//
// This function will try to get enough bits from input and
// try to decode the bits.
// If there are no enought bits in the input, this function will return -1.
//
public int GetNextSymbol(InputBuffer input)
{
// Try to load 16 bits into input buffer if possible and get the bitBuffer value.
// If there aren't 16 bits available we will return all we have in the
// input buffer.
uint bitBuffer = input.TryLoad16Bits();
if (input.AvailableBits == 0) // running out of input.
{
return(-1);
}
// decode an element
int symbol = table[bitBuffer & tableMask];
if (symbol < 0) // this will be the start of the binary tree
// navigate the tree
{
uint mask = (uint)1 << tableBits;
do
{
symbol = -symbol;
if ((bitBuffer & mask) == 0)
{
symbol = left[symbol];
}
else
{
symbol = right[symbol];
}
mask <<= 1;
} while (symbol < 0);
}
int codeLength = codeLengthArray[symbol];
// huffman code lengths must be at least 1 bit long
if (codeLength <= 0)
{
throw new InvalidDataException(SR.GetString(SR.InvalidHuffmanData));
}
//
// If this code is longer than the # bits we had in the bit buffer (i.e.
// we read only part of the code), we can hit the entry in the table or the tree
// for another symbol. However the length of another symbol will not match the
// available bits count.
if (codeLength > input.AvailableBits)
{
// We already tried to load 16 bits and maximum length is 15,
// so this means we are running out of input.
return(-1);
}
input.SkipBits(codeLength);
return(symbol);
}
public Int32 GetNextSymbol(InputBuffer input)
{
UInt32 num = input.TryLoad16Bits();
if (input.AvailableBits == 0)
{
return(-1);
}
Int32 num2 = (Int32)this.table[(Int32)(checked ((IntPtr)(unchecked ((UInt64)num & (UInt64)((Int64)this.tableMask)))))];
if (num2 < 0)
{
UInt32 num3 = 1u << this.tableBits;
do
{
num2 = -num2;
if ((num & num3) == 0u)
{
num2 = (Int32)this.left[num2];
}
else
{
num2 = (Int32)this.right[num2];
}
num3 <<= 1;
}while (num2 < 0);
}
Int32 num4 = (Int32)this.codeLengthArray[num2];
if (num4 <= 0)
{
throw new InvalidDataException(SR.GetString("Invalid Huffman data"));
}
if (num4 > input.AvailableBits)
{
return(-1);
}
input.SkipBits(num4);
return(num2);
}
//
// This function will try to get enough bits from input and
// try to decode the bits.
// If there are no enought bits in the input, this function will return -1.
//
public int GetNextSymbol(InputBuffer input)
{
// Try to load 16 bits into input buffer if possible and get the bitBuffer value.
// If there aren't 16 bits available we will return all we have in the
// input buffer.
uint bitBuffer = input.TryLoad16Bits();
if( input.AvailableBits == 0) { // running out of input.
return -1;
}
// decode an element
int symbol = table[bitBuffer & tableMask];
if( symbol < 0) { // this will be the start of the binary tree
// navigate the tree
uint mask = (uint)1 << tableBits;
do
{
symbol = -symbol;
if ((bitBuffer & mask) == 0)
symbol = left[symbol];
else
symbol = right[symbol];
mask <<= 1;
} while (symbol < 0);
}
int codeLength = codeLengthArray[symbol];
// huffman code lengths must be at least 1 bit long
if (codeLength <= 0)
{
throw new InvalidDataException(SR.GetString(SR.InvalidHuffmanData));
}
//
// If this code is longer than the # bits we had in the bit buffer (i.e.
// we read only part of the code), we can hit the entry in the table or the tree
// for another symbol. However the length of another symbol will not match the
// available bits count.
if (codeLength > input.AvailableBits)
{
// We already tried to load 16 bits and maximum length is 15,
// so this means we are running out of input.
return -1;
}
input.SkipBits(codeLength);
return symbol;
}
