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67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
package progressreadseeker
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import (
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"io"
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)
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type ProgressFn func(approxReadBytes int64, totalSize int64)
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type Reader struct {
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rs io.ReadSeeker
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pos int64
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totalSize int64
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partitionSize int64
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partitions []bool
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partitionsReadCount int64
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progressFn ProgressFn
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}
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func New(rs io.ReadSeeker, precision int64, totalSize int64, fn ProgressFn) *Reader {
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partitionSize := totalSize / precision
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if totalSize%precision != 0 {
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partitionSize++
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}
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return &Reader{
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rs: rs,
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totalSize: totalSize,
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partitionSize: partitionSize,
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partitions: make([]bool, precision),
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progressFn: fn,
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}
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}
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func (prs *Reader) Read(p []byte) (n int, err error) {
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n, err = prs.rs.Read(p)
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newPos := prs.pos + int64(n)
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lastPartitionsReadCount := prs.partitionsReadCount
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partStart := prs.pos / prs.partitionSize
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partEnd := newPos / prs.partitionSize
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for i := partStart; i < partEnd; i++ {
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if prs.partitions[i] {
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continue
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}
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prs.partitions[i] = true
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prs.partitionsReadCount++
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}
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if lastPartitionsReadCount != prs.partitionsReadCount {
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readBytes := prs.partitionSize * prs.partitionsReadCount
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if readBytes > prs.totalSize {
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readBytes = prs.totalSize
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}
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prs.progressFn(readBytes, prs.totalSize)
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}
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prs.pos = newPos
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return n, err
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}
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func (prs *Reader) Seek(offset int64, whence int) (int64, error) {
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pos, err := prs.rs.Seek(offset, whence)
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prs.pos = pos
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return pos, err
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}
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