/*
 * Buffer management.
 * Some of the functions are internal,
 * and some are actually attached to user
 * keys. Like everyone else, they set hints
 * for the display system.
 */
#include        <stdio.h>
#include        "ed.h"
 
/* USEBUFFER eXtended command.  Prompt for buffer name.  Store it in
 * external pattern lastbuf.  Call selbuf() to make the change.  Bound
 * to CTLX-B.
 */
usebuffer(f, n)
register int f, n;
{
        register int    s;
 
        if ((s=readpattern("Use buffer [DEFAULT] ", &lastbuf)) != TRUE)
                return (s);
        return(selbuf(lastbuf));
}
 
/*
 * Attach a buffer to a window. The
 * values of dot and mark come from the buffer
 * if the use count is 0. Otherwise, they come
 * from some other window.
 */
selbuf(bufname)
register char *bufname;
{
        register BUFFER *bp;
        register WINDOW *wp;
 
        /* Find a buffer.  If the buffer does not exist, then ask the user
         * whether a new buffer should be created.
         */
 
        if ((bp=bfind(bufname, MAYBE, 0)) == NULL)
                return (FALSE);
        strcpy(lastbuf, curbp->b_bname);        /* set up for return    */
        if (--curbp->b_nwnd == 0) {             /* Last use.            */
                curbp->b_dotp  = curwp->w_dotp;
                curbp->b_doto  = curwp->w_doto;
                curbp->b_markp = curwp->w_markp;
                curbp->b_marko = curwp->w_marko;
        }
        curbp = bp;                             /* Switch.              */
        curwp->w_bufp  = bp;
        curwp->w_linep = bp->b_linep;           /* For macros, ignored. */
        curwp->w_flag |= WFMODE|WFFORCE|WFHARD; /* Quite nasty.         */
        if (bp->b_nwnd++ == 0) {                /* First use.           */
                curwp->w_dotp  = bp->b_dotp;
                curwp->w_doto  = bp->b_doto;
                curwp->w_markp = bp->b_markp;
                curwp->w_marko = bp->b_marko;
                return (TRUE);
        }
        wp = wheadp;                            /* Look for old.        */
        while (wp != NULL) {
                if (wp!=curwp && wp->w_bufp==bp) {
                        curwp->w_dotp  = wp->w_dotp;
                        curwp->w_doto  = wp->w_doto;
                        curwp->w_markp = wp->w_markp;
                        curwp->w_marko = wp->w_marko;
                        break;
                }
                wp = wp->w_wndp;
        }
        return (TRUE);
}
 
/* KILLBUFFER  eXtended command.  Prompt for buffer name.  Call delbuf()
 * to do the actual kill.  Bound to CTLX-K.
 */
killbuffer(f, n)
register int f, n;
{
        register int    s;
 
        if ((s=readpattern("Kill buffer [DEFAULT] ", &lastbuf)) != TRUE)
                return (s);
        return(delbuf(lastbuf));
}
 
/*
 * Dispose of a buffer, by name.
 * Look up bufname (don't get too
 * upset if it isn't there at all!). Get quite upset
 * if the buffer is being displayed. Clear the buffer (ask
 * if the buffer has been changed). Then free the header
 * line and the buffer header.
 */
delbuf(bufname)
register char *bufname;
{
        register BUFFER *bp;
        register BUFFER *bp1;
        register BUFFER *bp2;
        register int    s;
 
        if ((bp=bfind(bufname, FALSE, 0)) == NULL)      /* Easy if unknown.*/
                return (TRUE);
        strcpy(lastbuf, curbp->b_bname);
        if (bp->b_nwnd != 0) {                  /* Error if on screen.  */
                mlwrite("Buffer is being displayed");
                return (FALSE);
        }
        if ((s=bclear(bp)) != TRUE)             /* Blow text away.      */
                return (s);
        free((char *) bp->b_linep);             /* Release header line. */
        bp1 = NULL;                             /* Find the header.     */
        bp2 = bheadp;
        while (bp2 != bp) {
                bp1 = bp2;
                bp2 = bp2->b_bufp;
        }
        bp2 = bp2->b_bufp;                      /* Next one in chain.   */
        if (bp1 == NULL)                        /* Unlink it.           */
                bheadp = bp2;
        else
                bp1->b_bufp = bp2;
        free((char *) bp);                      /* Release buffer block */
        return (TRUE);
}
 
