68 lines
1.3 KiB
Go
68 lines
1.3 KiB
Go
package streams
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import (
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"io"
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)
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type MetadataInjector struct {
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io.Writer
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offset int
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MetadataInterval int
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metadata Metadata
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}
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func NewMetadataInjector(w io.Writer, metadataInterval int) *MetadataInjector {
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return &MetadataInjector{
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Writer: w,
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MetadataInterval: metadataInterval,
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}
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}
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func (mi *MetadataInjector) SetMetadata(metadata Metadata) {
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mi.metadata = metadata
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}
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func (mi *MetadataInjector) writeMetadata() (n int, err error) {
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// the metadata generated here will be read on the next Read call
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metadataBytes := mi.metadata.Bytes()
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lenByte := (len(metadataBytes) + 15) / 16
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metadataBuf := make([]byte, int(lenByte)*16+1)
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metadataBuf[0] = byte(lenByte)
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copy(metadataBuf[1:], metadataBytes)
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if len(mi.metadata) > 0 {
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mi.metadata = Metadata{}
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}
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return mi.Writer.Write(metadataBuf)
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}
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func (mi *MetadataInjector) Write(data []byte) (n int, err error) {
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for n < len(data) {
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toWrite := mi.MetadataInterval - mi.offset
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if toWrite <= 0 {
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_, cerr := mi.writeMetadata()
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//n += cn
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if cerr != nil {
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err = cerr
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return
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}
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mi.offset = 0
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// toWrite = mi.MetadataInterval
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continue
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}
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outBytes := make([]byte, toWrite)
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copy(outBytes, data[mi.offset:mi.offset+toWrite])
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cn, cerr := mi.Writer.Write(outBytes)
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n += cn
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mi.offset += cn
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if cerr != nil {
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err = cerr
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return
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}
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}
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return
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}
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