Simple bit manipulation

bin.c

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

int main (int argc, char **argv) {
	unsigned char byte;
	unsigned char i;

	FILE *fi = stdin;
	FILE *fo = stdout;
	if (fi==NULL || fo==NULL) return 1;

	while ( fread(&byte, 1, 1, fi) ) {
	  for (i=0; i<8; i++) {
		  fputc( (byte>>7)==1?'1':'0', fo );
		  byte <<= 1;
	  }
	  fputc(' ', fo );
	}
	fputc('\n', fo);
	fclose(fo);
	fclose(fi);
	return 0;
}

bit_manipulation.md

C bit manipulation

Contenu

bin.c

Displays the contents of stdin as bits (a sequence of 0 and 1) on stdout

unbin.c

Does the contrary of bin.c. Decodes a sequence of 0 and 1 to actual binary data.

gray.c

Encodes stdin using grey code.

ungray.c

Decodes gray code.

Licence

Copyright (C) 2012 Ophir LOJKINE

All you want to do... Do it!

gray.c

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

int main (int argc, char **argv) {
	unsigned char b;

	FILE *fi = stdin;
	FILE *fo = stdout;
	if (fi==NULL || fo==NULL) return 1;

	while (fread(&b, 1, 1, fi)) {
		b = (b)^(b>>1);
		fwrite(&b, 1, 1, fo);
	}
	fclose(fi);fclose(fo);
	return 0;
}

unbin.c

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

int main (int argc, char **argv) {
	unsigned char b=0;
	unsigned char byte=0;
	unsigned char offset=0;

	FILE *fi = stdin;
	FILE *fo = stdout;
	if (fi==NULL || fo==NULL) return 1;

	while (fread(&b, 1, 1, fi)) {
		if (b=='1' || b=='0') {
			offset ++;
			byte <<= 1;
			if (b=='1') byte |= 1;
			if (offset == 8) {
				offset = 0;
				fwrite(&byte, 1, 1, fo);
			}
		}
	}
	fclose(fi);fclose(fo);
	return 0;
}

ungray.c

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

int main (int argc, char **argv) {
	unsigned char b;

	FILE *fi = stdin;
	FILE *fo = stdout;
	if (fi==NULL || fo==NULL) return 1;

	while (fread(&b, 1, 1, fi)) {
		b ^= (b>>1) ^ (b>>2) ^ (b>>3) ^ (b>>4) ^ (b>>5) ^ (b>>6) ^ (b>>7);
		fwrite(&b, 1, 1, fo);
	}
	fclose(fi);fclose(fo);
	return 0;
}