/*
 * List all of the active
 * buffers. First update the special
 * buffer that holds the list. Next make
 * sure at least 1 window is displaying the
 * buffer list, splitting the screen if this
 * is what it takes. Lastly, repaint all of
 * the windows that are displaying the
 * list. Bound to "C-X C-B".
 */
listbuffers(f, n)
register int f, n;
{
        register WINDOW *wp;
        register BUFFER *bp;
        register int    s;
 
        if (blistp == NULL)
                {
                blistp = bfind("[List]", TRUE, BFTEMP); /* Buffer list buffer*/
                if (blistp == NULL)
                        return(ABORT);
                }
        if ((s=makelist()) != TRUE)
                return (s);
        if (blistp->b_nwnd == 0) {              /* Not on screen yet.   */
                if ((wp=wpopup()) == NULL)
                        return (FALSE);
                bp = wp->w_bufp;
                if (--bp->b_nwnd == 0) {
                        bp->b_dotp  = wp->w_dotp;
                        bp->b_doto  = wp->w_doto;
                        bp->b_markp = wp->w_markp;
                        bp->b_marko = wp->w_marko;
                }
                wp->w_bufp  = blistp;
                ++blistp->b_nwnd;
        }
        wp = wheadp;
        while (wp != NULL) {
                if (wp->w_bufp == blistp) {
                        wp->w_linep = lforw(blistp->b_linep);
                        wp->w_dotp  = lforw(blistp->b_linep);
                        wp->w_doto  = 0;
                        wp->w_markp = NULL;
                        wp->w_marko = 0;
                        wp->w_flag |= WFMODE|WFHARD;
                }
                wp = wp->w_wndp;
        }
        return (TRUE);
}
 
/*
 * This routine rebuilds the
 * text in the special secret buffer
 * that holds the buffer list. It is called
 * by the list buffers command. Return TRUE
 * if everything works. Return FALSE if there
 * is an error (if there is no memory).
 */
makelist()
{
        register char   *cp1;
        register char   *cp2;
        register int    c;
        register BUFFER *bp;
        register LINE   *lp;
        register long   nbytes;
        register int    s;
        register int    type;
        char            b[6+1];
        char            line[128];
 
        blistp->b_flag &= ~BFCHG;               /* Don't complain!      */
        blistp->b_bmode |= BMNWRAP;
        if ((s=bclear(blistp)) != TRUE)         /* Blow old text away   */
                return (s);
        strcpy(blistp->b_fname, "");
        if (addline(blistp,"C   Size Buffer           File") == FALSE
        ||  addline(blistp,"-   ---- ------           ----") == FALSE)
                return (FALSE);
        bp = bheadp;                            /* For all buffers      */
        while (bp != NULL) {
                if ((bp->b_flag&BFTEMP) != 0) { /* Skip magic ones.     */
                        bp = bp->b_bufp;
                        continue;
                }
                cp1 = &line[0];                 /* Start at left edge   */
                if ((bp->b_flag&BFCHG) != 0)    /* "*" if changed       */
                        *cp1++ = '*';
                else
                        *cp1++ = ' ';
                *cp1++ = ' ';                   /* Gap.                 */
                nbytes = 0L;                    /* Count bytes in buf.  */
                lp = lforw(bp->b_linep);
                while (lp != bp->b_linep) {
                        nbytes += llength(lp)+1;
                        lp = lforw(lp);
                }
                ltoa(b, 6, nbytes);             /* 6 digit buffer size. */
                cp2 = &b[0];
                while ((c = *cp2++) != 0)
                        *cp1++ = c;
                *cp1++ = ' ';                   /* Gap.                 */
                cp2 = &bp->b_bname[0];          /* Buffer name          */
                while ((c = *cp2++) != 0)
                        *cp1++ = c;
                cp2 = &bp->b_fname[0];          /* File name            */
                if (*cp2 != 0) {
                        while (cp1 < &line[1+1+6+1+NBUFN+1])
                                *cp1++ = ' ';
                        while ((c = *cp2++) != 0) {
                                if (cp1 < &line[128-1])
                                        *cp1++ = c;
                        }
                }
                *cp1 = 0;                       /* Add to the buffer.   */
                if (addline(blistp, line) == FALSE)
                        return (FALSE);
                bp = bp->b_bufp;
        }
        return (TRUE);                          /* All done             */
}
 
ltoa(buf, width, num)
register char   buf[];
register int    width;
register long   num;
{
        buf[width] = 0;                         /* End of string.       */
        while (num >= 10L) {                    /* Conditional digits.  */
                buf[--width] = (int)(num%10L) + '0';
                num /= 10L;
        }
        buf[--width] = num + '0';               /* Always 1 digit.      */
        while (width != 0)                      /* Pad with blanks.     */
                buf[--width] = ' ';
}
 
/*
 * The argument "text" points to
 * a string. Append this line to the
 * buffer "bp" (one with BFTEMP set). Handcraft the EOL
 * on the end. Return TRUE if it worked and
 * FALSE if you ran out of room.
 */
addline(bp, text)
register BUFFER *bp;
register char *text;
{
        register LINE   *lp;
        register int    i;
        register int    ntext;
 
        ntext = strlen(text);
        if ((lp=lalloc(ntext)) == NULL)
                return (FALSE);
        for (i=0; i<ntext; ++i)
                lputc(lp, i, text[i]);
        bp->b_linep->l_bp->l_fp = lp;   /* Hook onto the end    */
        lp->l_bp = bp->b_linep->l_bp;
        bp->b_linep->l_bp = lp;
        lp->l_fp = bp->b_linep;
        if (bp->b_dotp == bp->b_linep)  /* If "." is at the end */
                bp->b_dotp = lp;                /* move it to new line  */
        return (TRUE);
}
 
