C++ BitString::getField方法代码示例

void BitString::setString( const BitString & i_sStr, uint32_t i_sPos,
                           uint32_t i_sLen, uint32_t i_dPos )
{
    // Ensure the source parameters are valid.
    PRDF_ASSERT( nullptr != i_sStr.getBufAddr() );
    PRDF_ASSERT( 0 < i_sLen ); // at least one bit to copy
    PRDF_ASSERT( i_sPos + i_sLen <= i_sStr.getBitLen() );

    // Ensure the destination has at least one bit available to copy.
    PRDF_ASSERT( nullptr != getBufAddr() );
    PRDF_ASSERT( i_dPos < getBitLen() );

    // If the source length is greater than the destination length than the
    // extra source bits are ignored.
    uint32_t actLen = std::min( i_sLen, getBitLen() - i_dPos );

    // The bit strings may be in overlapping memory spaces. So we need to copy
    // the data in the correct direction to prevent overlapping.
    uint32_t sRelOffset = 0, dRelOffset = 0;
    CPU_WORD * sRelAddr = i_sStr.getRelativePosition( sRelOffset, i_sPos );
    CPU_WORD * dRelAddr =        getRelativePosition( dRelOffset, i_dPos );

    // Copy the data.
    if ( (dRelAddr == sRelAddr) && (dRelOffset == sRelOffset) )
    {
        // Do nothing. The source and destination are the same.
    }
    else if ( (dRelAddr < sRelAddr) ||
              ((dRelAddr == sRelAddr) && (dRelOffset < sRelOffset)) )
    {
        // Copy the data forward.
        for ( uint32_t pos = 0; pos < actLen; pos += CPU_WORD_BIT_LEN )
        {
            uint32_t len = std::min( actLen - pos, CPU_WORD_BIT_LEN );

            CPU_WORD value = i_sStr.getField( i_sPos + pos, len );
            setField( i_dPos + pos, len, value );
        }
    }
    else // Copy the data backwards.
    {
        // Get the first position of the last chunk (CPU_WORD aligned).
        uint32_t lastPos = ((actLen-1) / CPU_WORD_BIT_LEN) * CPU_WORD_BIT_LEN;

        // Start with the last chunk and work backwards.
        for ( int32_t pos = lastPos; 0 <= pos; pos -= CPU_WORD_BIT_LEN )
        {
            uint32_t len = std::min( actLen - pos, CPU_WORD_BIT_LEN );

            CPU_WORD value = i_sStr.getField( i_sPos + pos, len );
            setField( i_dPos + pos, len, value );
        }
    }
}

void BitString::setPattern( uint32_t i_sPos, uint32_t i_sLen,
                            CPU_WORD i_pattern, uint32_t i_pLen )
{
    PRDF_ASSERT(nullptr != getBufAddr());        // must to have a valid address
    PRDF_ASSERT(0 < i_sLen);                     // must have at least one bit
    PRDF_ASSERT(i_sPos + i_sLen <= getBitLen()); // field must be within range
    PRDF_ASSERT(0 < i_pLen);                     // must have at least one bit
    PRDF_ASSERT(i_pLen <= CPU_WORD_BIT_LEN);     // i_pLen length must be valid

    // Get a bit string for the pattern subset (right justified).
    BitString bso ( i_pLen, &i_pattern, CPU_WORD_BIT_LEN - i_pLen );

    // Iterate the range in chunks the size of i_pLen.
    uint32_t endPos = i_sPos + i_sLen;
    for ( uint32_t pos = i_sPos; pos < endPos; pos += i_pLen )
    {
        // The true chunk size is either i_pLen or the leftovers at the end.
        uint32_t len = std::min( i_pLen, endPos - pos );

        // Get this chunk's pattern value, truncate (left justified) if needed.
        CPU_WORD pattern = bso.getField( 0, len );

        // Set the pattern in this string.
        setField( pos, len, pattern );
    }
}

bool BitString::isEqual( const BitString & i_str ) const
{
    if ( getBitLen() != i_str.getBitLen() )
        return false; // size not equal

    for ( uint32_t pos = 0; pos < getBitLen(); pos += CPU_WORD_BIT_LEN )
    {
        uint32_t len = std::min( getBitLen() - pos, CPU_WORD_BIT_LEN );

        if ( getField(pos, len) != i_str.getField(pos, len) )
            return false; // bit strings do not match
    }

    return true; // bit strings match
}

void BitString::maskString( const BitString & i_mask )
{
    // Get the length of the smallest string.
    uint32_t actLen = std::min( getBitLen(), i_mask.getBitLen() );

    for ( uint32_t pos = 0; pos < actLen; pos += CPU_WORD_BIT_LEN )
    {
        uint32_t len = std::min( actLen - pos, CPU_WORD_BIT_LEN );

        CPU_WORD dVal =        getField( pos, len );
        CPU_WORD sVal = i_mask.getField( pos, len );

        setField( pos, len, dVal & ~sVal );
    }
}

BitStringBuffer BitString::operator|( const BitString & i_bs ) const
{
    // Get the length of the smallest string.
    uint32_t actLen = std::min( getBitLen(), i_bs.getBitLen() );

    BitStringBuffer bsb( actLen );

    for ( uint32_t pos = 0; pos < actLen; pos += CPU_WORD_BIT_LEN )
    {
        uint32_t len = std::min( actLen - pos, CPU_WORD_BIT_LEN );

        CPU_WORD dVal =      getField( pos, len );
        CPU_WORD sVal = i_bs.getField( pos, len );

        bsb.setField( pos, len, dVal | sVal );
    }

    return bsb;
}