#ifndef Py_INTERNAL_PYHASH_H
#define Py_INTERNAL_PYHASH_H
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
// Similar to Py_HashPointer(), but don't replace -1 with -2.
static inline Py_hash_t
_Py_HashPointerRaw(const void *ptr)
{
uintptr_t x = (uintptr_t)ptr;
Py_BUILD_ASSERT(sizeof(x) == sizeof(ptr));
// Bottom 3 or 4 bits are likely to be 0; rotate x by 4 to the right
// to avoid excessive hash collisions for dicts and sets.
x = (x >> 4) | (x << (8 * sizeof(uintptr_t) - 4));
Py_BUILD_ASSERT(sizeof(x) == sizeof(Py_hash_t));
return (Py_hash_t)x;
}
// Export for '_datetime' shared extension
PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
/* Hash secret
*
* memory layout on 64 bit systems
* cccccccc cccccccc cccccccc uc -- unsigned char[24]
* pppppppp ssssssss ........ fnv -- two Py_hash_t
* k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t
* ........ ........ ssssssss djbx33a -- 16 bytes padding + one Py_hash_t
* ........ ........ eeeeeeee pyexpat XML hash salt
*
* memory layout on 32 bit systems
* cccccccc cccccccc cccccccc uc
* ppppssss ........ ........ fnv -- two Py_hash_t
* k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t (*)
* ........ ........ ssss.... djbx33a -- 16 bytes padding + one Py_hash_t
* ........ ........ eeee.... pyexpat XML hash salt
*
* (*) The siphash member may not be available on 32 bit platforms without
* an unsigned int64 data type.
*/
typedef union {
/* ensure 24 bytes */
unsigned char uc[24];
/* two Py_hash_t for FNV */
struct {
Py_hash_t prefix;
Py_hash_t suffix;
} fnv;
/* two uint64 for SipHash24 */
struct {
uint64_t k0;
uint64_t k1;
} siphash;
/* a different (!) Py_hash_t for small string optimization */
struct {
unsigned char padding[16];
Py_hash_t suffix;
} djbx33a;
struct {
unsigned char padding[16];
Py_hash_t hashsalt;
} expat;
} _Py_HashSecret_t;
// Export for '_elementtree' shared extension
PyAPI_DATA(_Py_HashSecret_t) _Py_HashSecret;
#ifdef Py_DEBUG
extern int _Py_HashSecret_Initialized;
#endif
struct pyhash_runtime_state {
struct {
#ifndef MS_WINDOWS
int fd;
dev_t st_dev;
ino_t st_ino;
#else
// This is a placeholder so the struct isn't empty on Windows.
int _not_used;
#endif
} urandom_cache;
};
#ifndef MS_WINDOWS
# define _py_urandom_cache_INIT \
{ \
.fd = -1, \
}
#else
# define _py_urandom_cache_INIT {0}
#endif
#define pyhash_state_INIT \
{ \
.urandom_cache = _py_urandom_cache_INIT, \
}
extern uint64_t _Py_KeyedHash(uint64_t key, const void *src, Py_ssize_t src_sz);
#endif // !Py_INTERNAL_PYHASH_H
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