107 lines
1.9 KiB
C
107 lines
1.9 KiB
C
/* $Source$
|
|
* $State$
|
|
* $Revision$
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <cpm.h>
|
|
#include "cpmsys.h"
|
|
|
|
ssize_t read(int fd, void* buffer, size_t count)
|
|
{
|
|
uint8_t* bbuffer = buffer;
|
|
struct FCBE* fcbe = &__fd[fd];
|
|
uint8_t olduser;
|
|
ssize_t result;
|
|
|
|
__init_file_descriptors();
|
|
if (fcbe->fcb.dr == 0)
|
|
{
|
|
/* Read from the console. */
|
|
|
|
if (count == 0)
|
|
return 0;
|
|
*(uint8_t*)buffer = cpm_conin();
|
|
return 1;
|
|
}
|
|
|
|
olduser = cpm_get_user();
|
|
cpm_set_user(fcbe->user);
|
|
|
|
if (U16(fcbe->fcb.r) >= fcbe->length)
|
|
goto done;
|
|
if (fcbe->offset || !SECTOR_ALIGNED(count))
|
|
{
|
|
uint8_t delta;
|
|
|
|
/* We need to read bytes until we're at a sector boundary. */
|
|
|
|
cpm_set_dma(__transfer_buffer);
|
|
if (cpm_read_random_safe(&fcbe->fcb) != 0)
|
|
goto eio;
|
|
|
|
/* Copy enough bytes to reach the end of the sector. */
|
|
|
|
delta = 128 - fcbe->offset;
|
|
if (delta > count)
|
|
delta = count;
|
|
memcpy(bbuffer, __transfer_buffer+fcbe->offset, delta);
|
|
fcbe->offset += delta;
|
|
count -= delta;
|
|
bbuffer += delta;
|
|
|
|
/* If we've read enough bytes, advance to the next sector. */
|
|
|
|
if (fcbe->offset == 128)
|
|
{
|
|
U16(fcbe->fcb.r)++;
|
|
fcbe->offset = 0;
|
|
}
|
|
}
|
|
|
|
while (count >= 128)
|
|
{
|
|
if (U16(fcbe->fcb.r) >= fcbe->length)
|
|
goto done;
|
|
|
|
/* Read entire sectors directly into the destination buffer. */
|
|
|
|
cpm_set_dma(bbuffer);
|
|
if (cpm_read_random_safe(&fcbe->fcb) != 0)
|
|
goto eio;
|
|
count -= 128;
|
|
bbuffer += 128;
|
|
U16(fcbe->fcb.r)++;
|
|
}
|
|
|
|
if (count != 0)
|
|
{
|
|
if (U16(fcbe->fcb.r) >= fcbe->length)
|
|
goto done;
|
|
|
|
/* There's some trailing data to read. */
|
|
|
|
cpm_set_dma(__transfer_buffer);
|
|
if (cpm_read_random_safe(&fcbe->fcb) != 0)
|
|
goto eio;
|
|
|
|
memcpy(bbuffer, __transfer_buffer, count);
|
|
fcbe->offset = count;
|
|
}
|
|
|
|
done:
|
|
result = bbuffer - (uint8_t*)buffer;
|
|
exit:
|
|
cpm_set_user(olduser);
|
|
return result;
|
|
|
|
eio:
|
|
errno = EIO;
|
|
result = -1;
|
|
goto exit;
|
|
}
|