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<html><head><title>dlib C++ Library - hash_abstract.h</title></head><body bgcolor='white'><pre> |
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<font color='#009900'>// Copyright (C) 2011 Davis E. King ([email protected]) |
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</font><font color='#009900'>// License: Boost Software License See LICENSE.txt for the full license. |
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</font><font color='#0000FF'>#undef</font> DLIB_HAsH_ABSTRACT_Hh_ |
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<font color='#0000FF'>#ifdef</font> DLIB_HAsH_ABSTRACT_Hh_ |
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<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='murmur_hash3_abstract.h.html'>murmur_hash3_abstract.h</a>" |
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<font color='#0000FF'>#include</font> <font color='#5555FF'><</font>vector<font color='#5555FF'>></font> |
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<font color='#0000FF'>#include</font> <font color='#5555FF'><</font>string<font color='#5555FF'>></font> |
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<font color='#0000FF'>#include</font> <font color='#5555FF'><</font>map<font color='#5555FF'>></font> |
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<font color='#0000FF'>namespace</font> dlib |
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<b>{</b> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::string<font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3() routine to compute the actual hash. |
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- This routine will always give the same hash value when presented |
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with the same input string. |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::wstring<font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3() routine to compute the actual hash. |
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- Note that if the memory layout of the elements in item change between |
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hardware platforms then hash() will give different outputs. If you want |
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hash() to always give the same output for the same input then you must |
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ensure that elements of item always have the same layout in memory. |
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Typically this means using fixed width types and performing byte swapping |
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to account for endianness before passing item to hash(). |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>template</font> <font color='#5555FF'><</font><font color='#0000FF'>typename</font> T, <font color='#0000FF'>typename</font> alloc<font color='#5555FF'>></font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::vector<font color='#5555FF'><</font>T,alloc<font color='#5555FF'>></font><font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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requires |
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- T is a standard layout type (e.g. a POD type like int, float, |
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or a simple struct). |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3() routine to compute the actual hash. |
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- Note that if the memory layout of the elements in item change between |
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hardware platforms then hash() will give different outputs. If you want |
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hash() to always give the same output for the same input then you must |
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ensure that elements of item always have the same layout in memory. |
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Typically this means using fixed width types and performing byte swapping |
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to account for endianness before passing item to hash(). |
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!*/</font> |
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|
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>template</font> <font color='#5555FF'><</font><font color='#0000FF'>typename</font> T, <font color='#0000FF'>typename</font> U, <font color='#0000FF'>typename</font> alloc<font color='#5555FF'>></font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::vector<font color='#5555FF'><</font>std::pair<font color='#5555FF'><</font>T,U<font color='#5555FF'>></font>,alloc<font color='#5555FF'>></font><font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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requires |
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- T and U are standard layout types (e.g. POD types like int, float, |
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or simple structs). |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3() routine to compute the actual hash. |
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- Note that if the memory layout of the elements in item change between |
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hardware platforms then hash() will give different outputs. If you want |
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hash() to always give the same output for the same input then you must |
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ensure that elements of item always have the same layout in memory. |
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Typically this means using fixed width types and performing byte swapping |
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to account for endianness before passing item to hash(). |
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!*/</font> |
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|
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>template</font> <font color='#5555FF'><</font><font color='#0000FF'>typename</font> T, <font color='#0000FF'>typename</font> U, <font color='#0000FF'>typename</font> comp, <font color='#0000FF'>typename</font> alloc<font color='#5555FF'>></font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::map<font color='#5555FF'><</font>T,U,comp,alloc<font color='#5555FF'>></font><font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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requires |
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- T and U are standard layout types (e.g. POD types like int, float, |
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or simple structs). |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3() routine to compute the actual hash. |
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- Note that if the memory layout of the elements in item change between |
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hardware platforms then hash() will give different outputs. If you want |
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hash() to always give the same output for the same input then you must |
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ensure that elements of item always have the same layout in memory. |
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Typically this means using fixed width types and performing byte swapping |
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to account for endianness before passing item to hash(). However, since |
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you can't modify the keys in a map you may have to copy it into a |
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std::vector and then work from there. |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>inline</font> uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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uint32 item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3_2() routine to compute the actual hash. |
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- This routine will always give the same hash value when presented |
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with the same input. |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>inline</font> uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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uint64 item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- uses the murmur_hash3_128bit_3() routine to compute the actual hash. |
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- This routine will always give the same hash value when presented |
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with the same input. |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<font color='#0000FF'>template</font> <font color='#5555FF'><</font><font color='#0000FF'>typename</font> T, <font color='#0000FF'>typename</font> U<font color='#5555FF'>></font> |
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uint32 <b><a name='hash'></a>hash</b> <font face='Lucida Console'>(</font> |
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<font color='#0000FF'>const</font> std::pair<font color='#5555FF'><</font>T,U<font color='#5555FF'>></font><font color='#5555FF'>&</font> item, |
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uint32 seed <font color='#5555FF'>=</font> <font color='#979000'>0</font> |
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<font face='Lucida Console'>)</font>; |
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<font color='#009900'>/*! |
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requires |
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- hash() is defined for objects of type T and U |
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ensures |
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- returns a 32bit hash of the data stored in item. |
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- Each value of seed results in a different hash function being used. |
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(e.g. hash(item,0) should generally not be equal to hash(item,1)) |
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- if (calling hash() on items of type T and U is always guaranteed to give the |
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same hash values when presented with the same input) then |
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- This routine will always give the same hash value when presented |
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with the same input. |
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!*/</font> |
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<font color='#009900'>// ---------------------------------------------------------------------------------------- |
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</font> |
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<b>}</b> |
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<font color='#0000FF'>#endif</font> <font color='#009900'>// DLIB_HAsH_ABSTRACT_Hh_ |
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</font> |
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</pre></body></html> |
