38 lines
1.2 KiB
Go
38 lines
1.2 KiB
Go
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package binaryio
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import "io"
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// MinimumReader is the implementation for MinReader.
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type MinimumReader struct {
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R io.Reader
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MinNumberOfBytesToRead int64 // Min number of bytes we need to read from the reader
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}
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// MinReader reads from R but ensures there is at least N bytes read from the reader.
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// The reader should call Close() when they are done reading.
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// Closing the MinReader will read and discard any unread bytes up to MinNumberOfBytesToRead.
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// CLosing the MinReader does NOT close the underlying reader.
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// The underlying implementation is a MinimumReader, which implements ReaderCloser.
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func MinReader(r io.Reader, minNumberOfBytesToRead int64) *MinimumReader {
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return &MinimumReader{
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R: r,
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MinNumberOfBytesToRead: minNumberOfBytesToRead,
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}
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}
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func (r *MinimumReader) Read(p []byte) (n int, err error) {
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n, err = r.R.Read(p)
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r.MinNumberOfBytesToRead -= int64(n)
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return n, err
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}
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// Close does not close the underlying reader, only the MinimumReader
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func (r *MinimumReader) Close() error {
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if r.MinNumberOfBytesToRead > 0 {
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b := make([]byte, r.MinNumberOfBytesToRead)
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_, err := r.R.Read(b)
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return err
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}
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return nil
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}
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