73 lines
1.3 KiB
Go
73 lines
1.3 KiB
Go
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package mq_coder
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import (
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"bytes"
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"io"
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"io/ioutil"
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)
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type chunkVReader struct {
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src io.Reader // the reader parts of V
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buf *bytes.Buffer // the bytes part of V
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totalSize int // size of whole buffer of this packet
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off int // last read op
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ChunkVSize int // the size of chunked V
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}
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// Read implement io.Reader interface
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func (r *chunkVReader) Read(p []byte) (n int, err error) {
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if r.src == nil {
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return 0, nil
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}
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if r.off >= r.totalSize {
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return 0, io.EOF
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}
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if r.off < r.totalSize-r.ChunkVSize {
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n, err := r.buf.Read(p)
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r.off += n
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if err != nil {
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if err == io.EOF {
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return n, nil
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} else {
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return 0, err
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}
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}
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return n, nil
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}
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n, err = r.src.Read(p)
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r.off += n
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if err != nil {
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return n, err
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}
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return n, nil
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}
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// WriteTo implement io.WriteTo interface
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func (r *chunkVReader) WriteTo(w io.Writer) (n int64, err error) {
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if r.src == nil {
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return 0, nil
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}
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// first, write existed buffer
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m, err := w.Write(r.buf.Bytes())
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if err != nil {
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return 0, err
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}
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n += int64(m)
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// last, write from reader
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buf, err := ioutil.ReadAll(r.src)
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if err != nil && err != io.EOF {
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return 0, errWriteFromReader
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}
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m, err = w.Write(buf)
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if err != nil {
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return 0, err
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}
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n += int64(m)
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return n, nil
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}
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