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disk_stream.h
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disk_stream.h
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/* disk_stream.h
*
* provides an interface for streaming data from a disk.
* allows us to work with arbitrary sizes from disk (e.g. 20 MB)
* without having to read from and work with disk in sector block sizes (512 bytes)
*/
#ifndef DISK_STREAM_H
#define DISK_STREAM_H
#include "disk.h"
struct disk_stream {
int pos; // The position we're at in the stream (seeking at in the disk). The disk is linearly byte addresseable via pos
struct disk *disk;
};
/* Returns a new disk stream for the disk associated with index disk_index
* Returns 0 on failure
*/
struct disk_stream *get_disk_stream(int disk_index);
/* Repositions the seeker (next byte to be read) to pos
* Returns 0 on success
*/
int disk_stream_seek(struct disk_stream *disk_stream, int pos);
/* Read bytes from disk stream
*
* disk_stream - the disk stream to read bytes from
* out - the read bytes are written to this buffer
* total - the number of bytes to read
*
* side effect: increments the disk stream's pos by the number of bytes read (total)
*
* returns 0 on success or < 0 on failure
*/
int disk_stream_read(struct disk_stream *disk_stream, void *out, int total);
/* Free the memory associated with disk_stream */
void disk_stream_close(struct disk_stream *disk_stream);
#endif