--- /dev/null
+/*
+ * 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;
+}
+
+void line6_midibuf_destroy(struct midi_buffer *this)
+{
+ kfree(this->buf);
+ this->buf = NULL;
+}
Code Review / kvmfornfv.git / blobdiff