/*  $Id: pl-buffe.h,v 1.1 1995/04/18 12:29:04 jan Exp $

    Part of XPCE
    Designed and implemented by Anjo Anjewierden and Jan Wielemaker
    E-mail: jan@swi.psy.uva.nl

    Copyright (C) 1993 University of Amsterdam. All rights reserved.
*/

typedef struct
{ char *	base;			/* allocated base */
  char *	top;			/* pointer to top */
  char *	max;			/* current location */
} buffer, *Buffer;

Buffer	newBuffer(void);
void	freeBuffer(Buffer);
void	growBuffer(Buffer, long);

#define addBuffer(b, obj, type) \
	do \
	{ if ( (b)->top + sizeof(type) > (b)->max ) \
	    growBuffer(b, sizeof(type)); \
 	  *((type *)(b)->top) = obj; \
          (b)->top += sizeof(type); \
	} while(0)
  
#define baseBuffer(b, type)	 ((type *) (b)->base)
#define topBuffer(b, type)       ((type *) (b)->top)
#define inBuffer(b, addr)        ((char *) (addr) >= (b)->base && \
				  (char *) (addr)  < (b)->top)

#define seekBuffer(b, cnt, type) ((b)->top = sizeof(type) * (cnt) + (b)->base)
#define sizeOfBuffer(b)          ((b)->top - (b)->base)
#define entriesBuffer(b, type)   (sizeOfBuffer(b) / sizeof(type))
#define initBuffer(b)            ((b)->base = (b)->max = (b)->top = NULL)

#define discardBuffer(b) \
	do \
	{ if ( (b)->base ) \
	    free((b)->base); \
	  initBuffer(b); \
	} while(0)