/*
 * Copyright (c) 2004, Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the uIP TCP/IP stack
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 * $Id: psock.c,v 1.1 2007/01/04 11:06:40 adamdunkels Exp $
 */
#include <stdio.h>
#include <string.h>

#include "uipopt.h"
#include "psock.h"
#include "uip.h"

#define STATE_NONE				0
#define STATE_ACKED				1
#define STATE_READ				2
#define STATE_BLOCKED_NEWDATA	3
#define STATE_BLOCKED_CLOSE		4
#define STATE_BLOCKED_SEND		5
#define STATE_DATA_SENT			6

/*
 * Return value of the buffering functions that indicates that a
 * buffer was not filled by incoming data.
 *
 */
#define BUF_NOT_FULL	0
#define BUF_NOT_FOUND	0

/*
 * Return value of the buffering functions that indicates that a
 * buffer was completely filled by incoming data.
 *
 */
#define BUF_FULL	1

/*
 * Return value of the buffering functions that indicates that an
 * end-marker byte was found.
 *
 */
#define BUF_FOUND	2

/*---------------------------------------------------------------------------*/
static void buf_setup( struct psock_buf *buf, u8_t *bufptr, u16_t bufsize )
{
	buf->ptr = bufptr;
	buf->left = bufsize;
}

/*---------------------------------------------------------------------------*/
static u8_t buf_bufdata( struct psock_buf *buf, u16_t len, u8_t **dataptr, u16_t *datalen )
{
	( void ) len;

	if( *datalen < buf->left )
	{
		memcpy( buf->ptr, *dataptr, *datalen );
		buf->ptr += *datalen;
		buf->left -= *datalen;
		*dataptr += *datalen;
		*datalen = 0;
		return BUF_NOT_FULL;
	}
	else if( *datalen == buf->left )
	{
		memcpy( buf->ptr, *dataptr, *datalen );
		buf->ptr += *datalen;
		buf->left = 0;
		*dataptr += *datalen;
		*datalen = 0;
		return BUF_FULL;
	}
	else
	{
		memcpy( buf->ptr, *dataptr, buf->left );
		buf->ptr += buf->left;
		*datalen -= buf->left;
		*dataptr += buf->left;
		buf->left = 0;
		return BUF_FULL;
	}
}

/*---------------------------------------------------------------------------*/
static u8_t buf_bufto( register struct psock_buf *buf, u8_t endmarker, register u8_t **dataptr, register u16_t *datalen )
{
	u8_t	c;
	while( buf->left > 0 && *datalen > 0 )
	{
		c = *buf->ptr = **dataptr;
		++ *dataptr;
		++buf->ptr;
		-- *datalen;
		--buf->left;

		if( c == endmarker )
		{
			return BUF_FOUND;
		}
	}

	if( *datalen == 0 )
	{
		return BUF_NOT_FOUND;
	}

	while( *datalen > 0 )
	{
		c = **dataptr;
		-- *datalen;
		++ *dataptr;

		if( c == endmarker )
		{
			return BUF_FOUND | BUF_FULL;
		}
	}

	return BUF_FULL;
}

/*---------------------------------------------------------------------------*/
static char send_data( register struct psock *s )
{
	if( s->state != STATE_DATA_SENT || uip_rexmit() )
	{
		if( s->sendlen > uip_mss() )
		{
			uip_send( s->sendptr, uip_mss() );
		}
		else
		{
			uip_send( s->sendptr, s->sendlen );
		}

		s->state = STATE_DATA_SENT;
		return 1;
	}

	return 0;
}

/*---------------------------------------------------------------------------*/
static char data_acked( register struct psock *s )
{
	if( s->state == STATE_DATA_SENT && uip_acked() )
	{
		if( s->sendlen > uip_mss() )
		{
			s->sendlen -= uip_mss();
			s->sendptr += uip_mss();
		}
		else
		{
			s->sendptr += s->sendlen;
			s->sendlen = 0;
		}

		s->state = STATE_ACKED;
		return 1;
	}

	return 0;
}

/*---------------------------------------------------------------------------*/
PT_THREAD( psock_send ( register struct psock *s, const char *buf, unsigned int len ) )
{
	PT_BEGIN( &s->psockpt );

	/* If there is no data to send, we exit immediately. */
	if( len == 0 )
	{
		PT_EXIT( &s->psockpt );
	}

	/* Save the length of and a pointer to the data that is to be
     sent. */
	s->sendptr = ( u8_t * ) buf;
	s->sendlen = len;

	s->state = STATE_NONE;

