int fsimage_gcr_read_half_track(const disk_image_t *image, unsigned int half_track,
disk_track_t *raw)
{
WORD track_len;
BYTE buf[4];
long offset;
fsimage_t *fsimage;
WORD max_track_length;
BYTE num_half_tracks;
fsimage = image->media.fsimage;
raw->data = NULL;
raw->size = 0;
offset = fsimage_gcr_seek_half_track(fsimage, half_track, &max_track_length, &num_half_tracks);
if (offset < 0) {
return -1;
}
if (offset != 0) {
if (util_fpread(fsimage->fd, buf, 2, offset) < 0) {
log_error(fsimage_gcr_log, "Could not read GCR disk image.");
return -1;
}
track_len = util_le_buf_to_word(buf);
if ((track_len < 1) || (track_len > max_track_length)) {
log_error(fsimage_gcr_log,
"Track field length %u is not supported.",
track_len);
return -1;
}
raw->data = lib_calloc(1, track_len);
raw->size = track_len;
if (fread(raw->data, track_len, 1, fsimage->fd) < 1) {
log_error(fsimage_gcr_log, "Could not read GCR disk image.");
return -1;
}
} else {
raw->size = disk_image_raw_track_size(image->type, half_track / 2);
raw->data = lib_malloc(raw->size);
memset(raw->data, 0x55, raw->size);
}
return 0;
}
static int disk_image_check_for_gcr(disk_image_t *image)
{
WORD max_track_length;
BYTE header[32];
fsimage_t *fsimage;
fsimage = image->media.fsimage;
if (util_fpread(fsimage->fd, header, sizeof (header), 0) < 0) {
log_error(disk_image_probe_log, "Cannot read image header.");
return 0;
}
if (strncmp("GCR-1541", (char*)header, 8)) {
return 0;
}
if (header[8] != 0) {
log_error(disk_image_probe_log,
"Import GCR: Unknown GCR image version %i.",
(int)header[8]);
return 0;
}
if (header[9] < 1 || header[9] > MAX_GCR_TRACKS * 2) {
log_error(disk_image_probe_log,
"Import GCR: Invalid number of tracks (%i).",
(int)header[9]);
return 0;
}
max_track_length = util_le_buf_to_word(&header[10]);
if (max_track_length > NUM_MAX_MEM_BYTES_TRACK) {
log_error(disk_image_probe_log, "Too large max track length.");
return 0;
}
image->type = DISK_IMAGE_TYPE_G64;
image->tracks = header[9] / 2;
image->max_half_tracks = header[9];
disk_image_check_log(image, "GCR");
return 1;
}
/*
The buffer pointer passed to this function points to the character
following '-' in the memory command.
The buffer pointer passed to the sub-functions points to the byte
after the first argument (address) which is passed separately.
*/
static int vdrive_command_memory(vdrive_t *vdrive, BYTE *buffer,
unsigned int length)
{
WORD addr;
if (length < 5) {
return CBMDOS_IPE_SYNTAX;
}
addr = util_le_buf_to_word(buffer + 1);
switch (*buffer) {
case 'W':
return vdrive_command_memory_write(vdrive, buffer + 3, addr, length);
case 'R':
return vdrive_command_memory_read(vdrive, buffer + 3, addr, length);
case 'E':
return vdrive_command_memory_exec(vdrive, NULL, addr, length);
default:
break;
}
return CBMDOS_IPE_INVAL;
}
static long fsimage_gcr_seek_half_track(fsimage_t *fsimage, unsigned int half_track,
WORD *max_track_length, BYTE *num_half_tracks)
{
BYTE buf[12];
if (fsimage->fd == NULL) {
log_error(fsimage_gcr_log, "Attempt to read without disk image.");
return -1;
}
if (util_fpread(fsimage->fd, buf, 12, 0) < 0) {
log_error(fsimage_gcr_log, "Could not read GCR disk image.");
return -1;
}
if (memcmp(gcr_image_header_expected, buf, sizeof(gcr_image_header_expected)) != 0) {
log_error(fsimage_gcr_log, "Unexpected GCR header found." );
return -1;
}
*num_half_tracks = buf[9];
if (*num_half_tracks > MAX_GCR_TRACKS) {
log_error(fsimage_gcr_log, "Too many half tracks." );
return -1;
}
*max_track_length = util_le_buf_to_word(&buf[10]);
if (*max_track_length > NUM_MAX_MEM_BYTES_TRACK) {
log_error(fsimage_gcr_log, "Too large max track length.");
return -1;
}
if (util_fpread(fsimage->fd, buf, 4, 12 + (half_track - 2) * 4) < 0) {
log_error(fsimage_gcr_log, "Could not read GCR disk image.");
return -1;
}
return util_le_buf_to_dword(buf);
}
