#include "ded.h"
#include "lines.h"

/************************************************************************
 *                                                                      *
 *                      copyright Richard Bornat 1981                   *
 *                                                                      *
 ************************************************************************/

/************************************************************************
 *                                                                      *
 *      procedures to move lines up or down to make or delete space     *
 *                                                                      *
 ************************************************************************/

shuffile(fline,incr,stretch)
int fline;
int incr,stretch;
 { xshuffile(fline, incr, stretch); adj_maxl(); }

/* the procedure which really does the work */
xshuffile(fline, incr, stretch)
register int fline;
register int incr;
int stretch;
 {  register int i;

    if (incr == 0) return;
    else
    if (incr > 0) /* moving up */
     {  if (maxl+incr > NLINES)
	  editerror("too many lines in file [xshuffile]");

	for (i=maxl; i>=fline; i--) l_offset[i+incr] = l_offset[i];
     }
    else
    if (incr < 0) /* moving down */
     {  if (fline < (-incr))
	  editerror("attempt to shuffle lines off top of file [xshuffile]");

	for (i=fline; i<=maxl; i++) l_offset[i+incr] = l_offset[i];
	stretch = 0; /* it must be this value when moving down */
     }

    /* alter topl */
    sh_sync(&topl, fline, incr, 0);

    /* alter ranges */
    for (i=0; i<NLETTS; i++)
     {  unsigned b = b_range[i], e = e_range[i];

	/* obliterate a range entirely within a negative increment */
	if (b != (unsigned)-1 && b<fline && b>=fline+incr &&
				 e<fline && e>=fline+incr)
	  b_range[i] = e_range[i] = (unsigned)-1;
	else
	 { sh_sync(&b_range[i], fline, incr, 0);
	   sh_sync(&e_range[i], fline-stretch, incr, 1);
	 }
     }

    /* fix maxl */
    maxl += incr;

    /* adjust topl and maxl */
    while (topl+LASTINROW>maxl) inc_maxl();

    tmp_changed = true;
 }

/* procedure to help keep ranges, etc. in line */
sh_sync(a_var, fline, incr, adj)
int *a_var;
register int fline;
register int incr;
int adj;
 {  register int var = *a_var;

#ifdef DBUG
    if (dbug('g'))
      dbugprintf("in sh_sync - var is %d, fline %d, incr %d",
			var, fline, incr);
#endif
    if (var>=fline) var += incr;
    else
    if (var>=fline+incr) var = fline+incr-adj;
		/* special treatment for negative increments */

    *a_var = var;
#ifdef DBUG
    if (dbug('g'))
      dbugprintf("and now var is %d, fline %d, incr %d",
			*a_var, fline, incr);
#endif
 }


/* procedures to shift lines about */
copyline(source, destination)
register int source, destination;
 { register unsigned ls;

    while(source>maxl) inc_maxl();
    ls = l_offset[source];
    /* don't let shuffile delete any lines */
    xshuffile(destination, 1, 0);
    l_offset[destination] = ls;
 }

moveline(source, destination)
int source, destination;
 { register int i;

    copyline(source, destination);
    if (source >= destination) source++;

    for (i=0; i<NLETTS; i++)
     { if (b_range[i]==source) b_range[i] = destination;
	if (e_range[i]==source) e_range[i] = destination;
     }

    /* don't let shuffile alter any lines */
    xshuffile(source+1, -1, 0);
 }