csu3_am335x/EVSE/GPL/plc-utils.LNX.2.1.20/source/tools/hexdecode.c

/*====================================================================*
 *
 *   size_t hexdecode (void const * memory, size_t extent,  char buffer [], size_t length);
 *
 *   memory.h
 *
 *   decode a memory region as a string of hex octets separated with 
 *   character HEX_EXTENDER;
 *
 *   allow three string characters for each memory byte; this means
 *   that the buffer must hold at least three characters or nothing
 *   will be decoded; the maximum number of bytes is the lesser of
 *   chars/3 and bytes; 
 *
 *   Motley Tools by Charles Maier <cmaier@cmassoc.net>;
 *   Copyright (c) 2001-2006 by Charles Maier Associates;
 *   Licensed under the Internet Software Consortium License;
 *
 *--------------------------------------------------------------------*/

#ifndef HEXDECODE_SOURCE
#define HEXDECODE_SOURCE

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

size_t hexdecode (void const * memory, register size_t extent, char buffer [], register size_t length) 

{ 
	register char * string = (char *) (buffer); 
	register byte * offset = (byte *) (memory); 
	if (length) 
	{ 
		length /= HEX_DIGITS +  1; 
		while ((length--) && (extent--)) 
		{ 
			* string++ = DIGITS_HEX [(* offset >> 4) & 0x0F]; 
			* string++ = DIGITS_HEX [(* offset >> 0) & 0x0F]; 
			if ((length) && (extent)) 
			{ 
				* string++ = HEX_EXTENDER; 
			} 
			offset++; 
		} 
		* string = (char) (0); 
	} 
	return (string - buffer); 
} 

#endif