/**
* Reads a small amount of data from across the boundary between two blocks.
* The {@link #_readIndex} of this (the second) block is updated accordingly.
* Note- this method (and other code) assumes that the second {@link DataInputBlock}
* always is big enough to complete the read without being exhausted.
*/
private void ReadSpanning(DataInputBlock prevBlock, int prevBlockAvailable, byte[] buf)
{
Array.Copy(prevBlock._buf, prevBlock._readIndex, buf, 0, prevBlockAvailable);
int secondReadLen = buf.Length - prevBlockAvailable;
Array.Copy(_buf, 0, buf, prevBlockAvailable, secondReadLen);
_readIndex = secondReadLen;
}
/**
* Reads a <c>short</c> which spans the end of <c>prevBlock</c> and the start of this block.
*/
public int ReadUshortLE(DataInputBlock prevBlock)
{
// simple case - will always be one byte in each block
int i = prevBlock._buf.Length - 1;
int b0 = prevBlock._buf[i++] & 0xFF;
int b1 = _buf[_readIndex++] & 0xFF;
return((b1 << 8) + (b0 << 0));
}
/**
* Reads an <c>int</c> which spans the end of <c>prevBlock</c> and the start of this block.
*/
public int ReadIntLE(DataInputBlock prevBlock, int prevBlockAvailable)
{
byte[] buf = new byte[4];
ReadSpanning(prevBlock, prevBlockAvailable, buf);
int b0 = buf[0] & 0xFF;
int b1 = buf[1] & 0xFF;
int b2 = buf[2] & 0xFF;
int b3 = buf[3] & 0xFF;
return((b3 << 24) + (b2 << 16) + (b1 << 8) + (b0 << 0));
}
/**
* Reads a <c>long</c> which spans the end of <c>prevBlock</c> and the start of this block.
*/
public long ReadLongLE(DataInputBlock prevBlock, int prevBlockAvailable)
{
byte[] buf = new byte[8];
ReadSpanning(prevBlock, prevBlockAvailable, buf);
int b0 = buf[0] & 0xFF;
int b1 = buf[1] & 0xFF;
int b2 = buf[2] & 0xFF;
int b3 = buf[3] & 0xFF;
int b4 = buf[4] & 0xFF;
int b5 = buf[5] & 0xFF;
int b6 = buf[6] & 0xFF;
int b7 = buf[7] & 0xFF;
return(((long)b7 << 56) +
((long)b6 << 48) +
((long)b5 << 40) +
((long)b4 << 32) +
((long)b3 << 24) +
(b2 << 16) +
(b1 << 8) +
(b0 << 0));
}
