// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// 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.
/**
* @fileoverview Utilities for string manipulation.
*/
/**
* Namespace for string utilities
*/
goog.provide('goog.string');
goog.provide('goog.string.Unicode');
/**
* Common Unicode string characters.
* @enum {string}
*/
goog.string.Unicode = {
NBSP: '\xa0'
};
/**
* Fast prefix-checker.
* @param {string} str The string to check.
* @param {string} prefix A string to look for at the start of {@code str}.
* @return {boolean} True if {@code str} begins with {@code prefix}.
*/
goog.string.startsWith = function(str, prefix) {
return str.lastIndexOf(prefix, 0) == 0;
};
/**
* Fast suffix-checker.
* @param {string} str The string to check.
* @param {string} suffix A string to look for at the end of {@code str}.
* @return {boolean} True if {@code str} ends with {@code suffix}.
*/
goog.string.endsWith = function(str, suffix) {
var l = str.length - suffix.length;
return l >= 0 && str.indexOf(suffix, l) == l;
};
/**
* Case-insensitive prefix-checker.
* @param {string} str The string to check.
* @param {string} prefix A string to look for at the end of {@code str}.
* @return {boolean} True if {@code str} begins with {@code prefix} (ignoring
* case).
*/
goog.string.caseInsensitiveStartsWith = function(str, prefix) {
return goog.string.caseInsensitiveCompare(
prefix, str.substr(0, prefix.length)) == 0;
};
/**
* Case-insensitive suffix-checker.
* @param {string} str The string to check.
* @param {string} suffix A string to look for at the end of {@code str}.
* @return {boolean} True if {@code str} ends with {@code suffix} (ignoring
* case).
*/
goog.string.caseInsensitiveEndsWith = function(str, suffix) {
return goog.string.caseInsensitiveCompare(
suffix, str.substr(str.length - suffix.length, suffix.length)) == 0;
};
/**
* Does simple python-style string substitution.
* subs("foo%s hot%s", "bar", "dog") becomes "foobar hotdog".
* @param {string} str The string containing the pattern.
* @param {...*} var_args The items to substitute into the pattern.
* @return {string} A copy of {@code str} in which each occurrence of
* {@code %s} has been replaced an argument from {@code var_args}.
*/
goog.string.subs = function(str, var_args) {
// This appears to be slow, but testing shows it compares more or less
// equivalent to the regex.exec method.
for (var i = 1; i < arguments.length; i++) {
// We cast to String in case an argument is a Function. Replacing $&, for
// example, with $$$& stops the replace from subsituting the whole match
// into the resultant string. $$$& in the first replace becomes $$& in the
// second, which leaves $& in the resultant string. Also:
// $$, $`, $', $n $nn
var replacement = String(arguments[i]).replace(/\$/g, '$$$$');
str = str.replace(/\%s/, replacement);
}
return str;
};
/**
* Converts multiple whitespace chars (spaces, non-breaking-spaces, new lines
* and tabs) to a single space, and strips leading and trailing whitespace.
* @param {string} str Input string.
* @return {string} A copy of {@code str} with collapsed whitespace.
*/
goog.string.collapseWhitespace = function(str) {
// Since IE doesn't include non-breaking-space (0xa0) in their \s character
// class (as required by section 7.2 of the ECMAScript spec), we explicitly
// include it in the regexp to enforce consistent cross-browser behavior.
return str.replace(/[\s\xa0]+/g, ' ').replace(/^\s+|\s+$/g, '');
};
/**
* Checks if a string is empty or contains only whitespaces.
* @param {string} str The string to check.
* @return {boolean} True if {@code str} is empty or whitespace only.
*/
goog.string.isEmpty = function(str) {
// testing length == 0 first is actually slower in all browsers (about the
// same in Opera).
// Since IE doesn't include non-breaking-space (0xa0) in their \s character
// class (as required by section 7.2 of the ECMAScript spec), we explicitly
// include it in the regexp to enforce consistent cross-browser behavior.
return /^[\s\xa0]*$/.test(str);
};
/**
* Checks if a string is null, empty or contains only whitespaces.
* @param {*} str The string to check.
* @return {boolean} True if{@code str} is null, empty, or whitespace only.
*/
goog.string.isEmptySafe = function(str) {
return goog.string.isEmpty(goog.string.makeSafe(str));
};
/**
* Checks if a string is all breaking whitespace.
* @param {string} str The string to check.
* @return {boolean} Whether the string is all breaking whitespace.
*/
goog.string.isBreakingWhitespace = function(str) {
return !/[^\t\n\r ]/.test(str);
};
/**
* Checks if a string contains all letters.
* @param {string} str string to check.
* @return {boolean} True if {@code str} consists entirely of letters.
*/
goog.string.isAlpha = function(str) {
return !/[^a-zA-Z]/.test(str);
};
/**
* Checks if a string contains only numbers.
* @param {*} str string to check. If not a string, it will be
* casted to one.
* @return {boolean} True if {@code str} is numeric.
*/
goog.string.isNumeric = function(str) {
return !/[^0-9]/.test(str);
};
/**
* Checks if a string contains only numbers or letters.
