expected string // expected SHA256
	}{
		{"shastring", "", "shastring"},
		{emptySHA256, "", emptySHA256},
		{"", "", emptySHA256},
		{"", "X-Amz-Credential=random", unsignedPayload},
		{"", "X-Amz-Credential=random&X-Amz-Content-Sha256=" + unsignedPayload, unsignedPayload},
		{"", "X-Amz-Credential=random&X-Amz-Content-Sha256=shastring", "shastring"},
	}

	for i, testCase := range testCases {

        return !isEmpty(text);
    }

    /**
     * Replaces all occurrences of a substring within a string with another string.
     *
     * @param text
     *            The original string.
     * @param fromText
     *            The substring to be replaced.
     * @param toText
     *            The replacement substring.
     * @return The resulting string after replacements.
     */

                if (lastIndex >= 0) {
                    String retVal = expr.substring(0, index);

                    if ((index > 0) && (expr.charAt(index - 1) == '$')) {
                        retVal += expr.substring(index + 1, lastIndex + 1);
                    } else {
                        Object subResult = evaluate(expr.substring(index, lastIndex + 1));

                        if (subResult != null) {

        if (lower.startsWith(allowPrefix)) {
            lower = lower.substring(allowPrefix.length());
            permission = permission.substring(allowPrefix.length());
            aclPrefix = StringUtil.EMPTY;
        } else if (lower.startsWith(denyPrefix)) {
            lower = lower.substring(denyPrefix.length());
            permission = permission.substring(denyPrefix.length());

            if (expandedNames.length > 0) {
                dr.server = expandedNames[0].substring(1).toLowerCase();
            } else {
                dr.server = ref.getSpecialName().substring(1).toLowerCase();
            }
            if (log.isDebugEnabled()) {
                log.debug("Server " + dr.server + " path " + reqPath + " remain " + reqPath.substring(consumed) + " path consumed "
                        + consumed);
            }

            } catch (final SmbException se) {
                fp = 0L;
            }
        }
        if (file instanceof SmbNamedPipe && file.unc.startsWith("\\pipe\\")) {
            file.unc = file.unc.substring(5);
            file.send(new TransWaitNamedPipe("\\pipe" + file.unc), new TransWaitNamedPipeResponse());
        }
        file.open(openFlags, access | SmbConstants.FILE_WRITE_DATA, SmbFile.ATTR_NORMAL, 0);

                }
            } else { /* Basic */
                final String auth = new String(Base64.decode(msg.substring(6)), "US-ASCII");
                int index = auth.indexOf(':');
                String user = index != -1 ? auth.substring(0, index) : auth;
                final String password = index != -1 ? auth.substring(index + 1) : "";
                index = user.indexOf('\\');
                if (index == -1) {

                this.share = this.canon.substring(1);
                this.unc = "\\";
            } else if (firstSep == prefixLen) {
                this.share = this.canon.substring(1, firstSep);
                this.unc = "\\";
            } else {
                this.share = this.canon.substring(1, firstSep);
                this.unc = this.canon.substring(firstSep, prefixLen + 1).replace('/', '\\');
            }

        String url = u;
        final String originalUrl = url;

        int idx = url.indexOf("://");
        if (idx >= 0) {
            url = url.substring(idx + 3);
        }

        idx = url.indexOf('/');
        if (idx >= 0) {
            url = url.substring(0, idx);
        }

        if (url.equals(originalUrl)) {
            return getFessConfig().getCrawlerDocumentUnknownHostname();
        }

            } else {
                final String auth = new String(Base64.decode(msg.substring(6)), "US-ASCII");
                int index = auth.indexOf(':');
                String user = index != -1 ? auth.substring(0, index) : auth;
                final String password = index != -1 ? auth.substring(index + 1) : "";
                index = user.indexOf('\\');
                if (index == -1) {