136 lines
3.0 KiB
Go
136 lines
3.0 KiB
Go
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package astisub
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import (
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"bufio"
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"io"
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"strconv"
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"strings"
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"time"
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"github.com/pkg/errors"
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)
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// Constants
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const (
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srtTimeBoundariesSeparator = " --> "
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)
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// Vars
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var (
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bytesSRTTimeBoundariesSeparator = []byte(srtTimeBoundariesSeparator)
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)
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// parseDurationSRT parses an .srt duration
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func parseDurationSRT(i string) (time.Duration, error) {
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return parseDuration(i, ",", 3)
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}
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// ReadFromSRT parses an .srt content
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func ReadFromSRT(i io.Reader) (o *Subtitles, err error) {
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// Init
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o = NewSubtitles()
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var scanner = bufio.NewScanner(i)
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// Scan
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var line string
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var s = &Item{}
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for scanner.Scan() {
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// Fetch line
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line = scanner.Text()
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// Line contains time boundaries
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if strings.Contains(line, srtTimeBoundariesSeparator) {
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// Remove last item of previous subtitle since it's the index
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s.Lines = s.Lines[:len(s.Lines)-1]
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// Remove trailing empty lines
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if len(s.Lines) > 0 {
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for i := len(s.Lines) - 1; i >= 0; i-- {
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if len(s.Lines[i].Items) > 0 {
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for j := len(s.Lines[i].Items) - 1; j >= 0; j-- {
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if len(s.Lines[i].Items[j].Text) == 0 {
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s.Lines[i].Items = s.Lines[i].Items[:j]
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} else {
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break
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}
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}
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if len(s.Lines[i].Items) == 0 {
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s.Lines = s.Lines[:i]
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}
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}
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}
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}
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// Init subtitle
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s = &Item{}
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// Fetch time boundaries
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boundaries := strings.Split(line, srtTimeBoundariesSeparator)
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if s.StartAt, err = parseDurationSRT(boundaries[0]); err != nil {
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err = errors.Wrapf(err, "astisub: parsing srt duration %s failed", boundaries[0])
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return
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}
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if s.EndAt, err = parseDurationSRT(boundaries[1]); err != nil {
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err = errors.Wrapf(err, "astisub: parsing srt duration %s failed", boundaries[1])
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return
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}
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// Append subtitle
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o.Items = append(o.Items, s)
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} else {
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// Add text
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s.Lines = append(s.Lines, Line{Items: []LineItem{{Text: line}}})
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}
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}
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return
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}
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// formatDurationSRT formats an .srt duration
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func formatDurationSRT(i time.Duration) string {
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return formatDuration(i, ",", 3)
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}
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// WriteToSRT writes subtitles in .srt format
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func (s Subtitles) WriteToSRT(o io.Writer) (err error) {
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// Do not write anything if no subtitles
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if len(s.Items) == 0 {
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err = ErrNoSubtitlesToWrite
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return
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}
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// Add BOM header
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var c []byte
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c = append(c, BytesBOM...)
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// Loop through subtitles
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for k, v := range s.Items {
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// Add time boundaries
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c = append(c, []byte(strconv.Itoa(k+1))...)
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c = append(c, bytesLineSeparator...)
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c = append(c, []byte(formatDurationSRT(v.StartAt))...)
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c = append(c, bytesSRTTimeBoundariesSeparator...)
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c = append(c, []byte(formatDurationSRT(v.EndAt))...)
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c = append(c, bytesLineSeparator...)
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// Loop through lines
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for _, l := range v.Lines {
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c = append(c, []byte(l.String())...)
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c = append(c, bytesLineSeparator...)
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}
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// Add new line
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c = append(c, bytesLineSeparator...)
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}
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// Remove last new line
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c = c[:len(c)-1]
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// Write
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if _, err = o.Write(c); err != nil {
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err = errors.Wrap(err, "astisub: writing failed")
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return
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}
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return
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}
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