text: /*
   * 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.h,v 1.3 2006/06/12 08:00:30 adam Exp $
   */
  
  /**
   * \defgroup psock Protosockets library
   * @{
   *
   * The protosocket library provides an interface to the uIP stack that is
   * similar to the traditional BSD socket interface. Unlike programs
   * written for the ordinary uIP event-driven interface, programs
   * written with the protosocket library are executed in a sequential
   * fashion and does not have to be implemented as explicit state
   * machines.
   *
   * Protosockets only work with TCP connections.
   *
   * The protosocket library uses \ref pt protothreads to provide
   * sequential control flow. This makes the protosockets lightweight in
   * terms of memory, but also means that protosockets inherits the
   * functional limitations of protothreads. Each protosocket lives only
   * within a single function. Automatic variables (stack variables) are
   * not retained across a protosocket library function call.
   *
   * \note Because the protosocket library uses protothreads, local
   * variables will not always be saved across a call to a protosocket
   * library function. It is therefore advised that local variables are
   * used with extreme care.
   *
   * The protosocket library provides functions for sending data without
   * having to deal with retransmissions and acknowledgements, as well
   * as functions for reading data without having to deal with data
   * being split across more than one TCP segment.
   *
   * Because each protosocket runs as a protothread, the protosocket has to be
   * started with a call to PSOCK_BEGIN() at the start of the function
   * in which the protosocket is used. Similarly, the protosocket protothread can
   * be terminated by a call to PSOCK_EXIT().
   *
   */
  
  /**
   * \file
   * Protosocket library header file
   * \author
   * Adam Dunkels <adam@sics.se>
   *
   */
  
  #ifndef __PSOCK_H__
  #define __PSOCK_H__
  
  #include "uipopt.h"
  #include "pt.h"
  
   /*
   * The structure that holds the state of a buffer.
   *
   * This structure holds the state of a uIP buffer. The structure has
   * no user-visible elements, but is used through the functions
   * provided by the library.
   *
   */
  struct psock_buf {
    u8_t *ptr;
    unsigned short left;
  };
  
  /**
   * The representation of a protosocket.
   *
   * The protosocket structrure is an opaque structure with no user-visible
   * elements.
   */
  struct psock {
    struct pt pt, psockpt; /* Protothreads - one that's using the psock
  			    functions, and one that runs inside the
  			    psock functions. */
    const u8_t *sendptr;   /* Pointer to the next data to be sent. */
    u8_t *readptr;         /* Pointer to the next data to be read. */
    
    char *bufptr;          /* Pointer to the buffer used for buffering
  			    incoming data. */
    
    u16_t sendlen;         /* The number of bytes left to be sent. */
    u16_t readlen;         /* The number of bytes left to be read. */
  
    struct psock_buf buf;  /* The structure holding the state of the
  			    input buffer. */
    unsigned int bufsize;  /* The size of the input buffer. */
    
    unsigned char state;   /* The state of the protosocket. */
  };
  
  void psock_init(struct psock *psock, char *buffer, unsigned int buffersize);
  /**
   * Initialize a protosocket.
   *
   * This macro initializes a protosocket and must be called before the
   * protosocket is used. The initialization also specifies the input buffer
   * for the protosocket.
   *
   * \param psock (struct psock *) A pointer to the protosocket to be
   * initialized
   *
   * \param buffer (char *) A pointer to the input buffer for the
   * protosocket.
   *
   * \param buffersize (unsigned int) The size of the input buffer.
   *
   * \hideinitializer
   */
  #define PSOCK_INIT(psock, buffer, buffersize) \
    psock_init(psock, buffer, buffersize)
  
  /**
   * Start the protosocket protothread in a function.
   *
   * This macro starts the protothread associated with the protosocket and
   * must come before other protosocket calls in the function it is used.
   *
   * \param psock (struct psock *) A pointer to the protosocket to be
   * started.
   *
   * \hideinitializer
   */
  #define PSOCK_BEGIN(psock) PT_BEGIN(&((psock)->pt))
  
  PT_THREAD(psock_send(struct psock *psock, const char *buf, unsigned int len));
  /**
   * Send data.
   *
   * This macro sends data over a protosocket. The protosocket protothread blocks
   * until all data has been sent and is known to have been received by
   * the remote end of the TCP connection.
   *
   * \param psock (struct psock *) A pointer to the protosocket over which
   * data is to be sent.
   *
   * \param data (char *) A pointer to the data that is to be sent.
   *
   * \param datalen (unsigned int) The length of the data that is to be
   * sent.
   *
   * \hideinitializer
   */
  #define PSOCK_SEND(psock, data, datalen)		\
      PT_WAIT_THREAD(&((psock)->pt), psock_send(psock, data, datalen))
  
  /**
   * \brief      Send a null-terminated string.
   * \param psock Pointer to the protosocket.
   * \param str  The string to be sent.
   *
   *             This function sends a null-terminated string over the
   *             protosocket.
   *
   * \hideinitializer
   */
  #define PSOCK_SEND_STR(psock, str)      		\
      PT_WAIT_THREAD(&((psock)->pt), psock_send(psock, str, strlen(str)))
  
  PT_THREAD(psock_generator_send(struct psock *psock,
  				unsigned short (*f)(void *), void *arg));
  
