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/*

 * 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 2 2011-07-17 20:13:17Z filepang@gmail.com $

 */

#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 = (unsigned char*)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, (unsigned char*)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, (unsigned char * ) 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, (unsigned char*) buffer, buffersize);

  PT_INIT(&psock->pt);

  PT_INIT(&psock->psockpt);

}

/*---------------------------------------------------------------------------*/