/*====================================================================*
 *
 *   size_t dataspec (char const * string,  void * memory, size_t extent);
 *
 *   memory.h
 *
 *   encode a memory region with a variable-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 semi-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 DATASPEC_SOURCE
#define DATASPEC_SOURCE

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

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

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

{ 
	char const * number = string; 
	byte * origin = (byte *) (memory); 
	byte * offset = (byte *) (memory); 
	if (! number) 
	{ 
		error (1, EFAULT, "dataspec"); 
	} 

#ifdef WIN32

	while (isspace ((unsigned char)* number))  
	{ 
		number++; 
	} 

#endif

	while ((* number) && (extent)) 
	{ 
		unsigned digit = 0; 

#ifdef WIN32

		if (isspace ((unsigned char)* number)) 
		{ 
			break; 
		} 

#endif

		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 (! * number) 
		{ 
			error (1, EINVAL, "Have '%s' but need another hex digit", string); 
		} 
		if ((digit = todigit (* number++)) >= 0x10) 
		{ 
			error (1, EINVAL, "Have '%s' but need valid hex data", string); 
		} 
		* offset |= digit; 
		offset++; 
		extent--; 
	} 

#ifdef WIN32

	while (isspace ((unsigned char)* number)) 
	{ 
		number++; 
	} 

#endif

	if (* number && ! extent) 
	{ 
		error (1, EINVAL, "'%s' exceeds %d bytes", string, (unsigned) (offset - origin - extent)); 
	} 
	if (* number) 
	{ 
		error (1, EINVAL, "String '%s' contains trash", string); 
	} 
	return (offset - origin); 
} 

#endif