自学教程：C++ FindBlock函数代码示例

bool Sequence::GetRMS(sampleCount start, sampleCount len,                         float * outRMS) const{   if (len == 0 || mBlock->Count() == 0) {      *outRMS = float(0.0);      return true;   }   double sumsq = 0.0;   sampleCount length = 0;   unsigned int block0 = FindBlock(start);   unsigned int block1 = FindBlock(start + len);   sampleCount s0, l0, maxl0;   // First calculate the rms of the blocks in the middle of this region;   // this is very fast because we have the rms of every entire block   // already in memory.   unsigned int b;   for (b = block0 + 1; b < block1; b++) {      float blockMin, blockMax, blockRMS;      mBlock->Item(b)->f->GetMinMax(&blockMin, &blockMax, &blockRMS);      sumsq += blockRMS * blockRMS * mBlock->Item(block0)->f->GetLength();      length += mBlock->Item(block0)->f->GetLength();   }   // Now we take the first and last blocks into account, noting that the   // selection may only partly overlap these blocks.   // If not, we need read some samples and summaries from disk.   s0 = start - mBlock->Item(block0)->start;   l0 = len;   maxl0 = mBlock->Item(block0)->start + mBlock->Item(block0)->f->GetLength() - start;   if (l0 > maxl0)      l0 = maxl0;   float partialMin, partialMax, partialRMS;   mBlock->Item(block0)->f->GetMinMax(s0, l0, &partialMin, &partialMax, &partialRMS);   sumsq += partialRMS * partialRMS * l0;   length += l0;   if (block1 > block0) {      s0 = 0;      l0 = (start + len) - mBlock->Item(block1)->start;      mBlock->Item(block1)->f->GetMinMax(s0, l0,                                         &partialMin, &partialMax, &partialRMS);      sumsq += partialRMS * partialRMS * l0;      length += l0;   }   *outRMS = sqrt(sumsq/length);   return true;}

int WaveTrack::FindBlock(sampleCount pos, sampleCount lo,                         sampleCount guess, sampleCount hi){   wxASSERT(block->Item(guess)->len > 0);   wxASSERT(lo <= guess && guess <= hi && lo <= hi);   if (pos >= block->Item(guess)->start &&       pos < block->Item(guess)->start + block->Item(guess)->len)      return guess;   if (pos < block->Item(guess)->start)      return FindBlock(pos, lo, (lo + guess) / 2, guess);   else      return FindBlock(pos, guess + 1, (guess + 1 + hi) / 2, hi);}

int Sequence::FindBlock(sampleCount pos, sampleCount lo,                        sampleCount guess, sampleCount hi) const{   wxASSERT(mBlock->Item(guess)->len > 0);   wxASSERT(lo <= guess && guess <= hi && lo <= hi);   if (pos >= mBlock->Item(guess)->start &&       pos < mBlock->Item(guess)->start + mBlock->Item(guess)->len)      return guess;   if (pos < mBlock->Item(guess)->start)      return FindBlock(pos, lo, (lo + guess) / 2, guess);   else      return FindBlock(pos, guess + 1, (guess + 1 + hi) / 2, hi);}

//======================================================int ParmFile::GetIntParm(const char* parm_nam){  int num;  char parm_str[20];  if(GetParmStr(parm_nam, parm_str)!=0)    {    FindBlock(Block_Name);    if(GetParmStr(parm_nam, parm_str) !=0)      {      ErrorStream <<  "Error: parameter '" << parm_nam                   << "' not found after 2 attempts" << endl;      exit(-1);      }    }  cout << "str = " << parm_str << endl;//  for(c_ptr=parm_str; c_ptr<parm_str+strlen(parm_str);c_ptr++) {//   if(!isdigit(*c_ptr)) {//      ErrorStream << "Error: non-numeric data where numeric expected" << endl;//      exit(-1);//      }//   }   if(!isnumeric(parm_str)) {      ErrorStream << "Error: non-numeric data where numeric expected" << endl;      exit(-1);      }  num = atoi(parm_str);  cout << "num = " << num << endl;  return(num);}

BOOL CSysinfo::GetProcessName (pid_t pid, char *dest, int sz){	// this code is deprecated. It was causing ACCESS_VIOLATIONS	// on Windows XP.#if 0	DWORD *block;	Refresh();	block = FindBlock (pid);	if (!block)	{		dest[0] = '/0';		return FALSE;	}	MakeAnsiString ((WORD*)(*(block+15)), dest);#endif	HANDLE Hnd;	if( ! (Hnd = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid))) {		return FALSE;	}	if ( ! GetModuleBaseName(Hnd, NULL, dest, sz) ) {		return FALSE;	}		return TRUE;}

