text: /*
   * Copyright (c) 1997  Metro Link Incorporated
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
   * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   * Except as contained in this notice, the name of the Metro Link shall not be
   * used in advertising or otherwise to promote the sale, use or other dealings
   * in this Software without prior written authorization from Metro Link.
   *
   */
  
  /*
  	X Input Serial Buffer routines for use in any XInput driver that accesses
  	a serial device.
  */
  
  /*****************************************************************************
   *	Standard Headers
   ****************************************************************************/
  
  #ifdef HAVE_XORG_CONFIG_H
  #include <xorg-config.h>
  #endif
  
  #include <misc.h>
  #include <xf86.h>
  #include <xf86_OSproc.h>
  #include <xf86_OSlib.h>
  #include <xf86Xinput.h>
  #include "xisb.h"
  
  /*****************************************************************************
   *	Local Headers
   ****************************************************************************/
  
  /*****************************************************************************
   *	Variables without includable headers
   ****************************************************************************/
  
  /*****************************************************************************
   *	Local Variables
   ****************************************************************************/
  
  /*****************************************************************************
   *	Function Definitions
   ****************************************************************************/
  
  XISBuffer *
  XisbNew(int fd, ssize_t size)
  {
      XISBuffer *b;
  
      b = malloc(sizeof(XISBuffer));
      if (!b)
          return NULL;
      b->buf = malloc((sizeof(unsigned char) * size));
      if (!b->buf) {
          free(b);
          return NULL;
      }
  
      b->fd = fd;
      b->trace = 0;
      b->block_duration = 0;
      b->current = 1;             /* force it to be past the end to trigger initial read */
      b->end = 0;
      b->buffer_size = size;
      return b;
  }
  
  void
  XisbFree(XISBuffer * b)
  {
      free(b->buf);
      free(b);
  }
  
  int
  XisbRead(XISBuffer * b)
  {
      int ret;
  
      if (b->current >= b->end) {
          if (b->block_duration >= 0) {
              if (xf86WaitForInput(b->fd, b->block_duration) < 1)
                  return -1;
          }
          else {
              /*
               * automatically clear it so if XisbRead is called in a loop
               * the next call will make sure there is data with select and
               * thus prevent a blocking read
               */
              b->block_duration = 0;
          }
  
          ret = xf86ReadSerial(b->fd, b->buf, b->buffer_size);
          switch (ret) {
          case 0:
              return -1;          /* timeout */
          case -1:
              return -2;          /* error */
          default:
              b->end = ret;
              b->current = 0;
              break;
          }
      }
      if (b->trace)
          ErrorF("read 0x%02x (%c)\n", b->buf[b->current],
                 isprint(b->buf[b->current]) ? b->buf[b->current] : '.');
  
      return b->buf[b->current++];
  }
  
  /* the only purpose of this function is to provide output tracing */
  ssize_t
  XisbWrite(XISBuffer * b, unsigned char *msg, ssize_t len)
  {
      if (b->trace) {
          int i = 0;
  
          for (i = 0; i < len; i++)
              ErrorF("\t\twrote 0x%02x (%c)\n", msg[i], msg[i]);
      }
      return (xf86WriteSerial(b->fd, msg, len));
  }
  
  /* turn tracing of this buffer on (1) or off (0) */
  void
  XisbTrace(XISBuffer * b, int trace)
  {
      b->trace = trace;
  }
  
  /*
   * specify a block_duration of -1 when you know the buffer's fd is ready to
   * read. After a read, it is automatically set to 0 so that the next read
   * will use check to select for data and prevent a block.
   * It is the caller's responsibility to set the block_duration to -1 if it
   * knows that there is data to read (because the main select loop triggered
   * the read) and want's to avoid the unnecessary overhead of the select call
   *
   * a zero or positive block duration will cause the select to block for the
   * give duration in usecs.
   */
  
  void
  XisbBlockDuration(XISBuffer * b, int block_duration)
  {
      b->block_duration = block_duration;
  }
  