vi/vs_relative.c

   1 /*-
   2  * Copyright (c) 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 1993, 1994, 1995, 1996
   5  *      Keith Bostic.  All rights reserved.
   6  *
   7  * See the LICENSE file for redistribution information.
   8  */
   9
  10 #include "config.h"
  11
  12 #ifndef lint
  13 static const char sccsid[] = "$Id: vs_relative.c,v 10.18 2001/07/08 13:02:48 skimo Exp $ (Berkeley) $Date: 2001/07/08 13:02:48 $";
  14 #endif /* not lint */
  15
  16 #include <sys/types.h>
  17 #include <sys/queue.h>
  18 #include <sys/time.h>
  19
  20 #include <bitstring.h>
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24
  25 #include "../common/common.h"
  26 #include "vi.h"
  27
  28 /*
  29  * vs_column --
  30  *      Return the logical column of the cursor in the line.
  31  *
  32  * PUBLIC: int vs_column __P((SCR *, size_t *));
  33  */
  34 int
  35 vs_column(SCR *sp, size_t *colp)
  36 {
  37         VI_PRIVATE *vip;
  38
  39         vip = VIP(sp);
  40
  41         *colp = (O_ISSET(sp, O_LEFTRIGHT) ?
  42             vip->sc_smap->coff : (vip->sc_smap->soff - 1) * sp->cols) +
  43             vip->sc_col - (O_ISSET(sp, O_NUMBER) ? O_NUMBER_LENGTH : 0);
  44         return (0);
  45 }
  46
  47 /*
  48  * vs_screens --
  49  *      Return the screens necessary to display the line, or if specified,
  50  *      the physical character column within the line, including space
  51  *      required for the O_NUMBER and O_LIST options.
  52  *
  53  * PUBLIC: size_t vs_screens __P((SCR *, db_recno_t, size_t *));
  54  */
  55 size_t
  56 vs_screens(SCR *sp, db_recno_t lno, size_t *cnop)
  57 {
  58         size_t cols, screens;
  59
  60         /* Left-right screens are simple, it's always 1. */
  61         if (O_ISSET(sp, O_LEFTRIGHT))
  62                 return (1);
  63
  64         /*
  65          * Check for a cached value.  We maintain a cache because, if the
  66          * line is large, this routine gets called repeatedly.  One other
  67          * hack, lots of time the cursor is on column one, which is an easy
  68          * one.
  69          */
  70         if (cnop == NULL) {
  71                 if (VIP(sp)->ss_lno == lno)
  72                         return (VIP(sp)->ss_screens);
  73         } else if (*cnop == 0)
  74                 return (1);
  75
  76         /* Figure out how many columns the line/column needs. */
  77         cols = vs_columns(sp, NULL, lno, cnop, NULL);
  78
  79         screens = (cols / sp->cols + (cols % sp->cols ? 1 : 0));
  80         if (screens == 0)
  81                 screens = 1;
  82
  83         /* Cache the value. */
  84         if (cnop == NULL) {
  85                 VIP(sp)->ss_lno = lno;
  86                 VIP(sp)->ss_screens = screens;
  87         }
  88         return (screens);
  89 }
  90
  91 /*
  92  * vs_columns --
  93  *      Return the screen columns necessary to display the line, or,
  94  *      if specified, the physical character column within the line.
  95  *
  96  * PUBLIC: size_t vs_columns __P((SCR *, CHAR_T *, db_recno_t, size_t *, size_t *));
  97  */
  98 size_t
  99 vs_columns(SCR *sp, CHAR_T *lp, db_recno_t lno, size_t *cnop, size_t *diffp)
 100 {
 101         size_t chlen, cno, curoff, last, len, scno;
 102         int ch, leftright, listset;
 103         CHAR_T *p;
 104
 105         /*
 106          * Initialize the screen offset.
 107          */
 108         scno = 0;
 109
 110         /* Leading number if O_NUMBER option set. */
 111         if (O_ISSET(sp, O_NUMBER))
 112                 scno += O_NUMBER_LENGTH;
 113
 114         /* Need the line to go any further. */
 115         if (lp == NULL) {
 116                 (void)db_get(sp, lno, 0, &lp, &len);
 117                 if (len == 0)
 118                         goto done;
 119         }
 120
 121         /* Missing or empty lines are easy. */
 122         if (lp == NULL) {
 123 done:           if (diffp != NULL)              /* XXX */
 124                         *diffp = 0;
 125                 return scno;
 126         }
 127
 128         /* Store away the values of the list and leftright edit options. */
 129         listset = O_ISSET(sp, O_LIST);
 130         leftright = O_ISSET(sp, O_LEFTRIGHT);
 131
 132         /*
 133          * Initialize the pointer into the buffer and current offset.
 134          */
 135         p = lp;
 136         curoff = 0;
 137
 138         /* Macro to return the display length of any signal character. */
 139 #define CHLEN(val) (ch = *(UCHAR_T *)p++) == '\t' &&                    \
 140             !listset ? TAB_OFF(val) : KEY_COL(sp, ch);
 141
 142         /*
 143          * If folding screens (the historic vi screen format), past the end
 144          * of the current screen, and the character was a tab, reset the
 145          * current screen column to 0, and the total screen columns to the
 146          * last column of the screen.  Otherwise, display the rest of the
 147          * character in the next screen.
