libcm is a C development framework with an emphasis on audio signal processing applications.
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cmMidiFile.h 6.6KB

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  1. #ifndef cmMidiFile_h
  2. #define cmMidiFile_h
  3. #ifdef __cplusplus
  4. extern "C" {
  5. #endif
  6. // MIDI file timing:
  7. // Messages in the MIDI file are time tagged with a delta offset in 'ticks'
  8. // from the previous message in the same track.
  9. //
  10. // A 'tick' can be converted to microsends as follows:
  11. //
  12. // microsecond per tick = micros per quarter note / ticks per quarter note
  13. //
  14. // MpT = MpQN / TpQN
  15. //
  16. // TpQN is given as a constant in the MIDI file header.
  17. // MpQN is given as the value of the MIDI file tempo message.
  18. //
  19. // See cmMidiFileSeekUSecs() for an example of converting ticks to milliseconds.
  20. //
  21. // As part of the file reading process, the status byte of note-on messages
  22. // with velocity=0 are is changed to a note-off message. See _cmMidiFileReadChannelMsg().
  23. typedef cmHandle_t cmMidiFileH_t;
  24. typedef unsigned cmMfRC_t;
  25. typedef struct
  26. {
  27. cmMidiByte_t hr;
  28. cmMidiByte_t min;
  29. cmMidiByte_t sec;
  30. cmMidiByte_t frm;
  31. cmMidiByte_t sfr;
  32. } cmMidiSmpte_t;
  33. typedef struct
  34. {
  35. cmMidiByte_t num;
  36. cmMidiByte_t den;
  37. cmMidiByte_t metro;
  38. cmMidiByte_t th2s;
  39. } cmMidiTimeSig_t;
  40. typedef struct
  41. {
  42. cmMidiByte_t key;
  43. cmMidiByte_t scale;
  44. } cmMidiKeySig_t;
  45. typedef struct
  46. {
  47. cmMidiByte_t ch;
  48. cmMidiByte_t d0;
  49. cmMidiByte_t d1;
  50. unsigned durTicks; // note duration calc'd by cmMidiFileCalcNoteDurations();
  51. } cmMidiChMsg_t;
  52. typedef struct cmMidiTrackMsg_str
  53. {
  54. unsigned uid; // uid's are unique among all msg's in the file
  55. unsigned dtick; // delta ticks
  56. unsigned atick; // accumulated ticks
  57. cmMidiByte_t status; // ch msg's have the channel value removed (it is stored in u.chMsgPtr->ch)
  58. cmMidiByte_t metaId; //
  59. unsigned short trkIdx; //
  60. unsigned byteCnt; // length of data pointed to by u.voidPtr (or any other pointer in the union)
  61. struct cmMidiTrackMsg_str* link; // link to next record in this track
  62. union
  63. {
  64. cmMidiByte_t bVal;
  65. unsigned iVal;
  66. unsigned short sVal;
  67. const char* text;
  68. const void* voidPtr;
  69. const cmMidiSmpte_t* smptePtr;
  70. const cmMidiTimeSig_t* timeSigPtr;
  71. const cmMidiKeySig_t* keySigPtr;
  72. const cmMidiChMsg_t* chMsgPtr;
  73. const cmMidiByte_t* sysExPtr;
  74. } u;
  75. } cmMidiTrackMsg_t;
  76. enum
  77. {
  78. kOkMfRC = cmOkRC, // 0
  79. kFileFailMfRC, // 1
  80. kNotAMidiFileMfRC, // 7
  81. kMemAllocFailMfRC, // 8
  82. kFileCorruptMfRC, // 9
  83. kMissingEoxMfRC, // 10
  84. kUnknownMetaIdMfRC, // 11
  85. kInvalidHandleMfRC, // 12
  86. kMissingNoteOffMfRC, // 13
  87. kInvalidStatusMfRC // 14
  88. };
  89. extern cmMidiFileH_t cmMidiFileNullHandle;
  90. cmMfRC_t cmMidiFileOpen( const char* fn, cmMidiFileH_t* hPtr, cmCtx_t* ctx );
  91. cmMfRC_t cmMidiFileClose( cmMidiFileH_t* hp );
  92. cmMfRC_t cmMidiFileWrite( cmMidiFileH_t h, const char* fn );
  93. bool cmMidiFileIsValid( cmMidiFileH_t h );
  94. // Returns track count or kInvalidCnt if 'h' is invalid.
