stringinput.java

来自「计算机代数系统」· Java 代码 · 共 49 行

package net.sf.yacas;


class StringInput extends LispInput
{
  public StringInput(StringBuffer aString, InputStatus aStatus)
  {
    super(aStatus);
    iString = aString;
    iCurrent = 0;
  }
  public char Next() throws Exception
	{
	  if (iCurrent == iString.length())
	    return '\0';
	  iCurrent++;
    char c = iString.charAt(iCurrent-1);
    if (c == '\n')
      iStatus.NextLine();
	  return c;
	}
	public char Peek() throws Exception
	{
	  if (iCurrent == iString.length())
	    return '\0';
	  return iString.charAt(iCurrent);
	}
  public boolean EndOfStream()
	{
	  return (iCurrent == iString.length());
	}
  public StringBuffer StartPtr()
	{
	  return iString;
	}
  public int Position()
	{
	  return iCurrent;
	}
  public void SetPosition(int aPosition)
	{
	  iCurrent = aPosition;
	}

  StringBuffer iString;
  int iCurrent;
}