 148          */
 149 #define TAB_RESET {                                                     \
 150         curoff += chlen;                                                \
 151         if (!leftright && curoff >= sp->cols)                           \
 152                 if (ch == '\t') {                                       \
 153                         curoff = 0;                                     \
 154                         scno -= scno % sp->cols;                        \
 155                 } else                                                  \
 156                         curoff -= sp->cols;                             \
 157 }
 158         if (cnop == NULL)
 159                 while (len--) {
 160                         chlen = CHLEN(curoff);
 161                         last = scno;
 162                         scno += chlen;
 163                         TAB_RESET;
 164                 }
 165         else
 166                 for (cno = *cnop;; --cno) {
 167                         chlen = CHLEN(curoff);
 168                         last = scno;
 169                         scno += chlen;
 170                         TAB_RESET;
 171                         if (cno == 0)
 172                                 break;
 173                 }
 174
 175         /* Add the trailing '$' if the O_LIST option set. */
 176         if (listset && cnop == NULL)
 177                 scno += KEY_LEN(sp, '$');
 178
 179         /*
 180          * The text input screen code needs to know how much additional
 181          * room the last two characters required, so that it can handle
 182          * tab character displays correctly.
 183          */
 184         if (diffp != NULL)
 185                 *diffp = scno - last;
 186         return (scno);
 187 }
 188
 189 /*
 190  * vs_rcm --
 191  *      Return the physical column from the line that will display a
 192  *      character closest to the currently most attractive character
 193  *      position (which is stored as a screen column).
 194  *
 195  * PUBLIC: size_t vs_rcm __P((SCR *, db_recno_t, int));
 196  */
 197 size_t
 198 vs_rcm(SCR *sp, db_recno_t lno, int islast)
 199 {
 200         size_t len;
 201
 202         /* Last character is easy, and common. */
 203         if (islast) {
 204                 if (db_get(sp, lno, 0, NULL, &len) || len == 0)
 205                         return (0);
 206                 return (len - 1);
 207         }
 208
 209         /* First character is easy, and common. */
 210         if (sp->rcm == 0)
 211                 return (0);
 212
 213         return (vs_colpos(sp, lno, sp->rcm));
 214 }
 215
 216 /*
 217  * vs_colpos --
 218  *      Return the physical column from the line that will display a
 219  *      character closest to the specified screen column.
 220  *
 221  * PUBLIC: size_t vs_colpos __P((SCR *, db_recno_t, size_t));
 222  */
 223 size_t
 224 vs_colpos(SCR *sp, db_recno_t lno, size_t cno)
 225 {
 226         size_t chlen, curoff, len, llen, off, scno;
 227         int ch, leftright, listset;
 228         CHAR_T *lp, *p;
 229
 230         /* Need the line to go any further. */
 231         (void)db_get(sp, lno, 0, &lp, &llen);
 232
 233         /* Missing or empty lines are easy. */
 234         if (lp == NULL || llen == 0)
 235                 return (0);
 236
 237         /* Store away the values of the list and leftright edit options. */
 238         listset = O_ISSET(sp, O_LIST);
 239         leftright = O_ISSET(sp, O_LEFTRIGHT);
 240
 241         /* Discard screen (logical) lines. */
 242         off = cno / sp->cols;
 243         cno %= sp->cols;
 244         for (scno = 0, p = lp, len = llen; off--;) {
 245                 for (; len && scno < sp->cols; --len)
 246                         scno += CHLEN(scno);
 247
 248                 /*
 249                  * If reached the end of the physical line, return the last
 250                  * physical character in the line.
 251                  */
 252                 if (len == 0)
 253                         return (llen - 1);
 254
 255                 /*
 256                  * If folding screens (the historic vi screen format), past
 257                  * the end of the current screen, and the character was a tab,
 258                  * reset the current screen column to 0.  Otherwise, the rest
 259                  * of the character is displayed in the next screen.
 260                  */
 261                 if (leftright && ch == '\t')
 262                         scno = 0;
 263                 else
 264                         scno -= sp->cols;
 265         }
 266
 267         /* Step through the line until reach the right character or EOL. */
 268         for (curoff = scno; len--;) {
 269                 chlen = CHLEN(curoff);
 270
 271                 /*
 272                  * If we've reached the specific character, there are three
 273                  * cases.
 274                  *
 275                  * 1: scno == cno, i.e. the current character ends at the
 276                  *    screen character we care about.
 277                  *      a: off < llen - 1, i.e. not the last character in
 278                  *         the line, return the offset of the next character.
 279                  *      b: else return the offset of the last character.
 280                  * 2: scno != cno, i.e. this character overruns the character
 281                  *    we care about, return the offset of this character.
 282                  */
 283                 if ((scno += chlen) >= cno) {
 284                         off = p - lp;
 285                         return (scno == cno ?
 286                             (off < llen - 1 ? off : llen - 1) : off - 1);
 287                 }
 288
 289                 TAB_RESET;
 290         }
 291
 292         /* No such character; return the start of the last character. */
 293         return (llen - 1);
 294 }