| /* |
| * Copyright 2011 Google Inc. |
| * |
| * 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.ipc.invalidation.external.client.types; |
| |
| |
| /** |
| * A utility class to format bytes to string for ease of reading and debugging. |
| * |
| */ |
| class BytesFormatter { |
| |
| /** |
| * Three arrays that store the representation of each character from 0 to 255. |
| * The ith number's octal representation is: CHAR_OCTAL_STRINGS1[i], |
| * CHAR_OCTAL_STRINGS2[i], CHAR_OCTAL_STRINGS3[i] |
| * <p> |
| * E.g., if the number 128, these arrays contain 2, 0, 0 at index 128. We use |
| * 3 char arrays instead of an array of strings since the code path for a |
| * character append operation is quite a bit shorter than the append operation |
| * for strings. |
| */ |
| private static final char[] CHAR_OCTAL_STRINGS1 = new char[256]; |
| private static final char[] CHAR_OCTAL_STRINGS2 = new char[256]; |
| private static final char[] CHAR_OCTAL_STRINGS3 = new char[256]; |
| |
| static { |
| // Initialize the array with the Octal string values so that we do not have |
| // to do String.format for every byte during runtime. |
| for (int i = 0; i < CHAR_OCTAL_STRINGS1.length; i++) { |
| // Unsophisticated way to get an octal string padded to 3 characters. |
| String intAsStr = Integer.toOctalString(i); |
| switch (intAsStr.length()) { |
| case 3: |
| break; |
| case 2: |
| intAsStr = "0" + intAsStr; |
| break; |
| case 1: |
| intAsStr = "00" + intAsStr; |
| break; |
| default: |
| throw new RuntimeException("Bad integer value: " + intAsStr); |
| } |
| if (intAsStr.length() != 3) { |
| throw new RuntimeException("Bad padding: " + intAsStr); |
| } |
| String value = '\\' + intAsStr; |
| CHAR_OCTAL_STRINGS1[i] = value.charAt(1); |
| CHAR_OCTAL_STRINGS2[i] = value.charAt(2); |
| CHAR_OCTAL_STRINGS3[i] = value.charAt(3); |
| } |
| } |
| |
| /** Returns a human-readable string for the contents of {@code bytes}. */ |
| public static String toString(byte[] bytes) { |
| if (bytes == null) { |
| return null; |
| } |
| StringBuilder builder = new StringBuilder(3 * bytes.length); |
| for (byte c : bytes) { |
| switch(c) { |
| case '\n': builder.append('\\'); builder.append('n'); break; |
| case '\r': builder.append('\\'); builder.append('r'); break; |
| case '\t': builder.append('\\'); builder.append('t'); break; |
| case '\"': builder.append('\\'); builder.append('"'); break; |
| case '\\': builder.append('\\'); builder.append('\\'); break; |
| default: |
| if ((c >= 32) && (c < 127) && c != '\'') { |
| builder.append((char) c); |
| } else { |
| int byteValue = c; |
| if (c < 0) { |
| byteValue = c + 256; |
| } |
| builder.append('\\'); |
| builder.append(CHAR_OCTAL_STRINGS1[byteValue]); |
| builder.append(CHAR_OCTAL_STRINGS2[byteValue]); |
| builder.append(CHAR_OCTAL_STRINGS3[byteValue]); |
| } |
| } |
| } |
| return builder.toString(); |
| } |
| |
| private BytesFormatter() { // To prevent instantiation. |
| } |
| } |