/[svn]/linuxsampler/trunk/src/engines/common/Event.cpp
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Annotation of /linuxsampler/trunk/src/engines/common/Event.cpp

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Revision 53 - (hide annotations) (download)
Mon Apr 26 17:15:51 2004 UTC (16 years, 2 months ago) by schoenebeck
File size: 4996 byte(s)
* completely restructured source tree
* implemented multi channel support
* implemented instrument manager, which controls sharing of instruments
  between multiple sampler engines / sampler channels
* created abstract classes 'AudioOutputDevice' and 'MidiInputDevice' for
  convenient implementation of further audio output driver and MIDI input
  driver for LinuxSampler
* implemented following LSCP commands: 'SET CHANNEL MIDI INPUT TYPE',
  'LOAD ENGINE', 'GET CHANNELS', 'ADD CHANNEL', 'REMOVE CHANNEL',
  'SET CHANNEL AUDIO OUTPUT TYPE'
* temporarily removed all command line options
* LSCP server is now launched by default

1 schoenebeck 53 /***************************************************************************
2     * *
3     * LinuxSampler - modular, streaming capable sampler *
4     * *
5     * Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck *
6     * *
7     * This program is free software; you can redistribute it and/or modify *
8     * it under the terms of the GNU General Public License as published by *
9     * the Free Software Foundation; either version 2 of the License, or *
10     * (at your option) any later version. *
11     * *
12     * This program is distributed in the hope that it will be useful, *
13     * but WITHOUT ANY WARRANTY; without even the implied warranty of *
14     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15     * GNU General Public License for more details. *
16     * *
17     * You should have received a copy of the GNU General Public License *
18     * along with this program; if not, write to the Free Software *
19     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20     * MA 02111-1307 USA *
21     ***************************************************************************/
22    
23     #include "Event.h"
24    
25     namespace LinuxSampler {
26    
27     /**
28     * Create an EventGenerator.
29     *
30     * @param SampleRate - sample rate of the sampler engine's audio output
31     * signal (in Hz)
32     */
33     EventGenerator::EventGenerator(uint SampleRate) {
34     uiSampleRate = SampleRate;
35     uiSamplesProcessed = 0;
36     FragmentTime.end = CreateTimeStamp();
37     }
38    
39     /**
40     * Updates the time stamps for the beginning and end of the current audio
41     * fragment. This is needed to be able to calculate the respective sample
42     * point later to which an event belongs to.
43     *
44     * @param SamplesToProcess - number of sample points to process in this
45     * audio fragment cycle
46     */
47     void EventGenerator::UpdateFragmentTime(uint SamplesToProcess) {
48     // update time stamp for this audio fragment cycle
49     FragmentTime.begin = FragmentTime.end;
50     FragmentTime.end = CreateTimeStamp();
51     // recalculate sample ratio for this audio fragment
52     time_stamp_t fragmentDuration = FragmentTime.end - FragmentTime.begin;
53     FragmentTime.sample_ratio = (float) uiSamplesProcessed / (float) fragmentDuration;
54     // store amount of samples to process for the next cycle
55     uiSamplesProcessed = SamplesToProcess;
56     }
57    
58     /**
59     * Create a new event with the current time as time stamp.
60     */
61     Event EventGenerator::CreateEvent() {
62     return Event(this, CreateTimeStamp());
63     }
64    
65     /**
66     * Creates a real time stamp for the current moment. Out of efficiency this
67     * is implemented in inline assembly for each CPU independently; we currently
68     * don't use a generic solution for CPUs that are not yet covered by the
69     * assembly code, instead an error message is prompted on compile time, forcing
70     * the user to contact us.
71     */
72     EventGenerator::time_stamp_t EventGenerator::CreateTimeStamp() {
73     #if defined(__i386__) || defined(__x86_64__)
74     uint64_t t;
75     __asm__ __volatile__ ("rdtsc" : "=A" (t));
76     return t >> 8;
77     #elif defined(__ia64__)
78     time_stamp_t t;
79     __asm__ __volatile__ ("mov %0=ar.itc" : "=r"(t));
80     return t;
81     #elif defined(__powerpc__)
82     time_stamp_t t;
83     __asm__ __volatile__ (
84     "98: mftb %0\n"
85     "99:\n"
86     ".section __ftr_fixup,\"a\"\n"
87     " .long %1\n"
88     " .long 0\n"
89     " .long 98b\n"
90     " .long 99b\n"
91     ".previous"
92     : "=r" (t) : "i" (0x00000100)
93     );
94     return t;
95     #elif defined(__alpha__)
96     time_stamp_t t;
97     __asm__ __volatile__ ("rpcc %0" : "=r"(t));
98     return t;
99     #else // we don't want to use a slow generic solution
100     # error Sorry, LinuxSampler lacks time stamp code for your system.
101     # error Please report this error and the CPU you are using to the LinuxSampler developers mailing list!
102     #endif
103     }
104    
105     /**
106     * Will be called by an EventGenerator to create a new Event.
107     */
108     Event::Event(EventGenerator* pGenerator, time_stamp_t Time) {
109     pEventGenerator = pGenerator;
110     TimeStamp = Time;
111     iFragmentPos = -1;
112     }
113    
114     } // namespace LinuxSampler

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