#ifndef ISTREAM_PRIVATE_H
#define ISTREAM_PRIVATE_H

#include "istream.h"
#include "iostream-private.h"

#define I_STREAM_MIN_SIZE IO_BLOCK_SIZE

struct io;

struct istream_private {
/* inheritance: */
	struct iostream_private iostream;

/* methods: */
	ssize_t (*read)(struct istream_private *stream);
	void (*seek)(struct istream_private *stream,
		     uoff_t v_offset, bool mark);
	void (*sync)(struct istream_private *stream);
	int (*stat)(struct istream_private *stream, bool exact);
	int (*get_size)(struct istream_private *stream, bool exact, uoff_t *size_r);
	void (*switch_ioloop)(struct istream_private *stream);

/* data: */
	struct istream istream;

	int fd;
	uoff_t abs_start_offset;
	struct stat statbuf;
	/* added by io_add_istream() -> i_stream_set_io() */
	struct io *io;

	const unsigned char *buffer;
	unsigned char *w_buffer; /* may be NULL */

	size_t buffer_size, max_buffer_size, init_buffer_size;
	size_t skip, pos, try_alloc_limit;
	/* If seeking backwards within the buffer, the next read() will
	   return again pos..high_pos */
	size_t high_pos;

	struct istream *parent; /* for filter streams */
	uoff_t parent_start_offset;

	/* parent stream's expected offset is kept here. i_stream_read()
	   always seeks parent stream to here before calling read(). */
	uoff_t parent_expected_offset;

	/* increased every time the stream is changed (e.g. seek, read).
	   this way streams can check if their parent streams have been
	   accessed behind them. */
	unsigned int access_counter;

	string_t *line_str; /* for i_stream_next_line() if w_buffer == NULL */
	unsigned int line_crlf:1;
	unsigned int return_nolf_line:1;
	unsigned int stream_size_passthrough:1; /* stream is parent's size */
	unsigned int nonpersistent_buffers:1;
};

struct istream * ATTR_NOWARN_UNUSED_RESULT
i_stream_create(struct istream_private *stream, struct istream *parent, int fd)
	ATTR_NULL(2);
/* Initialize parent lazily after i_stream_create() has already been called. */
void i_stream_init_parent(struct istream_private *_stream,
			  struct istream *parent);

void i_stream_compress(struct istream_private *stream);
void i_stream_grow_buffer(struct istream_private *stream, size_t bytes);
bool ATTR_NOWARN_UNUSED_RESULT
i_stream_try_alloc(struct istream_private *stream,
		   size_t wanted_size, size_t *size_r);
void *i_stream_alloc(struct istream_private *stream, size_t size);
ssize_t i_stream_read_copy_from_parent(struct istream *istream);
void i_stream_default_seek_nonseekable(struct istream_private *stream,
				       uoff_t v_offset, bool mark);
/* Returns FALSE if seeking must be done by starting from the beginning.
   The caller is then expected to reset the stream and call this function
   again, which should work then. If TRUE is returned, the seek was either
   successfully done or stream_errno is set. */
bool i_stream_nonseekable_try_seek(struct istream_private *stream,
				   uoff_t v_offset);

struct istream *i_stream_get_root_io(struct istream *stream);
void i_stream_set_io(struct istream *stream, struct io *io);
void i_stream_unset_io(struct istream *stream, struct io *io);

#endif