DECODER_getData.c File Reference

---

Detailed Description

This module provides decoder cache support.

REVISION

• 11/05/2003 M.GAO
  Initial creation.
• 01/25/2004 M.GAO
  Fix of over-cache problem when cache is full and the top cached track is actively playing back. Also do not shut down HD when huge file is active.
• 01/27/2004 M.GAO
  Added algorithm to preserve cache contents when audio interface is shut down.
• 02/06/2004 M.GAO
  Added code to advance play queue without modifying the cache structure. Also cache is carried over different playbacks, it is not safe to use cache header to determine "cached all" any more. CacheDepth is increased every time a cached track is found instead.
• 02/11/2004 M.GAO
  Do not void cache pointed to by cacheHead while decoder is reading from it.
• 02/17/2004 M.GAO
  Increased default cache depth to minimize break sound during caching.
• 02/27/2004 M.GAO
  Always check to sync the file pointer with cache when cache is not hit.
• 03/04/2004 M.GAO
  Boundary fix when playback hits the end of track. Corrected sector offset calculation algorithm when starting from the middle of file. Added cache state code to check cache only once when new file is dectected.
• 03/10/2004 M.GAO
  Cache sector offset shall always start on a sector boundary.
• 04/06/2004 M.GAO
  Check to set cache idle flag before any return from cache task.
• 05/17/2004 M.GAO
  Type cast seek offset to prevent sign overflow.

Definition in file DECODER_getData.c.

#include "../SYSTEM/sys_hardware.h"
#include "../SYSTEM/sys_main.h"
#include "../MESSAGE/message.h"
#include "../codec/codec.h"
#include "../coder/coder.h"
#include "../UI/playQ.h"
#include "decoder.h"

Include dependency graph for DECODER_getData.c:

Go to the source code of this file.

Data Structures
struct	st_CACHE
	Cache control structure definition. More...
Typedefs
typedef st_CACHE	st_CACHE
	Cache control structure definition.
Enumerations
enum	IN_CACHE_STATE { INCACHE_ALREADY, INCACHE_CHECK, INCACHE_WAIT }
	Cache check state definitions. More...
Functions
unsigned short	DECODER_getData (int *pD, unsigned long offset, unsigned short reqLen)
	Function feeds data into docoder bit stream/buffer.
void	DECODER_cache (void)
	Function serves as the decoder cache task handle.
BOOL	DECODER_cacheInit (void)
	Function initialized the decoder cache.
void	DECODER_cacheDepthReset (unsigned short mode)
	Function resets cache depth controls.

---

Enumeration Type Documentation

enum IN_CACHE_STATE

Cache check state definitions. Enumeration values: INCACHE_ALREADY  Data partially or wholly cached. INCACHE_CHECK  Check to see if data is cached already. INCACHE_WAIT  Data not in cache, wait till it is cached. Definition at line 76 of file DECODER_getData.c. { INCACHE_ALREADY, INCACHE_CHECK, INCACHE_WAIT } IN_CACHE_STATE;

---

Function Documentation

void DECODER_cache (  void   )

