csu3_am335x/EVSE/GPL/open-plc-utils-0.3/tools/strdecr.c

/*====================================================================*
 *
 *   signed strdecr (void * memory, size_t extent, byte min, byte max);
 *
 *   memory.h
 *
 *   decrement a multi-byte memory region; start at max and reset at
 *   min; return -1 if all bytes are min;
 *
 *   Motley Tools by Charles Maier;
 *   Copyright (c) 2001-2006 by Charles Maier Associates;
 *   Licensed under the Internet Software Consortium License;
 *
 *--------------------------------------------------------------------*/

#ifndef STRDECR_SOURCE
#define STRDECR_SOURCE

#include "../tools/memory.h"

signed strdecr (void * memory, register size_t extent, register byte min, register byte max)

{
	register byte * offset = (byte *)(memory);
	while (extent--)
	{
		if (-- offset [extent] >= min)
		{
			return (0);
		}
		offset [extent] = max;
	}
	return (-1);
}


#endif