blob: d679886cbc3a1a3bc8883aa2ecb1838a37cfc1a0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
/* Buffered input/output */
#ifndef _io_
#define _io_
#include "misc.h"
#include "mlvalues.h"
#ifndef IO_BUFFER_SIZE
#define IO_BUFFER_SIZE 4096
#endif
struct channel {
int fd; /* Unix file descriptor */
long offset; /* Absolute position of fd in the file */
char * curr; /* Current position in the buffer */
char * max; /* Logical end of the buffer */
char * end; /* Physical end of the buffer */
char buff[IO_BUFFER_SIZE]; /* The buffer itself */
};
/* For an output channel:
[offset] is the absolute position of the beginning of the buffer [buff].
For an input channel:
[offset] is the absolute position of the logical end of the buffer [max].
*/
#define putch(channel, ch) \
{ if ((channel)->curr >= (channel)->end) flush(channel); \
*((channel)->curr)++ = (ch); \
if ((channel)->curr > (channel)->max) (channel)->max = (channel)->curr; }
#define getch(channel) \
((channel)->curr >= (channel)->max \
? refill(channel) \
: (unsigned char) *((channel))->curr++)
struct channel * open_descr P((int));
value flush P((struct channel *));
void putword P((struct channel *, uint32));
void putblock P((struct channel *, char *, unsigned));
unsigned char refill P((struct channel *));
value pos_out P((struct channel *));
value seek_out P((struct channel *, value));
uint32 getword P((struct channel *));
unsigned getblock P((struct channel *, char *, unsigned));
int really_getblock P((struct channel *, char *, unsigned long));
value close_in P((struct channel *));
#endif /* _io_ */
|
