BrainFuck Interpreter

/*
 * bfun.c ; BrainFuck UNleashed! (or BrainFuck fUN w/e)
 */


#include <stdio.h>
#include <string.h>

static char cell[3000];
static char *ptr = cell;
static FILE *input;

static char pBck, pAdv, cInc, cDec, tInp, tOut, jInz, jOiz;
static char flow = 0, numpad = 0, wysiwyg = 0;

void process(char c, FILE *f);

int main(int argc, char **argv)
{
    switch(argc)
    {
        int argn;
        char *split;
        case 1:
            printf("bfun -- a C interpreter for Brainfuck ver 1.0\n"
            "\n"
            "Usage:\n"
            "\tbfun filename [options]\n"
            "Options:\n"
            "\t-f \t Dump workflow to STDOUT\n"
            "\t-n \t Use alternative charset for language (numpad keys)\n"
            "\t-w \t WYSIWYG - I/O integers by real value (not ASCII)\n");
            return 0;
        default:

            for(argn=2;argn < argc;++argn)
            {
                if (strlen(argv[argn]) == 2)
                {
                    if((split = strstr(argv[argn], "-")) == NULL)
                        goto Fail;

                    switch(split[strlen(split) -1])
                    {
                        case 'f':
                            flow = 1;
                        break;
                        case 'n':
                            numpad = 1;
                        break;
                        case 'w':
                            wysiwyg = 1;
                        break;
                        default:
                            goto Fail;
                    }
                }
                else
                {
                    Fail:
                    printf("bfun: invalid option '%s'\n"
                    "Usage: bfun filename [-f] [-n] [-w]\n", argv[argn]);
                    return 0;
                }
            }
        case 2:
            input = fopen(argv[1], "r");
            if (!input) {
                fprintf(stderr, "Error: No such file %s\n", argv[1]);
                return 0;
            }
    }
            ptr = &cell[0];

            if (numpad)
                pBck = '4',pAdv = '6',cInc = '+',cDec = '-',tInp = '1',tOut = '2',jInz = '9',jOiz = '3';
            else
                pBck = '<',pAdv = '>',cInc = '+',cDec = '-',tInp = ',',tOut = '.',jInz = '[',jOiz = ']';

            while(!feof(input))
                process(getc(input), input);

            fclose(input);

    return 1;
}
void process(char cur, FILE * input)
{
    long pos;
    char loopcom;

            if (cur == pBck)
                --ptr;
            else if (cur == pAdv)
                ++ptr;
            else if (cur == cInc)
                ++*ptr;
            else if (cur == cDec)
                --*ptr;
            else if (cur == tInp)
                *ptr = getchar();
            else if (cur == tOut)
                putchar(*ptr);
            else if (cur == jInz)
            {
                pos = ftell(input);
                while (*ptr != 0)
                {
                    fseek (input, pos, SEEK_SET);
                    loopcom = getc(input);
                    while(loopcom != jOiz && loopcom != EOF)
                    {
                        process(loopcom, input);
                        loopcom = getc(input);
                    }

                }
            }
}