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Contents of /linuxsampler/tags/start/stream.h

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1 /***************************************************************************
2 * *
3 * LinuxSampler - modular, streaming capable sampler *
4 * *
5 * Copyright (C) 2003 by Benno Senoner *
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 #ifndef __STREAM_H__
24 #define __STREAM_H__
25
26 #include <unistd.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <sys/mman.h>
31 #include <asm/page.h>
32 #include <unistd.h>
33 #include <fcntl.h>
34 #include <sys/stat.h>
35
36 #include "global.h"
37 #include "ringbuffer.h"
38 #include "gig.h"
39
40 #define STREAM_END_SILENCE_SAMPLES
41 class Stream {
42 public:
43 // Member Types
44 typedef uint32_t OrderID_t;
45 typedef uint32_t Handle; ///< unique identifier of a relationship between one stream and a consumer (Voice)
46 enum state_t { ///< streams go through severe cyclic state transition (unused->active->end->unused->...)
47 state_unused, ///< stream is not in use, thus can still be launched
48 state_active, ///< stream provides data in it's buffer to be read and hasn't reached the end yet (this is the usual case)
49 state_end ///< stream end reached but still providing data in it's buffer to be read (after the client read all remaining data from the stream buffer, state will change automatically to state_unused)
50 };
51 struct reference_t { ///< Defines the current relationship between the stream and a client (voice).
52 OrderID_t OrderID; ///< Unique identifier that identifies the creation order of a stream requested by a voice.
53 Handle hStream; ///< Unique identifier of the relationship between stream and client.
54 state_t State; ///< Current state of the stream that will be pretended to the client (the actual state of the stream might differ though, because the stream might already be in use by another client).
55 Stream* pStream; ///< Points to the assigned and activated stream or is NULL if the disk thread hasn't launched a stream yet.
56 };
57
58 // Methods
59 Stream(uint BufferSize, uint BufferWrapElements);
60 ~Stream();
61 int ReadAhead(unsigned long SampleCount);
62 void WriteSilence(unsigned long SilenceSampleWords);
63
64 inline int GetReadSpace() {
65 return (pRingBuffer && State == state_active) ? pRingBuffer->read_space() : 0;
66 }
67
68 inline int GetWriteSpace() {
69 return (pRingBuffer && State == state_active) ? pRingBuffer->write_space() : 0;
70 }
71
72 inline int GetWriteSpaceToEnd() {
73 return (pRingBuffer && State == state_active) ? pRingBuffer->write_space_to_end_with_wrap() : 0;
74 }
75
76 // adjusts the write space to avoid buffer boundaries which would lead to the wrap space
77 // within the buffer (needed for interpolation) getting filled only partially
78 // for more infos see the docs in ringbuffer.h at adjust_write_space_to_avoid_boundary()
79 inline int AdjustWriteSpaceToAvoidBoundary(int cnt, int capped_cnt) {
80 return pRingBuffer->adjust_write_space_to_avoid_boundary(cnt, capped_cnt);
81 }
82
83 inline sample_t* GetReadPointer() {
84 return pRingBuffer->get_read_ptr();
85 }
86
87 // gets the current read_ptr within the ringbuffer
88 inline sample_t* GetReadPtr(void) {
89 return pRingBuffer->get_read_ptr();
90 }
91
92 inline void IncrementReadPos(uint Count) {
93 uint leftspace = pRingBuffer->read_space();
94 pRingBuffer->increment_read_ptr(Min(Count, leftspace));
95 if (State == state_end && Count >= leftspace) {
96 Reset(); // quit relation between consumer (voice) and stream and reset stream right after
97 }
98 }
99
100 // Static Method
101 inline static uint GetUnusedStreams() { return UnusedStreams; }
102 protected:
103 // Methods
104 void Launch(reference_t* pExportReference, gig::Sample* pSample, unsigned long SampleOffset);
105 inline void Kill() { pExportReference = NULL; Reset(); } ///< Will be called by disk thread after a 'deletion' command from the audio thread (within the voice class)
106 inline Stream::Handle GetHandle() {
107 return (pExportReference) ? pExportReference->hStream : 0;
108 }
109 inline Stream::state_t GetState() { return State; }
110 friend class DiskThread; // only the disk thread should be able to launch and most important kill a disk stream to avoid race conditions
111 private:
112 // Attributes
113 reference_t* pExportReference;
114 state_t State;
115 gig::Sample* pSample;
116 unsigned long SampleOffset;
117 RingBuffer<sample_t>* pRingBuffer;
118
119 // Static Attributes
120 static uint UnusedStreams; //< Reflects how many stream objects of all stream instances are currently not in use.
121
122 // Methods
123 inline void Reset() {
124 pSample = NULL;
125 SampleOffset = 0;
126 pRingBuffer->init(); // reset ringbuffer
127 if (State != state_unused) {
128 // we can't do 'SetPos(state_unused)' here, due to possible race conditions)
129 if (pExportReference) {
130 pExportReference->State = state_unused;
131 pExportReference = NULL;
132 }
133 State = state_unused;
134 UnusedStreams++;
135 }
136 }
137 inline void SetState(state_t State) {
138 if (pExportReference) pExportReference->State = State;
139 this->State = State;
140 }
141 inline long Min(long a, long b) { return (a < b) ? a : b; }
142 };
143
144 #endif // __STREAM_H__

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