pa_stream.h (7247B)
1 #ifndef PA_STREAM_H 2 #define PA_STREAM_H 3 /* 4 * $Id$ 5 * Portable Audio I/O Library 6 * stream interface 7 * 8 * Based on the Open Source API proposed by Ross Bencina 9 * Copyright (c) 1999-2008 Ross Bencina, Phil Burk 10 * 11 * Permission is hereby granted, free of charge, to any person obtaining 12 * a copy of this software and associated documentation files 13 * (the "Software"), to deal in the Software without restriction, 14 * including without limitation the rights to use, copy, modify, merge, 15 * publish, distribute, sublicense, and/or sell copies of the Software, 16 * and to permit persons to whom the Software is furnished to do so, 17 * subject to the following conditions: 18 * 19 * The above copyright notice and this permission notice shall be 20 * included in all copies or substantial portions of the Software. 21 * 22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 23 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 25 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 26 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 27 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 28 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 29 */ 30 31 /* 32 * The text above constitutes the entire PortAudio license; however, 33 * the PortAudio community also makes the following non-binding requests: 34 * 35 * Any person wishing to distribute modifications to the Software is 36 * requested to send the modifications to the original developer so that 37 * they can be incorporated into the canonical version. It is also 38 * requested that these non-binding requests be included along with the 39 * license above. 40 */ 41 42 /** @file 43 @ingroup common_src 44 45 @brief Stream interfaces, representation structures and helper functions 46 used to interface between pa_front.c host API implementations. 47 */ 48 49 50 #include "portaudio.h" 51 52 #ifdef __cplusplus 53 extern "C" 54 { 55 #endif /* __cplusplus */ 56 57 58 #define PA_STREAM_MAGIC (0x18273645) 59 60 61 /** A structure representing an (abstract) interface to a host API. Contains 62 pointers to functions which implement the interface. 63 64 All PaStreamInterface functions are guaranteed to be called with a non-null, 65 valid stream parameter. 66 */ 67 typedef struct { 68 PaError (*Close)( PaStream* stream ); 69 PaError (*Start)( PaStream *stream ); 70 PaError (*Stop)( PaStream *stream ); 71 PaError (*Abort)( PaStream *stream ); 72 PaError (*IsStopped)( PaStream *stream ); 73 PaError (*IsActive)( PaStream *stream ); 74 PaTime (*GetTime)( PaStream *stream ); 75 double (*GetCpuLoad)( PaStream* stream ); 76 PaError (*Read)( PaStream* stream, void *buffer, unsigned long frames ); 77 PaError (*Write)( PaStream* stream, const void *buffer, unsigned long frames ); 78 signed long (*GetReadAvailable)( PaStream* stream ); 79 signed long (*GetWriteAvailable)( PaStream* stream ); 80 } PaUtilStreamInterface; 81 82 83 /** Initialize the fields of a PaUtilStreamInterface structure. 84 */ 85 void PaUtil_InitializeStreamInterface( PaUtilStreamInterface *streamInterface, 86 PaError (*Close)( PaStream* ), 87 PaError (*Start)( PaStream* ), 88 PaError (*Stop)( PaStream* ), 89 PaError (*Abort)( PaStream* ), 90 PaError (*IsStopped)( PaStream* ), 91 PaError (*IsActive)( PaStream* ), 92 PaTime (*GetTime)( PaStream* ), 93 double (*GetCpuLoad)( PaStream* ), 94 PaError (*Read)( PaStream* stream, void *buffer, unsigned long frames ), 95 PaError (*Write)( PaStream* stream, const void *buffer, unsigned long frames ), 96 signed long (*GetReadAvailable)( PaStream* stream ), 97 signed long (*GetWriteAvailable)( PaStream* stream ) ); 98 99 100 /** Dummy Read function for use in interfaces to a callback based streams. 