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

void setBit(char *bits, int n)
{
    bits[n/8] |= (1 << n%8);
}

int testBit(char *bits, int n)
{
    return bits[n/8] & (1 << n%8);
}

int isEscapedChar(char char1, char char2){
    if( char1=='\n'){
        return 10;
    }
    if( char1=='\a'){
        return 7;
    }
    if( char1=='\b'){
        return 8;
    }
    if( char1=='\e'){
        return 27;
    }
    if( char1=='\f'){
        return 12;
    }
    if( char1=='\r'){
        return 13;
    }
    else if( char1=='\t'){
        return 9;
    }
    if( char1=='\v'){
        return 1;
    }
    else if( char1=='\\' && char2=='-'){
        return 45;
    }
    else if ( char1=='\\'){
        return 92;
    }
    else return ;
    //if(character==92 || character==7 || character==8 || character==27 || character==12 || character==10 || character==13 || character==13
    // || character==9 || character==11)
}

char *classify(char *spec)
{
    char *class= malloc(32);	// 256 bits indicating if character N (bit position N) is in the class or not
    int index=0;
    while (spec[index] != '\0' ) {  //*spec
	// go through spec converting each entry in the spec into a set of bits in the class
	// test if the next thing is \ .
	// or test if you have X-Y (where X or Y might be a character or escaped character)
	//    \n-\r
       if (spec[index]=='-' && index!=0 && !(index==1 && spec[0]=='^') && spec[index+1]!='\0'){

            if(spec[index-1]<65 || spec[index+1]>122 || (spec[index-1]>90 && spec[index-1]<97) || (spec[index+1]>90 && spec[index+1]<97)){
                //= if(spec[index-1] or spec[index+1] are not letters)

                if((spec[index-1]>47 && spec[index-1]<57) || (spec[index+1]>47 && spec[index+1]<57) ){ //if it's a digit range
                    if(spec[index-1]>spec[index+1]){
                        printf("Error, first digit greater than the second one\n");
                    }
                    else{
                        for(int j=spec[index-1]; j<=spec[index+1] ; j++){
                            setBit(class,j);
                            printf("added digit : %c\n",j);
                            
                        }
                        index++;
                    }   
                }
                else{
                    printf("Error, bad use of range");
                    exit(1);
                }
            }
            else{
                if(spec[index-1]>spec[index+1]){
                printf("Error, first char greater than the second one\n");
                exit(1);
                }
                else if(spec[index-1]>=65 && spec[index-1]<=90 && spec[index+1]>=65 && spec[index+1]<=90 ){
                    for(int j=spec[index-1]; j<=spec[index+1] ; j++){
                            setBit(class,j);
                            printf("added char : %c\n",j);
                    }
                    index++;
                }
                else if( spec[index-1]>=97 && spec[index-1]<=122 && spec[index+1]>=97 && spec[index+1]<=122 ){
                    for(int j=spec[index-1]; j<=spec[index+1] ; j++){
                            setBit(class,j);
                            printf("added char : %c\n",j);
                            
                    }
                    index++;
                }
                else{
                    printf("Bad use of char range");
                    exit(1);
                }
            }

       }
       else if((spec[index]>=65 && spec[index]<=90) || (spec[index]>=97 && spec[index]<=122)){
           setBit(class,spec[index]);
           printf("added char : %c\n",spec[index]);
       }
       else if(isEscapedChar(spec[index],spec[index+1])!=0){
           if(isEscapedChar(spec[index],spec[index+1])==45){
               index++;
           }
           setBit(class,isEscapedChar(spec[index],spec[index+1]));
       }
        printf("%c\n",spec[index]);
        printf("%i\n",index);
        index++;
    }

    if (spec[0]=="^") {
	for (int i= 0;  i < 8;  ++i) class[i] ^= 255;   // invert all bits in the class
    }

    return class;
}

int main()
{
    char   *line=0;
    size_t  line_max=0;
    ssize_t line_len=0;
    char a='a';
    printf("%i\n",(int)a);
    printf("%s",classify("fgmfa\\-c"));
    while ((line_len= getline(&line,&line_max,stdin)) >= 0) {
        if (line_len>0 && line[line_len-1]=='\n') {
            line[line_len-1]=0;
        }
	char *class= classify(line);
	for (int i= 0;  i < 256;  ++i)
	    if (testBit(class, i))
		printf("%02x is set\n", i);
    }

    return 0;
}