forked from mirrors/gecko-dev
146 lines
4.3 KiB
JavaScript
146 lines
4.3 KiB
JavaScript
/*
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Copyright (c) 2006 Lawrence Oluyede <l.oluyede@gmail.com>
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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/*
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startsWith(str, prefix[, start[, end]]) -> bool
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Return true if str ends with the specified prefix, false otherwise.
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With optional start, test str beginning at that position.
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With optional end, stop comparing str at that position.
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prefix can also be an array of strings to try.
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*/
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var EXPORTED_SYMBOLS = ['startsWith', 'endsWith'];
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function startsWith(str, prefix, start, end) {
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if (arguments.length < 2) {
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throw new TypeError('startsWith() requires at least 2 arguments');
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}
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// check if start and end are null/undefined or a 'number'
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if ((start == null) || (isNaN(new Number(start)))) {
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start = 0;
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}
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if ((end == null) || (isNaN(new Number(end)))) {
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end = Number.MAX_VALUE;
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}
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// if it's an array
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if (typeof prefix == "object") {
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for (var i = 0, j = prefix.length; i < j; i++) {
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var res = _stringTailMatch(str, prefix[i], start, end, true);
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if (res) {
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return true;
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}
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}
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return false;
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}
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return _stringTailMatch(str, prefix, start, end, true);
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}
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/*
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endsWith(str, suffix[, start[, end]]) -> bool
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Return true if str ends with the specified suffix, false otherwise.
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With optional start, test str beginning at that position.
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With optional end, stop comparing str at that position.
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suffix can also be an array of strings to try.
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*/
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function endsWith(str, suffix, start, end) {
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if (arguments.length < 2) {
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throw new TypeError('endsWith() requires at least 2 arguments');
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}
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// check if start and end are null/undefined or a 'number'
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if ((start == null) || (isNaN(new Number(start)))) {
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start = 0;
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}
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if ((end == null) || (isNaN(new Number(end)))) {
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end = Number.MAX_VALUE;
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}
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// if it's an array
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if (typeof suffix == "object") {
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for (var i = 0, j = suffix.length; i < j; i++) {
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var res = _stringTailMatch(str, suffix[i], start, end, false);
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if (res) {
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return true;
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}
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}
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return false;
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}
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return _stringTailMatch(str, suffix, start, end, false);
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}
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/*
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Matches the end (direction == false) or start (direction == true) of str
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against substr, using the start and end arguments. Returns false
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if not found and true if found.
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*/
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function _stringTailMatch(str, substr, start, end, fromStart) {
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var len = str.length;
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var slen = substr.length;
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var indices = _adjustIndices(start, end, len);
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start = indices[0]; end = indices[1]; len = indices[2];
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if (fromStart) {
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if (start + slen > len) {
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return false;
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}
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} else {
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if (end - start < slen || start > len) {
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return false;
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}
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if (end - slen > start) {
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start = end - slen;
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}
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}
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if (end - start >= slen) {
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return str.substr(start, slen) == substr;
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}
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return false;
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}
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function _adjustIndices(start, end, len)
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{
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if (end > len) {
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end = len;
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} else if (end < 0) {
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end += len;
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}
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if (end < 0) {
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end = 0;
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}
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if (start < 0) {
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start += len;
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}
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if (start < 0) {
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start = 0;
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}
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return [start, end, len];
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}
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