| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.tomcat.util.buf; |
| |
| /** |
| * This class implements some basic ASCII character handling functions. |
| * |
| * @author dac@eng.sun.com |
| * @author James Todd [gonzo@eng.sun.com] |
| */ |
| public final class Ascii { |
| /* |
| * Character translation tables. |
| */ |
| private static final byte[] toLower = new byte[256]; |
| |
| /* |
| * Character type tables. |
| */ |
| private static final boolean[] isDigit = new boolean[256]; |
| |
| private static final long OVERFLOW_LIMIT = Long.MAX_VALUE / 10; |
| |
| /* |
| * Initialize character translation and type tables. |
| */ |
| static { |
| for (int i = 0; i < 256; i++) { |
| toLower[i] = (byte)i; |
| } |
| |
| for (int lc = 'a'; lc <= 'z'; lc++) { |
| int uc = lc + 'A' - 'a'; |
| |
| toLower[uc] = (byte)lc; |
| } |
| |
| for (int d = '0'; d <= '9'; d++) { |
| isDigit[d] = true; |
| } |
| } |
| |
| /** |
| * Returns the lower case equivalent of the specified ASCII character. |
| */ |
| |
| public static int toLower(int c) { |
| return toLower[c & 0xff] & 0xff; |
| } |
| |
| /** |
| * Returns true if the specified ASCII character is a digit. |
| */ |
| private static boolean isDigit(int c) { |
| return isDigit[c & 0xff]; |
| } |
| |
| /** |
| * Parses an unsigned long from the specified subarray of bytes. |
| * @param b the bytes to parse |
| * @param off the start offset of the bytes |
| * @param len the length of the bytes |
| * @exception NumberFormatException if the long format was invalid |
| */ |
| public static long parseLong(byte[] b, int off, int len) |
| throws NumberFormatException |
| { |
| int c; |
| |
| if (b == null || len <= 0 || !isDigit(c = b[off++])) { |
| throw new NumberFormatException(); |
| } |
| |
| long n = c - '0'; |
| while (--len > 0) { |
| if (isDigit(c = b[off++]) && |
| (n < OVERFLOW_LIMIT || (n == OVERFLOW_LIMIT && (c - '0') < 8))) { |
| n = n * 10 + c - '0'; |
| } else { |
| throw new NumberFormatException(); |
| } |
| } |
| |
| return n; |
| } |
| } |