Commit 42918ba5 authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(compute_motion): Initialize prev_hpos.

(Fcompute_motion): New function.
parent a867a90a
......@@ -447,7 +447,7 @@ compute_motion (from, fromvpos, fromhpos, to, tovpos, tohpos, width, hscroll, ta
= XTYPE (current_buffer->selective_display) == Lisp_Int
? XINT (current_buffer->selective_display)
: !NILP (current_buffer->selective_display) ? -1 : 0;
int prev_vpos, prev_hpos;
int prev_vpos, prev_hpos = 0;
int selective_rlen
= (selective && dp && XTYPE (DISP_INVIS_VECTOR (dp)) == Lisp_Vector
? XVECTOR (DISP_INVIS_VECTOR (dp))->size : 0);
......@@ -605,6 +605,76 @@ compute_motion (from, fromvpos, fromhpos, to, tovpos, tohpos, width, hscroll, ta
return &val_compute_motion;
}
DEFUN ("compute-motion", Fcompute_motion, Scompute_motion, 6, 6, 0,
"Scan through the current buffer, calculating screen position.\n\
Scan the current buffer forward from offset FROM,\n\
assuming it is at position FROMPOS--a cons of the form (HPOS . VPOS)--\n\
to position TO or position TOPOS--another cons of the form (HPOS . VPOS)--\n\
and return the ending buffer position and screen location.\n\
\n\
There are two additional arguments:\n\
\n\
WIDTH is the number of columns available to display text;\n\
this affects handling of continuation lines.\n\
Use the value returned by `window-width' for the window of your choice.\n\
\n\
OFFSETS is either nil or a cons cell (HSCROLL . TAB-OFFSET).\n\
HSCROLL is the number of columns not being displayed at the left\n\
margin; this is usually taken from a window's hscroll member.\n\
TAB-OFFSET is the number of columns of the first tab that aren't\n\
being displayed, perhaps because the line was continued within it.\n\
\n\
The value is a list of five elements:\n\
(POS VPOS HPOS PREVHPOS CONTIN)\n\
POS is the buffer position where the scan stopped.\n\
VPOS is the vertical position where the scan stopped.\n\
HPOS is the horizontal position where the scan stopped.\n\
\n\
PREVHPOS is the horizontal position one character back from POS.\n\
CONTIN is t if a line was continued after (or within) the previous character.\n\
\n\
For example, to find the buffer position of column COL of line LINE\n\
of a certain window, pass the window's starting location as FROM\n\
and the window's upper-left coordinates as FROMPOS.\n\
Pass the buffer's (point-max) as TO, to limit the scan to the end of the\n\
visible section of the buffer, and pass LINE and COL as TOPOS.")
(from, frompos, to, topos, width, offsets)
Lisp_Object from, frompos, to, topos;
Lisp_Object width, offsets;
{
Lisp_Object bufpos, hpos, vpos, prevhpos, contin;
struct position *pos;
int hscroll, tab_offset;
CHECK_CONS (frompos, 0);
CHECK_CONS (topos, 0);
if (!NILP (offsets))
{
CHECK_CONS (offsets, 0);
hscroll = XINT (XCONS (offsets)->car);
tab_offset = XINT (XCONS (offsets)->cdr);
}
else
hscroll = tab_offset = 0;
pos = compute_motion (XINT (from), XINT (XCONS (frompos)->cdr),
XINT (XCONS (frompos)->car),
XINT (to), XINT (XCONS (topos)->cdr),
XINT (XCONS (topos)->car),
XINT (width), hscroll, tab_offset);
XFASTINT (bufpos) = pos->bufpos;
XFASTINT (hpos) = pos->hpos;
XSET (vpos, Lisp_Int, pos->vpos);
XFASTINT (prevhpos) = pos->prevhpos;
return Fcons (bufpos,
Fcons (hpos,
Fcons (vpos,
Fcons (prevhpos,
Fcons (pos->contin ? Qt : Qnil, Qnil)))));
}
/* Return the column of position POS in window W's buffer,
rounded down to a multiple of the internal width of W.
......@@ -771,4 +841,5 @@ Setting this variable automatically makes it local to the current buffer.");
defsubr (&Scurrent_column);
defsubr (&Smove_to_column);
defsubr (&Svertical_motion);
defsubr (&Scompute_motion);
}
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