history.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/*
 *  HISTORY.C - command line history.
 *
 *
 *  History:
 *
 *    14/01/95 (Tim Norman)
 *        started.
 *
 *    08/08/95 (Matt Rains)
 *        i have cleaned up the source code. changes now bring this source
 *        into guidelines for recommended programming practice.
 *
 *    27-Jul-1998 (John P Price <[e-mail]>)
 *        added config.h include
 *
 *    25-Jan-1999 (Eric Kohl)
 *        Cleanup!
 *        Unicode and redirection safe!
 *
 *    25-Jan-1999 (Paolo Pantaleo <[e-mail]>)
 *        Added lots of comments (beginning studying the source)
 *        Added command.com's F3 support (see cmdinput.c)
 *
 */



/*
 *  HISTORY.C - command line history. Second version
 *
 *
 *  History:
 *
 *    06/12/99 (Paolo Pantaleo <[e-mail]>)
 *        started.
 *
 */

#include <precomp.h>

#ifdef FEATURE_HISTORY

typedef struct tagHISTORY
{
	struct tagHISTORY *prev;
	struct tagHISTORY *next;
	LPTSTR string;
} HIST_ENTRY, * LPHIST_ENTRY;

static INT size,
	max_size=100;



static LPHIST_ENTRY Top;
static LPHIST_ENTRY Bottom;


static LPHIST_ENTRY curr_ptr=0;


VOID InitHistory(VOID);
VOID History_move_to_bottom(VOID);
VOID History (INT dir, LPTSTR commandline);
VOID CleanHistory(VOID);
VOID History_del_current_entry(LPTSTR str);

/*service functions*/
static VOID del(LPHIST_ENTRY item);
static VOID add_at_bottom(LPTSTR string);
/*VOID add_before_last(LPTSTR string);*/
VOID set_size(INT new_size);



INT CommandHistory (LPTSTR cmd, LPTSTR param)
{
	LPTSTR tmp;
	INT tmp_int;
	LPHIST_ENTRY h_tmp;
	TCHAR szBuffer[2048];

	tmp=_tcschr(param,_T('/'));

	if (tmp)
	{
		param=tmp;
		switch (_totupper(param[1]))
		{
			case _T('F'):/*delete history*/
				CleanHistory();InitHistory();
				break;

			case _T('R'):/*read history from standard in*/
				//hIn=GetStdHandle (STD_INPUT_HANDLE);

				for(;;)
				{
					ConInString(szBuffer,sizeof(szBuffer)/sizeof(TCHAR));
					if (*szBuffer!=_T('\0'))
						History(0,szBuffer);
					else
						break;
				}
				break;

			case _T('A'):/*add an antry*/
				History(0,param+2);
				break;

			case _T('S'):/*set history size*/
				if ((tmp_int=_ttoi(param+2)))
					set_size(tmp_int);
				break;

			default:
				return 1;
		}
	}
	else
	{
		for (h_tmp = Top->prev; h_tmp != Bottom; h_tmp = h_tmp->prev)
			ConErrPuts(h_tmp->string);
	}
	return 0;
}

VOID set_size(INT new_size)
{
	while (new_size<size)
		del(Top->prev);

	max_size=new_size;
}


VOID InitHistory(VOID)
{
	size=0;

	Top = cmd_alloc(sizeof(HIST_ENTRY));
	Bottom = cmd_alloc(sizeof(HIST_ENTRY));

	Top->prev = Bottom;
	Top->next = NULL;
	Top->string = NULL;

	Bottom->prev = NULL;
	Bottom->next = Top;
	Bottom->string = NULL;

	curr_ptr=Bottom;
}




VOID CleanHistory(VOID)
{
	while (Bottom->next!=Top)
		del(Bottom->next);

	cmd_free(Top);
	cmd_free(Bottom);
}


VOID History_del_current_entry(LPTSTR str)
{
	LPHIST_ENTRY tmp;

	if (size == 0)
		return;

	if (curr_ptr == Bottom)
		curr_ptr=Bottom->next;

	if (curr_ptr == Top)
		curr_ptr=Top->prev;


	tmp = curr_ptr;
	curr_ptr = curr_ptr->prev;
	del(tmp);
	History(-1, str);
}


static
VOID del(LPHIST_ENTRY item)
{
	if (item==NULL || item==Top || item==Bottom)
	{
#ifdef _DEBUG
		DebugPrintf(_T("del in ") _T(__FILE__)  _T(": retrning\n")
			    _T("item is 0x%08x (Bottom is0x%08x)\n"),
			    item, Bottom);
#endif
		return;
	}



	/*free string's mem*/
	if (item->string)
		cmd_free(item->string);

	/*set links in prev and next item*/
	item->next->prev=item->prev;
	item->prev->next=item->next;

	cmd_free(item);

	size--;
}


#if 0
static
VOID add_before_last(LPTSTR string)
{
	LPHIST_ENTRY tmp,before,after;

	/*delete first entry if maximum number of entries is reached*/
	while(size>=max_size)
		del(Top->prev);

	while (_istspace(*string))
		string++;

	if (*string==_T('\0'))
		return;

