Jack2  1.9.9
JackLoopbackDriver.cpp
1 /*
2 Copyright (C) 2001 Paul Davis
3 Copyright (C) 2004-2008 Grame
4 
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9 
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14 
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 
19 */
20 
21 #include "JackSystemDeps.h"
22 #include "JackLoopbackDriver.h"
23 #include "JackDriverLoader.h"
24 #include "JackEngineControl.h"
25 #include "JackGraphManager.h"
26 #include "JackError.h"
27 #include <iostream>
28 #include <assert.h>
29 
30 namespace Jack
31 {
32 
33 // When used in "slave" mode
34 
35 int JackLoopbackDriver::ProcessReadSync()
36 {
37  int res = 0;
38 
39  // Loopback copy
40  for (int i = 0; i < fCaptureChannels; i++) {
41  memcpy(GetInputBuffer(i), GetOutputBuffer(i), sizeof(jack_default_audio_sample_t) * fEngineControl->fBufferSize);
42  }
43 
44  // Resume connected clients in the graph
45  if (ResumeRefNum() < 0) {
46  jack_error("JackLoopbackDriver::ProcessReadSync - ResumeRefNum error");
47  res = -1;
48  }
49 
50  return res;
51 }
52 
53 int JackLoopbackDriver::ProcessWriteSync()
54 {
55  // Suspend on connected clients in the graph
56  if (SuspendRefNum() < 0) {
57  jack_error("JackLoopbackDriver::ProcessWriteSync SuspendRefNum error");
58  return -1;
59  }
60  return 0;
61 }
62 
63 int JackLoopbackDriver::ProcessReadAsync()
64 {
65  int res = 0;
66 
67  // Loopback copy
68  for (int i = 0; i < fCaptureChannels; i++) {
69  memcpy(GetInputBuffer(i), GetOutputBuffer(i), sizeof(jack_default_audio_sample_t) * fEngineControl->fBufferSize);
70  }
71 
72  // Resume connected clients in the graph
73  if (ResumeRefNum() < 0) {
74  jack_error("JackLoopbackDriver::ProcessReadAsync - ResumeRefNum error");
75  res = -1;
76  }
77 
78  return res;
79 }
80 
81 int JackLoopbackDriver::ProcessWriteAsync()
82 {
83  return 0;
84 }
85 
86 } // end of namespace
87 
88 #ifdef __cplusplus
89 extern "C"
90 {
91 #endif
92 
93  SERVER_EXPORT jack_driver_desc_t * driver_get_descriptor()
94  {
95  jack_driver_desc_t * desc;
98 
99  desc = jack_driver_descriptor_construct("loopback", JackDriverSlave, "Loopback backend", &filler);
100 
101  value.i = 0;
102  jack_driver_descriptor_add_parameter(desc, &filler, "channels", 'c', JackDriverParamInt, &value, NULL, "Maximum number of loopback ports", NULL);
103 
104  return desc;
105  }
106 
107  SERVER_EXPORT Jack::JackDriverClientInterface* driver_initialize(Jack::JackLockedEngine* engine, Jack::JackSynchro* table, const JSList* params)
108  {
109  const JSList * node;
110  const jack_driver_param_t * param;
111  int channels = 2;
112 
113  for (node = params; node; node = jack_slist_next (node)) {
114  param = (const jack_driver_param_t *) node->data;
115 
116  switch (param->character) {
117 
118  case 'c':
119  channels = param->value.ui;
120  break;
121  }
122  }
123 
124  Jack::JackDriverClientInterface* driver = new Jack::JackLoopbackDriver(engine, table);
125  if (driver->Open(1, 1, channels, channels, false, "loopback", "loopback", 0, 0) == 0) {
126  return driver;
127  } else {
128  delete driver;
129  return NULL;
130  }
131  }
132 
133 #ifdef __cplusplus
134 }
135 #endif
Inter process synchronization using using Mach semaphore.
Locked Engine, access to methods is serialized using a mutex.
SERVER_EXPORT void jack_error(const char *fmt,...)
Definition: JackError.cpp:91
The base interface for drivers clients.
Definition: JackDriver.h:122
The loopback driver : to be used to &quot;pipeline&quot; applications connected in sequence.