shift.c

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

const char* byte_to_binary(int x)
{
    static char b[9];
    b[0] = '\0';

    int z;
    for (z = 128; z > 0; z >>= 1)
    {
        strcat(b, ((x & z) == z) ? "1" : "0");
    }

    return b;
}

char* set_bits(char* bitmap, int index, char* msg)
{
     char x = msg[index];
     printf("Value: %s\n", byte_to_binary(x));
     char y = x >> 5;
     printf("Left Shift: %s\n", byte_to_binary(y)); // 3 → 00000011
     printf("R:          %s\n", byte_to_binary(bitmap[0]));
     bitmap[0] |= y;
     printf("Bitwise or: %s\n", byte_to_binary(bitmap[0]));
     y = x << 3;
     y >>= 5;
     if(y == 0)
     {
         printf("Next Left Shift: %s\n", byte_to_binary(y));
         printf("G:               %s\n", byte_to_binary(bitmap[1]));
         bitmap[1] >>= 3;
         bitmap[1] <<= 3;
         printf("Replacement:     %s\n", byte_to_binary(bitmap[1]));
     }

     unsigned char mask = 0;
     y = x << 6;
     y >>= 5;
     y |= mask;
     index++;
     printf("Mask:    %s\n", byte_to_binary(y));
     x = msg[index];
     char z = x >> 7;
     printf("Submask: %s\n", byte_to_binary(z));
     y |= z;
     printf("Value: %s\n", byte_to_binary(x));
     printf("Next shift:  %s\n", byte_to_binary(y));
     printf("B:           %s\n", byte_to_binary(bitmap[2]));
     bitmap[2] |= y;
     printf("Replacement: %s\n", byte_to_binary(bitmap[2]));
}

int main()
{
/*    unsigned char x = 97; // a 97 → 01100001*/
/*    printf("%c\n", x);*/
/*    unsigned char y = 1;*/
/*    unsigned int n = 2;*/
/*    x |= (1 << n);*/
/*    printf("%c\n", x);*/
/*    printf("%d\n", (int) sizeof(unsigned char));*/

    unsigned char *s;
    s = (unsigned char*) calloc(12, sizeof(unsigned char));
    s[0] = 154;
    s[1] = 179;
    s[2] = 216;
    s[3] = 179;
    s[4] = 27;
    s[5] = 86;
    s[6] = 63;
    s[7] = 1;
    s[8] = 67;
    s[9] = 227;
    s[10] = 31;
    s[11] = 88;
    for(int i = 0; i < 12; i++)
    {
        printf("Index: %d, Value: %d\n", i, s[i]);
    }

    char a[2];
    strcpy(a, "am");
    for(int i = 0; i < 2; i++)
    {
        printf("%d\n", a[i]);
    }

    int n_space = sizeof(a)*sizeof(char)*8 / 3;
    printf("Space: %d\n", n_space);

    set_bits(s, 0, a);

    for(int i = 0; i < 12; i++)
    {
        printf("Index: %d, Value: %d\n", i, s[i]);
    }

    return 0;
}