  95. unsigned cmMidiFileTrackCount( cmMidiFileH_t h );
  96. // Return midi file format id (0,1,2) or kInvalidId if 'h' is invalid.
  97. unsigned cmMidiFileType( cmMidiFileH_t h );
  98. // Returns ticks per quarter note or kInvalidMidiByte if 'h' is invalid or 0 if file uses SMPTE ticks per frame time base.
  99. unsigned cmMidiFileTicksPerQN( cmMidiFileH_t h );
  100. // The file name used in an earlier call to midiFileOpen() or NULL if this
  101. // midi file did not originate from an actual file.
  102. const char* cmMidiFileName( cmMidiFileH_t h );
  103. // Returns SMPTE ticks per frame or kInvalidMidiByte if 'h' is invalid or 0 if file uses ticks per quarter note time base.
  104. cmMidiByte_t cmMidiFileTicksPerSmpteFrame( cmMidiFileH_t h );
  105. // Returns SMPTE format or kInvalidMidiByte if 'h' is invalid or 0 if file uses ticks per quarter note time base.
  106. cmMidiByte_t cmMidiFileSmpteFormatId( cmMidiFileH_t h );
  107. // Returns count of records in track 'trackIdx' or kInvalidCnt if 'h' is invalid.
  108. unsigned cmMidiFileTrackMsgCount( cmMidiFileH_t h, unsigned trackIdx );
  109. // Returns base of record chain from track 'trackIdx' or NULL if 'h' is invalid.
  110. const cmMidiTrackMsg_t* cmMidiFileTrackMsg( cmMidiFileH_t h, unsigned trackIdx );
  111. // Returns the total count of records in the midi file and the number in the array returned by cmMidiFileMsgArray().
  112. // Return kInvalidCnt if 'h' is invalid.
  113. unsigned cmMidiFileMsgCount( cmMidiFileH_t h );
  114. // Returns a pointer to the base of an array of pointers to each record in the file sorted in ascending time order.
  115. // Returns NULL if 'h' is invalid.
  116. const cmMidiTrackMsg_t** cmMidiFileMsgArray( cmMidiFileH_t h );
  117. // Return a pointer to the first msg at or after 'usecsOffs' or kInvalidIdx if no
  118. // msg exists after 'usecsOffs'. Note that 'usecOffs' is an offset from the beginning
  119. // of the file.
  120. // On return *'msgUsecsPtr' is set to the actual time of the msg.
  121. // (which will be equal to or greater than 'usecsOffs').
  122. unsigned cmMidiFileSeekUsecs( cmMidiFileH_t h, unsigned usecsOffs, unsigned* msgUsecsPtr, unsigned* newMicrosPerTickPtr );
  123. double cmMidiFileDurSecs( cmMidiFileH_t h );
  124. // Convert the track message 'dtick' field to delta-microseconds.
  125. void cmMidiFileTickToMicros( cmMidiFileH_t h );
  126. // Convert the track message 'dtick' field to samples.
  127. // If the absFl is set then the delta times are converted to absolute time.
  128. void cmMidiFileTickToSamples( cmMidiFileH_t h, double srate, bool absFl );
  129. // Calculate Note Duration
  130. void cmMidiFileCalcNoteDurations( cmMidiFileH_t h );
  131. // Set the delay prior to the first non-zero msg.
  132. void cmMidiFileSetDelay( cmMidiFileH_t h, unsigned ticks );
  133. // This function packs a track msg into a single consecutive
  134. // block of memory buf[ bufByteCnt ]. Call cmMidiFilePackTracMsgBufByteCount()
  135. // to get the required buffer length for any given cmMidiTrackMsg_t instance.
  136. cmMidiTrackMsg_t* cmMidiFilePackTrackMsg( const cmMidiTrackMsg_t* m, void* buf, unsigned bufByteCnt );
  137. unsigned cmMidiFilePackTrackMsgBufByteCount( const cmMidiTrackMsg_t* m );
  138. void cmMidiFilePrint( cmMidiFileH_t h, unsigned trkIdx, cmRpt_t* rpt );
  139. bool cmMidiFileIsNull( cmMidiFileH_t h );
  140. void cmMidiFileTest( const char* fn, cmCtx_t* ctx );
  141. #ifdef __cplusplus
  142. }
  143. #endif
  144. #endif