Compression Format 7zip Unless Explicitly Defined When Extension Provided for Archive

[onyxhat]

I noticed that the archives always seemed to be using the 7z packaging regardless of what I specified saving the archive as (e.g. .zip, .bzip, .tar, etc.). I implemented a basic switch that correctly infers the archive format based on the archive extension - the ArchiveFormat flag can still be used as an override, but otherwise seems unnecessary and this reduced instances where the flag isn't passed and other extraction utilities think they have a .tar.gz but are in fact needing to decompress a 7z archive which they may be unable to handle correctly.

Quick and dirty implementation, but worked in my fork;

                switch (System.IO.Path.GetExtension(archiveFileName).ToLowerInvariant()) {
                    case ".7z":
                        _cmdlet.Format = OutArchiveFormat.SevenZip;
                        break;
                    case ".zip":
                        _cmdlet.Format = OutArchiveFormat.Zip;
                        break;
                    case ".gz":
                        _cmdlet.Format = OutArchiveFormat.GZip;
                        break;
                    case ".bz2":
                        _cmdlet.Format = OutArchiveFormat.BZip2;
                        break;
                    case ".tar":
                        _cmdlet.Format = OutArchiveFormat.Tar;
                        break;
                    case ".xz":
                        _cmdlet.Format = OutArchiveFormat.XZ;
                        break;
                }

[thoemmi]

I like the idea. I think I'll introduce a new enum for the output format with the same members as OutArchiveFormat plus Auto. If Auto is passed (which would be the default), it would try to infer the format from the archive file name, otherwise as specified.

private OutArchiveFormat GetInferredOutArchiveFormat() {
    switch (Format) {
        case OutputFormat.Auto:
            switch (System.IO.Path.GetExtension(ArchiveFileName).ToLowerInvariant()) {
                case ".zip":
                    return OutArchiveFormat.Zip;
                case ".gz":
                    return OutArchiveFormat.GZip;
                case ".bz2":
                    return OutArchiveFormat.BZip2;
                case ".tar":
                    return OutArchiveFormat.Tar;
                case ".xz":
                    return OutArchiveFormat.XZ;
                default:
                    return OutArchiveFormat.SevenZip;
            }
        case OutputFormat.SevenZip:
            return OutArchiveFormat.SevenZip;
        case OutputFormat.Zip:
            return OutArchiveFormat.Zip;
        case OutputFormat.GZip:
            return OutArchiveFormat.GZip;
        case OutputFormat.BZip2:
            return OutArchiveFormat.BZip2;
        case OutputFormat.Tar:
            return OutArchiveFormat.Tar;
        case OutputFormat.XZ:
            return OutArchiveFormat.XZ;
        default:
            throw new ArgumentOutOfRangeException();
    }
}

[thoemmi]

This change is included in V1.7, released today.