/* Jackson JSON-processor.
*
* Copyright (c) 2007- Tatu Saloranta, tatu.saloranta@iki.fi
*
* Licensed under the License specified in file LICENSE, included with
* the source code and binary code bundles.
* You may not use this file except in compliance with the License.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.fasterxml.jackson.core;
/**
* Container for commonly used Base64 variants.
*
* @author Tatu Saloranta
*/
public final class Base64Variants
{
final static String STD_BASE64_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* This variant is what most people would think of "the standard"
* Base64 encoding.
*<p>
* See <a href="">wikipedia Base64 entry</a> for details.
*<p>
* Note that although this can be thought of as the standard variant,
* it is <b>not</b> the default for Jackson: no-linefeeds alternative
* is because of JSON requirement of escaping all linefeeds.
*/
public final static Base64Variant MIME;
static {
MIME = new Base64Variant("MIME", STD_BASE64_ALPHABET, true, '=', 76);
}
/**
* Slightly non-standard modification of {@link #MIME} which does not
* use linefeeds (max line length set to infinite). Useful when linefeeds
* wouldn't work well (possibly in attributes), or for minor space savings
* (save 1 linefeed per 76 data chars, ie. ~1.4% savings).
*/
public final static Base64Variant MIME_NO_LINEFEEDS;
static {
MIME_NO_LINEFEEDS = new Base64Variant(MIME, "MIME-NO-LINEFEEDS", Integer.MAX_VALUE);
}
/**
* This variant is the one that predates {@link #MIME}: it is otherwise
* identical, except that it mandates shorter line length.
*/
public final static Base64Variant PEM = new Base64Variant(MIME, "PEM", true, '=', 64);
/**
* This non-standard variant is usually used when encoded data needs to be
* passed via URLs (such as part of GET request). It differs from the
* base {@link #MIME} variant in multiple ways.
* First, no padding is used: this also means that it generally can not
* be written in multiple separate but adjacent chunks (which would not
* be the usual use case in any case). Also, no linefeeds are used (max
* line length set to infinite). And finally, two characters (plus and
* slash) that would need quoting in URLs are replaced with more
* optimal alternatives (hyphen and underscore, respectively).
*/
public final static Base64Variant MODIFIED_FOR_URL;
static {
StringBuffer sb = new StringBuffer(STD_BASE64_ALPHABET);
// Replace plus with hyphen, slash with underscore (and no padding)
sb.setCharAt(sb.indexOf("+"), '-');
sb.setCharAt(sb.indexOf("/"), '_');
/* And finally, let's not split lines either, wouldn't work too
* well with URLs
*/
MODIFIED_FOR_URL = new Base64Variant("MODIFIED-FOR-URL", sb.toString(), false, Base64Variant.PADDING_CHAR_NONE, Integer.MAX_VALUE);
}
/**
* Method used to get the default variant ("MIME_NO_LINEFEEDS") for cases
* where caller does not explicitly specify the variant.
* We will prefer no-linefeed version because linefeeds in JSON values
* must be escaped, making linefeed-containing variants sub-optimal.
*/
public static Base64Variant getDefaultVariant() {
return MIME_NO_LINEFEEDS;
}
}