57 lines
1.1 KiB
Go
57 lines
1.1 KiB
Go
package chart
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import (
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"bufio"
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"io"
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"os"
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)
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var (
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// File contains file utility functions
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File = fileUtil{}
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)
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type fileUtil struct{}
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// ReadByLines reads a file and calls the handler for each line.
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func (fu fileUtil) ReadByLines(filePath string, handler func(line string) error) error {
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var f *os.File
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var err error
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if f, err = os.Open(filePath); err == nil {
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defer f.Close()
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var line string
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scanner := bufio.NewScanner(f)
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for scanner.Scan() {
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line = scanner.Text()
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err = handler(line)
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if err != nil {
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return err
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}
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}
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}
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return err
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}
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// ReadByChunks reads a file in `chunkSize` pieces, dispatched to the handler.
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func (fu fileUtil) ReadByChunks(filePath string, chunkSize int, handler func(line []byte) error) error {
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var f *os.File
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var err error
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if f, err = os.Open(filePath); err == nil {
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defer f.Close()
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chunk := make([]byte, chunkSize)
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for {
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readBytes, err := f.Read(chunk)
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if err == io.EOF {
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break
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}
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readData := chunk[:readBytes]
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err = handler(readData)
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if err != nil {
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return err
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}
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}
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}
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return err
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}
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