converts a string representing a hex number into 8-bit RGB values

HexToRGB.cpp

#include <iostream>
#include <stdint.h>
#include <string.h>





// this solution is dependent on endianess, and is thus not cross-platform
struct RGB_t {
		union {
			struct {
				// NOTE: this program does not handle middle-endian and
				// may produce undefined behavior on such archatectures
				#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
					unsigned char b, g, r;
				#else // __ORDER_BIG_ENDIAN__
					unsigned char r, g, b;
				#endif // __ORDER_PDP_ENDIAN__
			};
			unsigned int val : 32;
			
		};
};


RGB_t hexToClr(const char* hex){
	RGB_t ret = { 0 };
	
	for (uint8_t i = 0; i < 6; i++) {
		ret.val <<= 4;
		switch (hex[i]){
		case '0': break; 
		case '1': ret.val += 1; break;
		case '2': ret.val += 2; break;
		case '3': ret.val += 3; break;
		case '4': ret.val += 4; break;
		case '5': ret.val += 5; break;
		case '6': ret.val += 6; break;
		case '7': ret.val += 7; break;
		case '8': ret.val += 8; break;
		case '9': ret.val += 9; break;
		case 'A': case 'a': 
			ret.val += 10; 
			break;
		case 'B': case 'b': 
			ret.val += 11; 
			break;
		case 'C': case 'c': 
			ret.val += 12; 
			break;
		case 'D': case 'd': 
			ret.val += 13; 
			break;
		case 'E': case 'e': 
			ret.val += 14; 
			break;
		case 'F': case 'f': 
			ret.val += 15; 
			break;
		default:
			std::cerr <<"FUCK YOU!\n";
			break;
		}	
	}
	return ret;
}

RGB_t hex3ToClr(const char* hex){
	RGB_t ret = {0};
	
	for (uint8_t i = 0; i < 3; i++) {
		for (uint8_t b = 0; b < 2; b++){
			ret.val <<= 4;
			switch (hex[i]){
			case '0': break; 
			case '1': ret.val += 1; break;
			case '2': ret.val += 2; break;
			case '3': ret.val += 3; break;
			case '4': ret.val += 4; break;
			case '5': ret.val += 5; break;
			case '6': ret.val += 6; break;
			case '7': ret.val += 7; break;
			case '8': ret.val += 8; break;
			case '9': ret.val += 9; break;
			case 'A': case 'a': 
				ret.val += 10; 
				break;
			case 'B': case 'b': 
				ret.val += 11; 
				break;
			case 'C': case 'c': 
				ret.val += 12; 
				break;
			case 'D': case 'd': 
				ret.val += 13; 
				break;
			case 'E': case 'e': 
				ret.val += 14; 
				break;
			case 'F': case 'f': 
				ret.val += 15; 
				break;
			default:
				std::cerr <<"FUCK YOU!\n";
				break;
			}
		}
	}
	return ret;
}


int main(){
	
	std::cout <<"enter a color: #";
	char hex[10];
	std::cin >>hex;
	
	RGB_t color = {0};
	
	if (strlen(hex) == 3)
		color = hex3ToClr(hex);
	else 
		color = hexToClr(hex);
	
	std::cout <<"\nred = " <<(int) color.r
			  <<"\ngreen = " <<(int) color.g
			  <<"\nblue = " <<(int) color.b <<'\n';
			  
	


}