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

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

/* to allow for differing screen sizes, ded must
 * allocate its own store
 */

extern char *sbrk(); /* declaration to shut lint up */

char *my_alloc(size)
int size;
 {  register char *new;
    register int rsize = (size+sizeof(int)) & ~(sizeof(int)-1);

    if ( (new = sbrk(rsize)) == (char *) -1)
      editerror("no more room (my_alloc)");

    curr_break = new+rsize;
    return(new);
 }

char **newscreen()
 {  register char **res, *map;
    register int row;
    int width;

    res = (char **) my_alloc(nrows*sizeof(char *));
    width = (ncols+sizeof(int)) & ~(sizeof(int)-1);
    map = my_alloc(nrows*width);

    /* set pointers in map */
    for (row=0; row<nrows; row++)
      res[row] = map+row*width;

    return(res);
 }

/************************************************************************
 *                                                                      *
 *                      procedures to handle                            *
 *                      topl and maxl                                   *
 *                                                                      *
 ************************************************************************/

inc_topl()
 {  topl++;
    while (topl+LASTINROW>maxl) inc_maxl();
 }

dec_topl()
 { topl--; adj_maxl(); }

inc_maxl()
 { if (++maxl>NLINES)
      editerror("too many lines in file (inc_topl)");
    else
      l_offset[maxl] = -1;
 }

/* strip trailing blank lines from the file -
 * but not if there are any refs to the last line
 */
adj_maxl()
{  register int i;
   while (maxl>topl+LASTINROW && l_offset[maxl] == (unsigned) -1)
    { for (i=0; i<NLETTS; i++)
	 if (b_range[i]==maxl || e_range[i]==maxl) return;
       maxl--;
    }
 }

/* make a reasonable value of topl and maxl at beginning of edit */
adj_origin(fline)
 {  while (topl<0) topl++;
    while (topl>0 && maxl<topl+LASTINROW && fline<topl+LASTINROW) topl--;
    while (maxl<topl+LASTINROW) inc_maxl();
 }