/* History: Theory and Culture
 * common.js: The common JavaScript subroutines.
 */

/*  Copyright (c) 2000-2018 imacat.
 * 
 *  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.
 */

/* Author: imacat <imacat@mail.imacat.idv.tw>
 * First written: 2000-07-25
 */

// _: Gettext
function _(msg) {
    var i;
    for (i = 0; i < lc_messages.length; i++) {
        if (lc_messages[i][0] == msg) {
            return lc_messages[i][1];
        }
    }
    return msg;
}
// The messages
lc_messages = [];

// isEmail: Check if an email address is legal
function isEmail(a) {
    var i, c, re;
    if (typeof(RegExp) == "undefined") return true;
    re = new RegExp("^[\\w\\-]+(\\.[\\w\\-]+)*\\@([\\w\\-]+\\.)+[\\w\\-]+$");
    if (typeof(a) != "string") return false;
    a = a.toLowerCase();
    if (re.exec(a) == null) return false;
    return true;
}

// trim: Trim the leading and tailing spaces
function trim(a) {
    var pos, start, len, spaces;
    start = 0;
    len = a.length;
    spaces = " \t\f\n\r";
    for (start = 0; start < a.length && spaces.indexOf(a.charAt(start)) >= 0; start++, len--);
    for (pos = a.length - 1; pos >= 0 && spaces.indexOf(a.charAt(pos)) >= 0; pos--, len--);
    return a.substr(start, len);
}
function trimText(a) {
    var pos, start, len, spaces, newlines;
    start = 0;
    len = a.length;
    spaces = " \t\f\n\r";
    newlines = "\n\r";
    for (start = 0; start < a.length && spaces.indexOf(a.charAt(start)) >= 0; start++, len--);
    for ( ; start-1 >= 0 && newlines.indexOf(a.charAt(start-1)) < 0; start--, len++);
    for (pos = a.length - 1; pos >= 0 && spaces.indexOf(a.charAt(pos)) >= 0; pos--, len--);
    return a.substr(start, len);
}

// replace: Replace one phace with another in a string
function replace(source, oldStr, newStr) {
    var pos;
    pos = 0;
    while (true) {
        pos = source.indexOf(oldStr, pos);
        if (pos == -1) break;
        source = source.substr(0, pos) + newStr + source.substr(pos + oldStr.length)
        pos += newStr.length;
    }
    return source;
}

// clearDefault: Clear the default value of a column
function clearDefault(col, deftext) {
    if (col.value == deftext) {
        col.value = "";
    }
}