Hex to Base64 in C

gistfile1.c

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

int convert_int_to_base_64(int arg)
{
	char result;
	switch(arg)
	{
		case 0: result = 'A'; break;
		case 1: result = 'B'; break;
		case 2: result = 'C'; break;
		case 3: result = 'D'; break;
		case 4: result = 'E'; break;
		case 5: result = 'F'; break;
		case 6: result = 'G'; break;
		case 7: result = 'H'; break;
		case 8: result = 'I'; break;
		case 9: result = 'J'; break;
		case 10: result = 'K'; break;
		case 11: result = 'L'; break;
		case 12: result = 'M'; break;
		case 13: result = 'N'; break;
		case 14: result = 'O'; break;
		case 15: result = 'P'; break;
		case 16: result = 'Q'; break;
		case 17: result = 'R'; break;
		case 18: result = 'S'; break;
		case 19: result = 'T'; break; 
		case 20: result = 'U'; break;
		case 21: result = 'V'; break; 
		case 22: result = 'W'; break; 
		case 23: result = 'X'; break; 
		case 24: result = 'Y'; break; 
		case 25: result = 'Z'; break; 
		case 26: result = 'a'; break;
		case 27: result = 'b'; break;
		case 28: result = 'c'; break;
		case 29: result = 'd'; break;
		case 30: result = 'e'; break;
		case 31: result = 'f'; break;
		case 32: result = 'g'; break;
		case 33: result = 'h'; break;
		case 34: result = 'i'; break;
		case 35: result = 'j'; break;
		case 36: result = 'k'; break;
		case 37: result = 'l'; break;
		case 38: result = 'm'; break;
		case 39: result = 'n'; break;
		case 40: result = 'o'; break;
		case 41: result = 'p'; break;
		case 42: result = 'q'; break;
		case 43: result = 'r'; break;
		case 44: result = 's'; break;
		case 45: result = 't'; break;
		case 46: result = 'u'; break;
		case 47: result = 'v'; break;
		case 48: result = 'w'; break;
		case 49: result = 'x'; break;
		case 50: result = 'y'; break;
		case 51: result = 'z'; break;
		case 52: result = '0'; break;
		case 53: result = '1'; break;
		case 54: result = '2'; break;
		case 55: result = '3'; break;
		case 56: result = '4'; break;
		case 57: result = '5'; break;
		case 58: result = '6'; break;
		case 59: result = '7'; break;
		case 60: result = '8'; break;
		case 61: result = '9'; break;
		case 62: result = '+'; break;
		case 63: result = '/'; break;
	}
	return result;
}

void convert_bin_to_int(char arg[])
{
	unsigned long arg_len = strlen(arg) - 1;
	int i;
	int j;
	double result = 0.00;
	for (i = 0; i <= arg_len; i++)
	{
		if (arg[i] == 49)
		{
			result += pow(2, (arg_len - (i)));
		}
	}
	printf("%c", convert_int_to_base_64(result));
}

void split_to_six_bits(char arg[])
{
	char six_bit[7];
	unsigned long arg_len = strlen(arg);
	int i = 0;
	int j = 0;
	for (i = 0; i <= arg_len; i++) {
		if (j == 6)
		{
			convert_bin_to_int(six_bit);
			j = 0;
		}
		six_bit[j] = arg[i];
		j++;
	}
}

char* convert_to_binary(char arg)
{
	char* result;
	switch(arg)
	{
		case '0': result = "0000"; break;
		case '1': result = "0001"; break;
		case '2': result = "0010"; break;
		case '3': result = "0011"; break;
		case '4': result = "0100"; break;
		case '5': result = "0101"; break;
		case '6': result = "0110"; break;
		case '7': result = "0111"; break;
		case '8': result = "1000"; break;
		case '9': result = "1001"; break;
		case 'A': result = "1010"; break;
		case 'B': result = "1011"; break;
		case 'C': result = "1100"; break;
		case 'D': result = "1101"; break;
		case 'E': result = "1110"; break;
		case 'F': result = "1111"; break;
		case 'a': result = "1010"; break;
		case 'b': result = "1011"; break;
		case 'c': result = "1100"; break;
		case 'd': result = "1101"; break;
		case 'e': result = "1110"; break;
		case 'f': result = "1111"; break;
	}
	return result;
}

void convert_hex(char arg[])
{
	int i = 0;
	char result[512];
	for (i = 0; i < strlen(arg); i++)
	{
		if (i == 0)
		{
			strcpy(result, convert_to_binary(arg[i]));
		}
		else 
		{
			strcat(result, convert_to_binary(arg[i]));
		}
	}
	split_to_six_bits(result);
}

int main(int argc, char *argv[]) 
{
	convert_hex(argv[1]);
	return 0;
}