Function loadFileToBuffer

io.go:324–440

load file content to buffer (synchronous version for small files or when preferred)

(fn string, b *Buffer)

// load file content to buffer (synchronous version for small files or when preferred)
func loadFileToBuffer(fn string, b *Buffer) error {
	totalAddedLN := 0 //the number of lines has been added into buffer

	// Get file size for progress tracking
	fileInfo, err := os.Stat(fn)
	if err != nil {
		return err
	}
	var fileSize int64
	if !fileInfo.IsDir() {
		fileSize = fileInfo.Size()
	}

	// Create progress tracker
	progress := newProgressTracker(fileSize, true)

	scanner, err := getFileScanner(fn)
	if err != nil {
		return err
	}
	scanner.Split(bufio.ScanLines)
	//set separator, if user does not provide it.
	var detectLines []string //lines as detect separator data
	if b.sep == 0 {
		//read 10 lines to detect separator
		lineNumber := 10
		for scanner.Scan() {
			line := scanner.Text()
			//skip empty line
			if line == "\n" {
				continue
			}
			//ignore first n lines
			if args.SkipNum > 0 {
				args.SkipNum--
				continue
			}
			//ignore line with specified prefix
			if skipLine(line, args.SkipSymbol) {
				continue
			}
			detectLines = append(detectLines, line)
			if len(detectLines) >= lineNumber {
				break
			}
		}
		//if the suffix of file name is ".csv", set separator to ",".
		//if the suffix of file name is "tsv", set separator to "\t".
		if strings.HasSuffix(fn, ".csv") {
			b.sep = ','
		} else if strings.HasSuffix(fn, ".tsv") {
			b.sep = '\t'
		} else {
			sd := sepDetecor{}
			b.sep = sd.sepDetect(detectLines)
		}

	}