Function serves as the decoder cache task handle. This task feeds the cache. Definition at line 156 of file DECODER_getData.c. References st_CACHE::actvFileSize, st_CACHE::actvStartClus, Audio, st_AUDIO::cachefile, DECODER_cacheDepthReset(), st_CACHE::done, st_CACHE::endSec, FAT_fread(), FAT_fseek(), st_AUDIO::file, st_CODER::flag, NAND_writeSec(), st_CACHE::next, st_CACHE::prev, SCURRENTAUDIOFILE, st_CACHE::secNum, st_CACHE::secOffset, SEEK_HEAD, File::size, SNEXTAUDIOFILE, File::startClus, and st_CACHE::startSec. { unsigned short len; st_CACHE * c; unsigned short buf[256]; if( F_CODER_CACHESETIDLE & Coder.flag ) { SEM_post(SEM_cacheIdle); return; } // On entry, check the lower threshold. if( (!(F_CODER_CACHESHUTDOWN & Coder.flag)) && (cacheDepth > cacheLowerThreshold) ) { CACHE_RETURN(); } while(1) { if( F_CODER_CACHESHUTDOWN & Coder.flag ) { _cacheShutdown(buf); SEM_post(SEM_cacheIdle); CACHE_RETURN(); } if( F_CODER_CACHESETIDLE & Coder.flag ) { SEM_post(SEM_cacheIdle); } // Every time cache gets posted, check will be done // in the following order, // 1) Is current audio file in cache queue and has it been fully cached? // 2) Is it necessary to update cache to read in more new data? // File in cache and fully cached, check to read in more. if( (rdCache->actvStartClus == Audio.file.startClus)&& (rdCache->actvFileSize == Audio.file.size)&& (rdCache->done == TRUE) ) { if(wrCache->done == TRUE) { // Try next file. mMSG_send(uiParentMsgQ, SYS_MSG_ID, SNEXTAUDIOFILE, 1, SYS_FOREVER); // Get a copy of cachefile handle. //TSK_disable(); cachefile = Audio.cachefile; //TSK_enable(); c = _cachePosition(&cachefile); //if( (c->done == TRUE)&&(c == cacheHead) ) //{ // Already cached all tracks. //msgOUT.id = SYS_MSG_ID; //msgOUT.d1 = SCURRENTAUDIOFILE; //mMSG_send(uiParentMsgQ, &msgOUT, SYS_FOREVER); //CACHE_RETURN(); //} //else if( (c->actvStartClus == cachefile.startClus)&& (c->actvFileSize == cachefile.size)&& (c->done == TRUE) ) { cacheDepth += c->secNum; if(c->actvStartClus != wrCache->actvStartClus) { wrCacheSec += c->secNum; if(wrCacheSec > SYS_cacheEndSec()) wrCacheSec -= SYS_cacheSecNum(); } CACHE_RETURN(); //continue; } else { FAT_fseek(&cachefile, 0, SEEK_HEAD); //TSK_disable(); cacheTail = c->next; cacheTail->actvStartClus = 0; cacheTail->done = FALSE; if(cacheTail == cacheHead) cacheHead = cacheHead->next; wrCache = c; wrCacheSec = wrCache->startSec = wrCache->endSec = c->prev->endSec; wrCache->secNum = 0; wrCache->secOffset= 0; wrCache->actvStartClus = cachefile.startClus; wrCache->actvFileSize = cachefile.size; wrCache->done = FALSE; //TSK_enable(); } } } else { if( (wrCache->actvStartClus != Audio.file.startClus)|| (wrCache->actvFileSize != Audio.file.size)|| (wrCache != rdCache)) { ULONG secOffset = 0; mMSG_send(uiParentMsgQ, SYS_MSG_ID, SCURRENTAUDIOFILE, DONTCARE, SYS_FOREVER); //TSK_disable(); cachefile = Audio.file; //TSK_enable(); if(prevOffset > 0x40000) { secOffset = prevOffset/256; FAT_fseek(&cachefile, secOffset*256, SEEK_HEAD); } else FAT_fseek(&cachefile, 0, SEEK_HEAD); //TSK_disable(); if(wrCache->done == TRUE) { wrCacheSec = wrCache->endSec; wrCache = wrCache->next; wrCache->startSec = wrCacheSec; } else wrCacheSec = wrCache->startSec; cacheTail = wrCache->next; cacheTail->actvStartClus = 0; cacheTail->done = FALSE; if(cacheTail == cacheHead) cacheHead = cacheHead->next; wrCache->actvStartClus = cachefile.startClus; wrCache->actvFileSize = cachefile.size; wrCache->endSec = wrCacheSec ; wrCache->secNum = 0; wrCache->done = FALSE; wrCache->secOffset= secOffset; rdCache = wrCache; cacheDepth = 0; //TSK_enable(); } } // Check cache depth. if(cacheDepth > cacheUpperThreshold) { DECODER_cacheDepthReset(2); mMSG_send(uiParentMsgQ, SYS_MSG_ID, SNEXTAUDIOFILE, 0, SYS_FOREVER); CACHE_RETURN(); } if(SYS_nextCacheSec(wrCache->endSec) == cacheHead->startSec) { //TSK_disable(); if( (cacheHead != wrCache) ) { if(cacheHead != rdCache) cacheHead = cacheHead->next; else CACHE_RETURN(); } else { // Cache is full. cacheHead->secOffset++; cacheHead->secNum--; cacheHead->startSec = SYS_nextCacheSec(cacheHead->startSec); } //TSK_enable(); } len = FAT_fread(&cachefile, buf, 256); NAND_writeSec(wrCacheSec, buf, FALSE); cacheDepth++; wrCacheSec = SYS_nextCacheSec(wrCacheSec); wrCache->endSec = wrCacheSec; wrCache->secNum++; if(len<256) wrCache->done = TRUE; SYS_swWdtReset(); } }

Here is the call graph for this function:

void DECODER_cacheDepthReset (  unsigned short  mode  )

Function resets cache depth controls. This function also resets cache check state to verify if file exists in cache. Parameters: mode  Cache depth control mode. 0: reset to default. 1: Double current. 2: Increment. Definition at line 406 of file DECODER_getData.c. Referenced by DECODER_cache(), DECODER_cacheInit(), and UI_PSF_play(). { TSK_disable(); inCacheState = INCACHE_CHECK; if(0 == mode) { cacheUpperThreshold = 0x1000; cacheLowerThreshold = 0x800; } else { if(1 == mode) // Double upper threshold. { cacheUpperThreshold <<= 1; } else // Increment upper threshold. { cacheUpperThreshold += 0x1000; } if(cacheUpperThreshold >= SYS_cacheSecNum() ) { // Aligned to NAND page boundary. cacheUpperThreshold = SYS_cacheSecNum() - 62; } } TSK_enable(); }

unsigned short DECODER_getData (  int *  pD, unsigned long  offset, unsigned short  reqLen )

Function feeds data into docoder bit stream/buffer. A NAND cache is managed here if HDD is present. Parameters: pD  Decoder input data pointer. offset  Requested data offset in media file. reqLen  Requested data length in words. Returns: Available data length in words. Definition at line 132 of file DECODER_getData.c. References Audio, FAT_fread(), FAT_fseek(), st_AUDIO::file, File::ptr, and SEEK_MID. Referenced by DECODER__mp3media(), DECODER__oggRead(), DECODER__wavmedia(), and DECODER__wmamedia(). { unsigned short len; File * fp = &Audio.file; if(FALSE == _isCacheHit(fp, offset, &reqLen)) { if(offset != fp->ptr) FAT_fseek(fp, (long)(offset-fp->ptr), SEEK_MID); len = FAT_fread(fp, (unsigned short*)pD, reqLen); } else { len = _cacheRead(offset, (unsigned short*)pD, reqLen); } if(len == 0) DECODER_stop(); return len; }

Here is the call graph for this function:

---