	/* We loop here until all data is sent. The s->sendlen variable is
     updated by the data_sent() function. */
	while( s->sendlen > 0 )
	{
		/*
     * The condition for this PT_WAIT_UNTIL is a little tricky: the
     * protothread will wait here until all data has been acknowledged
     * (data_acked() returns true) and until all data has been sent
     * (send_data() returns true). The two functions data_acked() and
     * send_data() must be called in succession to ensure that all
     * data is sent. Therefore the & operator is used instead of the
     * && operator, which would cause only the data_acked() function
     * to be called when it returns false.
     */
		PT_WAIT_UNTIL( &s->psockpt, data_acked(s) & send_data(s) );
	}

	s->state = STATE_NONE;

	PT_END( &s->psockpt );
}

/*---------------------------------------------------------------------------*/
PT_THREAD( psock_generator_send ( register struct psock *s, unsigned short ( *generate ) ( void * ), void *arg ) )
{
	PT_BEGIN( &s->psockpt );

	/* Ensure that there is a generator function to call. */
	if( generate == NULL )
	{
		PT_EXIT( &s->psockpt );
	}

	/* Call the generator function to generate the data in the
     uip_appdata buffer. */
	s->sendlen = generate( arg );
	s->sendptr = uip_appdata;

	s->state = STATE_NONE;
	do
	{
		/* Call the generator function again if we are called to perform a
       retransmission. */
		if( uip_rexmit() )
		{
			generate( arg );
		}

		/* Wait until all data is sent and acknowledged. */
		PT_WAIT_UNTIL( &s->psockpt, data_acked(s) & send_data(s) );
	} while( s->sendlen > 0 );

	s->state = STATE_NONE;

	PT_END( &s->psockpt );
}

/*---------------------------------------------------------------------------*/
u16_t psock_datalen( struct psock *psock )
{
	return psock->bufsize - psock->buf.left;
}

/*---------------------------------------------------------------------------*/
char psock_newdata( struct psock *s )
{
	if( s->readlen > 0 )
	{
		/* There is data in the uip_appdata buffer that has not yet been
       read with the PSOCK_READ functions. */
		return 1;
	}
	else if( s->state == STATE_READ )
	{
		/* All data in uip_appdata buffer already consumed. */
		s->state = STATE_BLOCKED_NEWDATA;
		return 0;
	}
	else if( uip_newdata() )
	{
		/* There is new data that has not been consumed. */
		return 1;
	}
	else
	{
		/* There is no new data. */
		return 0;
	}
}

/*---------------------------------------------------------------------------*/
PT_THREAD( psock_readto ( register struct psock *psock, unsigned char c ) )
{
	PT_BEGIN( &psock->psockpt );

	buf_setup( &psock->buf, ( u8_t * ) psock->bufptr, psock->bufsize );

	/* XXX: Should add buf_checkmarker() before do{} loop, if
     incoming data has been handled while waiting for a write. */
	do
	{
		if( psock->readlen == 0 )
		{
			PT_WAIT_UNTIL( &psock->psockpt, psock_newdata(psock) );
			psock->state = STATE_READ;
			psock->readptr = ( u8_t * ) uip_appdata;
			psock->readlen = uip_datalen();
		}
	} while( (buf_bufto(&psock->buf, c, &psock->readptr, &psock->readlen) & BUF_FOUND) == 0 );

	if( psock_datalen(psock) == 0 )
	{
		psock->state = STATE_NONE;
		PT_RESTART( &psock->psockpt );
	}

	PT_END( &psock->psockpt );
}

/*---------------------------------------------------------------------------*/
PT_THREAD( psock_readbuf ( register struct psock *psock ) )
{
	PT_BEGIN( &psock->psockpt );

	buf_setup( &psock->buf, ( u8_t * ) psock->bufptr, psock->bufsize );

	/* XXX: Should add buf_checkmarker() before do{} loop, if
     incoming data has been handled while waiting for a write. */
	do
	{
		if( psock->readlen == 0 )
		{
			PT_WAIT_UNTIL( &psock->psockpt, psock_newdata(psock) );
			printf( "Waited for newdata\n" );
			psock->state = STATE_READ;
			psock->readptr = ( u8_t * ) uip_appdata;
			psock->readlen = uip_datalen();
		}
	} while( buf_bufdata(&psock->buf, psock->bufsize, &psock->readptr, &psock->readlen) != BUF_FULL );

	if( psock_datalen(psock) == 0 )
	{
		psock->state = STATE_NONE;
		PT_RESTART( &psock->psockpt );
	}

	PT_END( &psock->psockpt );
}

/*---------------------------------------------------------------------------*/
void psock_init( register struct psock *psock, char *buffer, unsigned int buffersize )
{
	psock->state = STATE_NONE;
	psock->readlen = 0;
	psock->bufptr = buffer;
	psock->bufsize = buffersize;
	buf_setup( &psock->buf, ( u8_t * ) buffer, buffersize );
	PT_INIT( &psock->pt );
	PT_INIT( &psock->psockpt );
}

/*---------------------------------------------------------------------------*/