history.c

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/*
 *  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 <linux-guru@gcfl.net>)
 *        added config.h include
 *
 *    25-Jan-1999 (Eric Kohl)
 *        Cleanup!
 *        Unicode and redirection safe!
 *
 *    25-Jan-1999 (Paolo Pantaleo <paolopan@freemail.it>)
 *        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 <paolopan@freemail.it>)
 *        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 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)
    {
        TRACE ("del in " __FILE__ ": returning\n"
                "item is 0x%08x (Bottom is0x%08x)\n",
                item, Bottom);
        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--;
}

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;

}

LPCTSTR PeekHistory(INT dir)
{
    LPHIST_ENTRY entry = curr_ptr;

    if (dir == 0)
        return NULL;

    if (dir < 0)
    {
        /* key up */
        if (entry->next == Top || entry == Top)
        {
#ifdef WRAP_HISTORY
            entry = Bottom;
#else
            return NULL;
#endif
        }
        entry = entry->next;
    }
    else
    {
        /* key down */
        if (entry->next == Bottom || entry == Bottom)
        {
#ifdef WRAP_HISTORY
            entry = Top;
#else
            return NULL;
#endif
        }
        entry = entry->prev;
    }

    return entry->string;
}

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);

    }
}

#endif //#if FEATURE_HISTORY