Function getEncodedRootLength

test/fixtures/snapshot/typescript.js:7657–7710

* Returns length of the root part of a path or URL (i.e. length of "/", "x:/", "//server/share/, file:///user/files"). * If the root is part of a URL, the twos-complement of the root length is returned.

(path)

     * If the root is part of a URL, the twos-complement of the root length is returned.
     */
    function getEncodedRootLength(path) {
        if (!path)
            return 0;
        var ch0 = path.charCodeAt(0);
        // POSIX or UNC
        if (ch0 === 47 /* CharacterCodes.slash */ || ch0 === 92 /* CharacterCodes.backslash */) {
            if (path.charCodeAt(1) !== ch0)
                return 1; // POSIX: "/" (or non-normalized "\")
            var p1 = path.indexOf(ch0 === 47 /* CharacterCodes.slash */ ? ts.directorySeparator : ts.altDirectorySeparator, 2);
            if (p1 < 0)
                return path.length; // UNC: "//server" or "\\server"
            return p1 + 1; // UNC: "//server/" or "\\server\"
        }
        // DOS
        if (isVolumeCharacter(ch0) && path.charCodeAt(1) === 58 /* CharacterCodes.colon */) {
            var ch2 = path.charCodeAt(2);
            if (ch2 === 47 /* CharacterCodes.slash */ || ch2 === 92 /* CharacterCodes.backslash */)
                return 3; // DOS: "c:/" or "c:\"
            if (path.length === 2)
                return 2; // DOS: "c:" (but not "c:d")
        }
        // URL
        var schemeEnd = path.indexOf(urlSchemeSeparator);
        if (schemeEnd !== -1) {
            var authorityStart = schemeEnd + urlSchemeSeparator.length;
            var authorityEnd = path.indexOf(ts.directorySeparator, authorityStart);
            if (authorityEnd !== -1) { // URL: "file:///", "file://server/", "file://server/path"
                // For local "file" URLs, include the leading DOS volume (if present).
                // Per https://www.ietf.org/rfc/rfc1738.txt, a host of "" or "localhost" is a
                // special case interpreted as "the machine from which the URL is being interpreted".
                var scheme = path.slice(0, schemeEnd);
                var authority = path.slice(authorityStart, authorityEnd);
                if (scheme === "file" && (authority === "" || authority === "localhost") &&
                    isVolumeCharacter(path.charCodeAt(authorityEnd + 1))) {
                    var volumeSeparatorEnd = getFileUrlVolumeSeparatorEnd(path, authorityEnd + 2);
                    if (volumeSeparatorEnd !== -1) {
                        if (path.charCodeAt(volumeSeparatorEnd) === 47 /* CharacterCodes.slash */) {
                            // URL: "file:///c:/", "file://localhost/c:/", "file:///c%3a/", "file://localhost/c%3a/"
                            return ~(volumeSeparatorEnd + 1);
                        }
                        if (volumeSeparatorEnd === path.length) {
                            // URL: "file:///c:", "file://localhost/c:", "file:///c$3a", "file://localhost/c%3a"
                            // but not "file:///c:d" or "file:///c%3ad"
                            return ~volumeSeparatorEnd;
                        }
                    }
                }
                return ~(authorityEnd + 1); // URL: "file://server/", "http://server/"
            }
            return ~path.length; // URL: "file://server", "http://server"
        }
        // relative
        return 0;
    }
    /**
     * Returns length of the root part of a path or URL (i.e. length of "/", "x:/", "//server/share/, file:///user/files").
     *