hexdecode.c
Author: cmaier@cmassoc.net

    /*====================================================================*
     *
     *   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

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