= Duplicate code analysis =

In large program systems often occure duplicate codes, which is a computer 
programming term for a sequence of source code that occurs more than once. There 
are two ways in which two code sequences can be duplicates of each other: 
syntactically and functionally. This new feature can detect the syntactically 
similar duplicates, that only differ in atoms, constants (integer, float and 
string) and the name of variables. A lot of identical or very similar code 
fragments can result the application of copy and paste, for example.

== Parameters ==

Parameters can be defined by a proplist. The possible properties are summed up 
in the table below. All the properties are optional.

||=Property=||=Description=||=Type=||=Default value=||=Example=||
||files||specify files to search||[Module::atom() [[BR]] |Filepath::string() [[BR]] |RegExp::string() [[BR]] |File::string()]||all files from the database||{files,["/usr/local/lib/erlang/lib/mnesia-4.5/src/mnesia_log.erl", module]}||
||minlen||minimal length of a clone(length is in tokens)||integer()||10||{minlen,50}||
||minnum||minimal number of clones in one clone group||integer()||2||{minnum,5}||
||overlap||maximum length that duplicates can overlap each other (length is in tokens)||integer()||0||{overlap,1}||
||output||name of the file in which the results are saved||string()||-||{output,"result.txt"}||
||name||name of the result in the table||atom()||the atom 'temp' concatenated with the timestamp||{name,referl}||

== Interfaces ==

=== Web interface ===
See [wiki:WebInterface/CodeDuplicates Duplicate code analysis] on the web interface.

=== Console interface ===

==== Analyser functions ====

* search_duplicates/0: uses the default values of the properties.
* search_duplicates/1: takes a proplist as parameter described above.

Both interface function provide information about the progress of the process. 
The result is the list of clone groups. Every clones are defined by the path of 
the file and information about the start and end positions (line and column number).
Results are saved. An example can be found at the bottom of the page.

==== Result query functions ====

||=Function=||=Parameters=||=Description=||=Example=||
||stored_dupcode_results/0||-||queries all saved results (name and information about the parameters of the analysis)||{{{ri:stored_dupcode_results()}}}||
||save_dupcode_result/2||Name::atom() - name associated with the result,[[BR]]Filename::string() - name of the file||saves the given result in the file||{{{ri:save_dupcode_result(temp20120527205412,"result.txt")}}}||
||show_dupcode/1||Name::atom() - name associated with the result||lists the result's all clone groupes||{{{ri:show_dupcode(temp20120527205412)}}}||
||show_dupcode_group/2||Name::atom() - name associated with the result,[[BR]]GroupNumber::integer() - the required clone group's number||lists the given clone group of the result||{{{ri:show_dupcode_group(temp20120527205412, 2)}}}||

== Examples ==

=== Analysis functions ===

Allowed parameterizations:

{{{#!erlang
ri:search_duplicates().
}}}

{{{#!erlang
ri:search_duplicates([
	{files, [dup2,
                 "/home/user/dups/dup1.erl",
	         "/home/[0-9a-zA-Z/_.\-]+/src"]},
	{minlen, 50},
	{minnum, 3},
	{overlap, 1},
	{output, "result.txt"},
	{name, filtered}]).
}}}

Return value and the progress report (only if the analysis was not run yet):

{{{#!erlang
(refactorerl@localhost)3> ri:search_duplicates([{files,[dup1,dup2]}]).

Initial clone detection started.
Initial clone detection finished.
Trimming clones started.
Trimming clones finished.
Filter clones finished.
Calculating positions started.
Calculating positions finished.
2 clone groups found.
Result saved to temp20120527234307...
run ri:show_dupcode(temp20120527234307) to see the result.
ok

(refactorerl@localhost)4> ri:search_duplicates([{files,[dup1,dup2]}]).
2 clone groups found.
Result saved to temp20120527234307...
run ri:show_dupcode(temp20120527234307) to see the result.
ok
}}}

=== Result query functions ===

{{{#!erlang
(refactorerl@localhost)5> ri:stored_dupcode_results().
[[temp20120527234307,
  [{files,["/home/user/dups/dup1.erl",
           "/home/user/dups/dup2.erl"]},
   {minlen,10},
   {minnum,2},
   {overlap,0}]],
 [temp20120527235556,
  [{files,["/usr/local/lib/erlang/lib/mnesia-4.5/src/mnesia_schema.erl"]},
   {minlen,20},
   {minnum,3},
   {overlap,0}]]]
}}}

{{{#!erlang
(refactorerl@localhost)17> ri:show_dupcode(temp20120527234307).        
[{1,
  [[{filepath,"/home/user/dups/dup1.erl"},
    {startpos,{8,1}},
    {endpos,{18,11}}],
   [{filepath,"/home/user/dups/dup2.erl"},
    {startpos,{5,1}},
    {endpos,{15,11}}]]},
 {2,
  [[{filepath,"/home/user/dups/dup1.erl"},
    {startpos,{6,5}},
    {endpos,{6,62}}],
   [{filepath,"/home/user/dups/dup2.erl"},
    {startpos,{18,5}},
    {endpos,{18,58}}]]}]
Contains 2 clone groups...
run ri:show_dupcode_group(temp20120527234307, GroupNumber::integer()) to see one of the clone groups.
ok
}}}

{{{#!erlang
(refactorerl@localhost)16> ri:show_dupcode_group(temp20120527234307,2).
[[{filepath,"/home/user/dups/dup1.erl"},
  {startpos,{6,5}},
  {endpos,{6,62}}],
 [{filepath,"/home/user/dups/dup2.erl"},
  {startpos,{18,5}},
  {endpos,{18,58}}]]
Contains 2 members.
ok
}}}