#include "ded.h"
#include "char.h"

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

/************************************************************************
 *                                                                      *
 *                      the Harold Thimbleby                            *
 *                      word boundary algorithm                         *
 *                                                                      *
 ************************************************************************/

wordb(str, scol, lmarg, rmarg)
char *str;
register int scol;
int lmarg, rmarg;
 {  register char *rp = str+scol;
    register char c = *rp--; /* point rp one position back */

    if (scol<=lmarg || scol>rmarg) return(true);
    else
    if (c==c_SPACE)
      /* only if previous char is space and one before that isn't */
      return(scol>lmarg+1 && *rp--==c_SPACE && *rp--!=c_SPACE);
    else
    if (alphmer(c)) return(!alphmer(*rp));
    else
      return(true); /* always word boundary at punctuation */
 }

/************************************************************************
 *                                                                      *
 *              find start of word back (left) or next (right)          *
 *                                                                      *
 ************************************************************************/

left_word(scol)
int scol;
 {  register int vcr = virt_c.row;
    char *rp = rowmap[vcr];

    return(l_word(rp, scol, lmargin(vcr), rmargin(vcr)));
 }

l_word(rp, scol, lmarg, rmarg)
char *rp;
register int scol;
register int lmarg;
register int rmarg;
 {  if (scol<=lmarg) scol=lmarg;
    else
    if (scol>rmarg+1) scol=rmarg+1;
    else
      do scol--; while (!wordb(rp, scol, lmarg, rmarg));

    return(scol);
 }

right_word(scol)
int scol;
 {   register int vcr = virt_c.row, rgc = rightcol;
     char *rp = rowmap[vcr];
     register int rw;

    rw = r_word(rp, scol, lmargin(vcr), rmargin(vcr));
    if (rw>rgc && rp[rgc]==c_SPACE) rw=rgc;

    return(rw);
 }

r_word(rp, scol, lmarg, rmarg)
register char *rp;
register int scol;
int lmarg;
register int rmarg;
 {  if (scol>=rmarg) scol=rmarg+1;
    else
    if (scol<lmarg) scol=lmarg;
    else
     {  if (rp[scol]==c_SPACE && rp[scol+1]==c_SPACE) scol++;
	do scol++; while (!wordb(rp, scol, lmarg, rmarg));
     }

    return(scol);
 }