	/*allocte entry and string*/
	tmp=cmd_alloc(sizeof(HIST_ENTRY));
	tmp->string=cmd_alloc((_tcslen(string)+1)*sizeof(TCHAR));
	_tcscpy(tmp->string,string);

	/*set links*/
	before=Bottom->next;
	after=before->next;

	tmp->prev=before;
	tmp->next=after;

	after->prev=tmp;
	before->next=tmp;

	/*set new size*/
	size++;


}
#endif/*0*/

static
VOID add_at_bottom(LPTSTR string)
{


	LPHIST_ENTRY tmp;


	/*delete first entry if maximum number of entries is reached*/
	while(size>=max_size)
		del(Top->prev);

	while (_istspace(*string))
		string++;

	if (*string==_T('\0'))
		return;


	/*if new entry is the same than the last do not add it*/
	if(size)
		if(_tcscmp(string,Bottom->next->string)==0)
			return;


	/*fill bottom with string, it will become Bottom->next*/
	Bottom->string=cmd_alloc((_tcslen(string)+1)*sizeof(TCHAR));
	_tcscpy(Bottom->string,string);

	/*save Bottom value*/
	tmp=Bottom;


	/*create new void Bottom*/
	Bottom=cmd_alloc(sizeof(HIST_ENTRY));
	Bottom->next=tmp;
	Bottom->prev=NULL;
	Bottom->string=NULL;

	tmp->prev=Bottom;

	/*set new size*/
	size++;

}



VOID History_move_to_bottom(VOID)
{
	curr_ptr=Bottom;

}


VOID History (INT dir, LPTSTR commandline)
{

	if(dir==0)
	{
		add_at_bottom(commandline);
		curr_ptr=Bottom;
		return;
	}

	if (size==0)
	{
		commandline[0]=_T('\0');
		return;
	}


	if(dir<0)/*key up*/
	{
		if (curr_ptr->next==Top || curr_ptr==Top)
		{
#ifdef WRAP_HISTORY
			curr_ptr=Bottom;
#else
			curr_ptr=Top;
			commandline[0]=_T('\0');
			return;
#endif
		}


		curr_ptr = curr_ptr->next;
		if(curr_ptr->string)
			_tcscpy(commandline,curr_ptr->string);

	}





	if(dir>0)
	{

		if (curr_ptr->prev==Bottom || curr_ptr==Bottom)
		{
#ifdef WRAP_HISTORY
			curr_ptr=Top;
#else
			curr_ptr=Bottom;
			commandline[0]=_T('\0');
			return;
#endif
		}

		curr_ptr=curr_ptr->prev;
		if(curr_ptr->string)
			_tcscpy(commandline,curr_ptr->string);

	}
}






#if 0

LPTSTR history = NULL;	/*buffer to sotre all the lines*/
LPTSTR lines[MAXLINES];	/*array of pointers to each line(entry)*/
						/*located in history buffer*/

INT curline = 0;		/*the last line recalled by user*/
INT numlines = 0;		/*number of entries, included the last*/
						/*empty one*/

INT maxpos = 0;			/*index of last byte of last entry*/



VOID History (INT dir, LPTSTR commandline)
{

	INT count;						/*used in for loops*/
	INT length;						/*used in the same loops of count*/
									/*both to make room when is full
									either history or lines*/

	/*first time History is called allocate mem*/
	if (!history)
	{
		history = cmd_alloc (history_size * sizeof (TCHAR));
		lines[0] = history;
		history[0] = 0;
	}

	if (dir > 0)
	{
		/* next command */
		if (curline < numlines)
		{
			curline++;
		}

		if (curline == numlines)
		{
			commandline[0] = 0;
		}
		else
		{
			_tcscpy (commandline, lines[curline]);
		}
	}
	else if (dir < 0)
	{
		/* prev command */
		if (curline > 0)
		{
			curline--;
		}

		_tcscpy (commandline, lines[curline]);
	}
	else
	{
		/* add to history */
		/* remove oldest string until there's enough room for next one */
		/* strlen (commandline) must be less than history_size! */
		while ((maxpos + (INT)_tcslen (commandline) + 1 > history_size) || (numlines >= MAXLINES))
		{
			length = _tcslen (lines[0]) + 1;

			for (count = 0; count < maxpos && count + (lines[1] - lines[0]) < history_size; count++)
			{
				history[count] = history[count + length];
			}

			maxpos -= length;

			for (count = 0; count <= numlines && count < MAXLINES; count++)
			{
				lines[count] = lines[count + 1] - length;
			}

			numlines--;
#ifdef DEBUG
			ConOutPrintf (_T("Reduced size:  %ld lines\n"), numlines);

			for (count = 0; count < numlines; count++)
			{
				ConOutPrintf (_T("%d: %s\n"), count, lines[count]);
			}
#endif
		}

		/*copy entry in the history bufer*/
		_tcscpy (lines[numlines], commandline);
		numlines++;

		/*set last lines[numlines] pointer next the end of last, valid,
		just setted entry (the two lines above)*/
		lines[numlines] = lines[numlines - 1] + _tcslen (commandline) + 1;
		maxpos += _tcslen (commandline) + 1;
		/* last line, empty */

		curline = numlines;
	}

	return;
}

#endif

#endif //#if 0