| // Copyright (C) 2012 The Android Open Source Project |
| // |
| // 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. |
| |
| package com.google.gerrit.server; |
| |
| public class StringUtil { |
| /** |
| * An array of the string representations that should be used in place |
| * of the non-printable characters in the beginning of the ASCII table |
| * when escaping a string. The index of each element in the array |
| * corresponds to its ASCII value, i.e. the string representation of |
| * ASCII 0 is found in the first element of this array. |
| */ |
| static String[] NON_PRINTABLE_CHARS = |
| { "\\x00", "\\x01", "\\x02", "\\x03", "\\x04", "\\x05", "\\x06", "\\a", |
| "\\b", "\\t", "\\n", "\\v", "\\f", "\\r", "\\x0e", "\\x0f", |
| "\\x10", "\\x11", "\\x12", "\\x13", "\\x14", "\\x15", "\\x16", "\\x17", |
| "\\x18", "\\x19", "\\x1a", "\\x1b", "\\x1c", "\\x1d", "\\x1e", "\\x1f" }; |
| |
| /** |
| * Escapes the input string so that all non-printable characters |
| * (0x00-0x1f) are represented as a hex escape (\x00, \x01, ...) |
| * or as a C-style escape sequence (\a, \b, \t, \n, \v, \f, or \r). |
| * Backslashes in the input string are doubled (\\). |
| */ |
| public static String escapeString(final String str) { |
| // Allocate a buffer big enough to cover the case with a string needed |
| // very excessive escaping without having to reallocate the buffer. |
| final StringBuilder result = new StringBuilder(3 * str.length()); |
| |
| for (int i = 0; i < str.length(); i++) { |
| char c = str.charAt(i); |
| if (c < NON_PRINTABLE_CHARS.length) { |
| result.append(NON_PRINTABLE_CHARS[c]); |
| } else if (c == '\\') { |
| result.append("\\\\"); |
| } else { |
| result.append(c); |
| } |
| } |
| return result.toString(); |
| } |
| } |