supaplex level compression

#include <stdio.h>
#include <stdlib.h>

int bitcounter = 0, bytecounter = 0;
char compressed[2000];      //aka stack

int max(int a, int b) {
    return (a > b) ? a : b;
}

void findnext(char c, FILE *ifp) {
    int i;
    do {
    i = getc(ifp);
    } while ( i != EOF && i != c);
}

int chartohex(char c) {
    c = (c >= 'a' && c <= 'f') ? c - 32 : c;        //converteert naar hoofdletters
    if (c >= '0' && c <= '9')
        return c - '0';
    if (c >= 'A' && c <= 'F')
        return c - 'A' + 10;
    return 0;
}

void error(char str[]) {
    printf("\n%s\npress any key to quit\n",str);
    getchar();
    exit(1);
}

int *findstr(int *array, int start) {
    //printf("atempting to find string at #%d\n",start);
    int i;
    static int value[2];
    for(int lengt = 32+4; lengt > 4; lengt--) {
        //printf("lengt:%d\n",lengt);
        for(int backtrack = -1; backtrack >= max(-255,-start) ; backtrack--){
            //printf("\rcurrent lengt: %d\tcurrent backtrack: %d\t\n",lengt, backtrack);
            value[0] = backtrack;
            value[1] = lengt;
            for(i = 0;(i < lengt) &&(array[start+i] == array[start+backtrack+i]); i++);
            if ((i)>=lengt) {
            return value;
            }
        }
    }
    return NULL;
}

void pushbit(int i) {
    compressed[bytecounter] = compressed[bytecounter] << 1;
    if (i != 0)
        compressed[bytecounter]++;
    bitcounter++;
    if (bitcounter != 4)
        return;
    bitcounter = 0;
    bytecounter++;
}

void pushbyte(int byte, int bits) {
    //printf(".%x%d",byte,bits);
    for(; bits > 0; bits--)
        pushbit((1 << (bits - 1)) & byte);
}

char int2char(int i) {
    return i + '0' + (('A'-'9'-1) * (i > 9));
}

int main(int argc, char *argv[]) {

    for(int i = 0; i < 2000; i++)   //leeg compressed array
        compressed[i] = 0;

    if (argc < 2)
        error("too few args");

    printf("atempting to compress: %s....\n",argv[1]);

    FILE *ifp = fopen(argv[1], "r");
    if (ifp == NULL)
        error("unable to open file");



    int hex, hex2, c;
    int tilemap[58*22];
    int pointer = 0;
    int tilemap_x = 0, tilemap_y = 0;
    while (c != EOF) {          //load tilemap loop
        c = getc(ifp);
        if (';' == c)           //comment?
            findnext('\n',ifp); //zoek eerstvolgende nieuwe regel
        if ('.' == c) { //&& 'd' == getc(ifp) && ('b' == getc(ifp)))    {       //.db??
            while (c != '\n' && c != ';' && c != EOF) {                 //zolang GEEN nieuwe regel of comment..
                c = getc(ifp);
                if (c == '$') {
                    tilemap[pointer] = (chartohex(getc(ifp)) << 4) + (chartohex(getc(ifp)));        //haal eerste hex-char op
                    //printf("%d\t%d\n", pointer, tilemap[pointer]);
                    pointer++;
                    if (pointer > 22*58)
                        error("target is not a valid 58*22 tilemap: tilemap is too large");

                }
            }
        }
    }
    if (pointer < 22*58)
        error("no vailid 58*22 tilemap found");

    pointer = 0;
    printf("valid tilemap found, starting LZ77 compression...\n");
    while (pointer < 22*58) {
        int *value = findstr(&tilemap[0], pointer);
        //printf("pointer: %d\n",pointer);
        if (value != 0) {   //als er een geldige string is gevonden, push 3 bytes op de stack

            //printf("pushing values on stack\n");
            pushbyte(7,3);
            pushbyte(-(value[0]),8);
            pushbyte(value[1]-5,5);
            //printf("backtrack: %d (%d)\tlengt:%d (%d)\n", value[0], -(value[0]), value[1], value[1]-5);
            pointer += value[1];    //update pointer naar array
        }
        else {          //zoniet, bepaal de byte, en push die op de stack
            int tile = tilemap[pointer];
            //printf("no string was found\ncurrent tile is: %d\n",tile);
            if (tile <=5)   //als tile in 3 bits past
                pushbyte(tile, 3);
            else {
                pushbyte(6, 3);
                tile = (tile >= 21) ? (tile - 1) : tile;
                tile = (tile >= 19) ? (tile - 1) : tile;
                tile -= 6;  //conversie naar tiles die daadwerkelijk worden gebruikt...
                pushbyte(tile, 4);
            }
        pointer++;
        }
    }
    printf("compression finished, compressed data is %d bytes (%d, %d)\n",(bytecounter + 2 - (bitcounter == 0)) / 2, bytecounter, bitcounter);

    char *path = argv[1];
    char filename[255];
    int ptr, i;
    for(ptr = 0; path[ptr] != '\0'; ptr++); //zoek ende van pad
    for(; path[ptr] != '\\'; ptr--);    //zoek laatste \ in pad
    ptr++;
    for(i = 0; path[ptr + i - 1] != '\0'; filename[i] = path[ptr + i++]) {}         //kopieer filename
    ptr -= 2;
    for(; path[ptr] != '\\'; ptr--);    //zoek een-na laatste in pad
    ptr++;
    for(i = 0; path[ptr + i -1] != '\0'; path[ptr + i] = "compressed\\"[i++]) {}    //wijzig pad naar \compressed\.
    ptr += i -1;
    for(i = 0; path[ptr+i-1] != '\0'; path[ptr + i] = filename[i++]);       //plak filename
    printf("now outputting to file %s\n",path);
    FILE *ofp = fopen(path,"w");
    if (ofp == NULL)
        error("unable to open file");

    int counter = 0;
    int chars = (bytecounter + 2 - (bitcounter == 0)) / 2;
    while (counter < chars) {
        fprintf(ofp,".db ");
        for( int i = counter; i + 10 > counter; counter++) {
            if (counter < chars)
                fprintf(ofp, "$%c%c,", int2char(compressed[2*counter]), int2char(compressed[2*counter+1]));
        }
        fprintf(ofp, "\n");
    }
    printf("sucess!\n");
    getchar();
}