101 Pass to the Read parameter of PaUtil_InitializeStreamInterface. 102 @return An error code indicating that the function has no effect 103 because the stream is a callback stream. 104 */ 105 PaError PaUtil_DummyRead( PaStream* stream, 106 void *buffer, 107 unsigned long frames ); 108 109 110 /** Dummy Write function for use in an interfaces to callback based streams. 111 Pass to the Write parameter of PaUtil_InitializeStreamInterface. 112 @return An error code indicating that the function has no effect 113 because the stream is a callback stream. 114 */ 115 PaError PaUtil_DummyWrite( PaStream* stream, 116 const void *buffer, 117 unsigned long frames ); 118 119 120 /** Dummy GetReadAvailable function for use in interfaces to callback based 121 streams. Pass to the GetReadAvailable parameter of PaUtil_InitializeStreamInterface. 122 @return An error code indicating that the function has no effect 123 because the stream is a callback stream. 124 */ 125 signed long PaUtil_DummyGetReadAvailable( PaStream* stream ); 126 127 128 /** Dummy GetWriteAvailable function for use in interfaces to callback based 129 streams. Pass to the GetWriteAvailable parameter of PaUtil_InitializeStreamInterface. 130 @return An error code indicating that the function has no effect 131 because the stream is a callback stream. 132 */ 133 signed long PaUtil_DummyGetWriteAvailable( PaStream* stream ); 134 135 136 137 /** Dummy GetCpuLoad function for use in an interface to a read/write stream. 138 Pass to the GetCpuLoad parameter of PaUtil_InitializeStreamInterface. 139 @return Returns 0. 140 */ 141 double PaUtil_DummyGetCpuLoad( PaStream* stream ); 142 143 144 /** Non host specific data for a stream. This data is used by pa_front to 145 forward to the appropriate functions in the streamInterface structure. 146 */ 147 typedef struct PaUtilStreamRepresentation { 148 unsigned long magic; /**< set to PA_STREAM_MAGIC */ 149 struct PaUtilStreamRepresentation *nextOpenStream; /**< field used by multi-api code */ 150 PaUtilStreamInterface *streamInterface; 151 PaStreamCallback *streamCallback; 152 PaStreamFinishedCallback *streamFinishedCallback; 153 void *userData; 154 PaStreamInfo streamInfo; 155 } PaUtilStreamRepresentation; 156 157 158 /** Initialize a PaUtilStreamRepresentation structure. 159 160 @see PaUtil_InitializeStreamRepresentation 161 */ 162 void PaUtil_InitializeStreamRepresentation( 163 PaUtilStreamRepresentation *streamRepresentation, 164 PaUtilStreamInterface *streamInterface, 165 PaStreamCallback *streamCallback, 166 void *userData ); 167 168 169 /** Clean up a PaUtilStreamRepresentation structure previously initialized 170 by a call to PaUtil_InitializeStreamRepresentation. 171 172 @see PaUtil_InitializeStreamRepresentation 173 */ 174 void PaUtil_TerminateStreamRepresentation( PaUtilStreamRepresentation *streamRepresentation ); 175 176 177 /** Check that the stream pointer is valid. 178 179 @return Returns paNoError if the stream pointer appears to be OK, otherwise 180 returns an error indicating the cause of failure. 181 */ 182 PaError PaUtil_ValidateStreamPointer( PaStream *stream ); 183 184 185 /** Cast an opaque stream pointer into a pointer to a PaUtilStreamRepresentation. 186 187 @see PaUtilStreamRepresentation 188 */ 189 #define PA_STREAM_REP( stream )\ 190 ((PaUtilStreamRepresentation*) (stream) ) 191 192 193 /** Cast an opaque stream pointer into a pointer to a PaUtilStreamInterface. 194 195 @see PaUtilStreamRepresentation, PaUtilStreamInterface 196 */ 197 #define PA_STREAM_INTERFACE( stream )\ 198 PA_STREAM_REP( (stream) )->streamInterface 199 200 201 202 #ifdef __cplusplus 203 } 204 #endif /* __cplusplus */ 205 #endif /* PA_STREAM_H */