45 lines
722 B
Go
45 lines
722 B
Go
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package utils
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import (
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"bytes"
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"crypto/md5"
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"fmt"
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"io"
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"os"
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)
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// Reimplemented KOReader Partial MD5 Calculation
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func CalculatePartialMD5(filePath string) (string, error) {
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file, err := os.Open(filePath)
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if err != nil {
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return "", err
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}
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defer file.Close()
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var step int64 = 1024
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var size int64 = 1024
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var buf bytes.Buffer
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for i := -1; i <= 10; i++ {
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byteStep := make([]byte, size)
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var newShift int64 = int64(i * 2)
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var newOffset int64
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if i == -1 {
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newOffset = 0
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} else {
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newOffset = step << newShift
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}
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_, err := file.ReadAt(byteStep, newOffset)
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if err == io.EOF {
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break
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}
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buf.Write(byteStep)
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}
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allBytes := buf.Bytes()
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return fmt.Sprintf("%x", md5.Sum(allBytes)), nil
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}
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