* @param {string} str string to check.
* @return {boolean} True if {@code str} is alphanumeric.
*/
goog.string.isAlphaNumeric = function(str) {
return !/[^a-zA-Z0-9]/.test(str);
};
/**
* Checks if a character is a space character.
* @param {string} ch Character to check.
* @return {boolean} True if {code ch} is a space.
*/
goog.string.isSpace = function(ch) {
return ch == ' ';
};
/**
* Checks if a character is a valid unicode character.
* @param {string} ch Character to check.
* @return {boolean} True if {code ch} is a valid unicode character.
*/
goog.string.isUnicodeChar = function(ch) {
return ch.length == 1 && ch >= ' ' && ch <= '~' ||
ch >= '\u0080' && ch <= '\uFFFD';
};
/**
* Takes a string and replaces newlines with a space. Multiple lines are
* replaced with a single space.
* @param {string} str The string from which to strip newlines.
* @return {string} A copy of {@code str} stripped of newlines.
*/
goog.string.stripNewlines = function(str) {
return str.replace(/(\r\n|\r|\n)+/g, ' ');
};
/**
* Replaces Windows and Mac new lines with unix style: \r or \r\n with \n.
* @param {string} str The string to in which to canonicalize newlines.
* @return {string} {@code str} A copy of {@code} with canonicalized newlines.
*/
goog.string.canonicalizeNewlines = function(str) {
return str.replace(/(\r\n|\r|\n)/g, '\n');
};
/**
* Normalizes whitespace in a string, replacing all whitespace chars with
* a space.
* @param {string} str The string in which to normalize whitespace.
* @return {string} A copy of {@code str} with all whitespace normalized.
*/
goog.string.normalizeWhitespace = function(str) {
return str.replace(/\xa0|\s/g, ' ');
};
/**
* Normalizes spaces in a string, replacing all consecutive spaces and tabs
* with a single space. Replaces non-breaking space with a space.
* @param {string} str The string in which to normalize spaces.
* @return {string} A copy of {@code str} with all consecutive spaces and tabs
* replaced with a single space.
*/
goog.string.normalizeSpaces = function(str) {
return str.replace(/\xa0|[ \t]+/g, ' ');
};
/**
* Removes the breaking spaces from the left and right of the string and
* collapses the sequences of breaking spaces in the middle into single spaces.
* The original and the result strings render the same way in HTML.
* @param {string} str A string in which to collapse spaces.
* @return {string} Copy of the string with normalized breaking spaces.
*/
goog.string.collapseBreakingSpaces = function(str) {
return str.replace(/[\t\r\n ]+/g, ' ').replace(
/^[\t\r\n ]+|[\t\r\n ]+$/g, '');
};
/**
* Trims white spaces to the left and right of a string.
* @param {string} str The string to trim.
* @return {string} A trimmed copy of {@code str}.
*/
goog.string.trim = function(str) {
// Since IE doesn't include non-breaking-space (0xa0) in their \s character
// class (as required by section 7.2 of the ECMAScript spec), we explicitly
// include it in the regexp to enforce consistent cross-browser behavior.
return str.replace(/^[\s\xa0]+|[\s\xa0]+$/g, '');
};
/**
* Trims whitespaces at the left end of a string.
* @param {string} str The string to left trim.
* @return {string} A trimmed copy of {@code str}.
*/
goog.string.trimLeft = function(str) {
// Since IE doesn't include non-breaking-space (0xa0) in their \s character
// class (as required by section 7.2 of the ECMAScript spec), we explicitly
// include it in the regexp to enforce consistent cross-browser behavior.
return str.replace(/^[\s\xa0]+/, '');
};
/**
* Trims whitespaces at the right end of a string.
* @param {string} str The string to right trim.
* @return {string} A trimmed copy of {@code str}.
*/
goog.string.trimRight = function(str) {
// Since IE doesn't include non-breaking-space (0xa0) in their \s character
// class (as required by section 7.2 of the ECMAScript spec), we explicitly
// include it in the regexp to enforce consistent cross-browser behavior.
return str.replace(/[\s\xa0]+$/, '');
};
/**
* A string comparator that ignores case.
* -1 = str1 less than str2
* 0 = str1 equals str2
* 1 = str1 greater than str2
*
* @param {string} str1 The string to compare.
* @param {string} str2 The string to compare {@code str1} to.
* @return {number} The comparator result, as described above.
*/
goog.string.caseInsensitiveCompare = function(str1, str2) {
var test1 = String(str1).toLowerCase();
var test2 = String(str2).toLowerCase();
if (test1 < test2) {
return -1;
} else if (test1 == test2) {
return 0;
} else {
return 1;
}
};
/**
* Regular expression used for splitting a string into substrings of fractional
* numbers, integers, and non-numeric characters.
* @type {RegExp}
* @private
*/
goog.string.numerateCompareRegExp_ = /(\.\d+)|(\d+)|(\D+)/g;
/**
* String comparison function that handles numbers in a way humans might expect.
* Using this function, the string "File 2.jpg" sorts before "File 10.jpg". The
* comparison is mostly case-insensitive, though strings that are identical
* except for case are sorted with the upper-case strings before lower-case.
