| // Copyright 2010 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // 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. |
| |
| /** |
| * @fileoverview Functions for encoding strings according to MIME |
| * standards, especially RFC 1522. |
| */ |
| goog.provide('goog.i18n.mime'); |
| goog.provide('goog.i18n.mime.encode'); |
| |
| goog.require('goog.array'); |
| |
| |
| /** |
| * Regular expression for matching those characters that are outside the |
| * range that can be used in the quoted-printable encoding of RFC 1522: |
| * anything outside the 7-bit ASCII encoding, plus ?, =, _ or space. |
| * @type {RegExp} |
| * @private |
| */ |
| goog.i18n.mime.NONASCII_ = /[^!-<>@-^`-~]/g; |
| |
| |
| /** |
| * Like goog.i18n.NONASCII_ but also omits double-quotes. |
| * @type {RegExp} |
| * @private |
| */ |
| goog.i18n.mime.NONASCII_NOQUOTE_ = /[^!#-<>@-^`-~]/g; |
| |
| |
| /** |
| * Encodes a string for inclusion in a MIME header. The string is encoded |
| * in UTF-8 according to RFC 1522, using quoted-printable form. |
| * @param {string} str The string to encode. |
| * @param {boolean=} opt_noquote Whether double-quote characters should also |
| * be escaped (should be true if the result will be placed inside a |
| * quoted string for a parameter value in a MIME header). |
| * @return {string} The encoded string. |
| */ |
| goog.i18n.mime.encode = function(str, opt_noquote) { |
| var nonascii = opt_noquote ? |
| goog.i18n.mime.NONASCII_NOQUOTE_ : goog.i18n.mime.NONASCII_; |
| |
| if (str.search(nonascii) >= 0) { |
| str = '=?UTF-8?Q?' + str.replace(nonascii, |
| /** |
| * @param {string} c The matched char. |
| * @return {string} The quoted-printable form of utf-8 encoding. |
| */ |
| function(c) { |
| var i = c.charCodeAt(0); |
| if (i == 32) { |
| // Special case for space, which can be encoded as _ not =20 |
| return '_'; |
| } |
| var a = goog.array.concat('', goog.i18n.mime.getHexCharArray(c)); |
| return a.join('='); |
| }) + '?='; |
| } |
| return str; |
| }; |
| |
| |
| /** |
| * Get an array of UTF-8 hex codes for a given character. |
| * @param {string} c The matched character. |
| * @return {!Array<string>} A hex array representing the character. |
| */ |
| goog.i18n.mime.getHexCharArray = function(c) { |
| var i = c.charCodeAt(0); |
| var a = []; |
| // First convert the UCS-2 character into its UTF-8 bytes |
| if (i < 128) { |
| a.push(i); |
| } else if (i <= 0x7ff) { |
| a.push( |
| 0xc0 + ((i >> 6) & 0x3f), |
| 0x80 + (i & 0x3f)); |
| } else if (i <= 0xffff) { |
| a.push( |
| 0xe0 + ((i >> 12) & 0x3f), |
| 0x80 + ((i >> 6) & 0x3f), |
| 0x80 + (i & 0x3f)); |
| } else { |
| // (This is defensive programming, since ecmascript isn't supposed |
| // to handle code points that take more than 16 bits.) |
| a.push( |
| 0xf0 + ((i >> 18) & 0x3f), |
| 0x80 + ((i >> 12) & 0x3f), |
| 0x80 + ((i >> 6) & 0x3f), |
| 0x80 + (i & 0x3f)); |
| } |
| // Now convert those bytes into hex strings (don't do anything with |
| // a[0] as that's got the empty string that lets us use join()) |
| for (i = a.length - 1; i >= 0; --i) { |
| a[i] = a[i].toString(16); |
| } |
| return a; |
| }; |