1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
|
/*
* Line 6 Linux USB driver
*
* Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
*
* 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, version 2.
*
*/
#include <linux/slab.h>
#include "midibuf.h"
static int midibuf_message_length(unsigned char code)
{
int message_length;
if (code < 0x80)
message_length = -1;
else if (code < 0xf0) {
static const int length[] = { 3, 3, 3, 3, 2, 2, 3 };
message_length = length[(code >> 4) - 8];
} else {
/*
Note that according to the MIDI specification 0xf2 is
the "Song Position Pointer", but this is used by Line 6
to send sysex messages to the host.
*/
static const int length[] = { -1, 2, -1, 2, -1, -1, 1, 1, 1, 1,
1, 1, 1, -1, 1, 1
};
message_length = length[code & 0x0f];
}
return message_length;
}
static int midibuf_is_empty(struct midi_buffer *this)
{
return (this->pos_read == this->pos_write) && !this->full;
}
static int midibuf_is_full(struct midi_buffer *this)
{
return this->full;
}
void line6_midibuf_reset(struct midi_buffer *this)
{
this->pos_read = this->pos_write = this->full = 0;
this->command_prev = -1;
}
int line6_midibuf_init(struct midi_buffer *this, int size, int split)
{
this->buf = kmalloc(size, GFP_KERNEL);
if (this->buf == NULL)
return -ENOMEM;
this->size = size;
this->split = split;
line6_midibuf_reset(this);
return 0;
}
int line6_midibuf_bytes_free(struct midi_buffer *this)
{
return
midibuf_is_full(this) ?
0 :
(this->pos_read - this->pos_write + this->size - 1) % this->size +
1;
}
int line6_midibuf_bytes_used(struct midi_buffer *this)
{
return
midibuf_is_empty(this) ?
0 :
(this->pos_write - this->pos_read + this->size - 1) % this->size +
1;
}
int line6_midibuf_write(struct midi_buffer *this, unsigned char *data,
int length)
{
int bytes_free;
int length1, length2;
int skip_active_sense = 0;
if (midibuf_is_full(this) || (length <= 0))
return 0;
/* skip trailing active sense */
if (data[length - 1] == 0xfe) {
--length;
skip_active_sense = 1;
}
bytes_free = line6_midibuf_bytes_free(this);
if (length > bytes_free)
length = bytes_free;
if (length > 0) {
length1 = this->size - this->pos_write;
if (length < length1) {
/* no buffer wraparound */
memcpy(this->buf + this->pos_write, data, length);
this->pos_write += length;
} else {
/* buffer wraparound */
length2 = length - length1;
memcpy(this->buf + this->pos_write, data, length1);
memcpy(this->buf, data + length1, length2);
this->pos_write = length2;
}
if (this->pos_write == this->pos_read)
this->full = 1;
}
return length + skip_active_sense;
}
int line6_midibuf_read(struct midi_buffer *this, unsigned char *data,
int length)
{
int bytes_used;
int length1, length2;
int command;
int midi_length;
int repeat = 0;
int i;
/* we need to be able to store at least a 3 byte MIDI message */
if (length < 3)
return -EINVAL;
if (midibuf_is_empty(this))
return 0;
bytes_used = line6_midibuf_bytes_used(this);
if (length > bytes_used)
length = bytes_used;
length1 = this->size - this->pos_read;
/* check MIDI command length */
command = this->buf[this->pos_read];
if (command & 0x80) {
midi_length = midibuf_message_length(command);
this->command_prev = command;
} else {
if (this->command_prev > 0) {
int midi_length_prev =
midibuf_message_length(this->command_prev);
if (midi_length_prev > 0) {
midi_length = midi_length_prev - 1;
repeat = 1;
} else
midi_length = -1;
} else
midi_length = -1;
}
if (midi_length < 0) {
/* search for end of message */
if (length < length1) {
/* no buffer wraparound */
for (i = 1; i < length; ++i)
if (this->buf[this->pos_read + i] & 0x80)
break;
midi_length = i;
} else {
/* buffer wraparound */
length2 = length - length1;
for (i = 1; i < length1; ++i)
if (this->buf[this->pos_read + i] & 0x80)
break;
if (i < length1)
midi_length = i;
else {
for (i = 0; i < length2; ++i)
if (this->buf[i] & 0x80)
break;
midi_length = length1 + i;
}
}
if (midi_length == length)
midi_length = -1; /* end of message not found */
}
if (midi_length < 0) {
if (!this->split)
return 0; /* command is not yet complete */
} else {
if (length < midi_length)
return 0; /* command is not yet complete */
length = midi_length;
}
if (length < length1) {
/* no buffer wraparound */
memcpy(data + repeat, this->buf + this->pos_read, length);
this->pos_read += length;
} else {
/* buffer wraparound */
length2 = length - length1;
memcpy(data + repeat, this->buf + this->pos_read, length1);
memcpy(data + repeat + length1, this->buf, length2);
this->pos_read = length2;
}
if (repeat)
data[0] = this->command_prev;
this->full = 0;
return length + repeat;
}
int line6_midibuf_ignore(struct midi_buffer *this, int length)
{
int bytes_used = line6_midibuf_bytes_used(this);
if (length > bytes_used)
length = bytes_used;
this->pos_read = (this->pos_read + length) % this->size;
this->full = 0;
return length;
}
int line6_midibuf_skip_message(struct midi_buffer *this, unsigned short mask)
{
int cmd = this->command_prev;
if ((cmd >= 0x80) && (cmd < 0xf0))
if ((mask & (1 << (cmd & 0x0f))) == 0)
return 1;
return 0;
}
void line6_midibuf_destroy(struct midi_buffer *this)
{
kfree(this->buf);
this->buf = NULL;
}
|
