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