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https://github.com/python/cpython
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60 lines
1.6 KiB
C
60 lines
1.6 KiB
C
#ifndef Py_HASH_H
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#define Py_HASH_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Cutoff for small string DJBX33A optimization in range [1, cutoff).
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*
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* About 50% of the strings in a typical Python application are smaller than
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* 6 to 7 chars. However DJBX33A is vulnerable to hash collision attacks.
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* NEVER use DJBX33A for long strings!
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*
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* A Py_HASH_CUTOFF of 0 disables small string optimization. 32 bit platforms
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* should use a smaller cutoff because it is easier to create colliding
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* strings. A cutoff of 7 on 64bit platforms and 5 on 32bit platforms should
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* provide a decent safety margin.
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*/
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#ifndef Py_HASH_CUTOFF
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# define Py_HASH_CUTOFF 0
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#elif (Py_HASH_CUTOFF > 7 || Py_HASH_CUTOFF < 0)
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# error Py_HASH_CUTOFF must in range 0...7.
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#endif /* Py_HASH_CUTOFF */
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/* Hash algorithm selection
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*
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* The values for Py_HASH_* are hard-coded in the
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* configure script.
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*
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* - FNV and SIPHASH* are available on all platforms and architectures.
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* - With EXTERNAL embedders can provide an alternative implementation with::
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*
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* PyHash_FuncDef PyHash_Func = {...};
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*
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* XXX: Figure out __declspec() for extern PyHash_FuncDef.
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*/
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#define Py_HASH_EXTERNAL 0
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#define Py_HASH_SIPHASH24 1
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#define Py_HASH_FNV 2
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#define Py_HASH_SIPHASH13 3
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#ifndef Py_HASH_ALGORITHM
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# ifndef HAVE_ALIGNED_REQUIRED
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# define Py_HASH_ALGORITHM Py_HASH_SIPHASH13
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# else
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# define Py_HASH_ALGORITHM Py_HASH_FNV
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# endif /* uint64_t && uint32_t && aligned */
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#endif /* Py_HASH_ALGORITHM */
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#ifndef Py_LIMITED_API
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# define Py_CPYTHON_HASH_H
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# include "cpython/pyhash.h"
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# undef Py_CPYTHON_HASH_H
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif // !Py_HASH_H
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