48 lines
1.4 KiB
Go
48 lines
1.4 KiB
Go
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package utils
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import "io"
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func NewPartialRangeWriter(writerIn io.Writer, httpRangeIn ContentRangeValue) io.Writer {
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return &PartialRangeWriter{
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passedWriter: writerIn,
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passedWriterIndex: 0,
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httpRange: httpRangeIn,
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exclusiveLastIndex: httpRangeIn.Start + httpRangeIn.Length,
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}
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}
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type PartialRangeWriter struct {
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passedWriter io.Writer
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passedWriterIndex int64
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exclusiveLastIndex int64
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httpRange ContentRangeValue
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}
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func (prw *PartialRangeWriter) Write(p []byte) (n int, err error) {
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var pOffsetIndex int64 = -1
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if prw.passedWriterIndex >= prw.httpRange.Start && prw.passedWriterIndex < prw.exclusiveLastIndex {
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pOffsetIndex = 0
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} else if prw.passedWriterIndex+int64(len(p)) > prw.httpRange.Start && prw.passedWriterIndex < prw.exclusiveLastIndex {
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pOffsetIndex = prw.httpRange.Start - prw.passedWriterIndex
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prw.passedWriterIndex += pOffsetIndex
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} else {
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prw.passedWriterIndex += int64(len(p))
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}
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if pOffsetIndex >= 0 {
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if prw.passedWriterIndex+(int64(len(p))-pOffsetIndex) <= prw.exclusiveLastIndex {
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written, err := prw.passedWriter.Write(p[pOffsetIndex:])
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prw.passedWriterIndex += int64(written)
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if err != nil {
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return written, err
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}
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} else {
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written, err := prw.passedWriter.Write(p[pOffsetIndex : prw.exclusiveLastIndex-prw.passedWriterIndex+pOffsetIndex])
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prw.passedWriterIndex += int64(written)
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if err != nil {
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return written, err
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}
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}
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}
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return n, nil
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}
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