| /* |
| * Copyright 2011 Rackspace |
| * |
| * 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. |
| * |
| */ |
| |
| var cache = {}; |
| |
| |
| // Do any others need escaping? |
| var TO_ESCAPE = { |
| '\'': '\\\'', |
| '\n': '\\n' |
| }; |
| |
| |
| function populate(formatter) { |
| var i, type, |
| key = formatter, |
| prev = 0, |
| arg = 1, |
| builder = 'return \''; |
| |
| for (i = 0; i < formatter.length; i++) { |
| if (formatter[i] === '%') { |
| type = formatter[i + 1]; |
| |
| switch (type) { |
| case 's': |
| builder += formatter.slice(prev, i) + '\' + arguments[' + arg + '] + \''; |
| prev = i + 2; |
| arg++; |
| break; |
| case 'j': |
| builder += formatter.slice(prev, i) + '\' + JSON.stringify(arguments[' + arg + ']) + \''; |
| prev = i + 2; |
| arg++; |
| break; |
| case '%': |
| builder += formatter.slice(prev, i + 1); |
| prev = i + 2; |
| i++; |
| break; |
| } |
| |
| |
| } else if (TO_ESCAPE[formatter[i]]) { |
| builder += formatter.slice(prev, i) + TO_ESCAPE[formatter[i]]; |
| prev = i + 1; |
| } |
| } |
| |
| builder += formatter.slice(prev) + '\';'; |
| cache[key] = new Function(builder); |
| } |
| |
| |
| /** |
| * A fast version of sprintf(), which currently only supports the %s and %j. |
| * This caches a formatting function for each format string that is used, so |
| * you should only use this sprintf() will be called many times with a single |
| * format string and a limited number of format strings will ever be used (in |
| * general this means that format strings should be string literals). |
| * |
| * @param {String} formatter A format string. |
| * @param {...String} var_args Values that will be formatted by %s and %j. |
| * @return {String} The formatted output. |
| */ |
| exports.sprintf = function(formatter, var_args) { |
| if (!cache[formatter]) { |
| populate(formatter); |
| } |
| |
| return cache[formatter].apply(null, arguments); |
| }; |