/*====================================================================*
 *
 *   size_t bytespec (char const *string,  void * memory, size_t extent);
 *
 *   memory.h
 *
 *   encode a memory region with a fixed-length hexadecimal string;
 *   return the number of bytes encoded or terminate the program on 
 *   error; 
 *
 *   the number of octets in string must equal the memory extent or
 *   an error will occur; octets may be seperated by colons; empty
 *   octets are illegal;
 *
 *   Motley Tools by Charles Maier <cmaier@cmassoc.net>;
 *   Copyright (c) 2001-2006 by Charles Maier Associates;
 *   Licensed under the Internet Software Consortium License;
 *
 *--------------------------------------------------------------------*/

#ifndef BYTESPEC_SOURCE
#define BYTESPEC_SOURCE

#include <ctype.h>
#include <errno.h>

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

size_t bytespec (char const * string, void * memory, size_t extent) 

{ 
	char const * number = string; 
	byte * origin = (byte *) (memory); 
	byte * offset = (byte *) (memory); 
	if (! number) 
	{ 
		error (1, EINVAL, "bytespec"); 
	} 
	while (isspace ((unsigned char)* number)) 
	{ 
		number++; 
	} 
	while ((* number) && (extent)) 
	{ 
		unsigned digit; 
		if ((offset > origin) && (* number == HEX_EXTENDER)) 
		{ 
			number++; 
		} 
		if ((digit = todigit (* number++)) >= RADIX_HEX) 
		{ 
			error (1, EINVAL, "Have '%s' but need a hex digit", string); 
		} 
		* offset = digit << 4; 
		if ((digit = todigit (* number++)) >= RADIX_HEX) 
		{ 
			error (1, EINVAL, "Have '%s' but need a hex digit", string); 
		} 
		* offset |= digit; 
		offset++; 
		extent--; 
	} 
	while (isspace ((unsigned char)* number))  
	{ 
		number++; 
	} 
	if ((* number) || (extent)) 
	{ 
		error (1, EINVAL, "%s is not %d bytes", string, (unsigned) (offset - origin +  extent)); 
	} 
	return (offset - origin); 
} 

#endif