/* 
 * 2010.12.10 Shinae Woo
 * Ring buffer structure for managing dynamically allocating ring buffer
 * 
 * put data to the tail
 * get/pop/remove data from the head
 * 
 * always garantee physically continuous ready in-memory data from data_offset to the data_offset+len
 * automatically increase total buffer size when buffer is full
 * for efficiently managing packet payload and chunking
 *
 */

#ifndef __MOS_RING_BUFFER_
#define __MOS_RING_BUFFER_

#include <stdint.h>
#include <sys/types.h>

/*----------------------------------------------------------------------------*/
enum rb_caller
{
	AT_APP, 
	AT_MTCP
};
/*----------------------------------------------------------------------------*/
struct tcp_stream;
typedef struct rb_manager* rb_manager_t;
/*----------------------------------------------------------------------------*/
struct fragment_ctx
{
	uint32_t seq;
	uint32_t len : 31,
		is_calloc : 1;
	struct fragment_ctx *next;
};
/*----------------------------------------------------------------------------*/
struct tcp_ring_buffer
{
	u_char* data;			/* buffered data */
	u_char* head;			/* pointer to the head */
	
	uint32_t head_offset;	/* offset for the head (head - data) */
	uint32_t tail_offset;	/* offset fot the last byte (null byte) */
	/* 
	 * offset that points to the tail-end of the monitoring stream offset.
	 */
	uint32_t monitor_read_tail_offset;
	
	int merged_len;			/* contiguously merged length */
	uint64_t cum_len;		/* cummulatively merged length */
	int last_len;			/* currently saved data length */
	int size;			/* total ring buffer size */
	
	/* TCP payload features */
	uint32_t head_seq;
	uint32_t init_seq;
	
	struct fragment_ctx* fctx;
};
/*----------------------------------------------------------------------------*/
uint32_t RBGetCurnum(rb_manager_t rbm);
void RBPrintInfo(struct tcp_ring_buffer* buff);
void RBPrintStr(struct tcp_ring_buffer* buff);
void RBPrintHex(struct tcp_ring_buffer* buff);
/*----------------------------------------------------------------------------*/
rb_manager_t RBManagerCreate(size_t chunk_size, uint8_t disable_rings, uint32_t concurrency);
/*----------------------------------------------------------------------------*/
struct tcp_ring_buffer* RBInit(rb_manager_t rbm,  uint32_t init_seq, uint8_t buffer_mgmt);
void RBFree(rb_manager_t rbm, struct tcp_ring_buffer* buff, uint8_t buffer_mgmt);
uint32_t RBIsDanger(rb_manager_t rbm);
/*----------------------------------------------------------------------------*/
/* data manupulation functions */
int RBPut(rb_manager_t rbm, struct tcp_stream *cur_stream, void *data, 
	  uint32_t len, uint32_t seq);
size_t RBGet(rb_manager_t rbm, struct tcp_ring_buffer* buff, size_t len);
size_t RBRemove(rb_manager_t rbm, struct tcp_ring_buffer* buff, 
		size_t len, int option, uint8_t buffer_mgmt);
/*----------------------------------------------------------------------------*/
extern inline int
RBDoesOverlap(rb_manager_t rbm, struct tcp_ring_buffer *rcvbuf,
			  uint32_t cur_seq, uint32_t len);
/*----------------------------------------------------------------------------*/

#endif /* !MOS_RING_BUFFER */