A C header file for reading and writing sub-byte sized data.
Very often, C programs require an ability to read and write data which aren't byte aligned or which take up less than a single byte. This is particularly common in video/image codecs and network protocols. Nibble is a small, self-contained library which simplifies the process of manipulating such data. It works by defining a number of struct types with bit-fields of various sizes. For instance u1, u2 and u3 take up one, two and three bits respecitvely.
Constructing sub-byte arrays is dead simple. Just declare the array as having type uX where X is an integer from 1-16.
#include "nibble.h"
// Create an array of unsigned 2-bit integers.
u2 array[4] = {
0b00,
0b01,
0b00,
0b11,
};
// Read the third value.
printf("%d\n", array[2].value);If binary literals are not supported use decimal or hexadecimal notation instead.
You can also easily read sub-byte values from an existing array via in-line casting.
#include "nibble.h"
char array[4] = "cool";
print("%d\n", (u2 *)