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/*
* Class for reading data from files, with base implementations
* for reading local filesystem files and previous session files.
*
* TODO this is kept private for now, it can be useful to make that
* public later.
*/
#ifndef FILE_SRC_H_
#define FILE_SRC_H_
#include <sys/types.h>
struct data_source;
struct iso_file_src {
/**
* Opens the file.
* This should be called before any call to read_block().
* @return 1 on success, <= 0 on error
*/
int (*open)(struct iso_file_src *src);
/**
* Close the file.
* This should be called when the iso_file_src is no more needed.
*/
void (*close)(struct iso_file_src *src);
/**
* Read data from the file in 2048 bytes chunks.
*
* A pointer to the contents of the file will be updated, in such a way
* that each time this function is called, new data is read to the buffer.
* It behaves in the same way as usual read(2) call this way.
*
* This always reads 2048 bytes, unless an EOF is found, or we reach the
* size previously returned by get_size(). In this case, the buffer is
* completed with 0s.
*
* @param buffer Buffer where the data will be written. Its size must
* be at least 2048 bytes.
* @return
* 1 if file contains more data. If we reach EOF before the expected
* size, this keeps returning 1, and next blocks are filled with 0s.
* 0 when we reach the expected size, that in normal usage is also EOF
* on file.
* < 0 on error. If such case, next calls to read_block will keep
* returning < 0 until we reach the expected size, filling blocks with
* 0s.
*/
int (*read_block)(struct iso_file_src *src, unsigned char *buffer);
/**
* Get the size in bytes of the file.
*
* This is set when the iso_file_src is created, and should not change. If
* the actual file size changes, it will be truncated or padding with 0s
* when the block is read
*/
off_t (*get_size)(struct iso_file_src *);
/** Clean up the source specific data */
void (*free_data)(struct iso_file_src *);
/** Source specific data */
void *data;
};
/**
* Get a iso_file_src() for reading from a local filesystem file.
*/
struct iso_file_src* iso_file_src_from_path(const char *path);
/**
* Get a iso_file_src() for reading from a previous image file.
* @param src data_source to read from previous image. It is not freed,
* so you need to free it when no more needed.
* @param block block on image where file begins
* @param nblocks number of block of the file
*/
struct iso_file_src*
iso_file_src_from_prev_img(struct data_source* src, int block, off_t size);
/**
* free a iso_file_src
*/
void iso_file_src_free(struct iso_file_src *src);
#endif /*FILE_SRC_H_*/