LineSocket.hxx

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/*
  Copyright (c) 2016, Matthew H. Reilly (kb1vc)
  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
 
  Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
  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.
 
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
  HOLDER 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.
*/
 
#ifndef LINESOCKET_HDR
#define LINESOCKET_HDR
#include "SoDaBase.hxx"
#include "IPSockets.hxx"
#include "UDSockets.hxx"
#include "Command.hxx"
#include <SoDa/Format.hxx>
 
#include <stdexcept>
 
namespace SoDa {
 
  namespace IP {

    class LineServerSocket : public ServerSocket {
    public: 
      LineServerSocket(int portnum, 
               TransportType transport = TCP) :
    ServerSocket(portnum, transport) {
    ready_line_count = 0; 
 
    // we want to use the nonblocking read.
    setNonBlocking();
      }

      static const unsigned int temp_buf_size = 128;
      
      int getLine(char * buf, unsigned int maxsize) {
    if(ready_line_count == 0) {
      // get a buffer; 
      int gotbytes = read(conn_socket, temp_buf, temp_buf_size);
      std::cerr << SoDa::Format("READ Got ret = %0 errno = %1 ready = %2\n")
        .addI(gotbytes)
        .addI(errno)
        .addC((char) (isReady() ? 'T' : 'F')); 
      if(gotbytes < 0) {
        if((errno != EWOULDBLOCK) && (errno != EAGAIN)) {
          std::cerr << SoDa::Format("READ got ret = %0  errno = %1\n")
        .addI(gotbytes)
        .addI(errno); 
          perror("READ: ");
          return -1; 
        }
      }
      if(gotbytes == 0) {
        // a nonblocking read that returns 0 is directed at 
        // a closed socket.  An open socket with nothing in it
        // will return -1 with EWOULDBLOCK.  So, if we get here, 
        // the remote connection has been closed.
        close(conn_socket);
        ready = false; 
        return -1; 
      }
      if(gotbytes > 0) {
        for(int i = 0; i < gotbytes; i++) {
          inbuf.push(temp_buf[i]); 
          if(temp_buf[i] == '\n') ready_line_count++; 
        }
      }
    }
 
    if(ready_line_count > 0) {
      // scan the buffer until we get to the newline. 
      ready_line_count--;
      char ch; 
      for(unsigned int i = 0; i < maxsize; i++) {
        ch = inbuf.front(); inbuf.pop();
        if(ch == '\n') {
          buf[i] = '\000';
          return i; 
        }
        else {
          buf[i] = ch; 
        }
      }
      // if we get here, we ran out of buffer space. 
      buf[maxsize-1] = '\000';
      // consume the queue up to the newline. 
      for(ch = '\000'; (ch != '\n') && !inbuf.empty(); ) {
        ch = inbuf.front(); inbuf.pop();
      }
      return maxsize; 
    }
    else {
      return 0; 
    }
      }
 
 
    protected:
      std::queue<char> inbuf; 

      int ready_line_count; 

      char temp_buf[temp_buf_size]; 
    }; 
  }
}
 
 
#endif