On Thu, Oct 12, 2000 at 11:46:59PM +0100, Nick Ing-Simmons wrote:
> It is late and I will respond again tomorrow but I think
> we need the table of functions to include:
>
> read - give me N bytes (with a magic "as much as is to hand" value)
> unread - take these bytes back
> seek - move to X (from start, here, end as usual)
> flush -
>
> on write side it is simpler 'cos I have not thought about it as much
> write
> seek
> flush - wait for drain etc.
> eof - that's all folks
> (and maybe "purge" = "forget what I told you we are in trouble").
/* Definitions for file objects and discipline stacks */
#ifndef _SYS_TYPES_H
#include <sys/types.h>
#endif
#define BUFFSIZE 1024
typedef struct _IOLayer IOLayer;
struct {
IOLayer* next;
IOLayer* prev; /* Has to be doubly linked. */
unsigned char id; /* Top two bits are layer, bottom 6 are sequence no. */
char** buff;
unsigned int buffsize;
void* (*Layer_read)();
void* (*Layer_write)();
void* (*Layer_lseek)();
void* (*Layer_tell)();
off_t Layer_where;
} _IOLayer;
typedef struct {
int filedes;
char flags;
/* System IO layer */
void* (*File_read)();
void* (*File_write)();
void* (*File_lseek)();
void* (*File_tell)();
off_t File_where;
char** buff;
unsigned int buffsize;
IOLayer* discipline[3]; /* Transformation layers */
} FileObject;
--
BEWARE! People acting under the influence of human nature.
