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#ifndef BUFFER_H
#define BUFFER_H
#include "stdint.h"
/*
* "start" and "end" denote the real boundaries of the buffer. "fill"
* denotes the offset to the first free block in the buffer. (If the
* buffer is full, "fill" will equal ( end - start ) ).
*
*/
struct buffer {
physaddr_t start;
physaddr_t end;
off_t fill;
};
/*
* Free blocks in the buffer start with a "tail byte". If non-zero,
* this byte indicates that the free block is the tail of the buffer,
* i.e. occupies all the remaining space up to the end of the buffer.
* When the tail byte is non-zero, it indicates that the remainder of
* the descriptor (the struct buffer_free_block) follows the tail
* byte.
*
* This scheme is necessary because we may end up with a tail that is
* smaller than a struct buffer_free_block.
*
*/
struct buffer_free_block {
char tail;
physaddr_t next_free;
physaddr_t end;
} __attribute__ (( packed ));
/* This must be provided by the architecture-dependent load_buffer.c */
extern struct buffer load_buffer;
/* Functions in buffer.c */
extern void init_buffer ( struct buffer *buffer );
extern int fill_buffer ( struct buffer *buffer, const void *data,
off_t offset, size_t len );
#endif /* BUFFER_H */
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