  /**
   * \brief      Generate data with a function and send it
   * \param psock Pointer to the protosocket.
   * \param generator Pointer to the generator function
   * \param arg   Argument to the generator function
   *
   *             This function generates data and sends it over the
   *             protosocket. This can be used to dynamically generate
   *             data for a transmission, instead of generating the data
   *             in a buffer beforehand. This function reduces the need for
   *             buffer memory. The generator function is implemented by
   *             the application, and a pointer to the function is given
   *             as an argument with the call to PSOCK_GENERATOR_SEND().
   *
   *             The generator function should place the generated data
   *             directly in the uip_appdata buffer, and return the
   *             length of the generated data. The generator function is
   *             called by the protosocket layer when the data first is
   *             sent, and once for every retransmission that is needed.
   *
   * \hideinitializer
   */
  #define PSOCK_GENERATOR_SEND(psock, generator, arg)     \
      PT_WAIT_THREAD(&((psock)->pt),					\
  		   psock_generator_send(psock, generator, arg))
  
  
  /**
   * Close a protosocket.
   *
   * This macro closes a protosocket and can only be called from within the
   * protothread in which the protosocket lives.
   *
   * \param psock (struct psock *) A pointer to the protosocket that is to
   * be closed.
   *
   * \hideinitializer
   */
  #define PSOCK_CLOSE(psock) uip_close()
  
  PT_THREAD(psock_readbuf(struct psock *psock));
  /**
   * Read data until the buffer is full.
   *
   * This macro will block waiting for data and read the data into the
   * input buffer specified with the call to PSOCK_INIT(). Data is read
   * until the buffer is full..
   *
   * \param psock (struct psock *) A pointer to the protosocket from which
   * data should be read.
   *
   * \hideinitializer
   */
  #define PSOCK_READBUF(psock)				\
    PT_WAIT_THREAD(&((psock)->pt), psock_readbuf(psock))
  
  PT_THREAD(psock_readto(struct psock *psock, unsigned char c));
  /**
   * Read data up to a specified character.
   *
   * This macro will block waiting for data and read the data into the
   * input buffer specified with the call to PSOCK_INIT(). Data is only
   * read until the specifieed character appears in the data stream.
   *
   * \param psock (struct psock *) A pointer to the protosocket from which
   * data should be read.
   *
   * \param c (char) The character at which to stop reading.
   *
   * \hideinitializer
   */
  #define PSOCK_READTO(psock, c)				\
    PT_WAIT_THREAD(&((psock)->pt), psock_readto(psock, c))
  
  /**
   * The length of the data that was previously read.
   *
   * This macro returns the length of the data that was previously read
   * using PSOCK_READTO() or PSOCK_READ().
   *
   * \param psock (struct psock *) A pointer to the protosocket holding the data.
   *
   * \hideinitializer
   */
  #define PSOCK_DATALEN(psock) psock_datalen(psock)
  
  u16_t psock_datalen(struct psock *psock);
  
  /**
   * Exit the protosocket's protothread.
   *
   * This macro terminates the protothread of the protosocket and should
   * almost always be used in conjunction with PSOCK_CLOSE().
   *
   * \sa PSOCK_CLOSE_EXIT()
   *
   * \param psock (struct psock *) A pointer to the protosocket.
   *
   * \hideinitializer
   */
  #define PSOCK_EXIT(psock) PT_EXIT(&((psock)->pt))
  
  /**
   * Close a protosocket and exit the protosocket's protothread.
   *
   * This macro closes a protosocket and exits the protosocket's protothread.
   *
   * \param psock (struct psock *) A pointer to the protosocket.
   *
   * \hideinitializer
   */
  #define PSOCK_CLOSE_EXIT(psock)		\
    do {						\
      PSOCK_CLOSE(psock);			\
      PSOCK_EXIT(psock);			\
    } while(0)
  
  /**
   * Declare the end of a protosocket's protothread.
   *
   * This macro is used for declaring that the protosocket's protothread
   * ends. It must always be used together with a matching PSOCK_BEGIN()
   * macro.
   *
   * \param psock (struct psock *) A pointer to the protosocket.
   *
   * \hideinitializer
   */
  #define PSOCK_END(psock) PT_END(&((psock)->pt))
  
  char psock_newdata(struct psock *s);
  
  /**
   * Check if new data has arrived on a protosocket.
   *
   * This macro is used in conjunction with the PSOCK_WAIT_UNTIL()
   * macro to check if data has arrived on a protosocket.
   *
   * \param psock (struct psock *) A pointer to the protosocket.
   *
   * \hideinitializer
   */
  #define PSOCK_NEWDATA(psock) psock_newdata(psock)
  
  /**
   * Wait until a condition is true.
   *
   * This macro blocks the protothread until the specified condition is
   * true. The macro PSOCK_NEWDATA() can be used to check if new data
   * arrives when the protosocket is waiting.
   *
   * Typically, this macro is used as follows:
   *
   \code
   PT_THREAD(thread(struct psock *s, struct timer *t))
   {
     PSOCK_BEGIN(s);
  
     PSOCK_WAIT_UNTIL(s, PSOCK_NEWADATA(s) || timer_expired(t));
     
     if(PSOCK_NEWDATA(s)) {
       PSOCK_READTO(s, '\n');
     } else {
       handle_timed_out(s);
     }
     
     PSOCK_END(s);
   }
   \endcode
   *
   * \param psock (struct psock *) A pointer to the protosocket.
   * \param condition The condition to wait for.
   *
   * \hideinitializer
   */
  #define PSOCK_WAIT_UNTIL(psock, condition)    \
    PT_WAIT_UNTIL(&((psock)->pt), (condition));
  
  #define PSOCK_WAIT_THREAD(psock, condition)   \
    PT_WAIT_THREAD(&((psock)->pt), (condition))
  
  #endif /* __PSOCK_H__ */
  
  /** @} */
  