Commit | Line | Data |
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705ececd MG |
1 | /* |
2 | * Line6 Linux USB driver - 0.8.0 | |
3 | * | |
4 | * Copyright (C) 2004-2009 Markus Grabner (grabner@icg.tugraz.at) | |
5 | * | |
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. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include "config.h" | |
13 | ||
14 | #include <linux/slab.h> | |
15 | ||
16 | #include "midibuf.h" | |
17 | ||
18 | ||
b702ed25 | 19 | static int midibuf_message_length(unsigned char code) |
705ececd | 20 | { |
ce9b490c | 21 | if (code < 0x80) |
705ececd | 22 | return -1; |
ce9b490c | 23 | else if (code < 0xf0) { |
705ececd MG |
24 | static const int length[] = { 3, 3, 3, 3, 2, 2, 3 }; |
25 | return length[(code >> 4) - 8]; | |
ce9b490c | 26 | } else { |
705ececd | 27 | /* |
ce9b490c GKH |
28 | Note that according to the MIDI specification 0xf2 is |
29 | the "Song Position Pointer", but this is used by Line6 | |
30 | to send sysex messages to the host. | |
705ececd | 31 | */ |
ce9b490c GKH |
32 | static const int length[] = { -1, 2, -1, 2, -1, -1, 1, 1, 1, 1, |
33 | 1, 1, 1, -1, 1, 1 }; | |
705ececd MG |
34 | return length[code & 0x0f]; |
35 | } | |
36 | } | |
37 | ||
38 | void midibuf_reset(struct MidiBuffer *this) | |
39 | { | |
40 | this->pos_read = this->pos_write = this->full = 0; | |
41 | this->command_prev = -1; | |
42 | } | |
43 | ||
44 | int midibuf_init(struct MidiBuffer *this, int size, int split) | |
45 | { | |
ce9b490c | 46 | this->buf = kmalloc(size, GFP_KERNEL); |
705ececd | 47 | |
536165d8 | 48 | if (this->buf == NULL) |
705ececd MG |
49 | return -ENOMEM; |
50 | ||
51 | this->size = size; | |
52 | this->split = split; | |
53 | midibuf_reset(this); | |
54 | return 0; | |
55 | } | |
56 | ||
57 | void midibuf_status(struct MidiBuffer *this) | |
58 | { | |
ce9b490c GKH |
59 | printk(KERN_DEBUG "midibuf size=%d split=%d pos_read=%d pos_write=%d " |
60 | "full=%d command_prev=%02x\n", this->size, this->split, | |
61 | this->pos_read, this->pos_write, this->full, this->command_prev); | |
705ececd MG |
62 | } |
63 | ||
b702ed25 | 64 | static int midibuf_is_empty(struct MidiBuffer *this) |
705ececd MG |
65 | { |
66 | return (this->pos_read == this->pos_write) && !this->full; | |
67 | } | |
68 | ||
b702ed25 | 69 | static int midibuf_is_full(struct MidiBuffer *this) |
705ececd MG |
70 | { |
71 | return this->full; | |
72 | } | |
73 | ||
74 | int midibuf_bytes_free(struct MidiBuffer *this) | |
75 | { | |
76 | return | |
77 | midibuf_is_full(this) ? | |
78 | 0 : | |
79 | (this->pos_read - this->pos_write + this->size - 1) % this->size + 1; | |
80 | } | |
81 | ||
82 | int midibuf_bytes_used(struct MidiBuffer *this) | |
83 | { | |
84 | return | |
85 | midibuf_is_empty(this) ? | |
86 | 0 : | |
87 | (this->pos_write - this->pos_read + this->size - 1) % this->size + 1; | |
88 | } | |
89 | ||
90 | int midibuf_write(struct MidiBuffer *this, unsigned char *data, int length) | |
91 | { | |
92 | int bytes_free; | |
93 | int length1, length2; | |
94 | int skip_active_sense = 0; | |
95 | ||
ce9b490c | 96 | if (midibuf_is_full(this) || (length <= 0)) |
705ececd MG |
97 | return 0; |
98 | ||
99 | /* skip trailing active sense */ | |
ce9b490c | 100 | if (data[length - 1] == 0xfe) { |
705ececd MG |
101 | --length; |
102 | skip_active_sense = 1; | |
103 | } | |
104 | ||
105 | bytes_free = midibuf_bytes_free(this); | |
106 | ||
ce9b490c | 107 | if (length > bytes_free) |
705ececd MG |
108 | length = bytes_free; |
109 | ||
ce9b490c | 110 | if (length > 0) { |
705ececd MG |
111 | length1 = this->size - this->pos_write; |
112 | ||
ce9b490c | 113 | if (length < length1) { |
705ececd MG |
114 | /* no buffer wraparound */ |
115 | memcpy(this->buf + this->pos_write, data, length); | |
116 | this->pos_write += length; | |
ce9b490c | 117 | } else { |
705ececd MG |
118 | /* buffer wraparound */ |
119 | length2 = length - length1; | |
120 | memcpy(this->buf + this->pos_write, data, length1); | |
121 | memcpy(this->buf, data + length1, length2); | |
122 | this->pos_write = length2; | |
123 | } | |
124 | ||
ce9b490c | 125 | if (this->pos_write == this->pos_read) |
705ececd MG |
126 | this->full = 1; |
127 | } | |
128 | ||
129 | return length + skip_active_sense; | |
130 | } | |
131 | ||
