RemoveHI issue

[adam42389]

Hi,
Thanks for this package! It does exactly what I needed.

Running it on 1700 files it panicked once on Subtitle.RemoveHI() method:

Exception has occurred: panic
"runtime error: index out of range [0] with length 0"
Stack:
	2  0x0000000100413cd4 in github.com/icza/srtgears.(*Subtitle).RemoveHI
	    at ./go/pkg/mod/github.com/icza/srtgears@v0.0.0-20220812134320-0c724b7bb537/subtitle.go:57
	3  0x0000000100413545 in github.com/icza/srtgears.(*SubsPack).RemoveHI
	    at ./go/pkg/mod/github.com/icza/srtgears@v0.0.0-20220812134320-0c724b7bb537/subspack.go:68
	(truncated)

Subtitle that caused it:

185
00:27:39,128 --> 00:27:43,923
<he explains how trap works>

Fixed with length check:

func (s *Subtitle) RemoveHI() (remove bool) {
	// It may be just some (e.g. first) lines are hearing impaired.
	for i := len(s.Lines) - 1; i >= 0; i-- {
		line := s.Lines[i]
		// Check without HTML formatting to recognize and remove these:
		// "<i>[PHONE RINGING]</i>"
		line = htmlPattern.ReplaceAllString(line, "")

        // BEGIN FIX

		if len(line) == 0 {
			remove = true
			s.Lines = append(s.Lines[:i], s.Lines[i+1:]...)
			continue
		}
		
        // END FIX

		first, last := line[0], line[len(line)-1]
		if first == '[' && last == ']' || first == '(' && last == ')' {
			remove = true
			s.Lines = append(s.Lines[:i], s.Lines[i+1:]...)
		}
	}
	return
}

Also, in subrip.go line 219, should have comma before milliseconds:

wr.prf("%02d:%02d:%02d,%03d", hour, min, sec, ms)

Hope this helps. Thanks again.

[icza]

Hi, thanks for reporting these.

I went ahead and just checked line length before indexing, but did not remove that line. I'm not sure if that always denotes a HI line.