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The C and C++ Include Header Files

cat -n /usr/include/python3.14/cpython/longintrepr.h

     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	   - PyLong_{As,From}ByteArray require that PyLong_SHIFT be at least 8
    25	
    26	   - long_hash() requires that PyLong_SHIFT is *strictly* less than the number
    27	     of bits in an unsigned long, as do the PyLong <-> long (or unsigned long)
    28	     conversion functions
    29	
    30	   - the Python int <-> size_t/Py_ssize_t conversion functions expect that
    31	     PyLong_SHIFT is strictly less than the number of bits in a size_t
    32	
    33	   - the marshal code currently expects that PyLong_SHIFT is a multiple of 15
    34	
    35	   - NSMALLNEGINTS and NSMALLPOSINTS should be small enough to fit in a single
    36	     digit; with the current values this forces PyLong_SHIFT >= 9
    37	
    38	  The values 15 and 30 should fit all of the above requirements, on any
    39	  platform.
    40	*/
    41	
    42	#if PYLONG_BITS_IN_DIGIT == 30
    43	typedef uint32_t digit;
    44	typedef int32_t sdigit; /* signed variant of digit */
    45	typedef uint64_t twodigits;
    46	typedef int64_t stwodigits; /* signed variant of twodigits */
    47	#define PyLong_SHIFT    30
    48	#define _PyLong_DECIMAL_SHIFT   9 /* max(e such that 10**e fits in a digit) */
    49	#define _PyLong_DECIMAL_BASE    ((digit)1000000000) /* 10 ** DECIMAL_SHIFT */
    50	#elif PYLONG_BITS_IN_DIGIT == 15
    51	typedef unsigned short digit;
    52	typedef short sdigit; /* signed variant of digit */
    53	typedef unsigned long twodigits;
    54	typedef long stwodigits; /* signed variant of twodigits */
    55	#define PyLong_SHIFT    15
    56	#define _PyLong_DECIMAL_SHIFT   4 /* max(e such that 10**e fits in a digit) */
    57	#define _PyLong_DECIMAL_BASE    ((digit)10000) /* 10 ** DECIMAL_SHIFT */
    58	#else
    59	#error "PYLONG_BITS_IN_DIGIT should be 15 or 30"
    60	#endif
    61	#define PyLong_BASE     ((digit)1 << PyLong_SHIFT)
    62	#define PyLong_MASK     ((digit)(PyLong_BASE - 1))
    63	
    64	/* Long integer representation.
    65	
    66	   Long integers are made up of a number of 30- or 15-bit digits, depending on
    67	   the platform. The number of digits (ndigits) is stored in the high bits of
    68	   the lv_tag field (lvtag >> _PyLong_NON_SIZE_BITS).
    69	
    70	   The absolute value of a number is equal to
    71	        SUM(for i=0 through ndigits-1) ob_digit[i] * 2**(PyLong_SHIFT*i)
    72	
    73	   The sign of the value is stored in the lower 2 bits of lv_tag.
    74	
    75	    - 0: Positive
    76	    - 1: Zero
    77	    - 2: Negative
    78	
    79	   The third lowest bit of lv_tag is
    80	   set to 1 for the small ints.
    81	
    82	   In a normalized number, ob_digit[ndigits-1] (the most significant
    83	   digit) is never zero.  Also, in all cases, for all valid i,
    84	        0 <= ob_digit[i] <= PyLong_MASK.
    85	
    86	   The allocation function takes care of allocating extra memory
    87	   so that ob_digit[0] ... ob_digit[ndigits-1] are actually available.
    88	   We always allocate memory for at least one digit, so accessing ob_digit[0]
    89	   is always safe. However, in the case ndigits == 0, the contents of
    90	   ob_digit[0] may be undefined.
    91	*/
    92	
    93	typedef struct _PyLongValue {
    94	    uintptr_t lv_tag; /* Number of digits, sign and flags */
    95	    digit ob_digit[1];
    96	} _PyLongValue;
    97	
    98	struct _longobject {
    99	    PyObject_HEAD
   100	    _PyLongValue long_value;
   101	};
   102	
   103	Py_DEPRECATED(3.14) PyAPI_FUNC(PyLongObject*) _PyLong_New(Py_ssize_t);
   104	
   105	// Return a copy of src.
   106	PyAPI_FUNC(PyObject*) _PyLong_Copy(PyLongObject *src);
   107	
   108	Py_DEPRECATED(3.14) PyAPI_FUNC(PyLongObject*) _PyLong_FromDigits(
   109	    int negative,
   110	    Py_ssize_t digit_count,
   111	    digit *digits);
   112	
   113	
   114	/* Inline some internals for speed. These should be in pycore_long.h
   115	 * if user code didn't need them inlined. */
   116	
   117	#define _PyLong_SIGN_MASK 3
   118	#define _PyLong_NON_SIZE_BITS 3
   119	
   120	
   121	static inline int
   122	_PyLong_IsCompact(const PyLongObject* op) {
   123	    assert(PyType_HasFeature(op->ob_base.ob_type, Py_TPFLAGS_LONG_SUBCLASS));
   124	    return op->long_value.lv_tag < (2 << _PyLong_NON_SIZE_BITS);
   125	}
   126	
   127	#define PyUnstable_Long_IsCompact _PyLong_IsCompact
   128	
   129	static inline Py_ssize_t
   130	_PyLong_CompactValue(const PyLongObject *op)
   131	{
   132	    Py_ssize_t sign;
   133	    assert(PyType_HasFeature(op->ob_base.ob_type, Py_TPFLAGS_LONG_SUBCLASS));
   134	    assert(PyUnstable_Long_IsCompact(op));
   135	    sign = 1 - (op->long_value.lv_tag & _PyLong_SIGN_MASK);
   136	    return sign * (Py_ssize_t)op->long_value.ob_digit[0];
   137	}
   138	
   139	#define PyUnstable_Long_CompactValue _PyLong_CompactValue
   140	
   141	
   142	/* --- Import/Export API -------------------------------------------------- */
   143	
   144	typedef struct PyLongLayout {
   145	    uint8_t bits_per_digit;
   146	    uint8_t digit_size;
   147	    int8_t digits_order;
   148	    int8_t digit_endianness;
   149	} PyLongLayout;
   150	
   151	PyAPI_FUNC(const PyLongLayout*) PyLong_GetNativeLayout(void);
   152	
   153	typedef struct PyLongExport {
   154	    int64_t value;
   155	    uint8_t negative;
   156	    Py_ssize_t ndigits;
   157	    const void *digits;
   158	    // Member used internally, must not be used for other purpose.
   159	    Py_uintptr_t _reserved;
   160	} PyLongExport;
   161	
   162	PyAPI_FUNC(int) PyLong_Export(
   163	    PyObject *obj,
   164	    PyLongExport *export_long);
   165	PyAPI_FUNC(void) PyLong_FreeExport(
   166	    PyLongExport *export_long);
   167	
   168	
   169	/* --- PyLongWriter API --------------------------------------------------- */
   170	
   171	typedef struct PyLongWriter PyLongWriter;
   172	
   173	PyAPI_FUNC(PyLongWriter*) PyLongWriter_Create(
   174	    int negative,
   175	    Py_ssize_t ndigits,
   176	    void **digits);
   177	PyAPI_FUNC(PyObject*) PyLongWriter_Finish(PyLongWriter *writer);
   178	PyAPI_FUNC(void) PyLongWriter_Discard(PyLongWriter *writer);
   179	
   180	#ifdef __cplusplus
   181	}
   182	#endif
   183	#endif /* !Py_LONGINTREPR_H */
   184	#endif /* Py_LIMITED_API */