common/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;
  96         jack_driver_desc_filler_t filler;
  97         jack_driver_param_value_t value;
  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(0, 0, 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