NetBSD-5.0.2/dist/nvi/vi/v_scroll.c
/* $NetBSD: v_scroll.c,v 1.1.1.2.6.1 2009/01/20 02:41:13 snj Exp $ */
/*-
* Copyright (c) 1992, 1993, 1994
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1992, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*
* See the LICENSE file for redistribution information.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "Id: v_scroll.c,v 10.12 2001/06/25 15:19:34 skimo Exp (Berkeley) Date: 2001/06/25 15:19:34";
#endif /* not lint */
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>
#include <bitstring.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include "../common/common.h"
#include "vi.h"
static void goto_adjust __P((VICMD *));
/*
* The historic vi had a problem in that all movements were by physical
* lines, not by logical, or screen lines. Arguments can be made that this
* is the right thing to do. For example, single line movements, such as
* 'j' or 'k', should probably work on physical lines. Commands like "dj",
* or "j.", where '.' is a change command, make more sense for physical lines
* than they do for logical lines.
*
* These arguments, however, don't apply to scrolling commands like ^D and
* ^F -- if the window is fairly small, using physical lines can result in
* a half-page scroll repainting the entire screen, which is not what the
* user wanted. Second, if the line is larger than the screen, using physical
* lines can make it impossible to display parts of the line -- there aren't
* any commands that don't display the beginning of the line in historic vi,
* and if both the beginning and end of the line can't be on the screen at
* the same time, you lose. This is even worse in the case of the H, L, and
* M commands -- for large lines, they may all refer to the same line and
* will result in no movement at all.
*
* Another issue is that page and half-page scrolling commands historically
* moved to the first non-blank character in the new line. If the line is
* approximately the same size as the screen, this loses because the cursor
* before and after a ^D, may refer to the same location on the screen. In
* this implementation, scrolling commands set the cursor to the first non-
* blank character if the line changes because of the scroll. Otherwise,
* the cursor is left alone.
*
* This implementation does the scrolling (^B, ^D, ^F, ^U, ^Y, ^E), and the
* cursor positioning commands (H, L, M) commands using logical lines, not
* physical.
*/
/*
* v_lgoto -- [count]G
* Go to first non-blank character of the line count, the last line
* of the file by default.
*
* PUBLIC: int v_lgoto __P((SCR *, VICMD *));
*/
int
v_lgoto(SCR *sp, VICMD *vp)
{
db_recno_t nlines;
if (F_ISSET(vp, VC_C1SET)) {
if (!db_exist(sp, vp->count)) {
/*
* !!!
* Historically, 1G was legal in an empty file.
*/
if (vp->count == 1) {
if (db_last(sp, &nlines))
return (1);
if (nlines == 0)
return (0);
}
v_eof(sp, &vp->m_start);
return (1);
}
vp->m_stop.lno = vp->count;
} else {
if (db_last(sp, &nlines))
return (1);
vp->m_stop.lno = nlines ? nlines : 1;
}
goto_adjust(vp);
return (0);
}
/*
* v_home -- [count]H
* Move to the first non-blank character of the logical line
* count - 1 from the top of the screen, 0 by default.
*
* PUBLIC: int v_home __P((SCR *, VICMD *));
*/
int
v_home(SCR *sp, VICMD *vp)
{
if (vs_sm_position(sp, &vp->m_stop,
F_ISSET(vp, VC_C1SET) ? vp->count - 1 : 0, P_TOP))
return (1);
goto_adjust(vp);
return (0);
}
/*
* v_middle -- M
* Move to the first non-blank character of the logical line
* in the middle of the screen.
*
* PUBLIC: int v_middle __P((SCR *, VICMD *));
*/
int
v_middle(SCR *sp, VICMD *vp)
{
/*
* Yielding to none in our quest for compatibility with every
* historical blemish of vi, no matter how strange it might be,
* we permit the user to enter a count and then ignore it.
*/
if (vs_sm_position(sp, &vp->m_stop, 0, P_MIDDLE))
return (1);
goto_adjust(vp);
return (0);
}
/*
* v_bottom -- [count]L
* Move to the first non-blank character of the logical line
* count - 1 from the bottom of the screen, 0 by default.
