Make git-merge and helpers Builtins

Hi,
   I have used Git for one year, and I join into this list for 3 or 4 
monthes. Sometime, I post some questions here and followed some 
disscusions. I have noticed that, there is a potential project in this 
GSoC "make git-merge and helplers builtins". I think I am one of the 
suitable students for this project because I am familiar with shell 
script programming and c language. And I post this message here to hope 
I can discuss more with the community about this project. 
    I have git clone the Git's source code for some days. And with some 
insight into the code, I found that some of the merge related code is 
located in sh script:  git-merge-octopus.sh  git-merge-one-file.sh 
git-merge-resovle.sh git-merge.sh git-mergetool.sh . And others are 
located in c source code: builtin-merge-base.c builtin-merge-file.c 
builtin-merge-ours.c builtin-merge-recrusive.c and merge-file.c 
merge-tree.c merge-index.c merge-recursive.h for two simple declarations.
   And git-mergetool.sh is itself an interactive shell process, I think 
there is no need to deal with it. So, the main work for this project is 
to change the other four scripts into c format. For deatails, instead of 
call the git merge-base in the shell, we make the final corresponding c 
code to call the functions in the builtin-merge-base.c. Could you please 
tell more about the work if I miss something?
  
   Finally, I have some questions about the merge code. I found there 
are many merge related code and I can't understand them at a short time. 
So, pleaes help me if you can.

   1. git-merge-file is used to merge one file, but what are 
merge-octopus and merge-resovle?
   2. I see in builtin-merge-file.c and merge-file.c, there are both 
functions used to merge file. And finally, they both call the xdl_merge 
. Could you please tell me how differenct of these to methods? I ask 
this question because I think there are some redundant code in the git 
source. Forgive me if I am wrong, I have no hostility but want to know 
why things are like that.

Thank you!

Regards! Bo