
)
_PyLong_Copy
(
PyLongObject
*
src
);
Py_DEPRECATED
(
3.14
)
PyAPI_FUNC
(
PyLongObject
*
)
_PyLong_FromDigits
(
int
negative
,
Py_ssize_t
digit_count
,
digit
*
digits
);
/* Inline some internals for speed. These should be in pycore_long.h
* if user code didn't need them inlined. */
#define
_PyLong_SIGN_MASK
3
#define
_PyLong_NON_SIZE_BITS
3
static
inline
int
_PyLong_IsCompact
(
const
PyLongObject
*
op
) {
assert
(
PyType_HasFeature
(
op
->
ob_base
.
ob_type
,
Py_TPFLAGS_LONG_SUBCLASS
));
return
op
->
long_value
.
lv_tag
<
(
2
<<
_PyLong_NON_SIZE_BITS
);
}
#define
PyUnstable_Long_IsCompact
_PyLong_IsCompact
static
inline
Py_ssize_t
_PyLong_CompactValue
(
const
PyLongObject
*
op
)
{
Py_ssize_t
sign
;
assert
(
PyType_HasFeature
(
op
->
ob_base
.
ob_type
,
Py_TPFLAGS_LONG_SUBCLASS
));
assert
(
PyUnstable_Long_IsCompact
(
op
));
sign
=
1
-
(
op
->
long_value
.
lv_tag
&
_PyLong_SIGN_MASK
);
if
(
sign
==
0
) {
// gh-147988: Make sure that the digit is zero.
// It helps detecting the usage of uninitialized digits.
assert
(
op
->
long_value
.
ob_digit
[
0
]
==
0
);
}
return
sign
*
(
Py_ssize_t
)
op
->
long_value
.
ob_digit
[
0
];
}
#define
PyUnstable_Long_CompactValue
_PyLong_CompactValue
#ifdef
__cplusplus
}
#endif
#endif
/* !Py_LONGINTREPR_H */
#endif
/* Py_LIMITED_API */
You can’t perform that action at this time.