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Add some links to the hash documentation, acknowledgements for the review,

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fixed some errors.


[SVN r28427]
This commit is contained in:
Daniel James
2005-04-22 22:08:49 +00:00
parent 90b21239b4
commit a461b5b1c7
1 changed files with 38 additions and 6 deletions
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44
hash/doc/hash.qbk
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@@ -1,7 +1,7 @@
[library Boost.Functional/Hash
[authors [James, Daniel]]
[copyright 2005 Daniel James]
[purpose Extendible hash function object]
[purpose Extendible TR1 hash function object]
[category higher-order]
[id hash]
[dirname hash]
@@ -66,7 +66,7 @@ __issues__, this adds support for:
When using a hash index with __multi-index-short__, you don't need to do
anything to use __boost_hash as it uses it by default.
To find out how to use a user-defined type, read the
[link hash.custom section on extending boost::hash].
[link hash.custom section on extending boost::hash for a custom data type].
If your standard library supplies its own implementation of the unordered
associative containers and you wish to use
@@ -182,6 +182,7 @@ The full example can be found in:
[@../../libs/functional/hash/examples/books.cpp /libs/functional/hash/examples/books.hpp]
and
[@../../libs/functional/hash/examples/books.cpp /libs/functional/hash/examples/books.cpp].
[blurb
When writing a hash function, first look at how the equality function works.
Objects that are equal must generate the same hash value.
@@ -245,14 +246,14 @@ When using __hash_combine the order of the
calls matters.
<programlisting>
std::size_t seed = 0;
__hash_combine(seed, 1);
__hash_combine(seed, 2);
boost::hash_combine(seed, 1);
boost::hash_combine(seed, 2);
</programlisting>
results in a different seed to:
<programlisting>
std::size_t seed = 0;
__hash_combine(seed, 2);
__hash_combine(seed, 1);
boost::hash_combine(seed, 2);
boost::hash_combine(seed, 1);
</programlisting>
If you are calculating a hash value for data where the order of the data
doesn't matter in comparisons (e.g. a set) you will have to ensure that the
@@ -887,11 +888,42 @@ return seed;
[/ Remove this comment and everything goes wrong! ;) ]
[endsect]
[section:links Links]
[*A Proposal to Add Hash Tables to the Standard Library]\n
[@http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1456.html]\n
The hash table proposal explains much of the design. The hash function object
is discussed in Section D.
[*The C++ Standard Library Technical Report.]\n
[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1745.pdf]\n
Contains the hash function specification in section 6.3.2.
[*Library Extension Technical Report Issues List.]\n
[@http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf]\n
The library implements the extension described in Issue 6.18.
[*Methods for Identifying Versioned and Plagiarised Documents]\n
Timothy C. Hoad, Justin Zobel\n
[@http://www.cs.rmit.edu.au/~jz/fulltext/jasist-tch.pdf]\n
Contains the hash function that __hash_combine is based on.
[endsect]
[section:acknowledgements Acknowledgements]
This library is based on the design by Peter Dimov. During the inital development
Joaquín M López Muñoz made many useful suggestions and contributed fixes.
The review was managed by Thorsten Ottosen, and the library reviewed by:
David Abrahams, Alberto Barbati, Topher Cooper, Caleb Epstein, Dave Harris,
Chris Jefferson, Bronek Kozicki, John Maddock, Tobias Swinger,Jaap Suter
and Rob Stewart.
The implementation of the hash function for pointers is based on suggestions
made by Alberto Barbati and Dave Harris. Dave Harris also suggested an
important improvement to __hash_combine that was taken up.
The original implementation came from Jeremy B. Maitin-Shepard's hash table
library, although this is a complete rewrite.