1. Finding File Clones in FreeBSD Ports Collection
Yusuke Sasaki
Tetsuo Yamamoto
Yasuhiro Hayase
Katsuro Inoue

2. File Clones Research about file-clones is scarce
Two or more files with the same content
Comments and code indentation ignored
Inside a project or between different projects
Research about file-clones is scarce
Get new knowledge about file-clones
Project A
Project B
int main() {
printf(“Hello msr!”);
return 0; }

3. FCFinder Input Output Faster than other tools Detection
.c and .h files
Output
File-clone sets
Faster than other tools
Detection
Tokenization
MD5 Hash Calculation
Exact Matching
Tool
Speed
CCFinder
1.4M files / 960 hours x1
1PC
D-CCFinder
1.4M files / 51 hours
x19
80PCs
FCFinder
1.4M files / hours
x55

4. These values follow the power law
Experiment
Target
Only .c and .h files in the FreeBSD Ports Collection
~1.4M files
~12 GB
17.16 hours
We measured:
File size
Number of files in each project
Size of each file-clone set
Number of file-clones in a project
These values follow the power law

5. File-clone Set Size file clone set size 5 10 50 100 Left：used in PHP5
Right：used in PHP4
used in both of PHP4 and 5 D E
L:650 sets
R:500 sets
419 sets
120 file clones 5 10 50
100
L:61 file clones
R:59 file clones
file clone set size
R*2 =

6. File-clones per Project
Right：PHP4 modules
Center：projects related bin-utils
Left：PHP5 modules G 5 10 50
100
500 1K K 10K
number of file clone sets
R*2 =

7. File-clones Between Projects (1/3)
* Nodes show the projects
* Edges between projects show the number of file clones
between two projects
Ex) gcc41 and gfortran shares 7691 file clones

8. File-clones Between Projects (2/3)
* Nodes show the projects
* Edges between projects show the number of file clones
between two projects

9. File-clones Between Projects (3/3)
* Nodes show the projects
* Edges between projects show the number of file clones
between two projects

10. Conclusions & Future Work
Measured several features of the FreeBSD Ports collection.
Found that the measured features follow the power law
Future Work
Projects logical coupling investigation