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Path: ~//opt/alt/python312/include/python3.12/internal/

File Content: `pycore_bitutils.h`

/* Bit and bytes utilities.

   Bytes swap functions, reverse order of bytes:

   - _Py_bswap16(uint16_t)
   - _Py_bswap32(uint32_t)
   - _Py_bswap64(uint64_t)
*/

#ifndef Py_INTERNAL_BITUTILS_H
#define Py_INTERNAL_BITUTILS_H
#ifdef __cplusplus
extern "C" {
#endif

#ifndef Py_BUILD_CORE
#  error "this header requires Py_BUILD_CORE define"
#endif

#if defined(__GNUC__) \
      && ((__GNUC__ >= 5) || (__GNUC__ == 4) && (__GNUC_MINOR__ >= 8))
   /* __builtin_bswap16() is available since GCC 4.8,
      __builtin_bswap32() is available since GCC 4.3,
      __builtin_bswap64() is available since GCC 4.3. */
#  define _PY_HAVE_BUILTIN_BSWAP
#endif

#ifdef _MSC_VER
   /* Get _byteswap_ushort(), _byteswap_ulong(), _byteswap_uint64() */
#  include <intrin.h>
#endif

static inline uint16_t
_Py_bswap16(uint16_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap16)
    return __builtin_bswap16(word);
#elif defined(_MSC_VER)
    Py_BUILD_ASSERT(sizeof(word) == sizeof(unsigned short));
    return _byteswap_ushort(word);
#else
    // Portable implementation which doesn't rely on circular bit shift
    return ( ((word & UINT16_C(0x00FF)) << 8)
           | ((word & UINT16_C(0xFF00)) >> 8));
#endif
}

static inline uint32_t
_Py_bswap32(uint32_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap32)
    return __builtin_bswap32(word);
#elif defined(_MSC_VER)
    Py_BUILD_ASSERT(sizeof(word) == sizeof(unsigned long));
    return _byteswap_ulong(word);
#else
    // Portable implementation which doesn't rely on circular bit shift
    return ( ((word & UINT32_C(0x000000FF)) << 24)
           | ((word & UINT32_C(0x0000FF00)) <<  8)
           | ((word & UINT32_C(0x00FF0000)) >>  8)
           | ((word & UINT32_C(0xFF000000)) >> 24));
#endif
}

static inline uint64_t
_Py_bswap64(uint64_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap64)
    return __builtin_bswap64(word);
#elif defined(_MSC_VER)
    return _byteswap_uint64(word);
#else
    // Portable implementation which doesn't rely on circular bit shift
    return ( ((word & UINT64_C(0x00000000000000FF)) << 56)
           | ((word & UINT64_C(0x000000000000FF00)) << 40)
           | ((word & UINT64_C(0x0000000000FF0000)) << 24)
           | ((word & UINT64_C(0x00000000FF000000)) <<  8)
           | ((word & UINT64_C(0x000000FF00000000)) >>  8)
           | ((word & UINT64_C(0x0000FF0000000000)) >> 24)
           | ((word & UINT64_C(0x00FF000000000000)) >> 40)
           | ((word & UINT64_C(0xFF00000000000000)) >> 56));
#endif
}


// Population count: count the number of 1's in 'x'
// (number of bits set to 1), also known as the hamming weight.
//
// Implementation note. CPUID is not used, to test if x86 POPCNT instruction
// can be used, to keep the implementation simple. For example, Visual Studio
// __popcnt() is not used this reason. The clang and GCC builtin function can
// use the x86 POPCNT instruction if the target architecture has SSE4a or
// newer.
static inline int
_Py_popcount32(uint32_t x)
{
#if (defined(__clang__) || defined(__GNUC__))