*
* PUBLIC: int v_bottom __P((SCR *, VICMD *));
*/
int
v_bottom(SCR *sp, VICMD *vp)
{
if (vs_sm_position(sp, &vp->m_stop,
F_ISSET(vp, VC_C1SET) ? vp->count - 1 : 0, P_BOTTOM))
return (1);
goto_adjust(vp);
return (0);
}
static void
goto_adjust(VICMD *vp)
{
/* Guess that it's the end of the range. */
vp->m_final = vp->m_stop;
/*
* Non-motion commands move the cursor to the end of the range, and
* then to the NEXT nonblank of the line. Historic vi always moved
* to the first nonblank in the line; since the H, M, and L commands
* are logical motions in this implementation, we do the next nonblank
* so that it looks approximately the same to the user. To make this
* happen, the VM_RCM_SETNNB flag is set in the vcmd.c command table.
*
* If it's a motion, it's more complicated. The best possible solution
* is probably to display the first nonblank of the line the cursor
* will eventually rest on. This is tricky, particularly given that if
* the associated command is a delete, we don't yet know what line that
* will be. So, we clear the VM_RCM_SETNNB flag, and set the first
* nonblank flag (VM_RCM_SETFNB). Note, if the lines are sufficiently
* long, this can cause the cursor to warp out of the screen. It's too
* hard to fix.
*
* XXX
* The G command is always first nonblank, so it's okay to reset it.
*/
if (ISMOTION(vp)) {
F_CLR(vp, VM_RCM_MASK);
F_SET(vp, VM_RCM_SETFNB);
} else
return;
/*
* If moving backward in the file, delete and yank move to the end
* of the range, unless the line didn't change, in which case yank
* doesn't move. If moving forward in the file, delete and yank
* stay at the start of the range. Ignore others.
*/
if (vp->m_stop.lno < vp->m_start.lno ||
(vp->m_stop.lno == vp->m_start.lno &&
vp->m_stop.cno < vp->m_start.cno)) {
if (ISCMD(vp->rkp, 'y') && vp->m_stop.lno == vp->m_start.lno)
vp->m_final = vp->m_start;
} else
vp->m_final = vp->m_start;
}
/*
* v_up -- [count]^P, [count]k, [count]-
* Move up by lines.
*
* PUBLIC: int v_up __P((SCR *, VICMD *));
*/
int
v_up(SCR *sp, VICMD *vp)
{
db_recno_t lno;
lno = F_ISSET(vp, VC_C1SET) ? vp->count : 1;
if (vp->m_start.lno <= lno) {
v_sof(sp, &vp->m_start);
return (1);
}
vp->m_stop.lno = vp->m_start.lno - lno;
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_cr -- [count]^M
* In a script window, send the line to the shell.
* In a regular window, move down by lines.
*
* PUBLIC: int v_cr __P((SCR *, VICMD *));
*/
int
v_cr(SCR *sp, VICMD *vp)
{
/* If it's a colon command-line edit window, it's an ex command. */
if (F_ISSET(sp, SC_COMEDIT))
return (v_ecl_exec(sp));
/* If it's a script window, exec the line. */
if (F_ISSET(sp, SC_SCRIPT))
return (sscr_exec(sp, vp->m_start.lno));
/* Otherwise, it's the same as v_down(). */
return (v_down(sp, vp));
}
/*
* v_down -- [count]^J, [count]^N, [count]j, [count]^M, [count]+
* Move down by lines.
*
* PUBLIC: int v_down __P((SCR *, VICMD *));
*/
int
v_down(SCR *sp, VICMD *vp)
{
db_recno_t lno;
lno = vp->m_start.lno + (F_ISSET(vp, VC_C1SET) ? vp->count : 1);
if (!db_exist(sp, lno)) {
v_eof(sp, &vp->m_start);
return (1);
}
vp->m_stop.lno = lno;
vp->m_final = ISMOTION(vp) ? vp->m_start : vp->m_stop;
return (0);
}
/*
* v_hpageup -- [count]^U
* Page up half screens.
*
* PUBLIC: int v_hpageup __P((SCR *, VICMD *));
*/
int
v_hpageup(SCR *sp, VICMD *vp)
{
/*
* Half screens always succeed unless already at SOF.
*
* !!!
* Half screens set the scroll value, even if the command
* ultimately failed, in historic vi. Probably a don't care.
*/
if (F_ISSET(vp, VC_C1SET))
sp->defscroll = vp->count;
if (vs_sm_scroll(sp, &vp->m_stop, sp->defscroll, CNTRL_U))
return (1);
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_hpagedown -- [count]^D
* Page down half screens.
*
* PUBLIC: int v_hpagedown __P((SCR *, VICMD *));
*/
int
v_hpagedown(SCR *sp, VICMD *vp)
{
/*
* Half screens always succeed unless already at EOF.
