Table of Contents
read_file()
The read_file() function is called when the user requests a file to be read from the source image.
Syntax
Declaration
Declared in src/mess/tools/imgtool/library.h as
imgtoolerr_t (*read_file)(
imgtool_partition *partition,
const char *filename,
const char *fork,
imgtool_stream *destf
);Parameters
partition– Pointer to an imgtool_partition where the file is.filename– Pointer to a string with the filename of the file the user wants to read.fork– Pointer to a string with a resource fork. Only used for Macintosh filesystems.destf– Pointer to an imgtool_stream to write the file data to.
Returns
An imgtoolerr_t with the type of error that occurred or IMGTOOLERR_SUCCESS if no error occurred.
Example
imgtoolerr_t mymodule_read_file(
imgtool_partition *partition,
const char *filename,
const char *fork,
imgtool_stream *destf
) {
imgtoolerr_t ret;
imgtool_image *image = imgtool_partition_image(partition);
int filesize, track, sector;
UINT8 buffer[SECTOR_SIZE];
directory_entry entry;
ret = mymodule_get_directory_entry(image, filename, &entry);
if (ret) return ret;
filesize = entry.end_address - entry.start_address;
track = entry.start_track;
sector = entry.start_sector;
while (filesize > 0) {
int bytes_left;
ret = mymodule_read_sector_data(image, track, sector, buffer);
if (ret) return ret;
/* detect sectors pointing to themselfs */
if ((track == pick_integer_le(buffer, DATA_SIZE, 1)) &&
(sector == pick_integer_le(buffer, DATA_SIZE + 1, 1)))
return IMGTOOLERR_CORRUPTIMAGE;
/* load next track and sector values */
track = pick_integer_le(buffer, DATA_SIZE, 1);
sector = pick_integer_le(buffer, DATA_SIZE + 1, 1);
/* track 0 is invalid */
if ((track == 0) && (filesize > DATA_SIZE))
return IMGTOOLERR_CORRUPTIMAGE;
/* write either DATA_SIZE or the remaining bytes */
bytes_left = filesize > DATA_SIZE ? DATA_SIZE : filesize;
if (stream_write(destf, buffer, bytes_left) != bytes_left)
return IMGTOOLERR_WRITEERROR;
filesize -= DATA_SIZE;
}
return IMGTOOLERR_SUCCESS;
}This is a simple example that doesn't use partitions.