#if SIZEOF_INT >= 4
    Py_BUILD_ASSERT(sizeof(x) <= sizeof(unsigned int));
    return __builtin_popcount(x);
#else
    // The C standard guarantees that unsigned long will always be big enough
    // to hold a uint32_t value without losing information.
    Py_BUILD_ASSERT(sizeof(x) <= sizeof(unsigned long));
    return __builtin_popcountl(x);
#endif

#else
    // 32-bit SWAR (SIMD Within A Register) popcount

    // Binary: 0 1 0 1 ...
    const uint32_t M1 = 0x55555555;
    // Binary: 00 11 00 11. ..
    const uint32_t M2 = 0x33333333;
    // Binary: 0000 1111 0000 1111 ...
    const uint32_t M4 = 0x0F0F0F0F;

    // Put count of each 2 bits into those 2 bits
    x = x - ((x >> 1) & M1);
    // Put count of each 4 bits into those 4 bits
    x = (x & M2) + ((x >> 2) & M2);
    // Put count of each 8 bits into those 8 bits
    x = (x + (x >> 4)) & M4;
    // Sum of the 4 byte counts.
    // Take care when considering changes to the next line. Portability and
    // correctness are delicate here, thanks to C's "integer promotions" (C99
    // §6.3.1.1p2). On machines where the `int` type has width greater than 32
    // bits, `x` will be promoted to an `int`, and following C's "usual
    // arithmetic conversions" (C99 §6.3.1.8), the multiplication will be
    // performed as a multiplication of two `unsigned int` operands. In this
    // case it's critical that we cast back to `uint32_t` in order to keep only
    // the least significant 32 bits. On machines where the `int` type has
    // width no greater than 32, the multiplication is of two 32-bit unsigned
    // integer types, and the (uint32_t) cast is a no-op. In both cases, we
    // avoid the risk of undefined behaviour due to overflow of a
    // multiplication of signed integer types.
    return (uint32_t)(x * 0x01010101U) >> 24;
#endif
}


// Return the index of the most significant 1 bit in 'x'. This is the smallest
// integer k such that x < 2**k. Equivalent to floor(log2(x)) + 1 for x != 0.
static inline int
_Py_bit_length(unsigned long x)
{
#if (defined(__clang__) || defined(__GNUC__))
    if (x != 0) {
        // __builtin_clzl() is available since GCC 3.4.
        // Undefined behavior for x == 0.
        return (int)sizeof(unsigned long) * 8 - __builtin_clzl(x);
    }
    else {
        return 0;
    }
#elif defined(_MSC_VER)
    // _BitScanReverse() is documented to search 32 bits.
    Py_BUILD_ASSERT(sizeof(unsigned long) <= 4);
    unsigned long msb;
    if (_BitScanReverse(&msb, x)) {
        return (int)msb + 1;
    }
    else {
        return 0;
    }
#else
    const int BIT_LENGTH_TABLE[32] = {
        0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
    };
    int msb = 0;
    while (x >= 32) {
        msb += 6;
        x >>= 6;
    }
    msb += BIT_LENGTH_TABLE[x];
    return msb;
#endif
}