*
* !!!
* Half screens set the scroll value, even if the command
* ultimately failed, in historic vi. Probably a don't care.
*/
if (F_ISSET(vp, VC_C1SET))
sp->defscroll = vp->count;
if (vs_sm_scroll(sp, &vp->m_stop, sp->defscroll, CNTRL_D))
return (1);
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_pagedown -- [count]^F
* Page down full screens.
* !!!
* Historic vi did not move to the EOF if the screen couldn't move, i.e.
* if EOF was already displayed on the screen. This implementation does
* move to EOF in that case, making ^F more like the the historic ^D.
*
* PUBLIC: int v_pagedown __P((SCR *, VICMD *));
*/
int
v_pagedown(SCR *sp, VICMD *vp)
{
db_recno_t offset;
/*
* !!!
* The calculation in IEEE Std 1003.2-1992 (POSIX) is:
*
* top_line = top_line + count * (window - 2);
*
* which was historically wrong. The correct one is:
*
* top_line = top_line + count * window - 2;
*
* i.e. the two line "overlap" was only subtracted once. Which
* makes no sense, but then again, an overlap makes no sense for
* any screen but the "next" one anyway. We do it the historical
* way as there's no good reason to change it.
*
* If the screen has been split horizontally, use the smaller of
* the current window size and the window option value.
*
* It possible for this calculation to be less than 1; move at
* least one line.
*/
offset = (F_ISSET(vp, VC_C1SET) ? vp->count : 1) * (IS_HSPLIT(sp) ?
MIN(sp->t_maxrows, O_VAL(sp, O_WINDOW)) : O_VAL(sp, O_WINDOW));
offset = offset <= 2 ? 1 : offset - 2;
if (vs_sm_scroll(sp, &vp->m_stop, offset, CNTRL_F))
return (1);
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_pageup -- [count]^B
* Page up full screens.
*
* !!!
* Historic vi did not move to the SOF if the screen couldn't move, i.e.
* if SOF was already displayed on the screen. This implementation does
* move to SOF in that case, making ^B more like the the historic ^U.
*
* PUBLIC: int v_pageup __P((SCR *, VICMD *));
*/
int
v_pageup(SCR *sp, VICMD *vp)
{
db_recno_t offset;
/*
* !!!
* The calculation in IEEE Std 1003.2-1992 (POSIX) is:
*
* top_line = top_line - count * (window - 2);
*
* which was historically wrong. The correct one is:
*
* top_line = (top_line - count * window) + 2;
*
* A simpler expression is that, as with ^F, we scroll exactly:
*
* count * window - 2
*
* lines.
*
* Bizarre. As with ^F, an overlap makes no sense for anything
* but the first screen. We do it the historical way as there's
* no good reason to change it.
*
* If the screen has been split horizontally, use the smaller of
* the current window size and the window option value.
*
* It possible for this calculation to be less than 1; move at
* least one line.
*/
offset = (F_ISSET(vp, VC_C1SET) ? vp->count : 1) * (IS_HSPLIT(sp) ?
MIN(sp->t_maxrows, O_VAL(sp, O_WINDOW)) : O_VAL(sp, O_WINDOW));
offset = offset <= 2 ? 1 : offset - 2;
if (vs_sm_scroll(sp, &vp->m_stop, offset, CNTRL_B))
return (1);
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_lineup -- [count]^Y
* Page up by lines.
*
* PUBLIC: int v_lineup __P((SCR *, VICMD *));
*/
int
v_lineup(SCR *sp, VICMD *vp)
{
/*
* The cursor moves down, staying with its original line, unless it
* reaches the bottom of the screen.
*/
if (vs_sm_scroll(sp,
&vp->m_stop, F_ISSET(vp, VC_C1SET) ? vp->count : 1, CNTRL_Y))
return (1);
vp->m_final = vp->m_stop;
return (0);
}
/*
* v_linedown -- [count]^E
* Page down by lines.
*
* PUBLIC: int v_linedown __P((SCR *, VICMD *));
*/
int
v_linedown(SCR *sp, VICMD *vp)
{
/*
* The cursor moves up, staying with its original line, unless it
* reaches the top of the screen.
*/
if (vs_sm_scroll(sp,
&vp->m_stop, F_ISSET(vp, VC_C1SET) ? vp->count : 1, CNTRL_E))
return (1);
vp->m_final = vp->m_stop;
return (0);
}