/*
 * Look through the list of
 * buffers. Return TRUE if there
 * are any changed buffers. Buffers
 * that hold magic internal stuff are
 * not considered; who cares if the
 * list of buffer names is hacked.
 * Return FALSE if no buffers
 * have been changed.
 */
anycb()
{
        register BUFFER *bp;
 
        bp = bheadp;
        while (bp != NULL) {
                if ((bp->b_flag&BFTEMP)==0 && (bp->b_flag&BFCHG)!=0)
                        return (TRUE);
                bp = bp->b_bufp;
        }
        return (FALSE);
}
 
/*
 * Find a buffer, by name. Return a pointer
 * to the BUFFER structure associated with it. If
 * the named buffer is found, but is a TEMP buffer (like
 * the buffer list) conplain. If the buffer is not found
 * and the "cflag" is TRUE, create it. The "bflag" is
 * the settings for the flags in in buffer.
 */
BUFFER  *
bfind(bname, cflag, bflag)
register char   *bname;
register int cflag, bflag;
{
        register BUFFER *bp;
        register LINE   *lp;
        char    *index(),*ptr;
 
        bp = bheadp;
        while (bp != NULL)
                {
                if (strcmp(bname, bp->b_bname) == 0)
                        {
                        if ((bp->b_flag&BFTEMP) != 0)
                                if (cflag == FALSE)
                                        {
                                        mlwrite("Cannot select builtin buffer");
                                        return (FALSE);
                                        }
                        return (bp);
                        }
                bp = bp->b_bufp;
                }
        /* Buffer does not exist.  Prompt the user to see if a new
         * buffer should be created.
         */
        if (cflag == MAYBE) {
                if (mlyesno("Create new buffer") != TRUE)
                        return(FALSE);
                cflag = TRUE;   /* yes, create it */
                }
        if (cflag == TRUE) {
                if ((bp=(BUFFER *)malloc(sizeof(BUFFER))) == NULL)
                        return (NULL);
                if ((lp=lalloc(0)) == NULL) {
                        free((char *) bp);
                        return (NULL);
                }
                /* clear all mode flags */
                bp->b_bmode &=~BMWRAP;
                bp->b_bmode &=~BMNWRAP;
                bp->b_bmode &=~BMCMODE;
                if (ptr=index(bname,'.'))
                        {
                        if (strncmp(ptr, ".mss",4)==0)
                                bp->b_bmode |= BMWRAP;
                        else if (strcmp(ptr,".c")==0)
                                bp->b_bmode |= BMCMODE;
                        else if (strcmp(ptr,".h")==0)
                                bp->b_bmode |= BMCMODE;
                        else
                                bp->b_bmode |= glmode;
                        }
                else
                        bp->b_bmode |= glmode;
                bp->b_bufp  = bheadp;
                bheadp = bp;
                bp->b_dotp  = lp;
                bp->b_doto  = 0;
                bp->b_markp = lp;       /* All new buffers begin with mark */
                bp->b_marko = 0;
                bp->b_flag  = bflag;
                bp->b_nwnd  = 0;
                bp->b_linep = lp;
                strcpy(bp->b_fname, "");
                strcpy(bp->b_bname, bname);
                lp->l_fp = lp;
                lp->l_bp = lp;
        }
        return (bp);
}
 
/*
 * This routine blows away all of the text
 * in a buffer. If the buffer is marked as changed
 * then we ask if it is ok to blow it away; this is
 * to save the user the grief of losing text. The
 * window chain is nearly always wrong if this gets
 * called; the caller must arrange for the updates
 * that are required. Return TRUE if everything
 * looks good.
 */
bclear(bp)
register BUFFER *bp;
{
        register LINE   *lp;
        register int    s;
 
        if ((bp->b_flag&BFTEMP) == 0            /* Not scratch buffer.  */
        && (bp->b_flag&BFCHG) != 0              /* Something changed    */
        && (s=mlyesno("Discard changes")) != TRUE)
                return (s);
        bp->b_flag  &= ~BFCHG;                  /* Not changed          */
        while ((lp=lforw(bp->b_linep)) != bp->b_linep)
                lfree(lp);
        bp->b_dotp  = bp->b_linep;              /* Fix "."              */
        bp->b_doto  = 0;
        bp->b_markp = NULL;                     /* Invalidate "mark"    */
        bp->b_marko = 0;
        return (TRUE);
}