[jira] [Updated] (THRIFT-2062) cpp flag for using unordered_set instead of set

["Konrad Grochowski (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/THRIFT-2062?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Konrad Grochowski updated THRIFT-2062:
--------------------------------------
    Fix Version/s:     (was: 0.9.2)
                   1.0

> cpp flag for using unordered_set instead of set
> -----------------------------------------------
>
>                 Key: THRIFT-2062
>                 URL: https://issues.apache.org/jira/browse/THRIFT-2062
>             Project: Thrift
>          Issue Type: Improvement
>          Components: C++ - Compiler
>            Reporter: Vitali Lovich
>            Assignee: Randy Abernethy
>             Fix For: 1.0
>
>
> It would be nice if the cpp compiler could generate code to use unordered_set instead of set.  unordered_set is faster & usually an unordered_set is wanted rather than an ordered one.  Furthermore, since unordered_set only needs a hash function, we could generate one for every type.
> The hash code generated can be along the lines of what Eclipse does for auto-generated hash codes:
> struct ThriftObj {
>    1: string f1;
>    2: i32 f2;
>    3: SomeOtherThriftObj f3;
> }
> // header file:
> namespace std {
>     template <> struct hash<ThriftObj> {
>         size_t operator()(const ThriftObj& o);
>     }
> }
> // cpp file:
> namespace std {
>     template <> struct hash<ThriftObj> {
>         size_t operator()(const ThriftObj& o)
>             constexpr size_t prime = 31;
>             size_t hashcode = 1;
>             hashcode += o.__isset.f1 ? prime * std::hash<decltype(o.f1)>()(o.f1) : 0;
>             hashcode += o.__isset.f2 ? prime * std::hash<decltype(o.f1)>()(o.f2) : 0;
>             hashcode += o.__isset.f3 ? prime * std::hash<decltype(o.f1)>()(o.f3) : 0;
>         }
>     }
> }



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)