/* * Copy data in specified file to specified block in channel data memory map */void CopyFileToMappedBlock(char *blockName, char *inputFilename) {	if (!FileExists(inputFilename)) {		printf( "ERROR: Input file %s does not exist!/n" );		return;	}	int fd = open(inputFilename, O_RDONLY);	if (fd < 0) {		printf( "ERROR: Unable to open input file %s: %s",			inputFilename, strerror(errno));		return;	}	if (OpenChannelControlMemoryMap() < 0) {		close(fd);		return;	}	if (OpenChannelMemoryMap() < 0) {		CloseChannelControlMemoryMap();		close(fd);		return;	}	if (OpenChannelPixelMap() < 0) {		CloseChannelMemoryMap();		CloseChannelControlMemoryMap();		close(fd);		return;	}	FPPChannelMemoryMapControlBlock *cb = FindBlock(blockName);	if (cb) {		char data[FPPD_MAX_CHANNELS];		int r = read(fd, data, cb->channelCount);		if (r != cb->channelCount) {			printf( "WARNING: Expected %d bytes of data but only read %d./n",				cb->channelCount, r);		} else {			int i;			int limit = cb->channelCount - 3;			for (i = 0; i <= limit; ) {				dataMap[pixelMap[cb->startChannel - 1 + i]] = data[i]; i++; // R |				dataMap[pixelMap[cb->startChannel - 1 + i]] = data[i]; i++; // G |- triplet				dataMap[pixelMap[cb->startChannel - 1 + i]] = data[i]; i++; // B |			}			printf( "Data imported/n" );		}	} else {		printf( "ERROR: Could not find MAP %s/n", blockName);	}	CloseChannelMemoryMap();	CloseChannelControlMemoryMap();	close(fd);}

int Sequence::FindBlock(sampleCount pos, sampleCount lo,                        sampleCount guess, sampleCount hi) const{   wxASSERT(mBlock->Item(guess)->f->GetLength() > 0);   wxASSERT(lo <= guess && guess <= hi && lo <= hi);   if (pos >= mBlock->Item(guess)->start &&       pos < mBlock->Item(guess)->start + mBlock->Item(guess)->f->GetLength())      return guess;   //this is a binary search, but we probably could benefit by something more like   //dictionary search where we guess something smarter than the binary division   //of the unsearched area, since samples are usually proportional to block file number.   if (pos < mBlock->Item(guess)->start)      return FindBlock(pos, lo, (lo + guess) / 2, guess);   else      return FindBlock(pos, guess + 1, (guess + 1 + hi) / 2, hi);}

status_tVolume::FindBlock(off_t logical, fsblock_t &physicalBlock){	off_t physical;	status_t status = FindBlock(logical, physical);	if (status != B_OK)		return status;	physicalBlock = physical / fBlockSize;	return B_OK;}

// Pass NULL to set silencebool Sequence::Set(samplePtr buffer, sampleFormat format,                   sampleCount start, sampleCount len){   if (start < 0 || start > mNumSamples ||       start+len > mNumSamples)      return false;   samplePtr temp = NULL;   if (format != mSampleFormat) {      temp = NewSamples(mMaxSamples, mSampleFormat);      wxASSERT(temp);   }   samplePtr silence = NULL;   if (!buffer) {      silence = NewSamples(mMaxSamples, format);      wxASSERT(silence);      ClearSamples(silence, format, 0, mMaxSamples);   }   int b = FindBlock(start);   while (len) {      int blen = mBlock->Item(b)->start + mBlock->Item(b)->len - start;      if (blen > len)         blen = len;      if (buffer) {         if (format == mSampleFormat)            CopyWrite(buffer, mBlock->Item(b), start - mBlock->Item(b)->start,                      blen);         else {            CopySamples(buffer, format, temp, mSampleFormat, blen);            CopyWrite(temp, mBlock->Item(b), start - mBlock->Item(b)->start,                      blen);         }         buffer += (blen * SAMPLE_SIZE(format));      } else         CopyWrite(silence, mBlock->Item(b), start - mBlock->Item(b)->start,                   blen);      len -= blen;      start += blen;      b++;   }   if (!buffer)      DeleteSamples(silence);   if (format != mSampleFormat)      DeleteSamples(temp);   return ConsistencyCheck("Set");}