#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_BITUTILS_H */

Edit Rename Chmod Delete

FILE FOLDER

Name	Size	Permission
pycore_abstract.h	611 bytes	0644
pycore_asdl.h	3035 bytes	0644
pycore_ast.h	31288 bytes	0644
pycore_ast_state.h	6749 bytes	0644
pycore_atexit.h	1149 bytes	0644
pycore_atomic.h	16979 bytes	0644
pycore_atomic_funcs.h	2438 bytes	0644
pycore_bitutils.h	6062 bytes	0644
pycore_blocks_output_buffer.h	8688 bytes	0644
pycore_bytes_methods.h	3384 bytes	0644
pycore_bytesobject.h	1339 bytes	0644
pycore_call.h	3920 bytes	0644
pycore_ceval.h	5265 bytes	0644
pycore_ceval_state.h	2744 bytes	0644
pycore_code.h	15835 bytes	0644
pycore_compile.h	3453 bytes	0644
pycore_condvar.h	2909 bytes	0644
pycore_context.h	1301 bytes	0644
pycore_descrobject.h	499 bytes	0644
pycore_dict.h	6384 bytes	0644
pycore_dict_state.h	1095 bytes	0644
pycore_dtoa.h	1615 bytes	0644
pycore_emscripten_signal.h	562 bytes	0644
pycore_exceptions.h	842 bytes	0644
pycore_faulthandler.h	2220 bytes	0644
pycore_fileutils.h	7910 bytes	0644
pycore_fileutils_windows.h	2724 bytes	0644
pycore_floatobject.h	1578 bytes	0644
pycore_flowgraph.h	4630 bytes	0644
pycore_format.h	480 bytes	0644
pycore_frame.h	9255 bytes	0644
pycore_function.h	611 bytes	0644
pycore_gc.h	7658 bytes	0644
pycore_genobject.h	1186 bytes	0644
pycore_getopt.h	490 bytes	0644
pycore_gil.h	1565 bytes	0644
pycore_global_objects.h	3035 bytes	0644
pycore_global_objects_fini_generated.h	115361 bytes	0644
pycore_global_strings.h	25438 bytes	0644
pycore_hamt.h	3742 bytes	0644
pycore_hashtable.h	4286 bytes	0644
pycore_import.h	6358 bytes	0644
pycore_initconfig.h	5706 bytes	0644
pycore_instruments.h	2998 bytes	0644
pycore_interp.h	9086 bytes	0644
pycore_intrinsics.h	1397 bytes	0644
pycore_list.h	1980 bytes	0644
pycore_long.h	7805 bytes	0644
pycore_memoryobject.h	383 bytes	0644
pycore_moduleobject.h	1192 bytes	0644
pycore_namespace.h	392 bytes	0644
pycore_object.h	14917 bytes	0644
pycore_object_state.h	1016 bytes	0644
pycore_obmalloc.h	27284 bytes	0644
pycore_obmalloc_init.h	2085 bytes	0644
pycore_opcode.h	20081 bytes	0644
pycore_opcode_utils.h	2686 bytes	0644
pycore_parser.h	1358 bytes	0644
pycore_pathconfig.h	606 bytes	0644
pycore_pyarena.h	2733 bytes	0644
pycore_pyerrors.h	3110 bytes	0644
pycore_pyhash.h	709 bytes	0644
pycore_pylifecycle.h	3365 bytes	0644
pycore_pymath.h	8600 bytes	0644
pycore_pymem.h	3040 bytes	0644
pycore_pymem_init.h	2654 bytes	0644
pycore_pystate.h	4982 bytes	0644
pycore_pythread.h	2075 bytes	0644
pycore_range.h	346 bytes	0644
pycore_runtime.h	8429 bytes	0644
pycore_runtime_init.h	5912 bytes	0644
pycore_runtime_init_generated.h	45751 bytes	0644
pycore_signal.h	2611 bytes	0644
pycore_sliceobject.h	414 bytes	0644
pycore_strhex.h	937 bytes	0644
pycore_structseq.h	923 bytes	0644
pycore_symtable.h	7035 bytes	0644
pycore_sysmodule.h	999 bytes	0644
pycore_time.h	388 bytes	0644
pycore_token.h	3050 bytes	0644
pycore_traceback.h	3501 bytes	0644
pycore_tracemalloc.h	3075 bytes	0644
pycore_tuple.h	2197 bytes	0644
pycore_typeobject.h	4731 bytes	0644
pycore_typevarobject.h	763 bytes	0644
pycore_ucnhash.h	898 bytes	0644
pycore_unicodeobject.h	2657 bytes	0644
pycore_unicodeobject_generated.h	125516 bytes	0644
pycore_unionobject.h	682 bytes	0644
pycore_warnings.h	740 bytes	0644

File Content: pycore_bitutils.h

File Content: `pycore_bitutils.h`