132 | int midibuf_read(struct MidiBuffer *this, unsigned char *data, int length) | |
133 | { | |
134 | int bytes_used; | |
135 | int length1, length2; | |
136 | int command; | |
137 | int midi_length; | |
138 | int repeat = 0; | |
139 | int i; | |
140 | ||
ce9b490c GKH |
141 | /* we need to be able to store at least a 3 byte MIDI message */ |
142 | if (length < 3) | |
143 | return -EINVAL; | |
705ececd | 144 | |
ce9b490c | 145 | if (midibuf_is_empty(this)) |
705ececd MG |
146 | return 0; |
147 | ||
148 | bytes_used = midibuf_bytes_used(this); | |
149 | ||
ce9b490c | 150 | if (length > bytes_used) |
705ececd MG |
151 | length = bytes_used; |
152 | ||
153 | length1 = this->size - this->pos_read; | |
154 | ||
155 | /* check MIDI command length */ | |
156 | command = this->buf[this->pos_read]; | |
157 | ||
ce9b490c | 158 | if (command & 0x80) { |
705ececd MG |
159 | midi_length = midibuf_message_length(command); |
160 | this->command_prev = command; | |
ce9b490c GKH |
161 | } else { |
162 | if (this->command_prev > 0) { | |
705ececd MG |
163 | int midi_length_prev = midibuf_message_length(this->command_prev); |
164 | ||
ce9b490c | 165 | if (midi_length_prev > 0) { |
705ececd MG |
166 | midi_length = midi_length_prev - 1; |
167 | repeat = 1; | |
ce9b490c | 168 | } else |
705ececd | 169 | midi_length = -1; |
ce9b490c | 170 | } else |
705ececd MG |
171 | midi_length = -1; |
172 | } | |
173 | ||
ce9b490c | 174 | if (midi_length < 0) { |
705ececd | 175 | /* search for end of message */ |
ce9b490c | 176 | if (length < length1) { |
705ececd | 177 | /* no buffer wraparound */ |
ce9b490c GKH |
178 | for (i = 1; i < length; ++i) |
179 | if (this->buf[this->pos_read + i] & 0x80) | |
705ececd MG |
180 | break; |
181 | ||
182 | midi_length = i; | |
ce9b490c | 183 | } else { |
705ececd MG |
184 | /* buffer wraparound */ |
185 | length2 = length - length1; | |
186 | ||
ce9b490c GKH |
187 | for (i = 1; i < length1; ++i) |
188 | if (this->buf[this->pos_read + i] & 0x80) | |
705ececd MG |
189 | break; |
190 | ||
ce9b490c | 191 | if (i < length1) |
705ececd MG |
192 | midi_length = i; |
193 | else { | |
ce9b490c GKH |
194 | for (i = 0; i < length2; ++i) |
195 | if (this->buf[i] & 0x80) | |
705ececd MG |
196 | break; |
197 | ||
198 | midi_length = length1 + i; | |
199 | } | |
200 | } | |
201 | ||
ce9b490c | 202 | if (midi_length == length) |
705ececd MG |
203 | midi_length = -1; /* end of message not found */ |
204 | } | |
205 | ||
ce9b490c GKH |
206 | if (midi_length < 0) { |
207 | if (!this->split) | |
705ececd | 208 | return 0; /* command is not yet complete */ |
ce9b490c GKH |
209 | } else { |
210 | if (length < midi_length) | |
705ececd MG |
211 | return 0; /* command is not yet complete */ |
212 | ||
213 | length = midi_length; | |
214 | } | |
215 | ||
ce9b490c | 216 | if (length < length1) { |
705ececd MG |
217 | /* no buffer wraparound */ |
218 | memcpy(data + repeat, this->buf + this->pos_read, length); | |
219 | this->pos_read += length; | |
ce9b490c | 220 | } else { |
705ececd MG |
221 | /* buffer wraparound */ |
222 | length2 = length - length1; | |
223 | memcpy(data + repeat, this->buf + this->pos_read, length1); | |
224 | memcpy(data + repeat + length1, this->buf, length2); | |
225 | this->pos_read = length2; | |
226 | } | |
227 | ||
ce9b490c | 228 | if (repeat) |
705ececd MG |
229 | data[0] = this->command_prev; |
230 | ||
231 | this->full = 0; | |
232 | return length + repeat; | |
233 | } | |
234 | ||
235 | int midibuf_ignore(struct MidiBuffer *this, int length) | |
236 | { | |
237 | int bytes_used = midibuf_bytes_used(this); | |
238 | ||
ce9b490c | 239 | if (length > bytes_used) |
705ececd MG |
240 | length = bytes_used; |
241 | ||
242 | this->pos_read = (this->pos_read + length) % this->size; | |
243 | this->full = 0; | |
244 | return length; | |
245 | } | |
246 | ||
247 | int midibuf_skip_message(struct MidiBuffer *this, unsigned short mask) | |
248 | { | |
249 | int cmd = this->command_prev; | |
250 | ||
ce9b490c GKH |
251 | if ((cmd >= 0x80) && (cmd < 0xf0)) |
252 | if ((mask & (1 << (cmd & 0x0f))) == 0) | |
705ececd MG |
253 | return 1; |
254 | ||
255 | return 0; | |
256 | } | |
257 | ||
258 | void midibuf_destroy(struct MidiBuffer *this) | |
259 | { | |
536165d8 GKH |
260 | kfree(this->buf); |
261 | this->buf = NULL; | |
705ececd | 262 | } |