void FIndirectLightingCache::UpdateCacheAllocation(	const FBoxSphereBounds& Bounds, 	int32 BlockSize,	bool bOpaqueRelevance,	FIndirectLightingCacheAllocation*& Allocation, 	TMap<FIntVector, FBlockUpdateInfo>& BlocksToUpdate,	TArray<FIndirectLightingCacheAllocation*>& TransitionsOverTimeToUpdate){	if (Allocation && Allocation->IsValid())	{		FIndirectLightingCacheBlock& Block = FindBlock(Allocation->MinTexel);		// Calculate a potentially new min and size based on the current bounds		FVector NewMin;		FVector NewSize;		CalculateBlockPositionAndSize(Bounds, Block.TexelSize, NewMin, NewSize);		// If the primitive has moved enough to change its block min and size, we need to interpolate it again		if (Allocation->bIsDirty || GCacheUpdateEveryFrame || !Block.Min.Equals(NewMin) || !Block.Size.Equals(NewSize))		{			// Update the block and primitive allocation with the new bounds			Block.Min = NewMin;			Block.Size = NewSize;			FVector NewScale;			FVector NewAdd;			FVector MinUV;			FVector MaxUV;			CalculateBlockScaleAndAdd(Allocation->MinTexel, Allocation->AllocationTexelSize, NewMin, NewSize, NewScale, NewAdd, MinUV, MaxUV);			Allocation->SetParameters(Allocation->MinTexel, Allocation->AllocationTexelSize, NewScale, NewAdd, MinUV, MaxUV, bOpaqueRelevance);			BlocksToUpdate.Add(Block.MinTexel, FBlockUpdateInfo(Block, Allocation));		}		if ((Allocation->SingleSamplePosition - Allocation->TargetPosition).SizeSquared() > DELTA)		{			TransitionsOverTimeToUpdate.AddUnique(Allocation);		}	}	else	{		delete Allocation;		Allocation = CreateAllocation(BlockSize, Bounds, bOpaqueRelevance);		if (Allocation->IsValid())		{			// Must interpolate lighting for this new block			BlocksToUpdate.Add(Allocation->MinTexel, FBlockUpdateInfo(VolumeBlocks.FindChecked(Allocation->MinTexel), Allocation));		}	}}

/* * Set a channel data map block as active/inactive. */void SetMappedBlockActive(char *blockName, int active) {	if (OpenChannelControlMemoryMap() < 0)		return;	FPPChannelMemoryMapControlBlock *cb = FindBlock(blockName);	if (cb) {		cb->isActive = active;	} else {		printf( "ERROR: Could not find MAP %s/n", blockName);	}	CloseChannelControlMemoryMap();}

static int FreeObject(ContainerHeap *heap,void *element){    ListElement *le = element;    le->Next = INVALID_POINTER_VALUE;#ifdef DEBUG_HEAP_FREELIST    { size_t idx,blockNr;        blockNr = FindBlock(heap,element,&idx);        if (blockNr > heap->CurrentBlock) return -1;    }#endif    memcpy(le->Data, &heap->FreeList,sizeof(ListElement *));	le->Next = heap->FreeList;    heap->FreeList = le;    heap->timestamp++;    return 1;}

bool CheckBlockList(struct in_addr* piaPeer){	block_node* pBlock = FindBlock(piaPeer);	// true means not blocked and can connect	// false means block still in effect	if (!pBlock)		return true;	if (pBlock->iExpires < 0)		return false;	if (pBlock->iExpires <= GetTime())	{		DeleteBlock(piaPeer);		return true;	}	return false;}

/* * Fill a channel data block with a single specified value */void FillMappedBlock(char *blockName, int channelData) {	if (OpenChannelControlMemoryMap() < 0) {		return;	}	if (OpenChannelMemoryMap() < 0) {		CloseChannelControlMemoryMap();		return;	}	FPPChannelMemoryMapControlBlock *cb = FindBlock(blockName);	if (cb) {		memset(dataMap + cb->startChannel - 1, channelData, cb->channelCount);	} else {		printf( "ERROR: Could not find MAP %s/n", blockName);	}	CloseChannelMemoryMap();	CloseChannelControlMemoryMap();}

/* * Display info on a named channel data block */void DumpMappedBlockInfo(char *blockName) {	if (OpenChannelControlMemoryMap() < 0) {		return;	}	FPPChannelMemoryMapControlBlock *cb = FindBlock(blockName);	if (cb) {		printf( "Block Name: %s/n", cb->blockName);		printf( "Channels  : %lld-%lld (%lld channels)/n",			cb->startChannel, cb->startChannel + cb->channelCount - 1,			cb->channelCount);		printf( "Status    : ");		switch (cb->isActive) {			case 0: printf("Idle");					break;			case 1: printf("Active");					break;			case 2: printf("Active (Transparent)");					break;			case 3: printf("Active (Transparent RGB)");					break;		}		printf( "/n");		printf( "Is Locked : ");		switch (cb->isLocked) {			case 0: printf("No");					break;			case 1: printf("Yes");					break;		}		printf("/n");	} else {		printf( "ERROR: Could not find MAP %s/n", blockName);	}	CloseChannelControlMemoryMap();}