/
streams.go
51 lines (46 loc) · 1.17 KB
/
streams.go
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package disk
import (
"io"
)
type BlockReaderStream struct {
blockIndex int
blockOffset int
file io.ReadSeeker
}
func (brs *BlockReaderStream) NextBlock() (*Block, error) {
block := newBlock()
err := readBlock(brs.file, block, brs.blockIndex)
block.StartFrom(brs.blockOffset)
brs.blockOffset = 0
brs.blockIndex += 1
return block, err
}
type BlockWriterStream struct {
blockOffset int
data []byte
file io.ReadWriteSeeker
}
// NextBlock gets the next block from the input stream
func (bws *BlockWriterStream) NextBlock() (*Block, error) {
block := newBlock()
block.EndAt(0)
// if this is a full block, return it
if bws.blockOffset == 0 && len(bws.data) >= payloadSize {
block.buf = bws.data[:payloadSize]
block.EndAt(payloadSize)
bws.data = bws.data[payloadSize:]
return block, nil
}
// if this is a partial block, copy data into it
payloadLen := payloadSize - bws.blockOffset
block.StartFrom(bws.blockOffset)
if len(bws.data) > payloadLen {
block.Copy(bws.blockOffset, bws.data[:payloadLen])
bws.data = bws.data[payloadLen:]
} else {
block.Copy(bws.blockOffset, bws.data)
bws.data = nil
}
bws.blockOffset = 0
return block, nil
}