view libutil/gsm7_pack.c @ 44:0bc89d61fc59

top Makefile: add serial
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 20 Mar 2021 21:53:31 +0000
parents 34bbb0585cab
children
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/*
 * This library module implements the function for packing septets into octets.
 */

#include <sys/types.h>

gsm7_pack(inbuf, outbuf, noctets)
	u_char *inbuf, *outbuf;
	unsigned noctets;
{
	u_char *ip = inbuf, *op = outbuf;
	unsigned n, c;

	for (n = 0; n < noctets; n++) {
		c = n % 7;
		*op++ = ((ip[1] << 7) | ip[0]) >> c;
		if (c == 6)
			ip += 2;
		else
			ip += 1;
	}
}