In the last hour or so I wrote this bdecode C-program (see the
specification of bencoding) since this python program doesn’t work and I hate wikis with logins (otherwise I’d posted it there).

#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
void tabber(int t){
while(t-->0) printf("\t");
}
int bdecode(char * data, int tab){
/*printf("data: %c%c%c%c%c\n", data[0],data[1],data[2],data[3],data[4]);*/
if (isdigit(data[0])){
int i=0;
int j=0;
while (isdigit(data[i])) {
i++;
}
data[i] = 0;
int len = atoi(data);
i++;
tabber(tab); printf("Bytestring (%d long): ", len);
for (;j<len;j++) {
printf("%c", data[j+i]);
}
printf("\n");
i+=len;
return i;
}else if(data[0] == 'i'){
int i=0;
int n=0;
int sign = 1;
i++;
if(data[1]=='-'){
sign = -1;
i++;
}
while (isdigit(data[i])){
n=n*10+data[i]-'0';
i++;
}
n*=sign;
tabber(tab); printf("Integer: %d\n", n);
i++;
return i;
}else if(data[0] == 'l'){
int i=0;
i++;
tabber(tab); printf("List: \n");
while(data[i] != 'e'){
i += bdecode(&data[i], tab+1);
/*printf("continuing at: %c%c%c%c%c\n", data[i+0],data[i+1],data[i+2],data[i+3],data[i+4]);*/
}
i++;
return i;
}else if(data[0] == 'd'){
int i = 0;
tabber(tab); printf("Dict: \n");
i++;
while(data[i] != 'e'){
i += bdecode(&data[i], tab+1);
/*printf("continuing at: %c%c%c%c%c\n", data[i+0],data[i+1],data[i+2],data[i+3],data[i+4]);*/
tabber(tab+1); printf(" => \n");
i += bdecode(&data[i], tab+2);
/*printf("continuing at: %c%c%c%c%c\n", data[i+0],data[i+1],data[i+2],data[i+3],data[i+4]);*/
printf("\n");
}
i++;
return i;
}
printf("Shouldn't be here\n");
return -1000;
}
int main(int argc, char ** argv){
if(argc>1)
bdecode(argv[1], 1);
else
printf("No arg, sucker!");
return 0;
}

Compile & execute (use the examples from the spec):

$ gcc bdecode2.c -o bdecode2.exe -Wall
$ ./bdecode2.exe d9:publisher3:bob18:publisher.location4:home17:publisher-webpage15:www.example.come
Dict:
Bytestring (9 long): publisher
=>
Bytestring (3 long): bob
Bytestring (18 long): publisher.location
=>
Bytestring (4 long): home
Bytestring (17 long): publisher-webpage
=>
Bytestring (15 long): www.example.com

Seriously, wikis with logins! Where even the discussion pages are locked.

Good old C… and don’t tell me about “Oh, you could save 2 lines there!” I got a compiler for that …

Of course it contains bugs! Good quality ones!

You can run your .torrent files against it:

$ ./bdecode2.exe "$(cat Apocalypto.torrent)" | less
Dict:
Bytestring (8 long): announce
=>
Bytestring (44 long): <a href="http://vip.tracker.thepiratebay.org/announce">http://vip.tracker.thepiratebay.org/announce</a>
Bytestring (13 long): announce-list
=>
List:
List:
Bytestring (44 long): <a href="http://vip.tracker.thepiratebay.org/announce">http://vip.tracker.thepiratebay.org/announce</a>
List:
Bytestring (44 long): <a href="http://tracker.torrentbox.com:2710/announce">http://tracker.torrentbox.com:2710/announce</a>.
List:
Bytestring (41 long): <a href="http://axxo.sladinki007.net:6500/announce">http://axxo.sladinki007.net:6500/announce</a>
List:
Bytestring (39 long): <a href="http://tracker.torrent.to:2710/announce">http://tracker.torrent.to:2710/announce</a>
Bytestring (13 long): creation date
=>
Integer: 1178231686
Bytestring (4 long): info
=>
Dict:
Bytestring (5 long): files
=>
List:
Dict:
Bytestring (6 long): length
=>
Integer: 943704064
Bytestring (4 long): path
=>
List:
Bytestring (45 long): Apocalypto[2006]DvDrip[Eng.Hard.Sub]-aXXo.avi
Dict:
Bytestring (6 long): length
=>
Integer: 623
Bytestring (4 long): path
=>
List:
Bytestring (52 long): IMPORTANT.Read carefully before enjoy this movie.txt
...

Reading metainfo about illegal movies is arguably allowed, I don’t download this. (Nor do I take anything away from anyone using violence, as piracy is defined.)