vshcursormenu.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This library is free software; you can redistribute it and/or modify it
//  under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation; either version 2.1 of the License, or (at
//  your option) any later version.
//
//  This library is distributed in the hope that it will be useful, but
//  WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
//  General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public License
//  along with this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  vshCursorMenu.c
//

// This contains some useful functions written for the shell

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/vsh.h>
#include <sys/api.h>


_X_ int vshCursorMenu(const char *prompt, char *items[], int numItems, int defaultSelection)
{
  // Desc: This will create a pretty cursor-changeable text menu with the supplied 'prompt' string at the stop.  Returns the integer (zero-based) selected item number, or else negative on error or no selection.

  int itemWidth = 0;
  char *buffer = NULL;
  int selectedOption = defaultSelection;
  textAttrs attrs;
  int count1, count2;

  // Check params
  if ((prompt == NULL) || (items == NULL))
    return (errno = ERR_NULLPARAMETER);

  bzero(&attrs, sizeof(textAttrs));

  // Get the width of the widest item and set our item width
  for (count1 = 0; count1 < numItems; count1 ++)
    if ((int) strlen(items[count1]) > itemWidth)
      itemWidth = strlen(items[count1]);
  itemWidth = min(itemWidth, textGetNumColumns());

  buffer = malloc(itemWidth + 1);
  if (buffer == NULL)
    return (errno = ERR_MEMORY);

  // Print prompt message
  printf("\n%s\n", prompt);

  // Now, print 'numItems' newlines before calculating the current row so
  // that we don't get messed up if the screen scrolls
  for (count1 = 0; count1 < (numItems + 3); count1 ++)
    printf("\n");

  int row = (textGetRow() - (numItems + 3));

  while(1)
    {
      textSetColumn(0);
      textSetRow(row);
      textSetCursor(0);
      
      for (count1 = 0; count1 < numItems; count1 ++)
	{
	  printf(" ");

	  sprintf(buffer, " %s ", items[count1]);
	  for (count2 = 0;
	       count2 < (itemWidth - (int) strlen(items[count1])); count2 ++)
	    strcat(buffer, " ");
	  if (selectedOption == count1)
	    attrs.flags = TEXT_ATTRS_REVERSE;
	  else
	    attrs.flags = 0;
	  textPrintAttrs(&attrs, buffer);
	  printf("\n");
	}

      printf("\n  [Cursor up/down to change, Enter to select, 'Q' to quit]\n");
      textInputSetEcho(0);
      char c = getchar();
      textInputSetEcho(1);

      switch(c)
	{
	case (unsigned char) 17:
	  // Cursor up.
	  if (selectedOption > 0)
	    selectedOption -= 1;
	  break;

	case (unsigned char) 20:
	  // Cursor down.
	  if (selectedOption < (numItems - 1))
	    selectedOption += 1;
	  break;

	case (unsigned char) 10:
	  // Enter
	  textSetCursor(1);
	  free(buffer);
	  return (selectedOption);

	case 'Q':
	case 'q':
	  // Cancel
	  textSetCursor(1);
	  free(buffer);
	  return (errno = ERR_CANCELLED);
	}
    }
}