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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 3 | pmbaty | 1 | /* |
| 2 | SMPEG - SDL MPEG Player Library |
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| 3 | Copyright (C) 1999 Loki Entertainment Software |
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| 4 | |||
| 5 | This library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Library General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2 of the License, or (at your option) any later version. |
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| 9 | |||
| 10 | This library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Library General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU Library General Public |
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| 16 | License along with this library; if not, write to the Free |
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| 17 | Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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| 18 | */ |
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| 19 | |||
| 20 | /* A ring-buffer class for multi-threaded applications. |
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| 21 | This assumes a single reader and a single writer, with blocking reads. |
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| 22 | */ |
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| 23 | |||
| 24 | #ifndef _MPEGRING_H |
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| 25 | #define _MPEGRING_H |
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| 26 | |||
| 27 | #include "SDL_types.h" |
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| 28 | #include "SDL_thread.h" |
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| 29 | |||
| 30 | class MPEG_ring { |
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| 31 | public: |
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| 32 | /* Create a ring with 'count' buffers, each 'size' bytes long */ |
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| 33 | MPEG_ring(Uint32 size, Uint32 count = 16); |
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| 34 | |||
| 35 | /* Release any waiting threads on the ring so they can be cleaned up. |
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| 36 | The ring isn't valid after this call, so when threads are done you |
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| 37 | should call MPRing_sdelete() on the ring. |
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| 38 | */ |
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| 39 | void ReleaseThreads(void); |
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| 40 | |||
| 41 | /* Destroy a ring after all threads are no longer using it */ |
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| 42 | virtual ~MPEG_ring(); |
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| 43 | |||
| 44 | /* Returns the maximum size of each buffer */ |
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| 45 | Uint32 BufferSize( void ) { |
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| 46 | return(bufSize); |
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| 47 | } |
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| 48 | /* Returns how many buffers have available data */ |
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| 49 | int BuffersWritten(void) { |
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| 50 | return(SDL_SemValue(ring->readwait)); |
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| 51 | } |
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| 52 | |||
| 53 | /* Reserve a buffer for writing in the ring */ |
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| 54 | Uint8 *NextWriteBuffer( void ); |
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| 55 | |||
| 56 | /* Release a buffer, written to in the ring */ |
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| 57 | void WriteDone( Uint32 len, double timestamp=-1 ); |
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| 58 | |||
| 59 | /* Reserve a buffer for reading in the ring */ |
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| 60 | Uint32 NextReadBuffer( Uint8** buffer ); |
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| 61 | |||
| 62 | /* Read the timestamp of the current buffer */ |
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| 63 | double ReadTimeStamp(void); |
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| 64 | |||
| 65 | /* Release a buffer having read some of it */ |
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| 66 | void ReadSome( Uint32 used ); |
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| 67 | |||
| 68 | /* Release a buffer having read all of it */ |
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| 69 | void ReadDone( void ); |
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| 70 | |||
| 71 | protected: |
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| 72 | MPEG_ring *ring; /* Converted from C code, an alias for 'this' */ |
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| 73 | |||
| 74 | /* read only */ |
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| 75 | Uint32 bufSize; |
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| 76 | |||
| 77 | /* private */ |
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| 78 | Uint8 *begin; |
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| 79 | Uint8 *end; |
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| 80 | |||
| 81 | double *timestamps; |
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| 82 | double *timestamp_read; |
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| 83 | double *timestamp_write; |
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| 84 | |||
| 85 | Uint8 *read; |
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| 86 | Uint8 *write; |
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| 87 | |||
| 88 | /* For read/write synchronization */ |
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| 89 | int active; |
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| 90 | SDL_semaphore *readwait; |
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| 91 | SDL_semaphore *writewait; |
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| 92 | }; |
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| 93 | |||
| 94 | #endif /* _MPEGRING_H */ |