2 * Line6 Linux USB driver - 0.8.0
4 * Copyright (C) 2004-2009 Markus Grabner (grabner@icg.tugraz.at)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2.
14 #include <linux/slab.h>
19 static int midibuf_message_length(unsigned char code
)
23 else if(code
< 0xf0) {
24 static const int length
[] = { 3, 3, 3, 3, 2, 2, 3 };
25 return length
[(code
>> 4) - 8];
29 Note that according to the MIDI specification 0xf2 is the "Song Position
30 Pointer", but this is used by Line6 to send sysex messages to the host.
32 static const int length
[] = { -1, 2, -1, 2, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 1 };
33 return length
[code
& 0x0f];
37 void midibuf_reset(struct MidiBuffer
*this)
39 this->pos_read
= this->pos_write
= this->full
= 0;
40 this->command_prev
= -1;
43 int midibuf_init(struct MidiBuffer
*this, int size
, int split
)
45 this->buf
= (unsigned char *)kmalloc(size
, GFP_KERNEL
);
47 if (this->buf
== NULL
)
56 void midibuf_status(struct MidiBuffer
*this)
58 printk("midibuf size=%d split=%d pos_read=%d pos_write=%d full=%d command_prev=%02x\n",
59 this->size
, this->split
, this->pos_read
, this->pos_write
, this->full
, this->command_prev
);
62 static int midibuf_is_empty(struct MidiBuffer
*this)
64 return (this->pos_read
== this->pos_write
) && !this->full
;
67 static int midibuf_is_full(struct MidiBuffer
*this)
72 int midibuf_bytes_free(struct MidiBuffer
*this)
75 midibuf_is_full(this) ?
77 (this->pos_read
- this->pos_write
+ this->size
- 1) % this->size
+ 1;
80 int midibuf_bytes_used(struct MidiBuffer
*this)
83 midibuf_is_empty(this) ?
85 (this->pos_write
- this->pos_read
+ this->size
- 1) % this->size
+ 1;
88 int midibuf_write(struct MidiBuffer
*this, unsigned char *data
, int length
)
92 int skip_active_sense
= 0;
94 if(midibuf_is_full(this) || (length
<= 0))
97 /* skip trailing active sense */
98 if(data
[length
- 1] == 0xfe) {
100 skip_active_sense
= 1;
103 bytes_free
= midibuf_bytes_free(this);
105 if(length
> bytes_free
)
109 length1
= this->size
- this->pos_write
;
111 if(length
< length1
) {
112 /* no buffer wraparound */
113 memcpy(this->buf
+ this->pos_write
, data
, length
);
114 this->pos_write
+= length
;
117 /* buffer wraparound */
118 length2
= length
- length1
;
119 memcpy(this->buf
+ this->pos_write
, data
, length1
);
120 memcpy(this->buf
, data
+ length1
, length2
);
121 this->pos_write
= length2
;
124 if(this->pos_write
== this->pos_read
)
128 return length
+ skip_active_sense
;
131 int midibuf_read(struct MidiBuffer
*this, unsigned char *data
, int length
)
134 int length1
, length2
;
141 return -EINVAL
; /* we need to be able to store at least a 3 byte MIDI message */
143 if(midibuf_is_empty(this))
146 bytes_used
= midibuf_bytes_used(this);
148 if(length
> bytes_used
)
151 length1
= this->size
- this->pos_read
;
153 /* check MIDI command length */
154 command
= this->buf
[this->pos_read
];
157 midi_length
= midibuf_message_length(command
);
158 this->command_prev
= command
;
161 if(this->command_prev
> 0) {
162 int midi_length_prev
= midibuf_message_length(this->command_prev
);
164 if(midi_length_prev
> 0) {
165 midi_length
= midi_length_prev
- 1;
175 if(midi_length
< 0) {
176 /* search for end of message */
177 if(length
< length1
) {
178 /* no buffer wraparound */
179 for(i
= 1; i
< length
; ++i
)
180 if(this->buf
[this->pos_read
+ i
] & 0x80)
186 /* buffer wraparound */
187 length2
= length
- length1
;
189 for(i
= 1; i
< length1
; ++i
)
190 if(this->buf
[this->pos_read
+ i
] & 0x80)
196 for(i
= 0; i
< length2
; ++i
)
197 if(this->buf
[i
] & 0x80)
200 midi_length
= length1
+ i
;
204 if(midi_length
== length
)
205 midi_length
= -1; /* end of message not found */
208 if(midi_length
< 0) {
210 return 0; /* command is not yet complete */
213 if(length
< midi_length
)
214 return 0; /* command is not yet complete */
216 length
= midi_length
;
219 if(length
< length1
) {
220 /* no buffer wraparound */
221 memcpy(data
+ repeat
, this->buf
+ this->pos_read
, length
);
222 this->pos_read
+= length
;
225 /* buffer wraparound */
226 length2
= length
- length1
;
227 memcpy(data
+ repeat
, this->buf
+ this->pos_read
, length1
);
228 memcpy(data
+ repeat
+ length1
, this->buf
, length2
);
229 this->pos_read
= length2
;
233 data
[0] = this->command_prev
;
236 return length
+ repeat
;
239 int midibuf_ignore(struct MidiBuffer
*this, int length
)
241 int bytes_used
= midibuf_bytes_used(this);
243 if(length
> bytes_used
)
246 this->pos_read
= (this->pos_read
+ length
) % this->size
;
251 int midibuf_skip_message(struct MidiBuffer
*this, unsigned short mask
)
253 int cmd
= this->command_prev
;
255 if((cmd
>= 0x80) && (cmd
< 0xf0))
256 if((mask
& (1 << (cmd
& 0x0f))) == 0)
262 void midibuf_destroy(struct MidiBuffer
*this)