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/*
* Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/**
* Jump scrolling
*
*/
#include <assert.h>
#include <ipxe/keys.h>
#include <ipxe/jumpscroll.h>
/**
* Handle keypress
*
* @v scroll Jump scroller
* @v key Key pressed by user
* @ret move Scroller movement, or zero
*/
int jump_scroll_key ( struct jump_scroller *scroll, int key ) {
/* Sanity checks */
assert ( scroll->rows != 0 );
assert ( scroll->count != 0 );
assert ( scroll->current < scroll->count );
assert ( scroll->first < scroll->count );
assert ( scroll->first <= scroll->current );
assert ( scroll->current < ( scroll->first + scroll->rows ) );
/* Handle key, if applicable */
switch ( key ) {
case KEY_UP:
return -1;
case KEY_DOWN:
return +1;
case KEY_PPAGE:
return ( scroll->first - scroll->current - 1 );
case KEY_NPAGE:
return ( scroll->first - scroll->current + scroll->rows );
case KEY_HOME:
return -( scroll->count );
case KEY_END:
return +( scroll->count );
default:
return 0;
}
}
/**
* Move scroller
*
* @v scroll Jump scroller
* @v move Scroller movement
* @ret move Continuing scroller movement (if applicable)
*/
int jump_scroll_move ( struct jump_scroller *scroll, int move ) {
int current = scroll->current;
int last = ( scroll->count - 1 );
/* Sanity checks */
assert ( move != 0 );
assert ( scroll->count != 0 );
/* Move to the new current item */
current += move;
/* Check for start/end of list */
if ( current < 0 ) {
/* We have attempted to move before the start of the
* list. Move to the start of the list and continue
* moving forwards (if applicable).
*/
scroll->current = 0;
return +1;
} else if ( current > last ) {
/* We have attempted to move after the end of the
* list. Move to the end of the list and continue
* moving backwards (if applicable).
*/
scroll->current = last;
return -1;
} else {
/* Update the current item and continue moving in the
* same direction (if applicable).
*/
scroll->current = current;
return ( ( move > 0 ) ? +1 : -1 );
}
}
/**
* Jump scroll to new page (if applicable)
*
* @v scroll Jump scroller
* @ret jumped Jumped to a new page
*/
int jump_scroll ( struct jump_scroller *scroll ) {
unsigned int index;
/* Sanity checks */
assert ( scroll->rows != 0 );
assert ( scroll->count != 0 );
assert ( scroll->current < scroll->count );
assert ( scroll->first < scroll->count );
/* Do nothing if we are already on the correct page */
index = ( scroll->current - scroll->first );
if ( index < scroll->rows )
return 0;
/* Move to required page */
while ( scroll->first < scroll->current )
scroll->first += scroll->rows;
while ( scroll->first > scroll->current )
scroll->first -= scroll->rows;
return 1;
}
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