1 /*
2 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 /**
27 * Jump scrolling
28 *
29 */
30
31 #include <assert.h>
32 #include <ipxe/keys.h>
33 #include <ipxe/jumpscroll.h>
34
35 /**
36 * Handle keypress
37 *
38 * @v scroll Jump scroller
39 * @v key Key pressed by user
40 * @ret move Scroller movement, or zero
41 */
jump_scroll_key(struct jump_scroller * scroll,int key)42 int jump_scroll_key ( struct jump_scroller *scroll, int key ) {
43
44 /* Sanity checks */
45 assert ( scroll->rows != 0 );
46 assert ( scroll->count != 0 );
47 assert ( scroll->current < scroll->count );
48 assert ( scroll->first < scroll->count );
49 assert ( scroll->first <= scroll->current );
50 assert ( scroll->current < ( scroll->first + scroll->rows ) );
51
52 /* Handle key, if applicable */
53 switch ( key ) {
54 case KEY_UP:
55 return -1;
56 case KEY_DOWN:
57 return +1;
58 case KEY_PPAGE:
59 return ( scroll->first - scroll->current - 1 );
60 case KEY_NPAGE:
61 return ( scroll->first - scroll->current + scroll->rows );
62 case KEY_HOME:
63 return -( scroll->count );
64 case KEY_END:
65 return +( scroll->count );
66 default:
67 return 0;
68 }
69 }
70
71 /**
72 * Move scroller
73 *
74 * @v scroll Jump scroller
75 * @v move Scroller movement
76 * @ret move Continuing scroller movement (if applicable)
77 */
jump_scroll_move(struct jump_scroller * scroll,int move)78 int jump_scroll_move ( struct jump_scroller *scroll, int move ) {
79 int current = scroll->current;
80 int last = ( scroll->count - 1 );
81
82 /* Sanity checks */
83 assert ( move != 0 );
84 assert ( scroll->count != 0 );
85
86 /* Move to the new current item */
87 current += move;
88
89 /* Check for start/end of list */
90 if ( current < 0 ) {
91 /* We have attempted to move before the start of the
92 * list. Move to the start of the list and continue
93 * moving forwards (if applicable).
94 */
95 scroll->current = 0;
96 return +1;
97 } else if ( current > last ) {
98 /* We have attempted to move after the end of the
99 * list. Move to the end of the list and continue
100 * moving backwards (if applicable).
101 */
102 scroll->current = last;
103 return -1;
104 } else {
105 /* Update the current item and continue moving in the
106 * same direction (if applicable).
107 */
108 scroll->current = current;
109 return ( ( move > 0 ) ? +1 : -1 );
110 }
111 }
112
113 /**
114 * Jump scroll to new page (if applicable)
115 *
116 * @v scroll Jump scroller
117 * @ret jumped Jumped to a new page
118 */
jump_scroll(struct jump_scroller * scroll)119 int jump_scroll ( struct jump_scroller *scroll ) {
120 unsigned int index;
121
122 /* Sanity checks */
123 assert ( scroll->rows != 0 );
124 assert ( scroll->count != 0 );
125 assert ( scroll->current < scroll->count );
126 assert ( scroll->first < scroll->count );
127
128 /* Do nothing if we are already on the correct page */
129 index = ( scroll->current - scroll->first );
130 if ( index < scroll->rows )
131 return 0;
132
133 /* Move to required page */
134 while ( scroll->first < scroll->current )
135 scroll->first += scroll->rows;
136 while ( scroll->first > scroll->current )
137 scroll->first -= scroll->rows;
138
139 return 1;
140 }
141