I've just written an interpreter for an obfuscated language of my own
design, which I call "tarfu." The language itself has no way of storing
information except within the code itself, meaning there are no variables.
Here's the source to the interpreter, I figured I'd post it here (because I
couldn't find a newsgroup devoted to obfuscated languages) and see if you
had any comments or questions.
comp.lang.misc is the usual place for posting random language
announcements. If you post to c.l.c you're going to get critiques
of your C coding style, which maybe is what you want.
Also, in either place you're going to get the admonishment not to try
attaching files to your message. If it's a binary, post to one of
the binaries groups. If it's a short text file, put it in the body
of your message. If it's large, put it online and give a link to it in
your message.
I've opened your attachment anyway, but some people may not see it at all.
So here it is, with my comments.
==begin file tarfu.c==
/* tarfu interpreter
* (c) 2003 by Harry Altman and G. Nick D'Andrea
* Provided under the terms of
* the GNU General Public License
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define RIGHT 1 /* Will we ever actually use these? */
#define LEFT -1
unsigned char *p;
size_t ip=0;
size_t sp=0;
size_t size;
int dir=1;
FILE *afile=NULL;
(My comment: You really should try to give global variables
expressive names. 'size' is NOT a good name to give to a global.
At least make them static, so they're not overly polluting
if you ever expand the program to more than one file.)
(snip)
int main(int argc, char **argv)
{
FILE *pfile;
(Oh dear, another 8-character tabber. Either that, or you didn't
detab your program before posting. That's ugly.)
int i;
if(argc==1)
{
puts("tarfu Interpreter.\n"
"Usage: tarfu [OPTIONS] FILE\n"
"Use \"tarfu -h\" for help");
exit(1);
(Non-standard return code.)
}
for(i=1;i<argc;i++)
{
if(!strcmp(argv
,"-h"))
As a style note, it might be more user-friendly to allow
"-H" to be a help screen, too.
{
puts("tarfu Interpreter.\n"
"Usage: tarfu [OPTIONS] FILE\n"
"FILE: Script file\n"
"OPTIONS:\n"
"-a\tInput file for the script");
exit(0);
}
else if(!strcmp(argv,"-a"))
{
if(!(afile=fopen(argv[++i],"r")))
What if i==argc-1? Then you're passing NULL to fopen.
That's not particularly good design, even if it is defined
to do something sensible (which I'm not going to bother looking
up).
{
fprintf(stderr, "File \"%s\" Not Found\n", argv);
exit(1);
}
}
else
{
if(!(pfile=fopen(argv,"r")))
{
fprintf(stderr, "File \"%s\" Not Found\n", argv);
exit(1);
}
}
}
if (afile==NULL) afile=stdin;
if(!(pfile))
{
fputs("Please specify an input file", stderr);
}
if(!(p=(char*)malloc((size=getsize(pfile))+1)))
Casting malloc is only required in C++, and never good style.
There's no reason to combine the assignments, either.
size = getsize(pfile);
p = malloc(size+1);
if (p == NULL) ...
See how much simpler that looks?
{
fputs("Not enough memory.\n",stderr);
exit(1);
}
/* Get the input */
slurp(pfile,p);
/* Do stuff with the input */
run();
Don't forget to
return 0;
at the end of main().
}
size_t getsize(FILE *f)
/* Precondition: FILE *f exists
* Postcondition: Returns the size of file *f
*/
{
size_t i=0;
while(getc(f)!=EOF)
i++;
rewind(f);
return i;
}
/* From Harry's Hexed Interpreter */
void slurp(FILE *infile, char *out)
/* Precondition: *infile exists, *out is the program text
* Postcondition: There is none, you fool!
*/
{
int c;
size_t i=0;
*out='\0';
while((c=fgetc(infile))!=EOF)
{
out[i++]=(char)c; out='\0';
}
}
(The non-I/O part of function can be speeded up by a factor of two.
void slurp(FILE *in, char *out)
{
int c;
while ((c = getc(in)) != EOF)
*out++ = (char) c;
*out = '\0';
return;
}
Why copy other people's code if it's so bad? Find code that
does what you want *quickly*.)
/* End code from Harry's Hexed Interpreter */
void run(void)
/* Precondition: Why don't you figure this out for yourself
* Postcondition: The script is executed
*/
{
while(1)
{
pre();
doStuff();
ip+=dir;
}
}
void pre(void)
/* Precondition: None
* Postcondition: Does the preprocessing for the iteration
*/
{
size_t i;
int dir2=(dir==RIGHT);
for(i=(dir2 ? 0 : size-1) ; i<size ; i+=dir) /* i is a size_t, and therefore unsigned */
{
if(p=='*')
{
if(i+dir==size || i+dir ==-1)
{
break; /*continue would also work here*/
}
if(p[i-dir]=='*')
{
continue;
}
(It is now obvious that you are not even trying to write clearly.
I'll make, say, two more comments and then stop reading.)
if('0' <= p[i+dir] && p[i+dir] <= '9')
{
p[i+dir]-='0';
if(!dir2) swap(p+i,p+i-1);
if(sp>= i+dir2) sp--;
if(ip>= i+dir2) ip--;
memmove(p+i-!dir2,p+i+dir2,size-i+!dir2); /*Nick is more confused.*/
(One.)
}
else if('a' <= p[i+dir] && p[i+dir] <= 'a'+30)
{
p[i+dir] -= ('a'-10);
if(!dir2) swap(p+i,p+i-1);
if(sp>= i+dir2) sp--;
if(ip>= i+dir2) ip--;
memmove(p+i-!dir2,p+i+dir2,size-i+!dir2); /*Nick is most confused.*/
(Two.)
-Arthur
