TSparseArray Class Reference

#include <CascMndx.h>

Public Member Functions
	TSparseArray ()
void	ExchangeWith (TSparseArray &TargetObject)
int	LoadFromStream (TByteStream &InStream)
int	LoadFromStream_Exchange (TByteStream &InStream)
DWORD	IsItemPresent (DWORD ItemIndex)
DWORD	GetItemValue (DWORD ItemIndex)

Public Attributes
TGenericArray	ItemBits
DWORD	TotalItemCount
DWORD	ValidItemCount
TGenericArray	BaseValues
TGenericArray	ArrayDwords_38
TGenericArray	ArrayDwords_50

Constructor & Destructor Documentation

TSparseArray::TSparseArray

(

)

{
 TotalItemCount = 0;
 ValidItemCount = 0;
}

Member Function Documentation

void TSparseArray::ExchangeWith

(

TSparseArray &

TargetObject

)

{
 TSparseArray WorkBuff;

 WorkBuff = *this;
 *this = Target;
 Target = WorkBuff;
}

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DWORD TSparseArray::GetItemValue

(

DWORD

ItemIndex

)

{
 PTRIPLET pTriplet;
 DWORD DwordIndex;
 DWORD BaseValue;
 DWORD BitMask;

 //
 // Divide the low-8-bits index to four parts:
 //
 // |-----------------------|---|------------|
 // | A (23 bits) | B | C |
 // |-----------------------|---|------------|
 //
 // A (23-bits): Index to the table (60 bits per entry)
 //
 // Layout of the table entry:
 // |--------------------------------|-------|--------|--------|---------|---------|---------|---------|-----|
 // | Base Value | val[0]| val[1] | val[2] | val[3] | val[4] | val[5] | val[6] | - |
 // | 32 bits | 7 bits| 8 bits | 8 bits | 9 bits | 9 bits | 9 bits | 9 bits |5bits|
 // |--------------------------------|-------|--------|--------|---------|---------|---------|---------|-----|
 //
 // B (3 bits) : Index of the variable-bit value in the array (val[#], see above)
 //
 // C (32 bits): Number of bits to be checked (up to 0x3F bits).
 // Number of set bits is then added to the values obtained from A and B

 // Upper 23 bits contain index to the table
 pTriplet = BaseValues.TripletArray + (ItemIndex >> 0x09);
 BaseValue = pTriplet->BaseValue;

 // Next 3 bits contain the index to the VBR
 switch(((ItemIndex >> 0x06) & 0x07) - 1)
 {
 case 0: // Add the 1st value (7 bits)
 BaseValue += (pTriplet->Value2 & 0x7F);
 break;

 case 1: // Add the 2nd value (8 bits)
 BaseValue += (pTriplet->Value2 >> 0x07) & 0xFF;
 break;

 case 2: // Add the 3rd value (8 bits)
 BaseValue += (pTriplet->Value2 >> 0x0F) & 0xFF;
 break;

 case 3: // Add the 4th value (9 bits)
 BaseValue += (pTriplet->Value2 >> 0x17);
 break;

 case 4: // Add the 5th value (9 bits)
 BaseValue += (pTriplet->Value3 & 0x1FF);
 break;

 case 5: // Add the 6th value (9 bits)
 BaseValue += (pTriplet->Value3 >> 0x09) & 0x1FF;
 break;

 case 6: // Add the 7th value (9 bits)
 BaseValue += (pTriplet->Value3 >> 0x12) & 0x1FF;
 break;
 }

 //
 // Take the upper 27 bits as an index to DWORD array, take lower 5 bits
 // as number of bits to mask. Then calculate number of set bits in the value
 // masked value.
 //

 // Get the index into the array of DWORDs
 DwordIndex = (ItemIndex >> 0x05);

 // Add number of set bits in the masked value up to 0x3F bits
 if(ItemIndex & 0x20)
 BaseValue += GetNumbrOfSetBits32(ItemBits.Uint32Array[DwordIndex - 1]);

 BitMask = (1 << (ItemIndex & 0x1F)) - 1;
 return BaseValue + GetNumbrOfSetBits32(ItemBits.Uint32Array[DwordIndex] & BitMask);
}

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DWORD TSparseArray::IsItemPresent ( DWORD  ItemIndex )

inline

 {
 return (ItemBits.Uint32Array[ItemIndex >> 0x05] & (1 << (ItemIndex & 0x1F)));
 }

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int TSparseArray::LoadFromStream

(

TByteStream &

InStream

)

{
 ARRAY_POINTER Pointer;
 int nError;

 nError = ItemBits.LoadDwordsArray_Copy(InStream);
 if(nError != ERROR_SUCCESS)
 return nError;

 nError = InStream.GetBytes(sizeof(DWORD), &Pointer);
 if(nError != ERROR_SUCCESS)
 return nError;
 TotalItemCount = Pointer.Uint32s[0];

 nError = InStream.GetBytes(sizeof(DWORD), &Pointer);
 if(nError != ERROR_SUCCESS)
 return nError;
 ValidItemCount = Pointer.Uint32s[0];

 if(ValidItemCount > TotalItemCount)
 return ERROR_FILE_CORRUPT;

 nError = BaseValues.LoadTripletsArray_Copy(InStream);
 if(nError != ERROR_SUCCESS)
 return nError;

 nError = ArrayDwords_38.LoadDwordsArray_Copy(InStream);
 if(nError != ERROR_SUCCESS)
 return nError;

 nError = ArrayDwords_50.LoadDwordsArray_Copy(InStream);
 if(nError != ERROR_SUCCESS)
 return nError;

 return ERROR_SUCCESS;
}

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int TSparseArray::LoadFromStream_Exchange

(

TByteStream &

InStream

)

{
 TSparseArray NewStruct68;
 int nError;

 nError = NewStruct68.LoadFromStream(InStream);
 if(nError != ERROR_SUCCESS)
 return nError;

 ExchangeWith(NewStruct68);
 return ERROR_SUCCESS;
}

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Member Data Documentation

TGenericArray TSparseArray::ArrayDwords_38

TGenericArray TSparseArray::ArrayDwords_50

TGenericArray TSparseArray::BaseValues

TGenericArray TSparseArray::ItemBits

DWORD TSparseArray::TotalItemCount

DWORD TSparseArray::ValidItemCount

---

The documentation for this class was generated from the following files:

• dep/CascLib/src/CascMndx.h
• dep/CascLib/src/CascRootFile_Mndx.cpp