/**
* Copyright (c) 2011-2017, James Zhan 詹波 (jfinal@126.com).
*
* 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.jfinal.template.stat;
/**
* CharTable 空间换时间优化字符判断性能
* 负值参数强转 char 会自动变正值,无需判断负值数组下标
* isLetter(EOF) 不会下标越界
*/
public class CharTable {
private static final char[] letterChars = buildLetterChars();
private static final char[] letterOrDigitChars = buildLetterOrDigitChars();
private static final char[] exprChars = buildExprChars();
private static final char NULL = 0;
private static final char SIZE = 128;
private CharTable(){}
private static char[] createCharArray() {
char[] ret = new char[SIZE];
for (char i=0; i<SIZE; i++) {
ret[i] = NULL;
}
return ret;
}
private static char[] buildLetterChars() {
char[] ret = createCharArray();
for (char i='a'; i<='z'; i++) {
ret[i] = i;
}
for (char i='A'; i<='Z'; i++) {
ret[i] = i;
}
ret['_'] = '_'; // 包含下划线字符 '_'
return ret;
}
private static char[] buildLetterOrDigitChars() {
char[] ret = buildLetterChars();
for (char i='0'; i<='9'; i++) {
ret[i] = i;
}
return ret;
}
private static char[] buildExprChars() {
char[] ret = createCharArray();
ret['\t'] = '\t';
ret['\n'] = '\n';
ret['\r'] = '\r';
for (char i=' '; i<='}'; i++) {
ret[i] = i;
}
ret['#'] = NULL;
ret['$'] = NULL;
ret['@'] = NULL;
ret['\\'] = NULL;
ret['^'] = NULL;
ret['`'] = NULL;
return ret;
}
public static boolean isLetter(char c) {
return c < SIZE && letterChars[c] != NULL;
}
public static boolean isLetterOrDigit(char c) {
return c < SIZE && letterOrDigitChars[c] != NULL;
}
public static boolean isExprChar(char c) {
return c < SIZE && exprChars[c] != NULL;
}
public static boolean isDigit(char c) {
return c >= '0' && c <= '9';
}
public static boolean isBlank(char c) {
return c == ' ' || c == '\t'; // \t\r\u000C
}
public static boolean isBlankOrLineFeed(char c) {
return c == ' ' || c == '\t' || c == '\r' || c == '\n'; // \t\r\n\u000C
}
public static boolean isHexadecimalDigit(char c) {
return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
}
public static boolean isOctalDigit(char c) {
return c >= '0' && c <= '7';
}
}