*
* This comparison function is significantly slower (about 500x) than either
* the default or the case-insensitive compare. It should not be used in
* time-critical code, but should be fast enough to sort several hundred short
* strings (like filenames) with a reasonable delay.
*
* @param {string} str1 The string to compare in a numerically sensitive way.
* @param {string} str2 The string to compare {@code str1} to.
* @return {number} less than 0 if str1 < str2, 0 if str1 == str2, greater than
* 0 if str1 > str2.
*/
goog.string.numerateCompare = function(str1, str2) {
if (str1 == str2) {
return 0;
}
if (!str1) {
return -1;
}
if (!str2) {
return 1;
}
// Using match to split the entire string ahead of time turns out to be faster
// for most inputs than using RegExp.exec or iterating over each character.
var tokens1 = str1.toLowerCase().match(goog.string.numerateCompareRegExp_);
var tokens2 = str2.toLowerCase().match(goog.string.numerateCompareRegExp_);
var count = Math.min(tokens1.length, tokens2.length);
for (var i = 0; i < count; i++) {
var a = tokens1[i];
var b = tokens2[i];
// Compare pairs of tokens, returning if one token sorts before the other.
if (a != b) {
// Only if both tokens are integers is a special comparison required.
// Decimal numbers are sorted as strings (e.g., '.09' < '.1').
var num1 = parseInt(a, 10);
if (!isNaN(num1)) {
var num2 = parseInt(b, 10);
if (!isNaN(num2) && num1 - num2) {
return num1 - num2;
}
}
return a < b ? -1 : 1;
}
}
// If one string is a substring of the other, the shorter string sorts first.
if (tokens1.length != tokens2.length) {
return tokens1.length - tokens2.length;
}
// The two strings must be equivalent except for case (perfect equality is
// tested at the head of the function.) Revert to default ASCII-betical string
// comparison to stablize the sort.
return str1 < str2 ? -1 : 1;
};
/**
* Regular expression used for determining if a string needs to be encoded.
* @type {RegExp}
* @private
*/
goog.string.encodeUriRegExp_ = /^[a-zA-Z0-9\-_.!~*'()]*$/;
/**
* URL-encodes a string
* @param {*} str The string to url-encode.
* @return {string} An encoded copy of {@code str} that is safe for urls.
* Note that '#', ':', and other characters used to delimit portions
* of URLs *will* be encoded.
*/
goog.string.urlEncode = function(str) {
str = String(str);
// Checking if the search matches before calling encodeURIComponent avoids an
// extra allocation in IE6. This adds about 10us time in FF and a similiar
// over head in IE6 for lower working set apps, but for large working set
// apps like Gmail, it saves about 70us per call.
if (!goog.string.encodeUriRegExp_.test(str)) {
return encodeURIComponent(str);
}
return str;
};
/**
* URL-decodes the string. We need to specially handle '+'s because
* the javascript library doesn't convert them to spaces.
* @param {string} str The string to url decode.
* @return {string} The decoded {@code str}.
*/
goog.string.urlDecode = function(str) {
return decodeURIComponent(str.replace(/\+/g, ' '));
};
/**
* Converts \n to <br>s or <br />s.
* @param {string} str The string in which to convert newlines.
* @param {boolean=} opt_xml Whether to use XML compatible tags.
* @return {string} A copy of {@code str} with converted newlines.
*/
goog.string.newLineToBr = function(str, opt_xml) {
return str.replace(/(\r\n|\r|\n)/g, opt_xml ? '<br />' : '<br>');
};
/**
* Escape double quote '"' characters in addition to '&', '<', and '>' so that a
* string can be included in an HTML tag attribute value within double quotes.
*
* It should be noted that > doesn't need to be escaped for the HTML or XML to
* be valid, but it has been decided to escape it for consistency with other
* implementations.
*
* NOTE(user):
* HtmlEscape is often called during the generation of large blocks of HTML.
* Using statics for the regular expressions and strings is an optimization
* that can more than half the amount of time IE spends in this function for
* large apps, since strings and regexes both contribute to GC allocations.
*
* Testing for the presence of a character before escaping increases the number
* of function calls, but actually provides a speed increase for the average
* case -- since the average case often doesn't require the escaping of all 4
* characters and indexOf() is much cheaper than replace().
* The worst case does suffer slightly from the additional calls, therefore the
* opt_isLikelyToContainHtmlChars option has been included for situations
* where all 4 HTML entities are very likely to be present and need escaping.
*
* Some benchmarks (times tended to fluctuate +-0.05ms):
* FireFox IE6
* (no chars / average (mix of cases) / all 4 chars)
* no checks 0.13 / 0.22 / 0.22 0.23 / 0.53 / 0.80
* indexOf 0.08 / 0.17 / 0.26 0.22 / 0.54 / 0.84
* indexOf + re test 0.07 / 0.17 / 0.28 0.19 / 0.50 / 0.85
*
* An additional advantage of checking if replace actually needs to be called
* is a reduction in the number of object allocations, so as the size of the
* application grows the difference between the various methods would increase.
*
* @param {string} str string to be escaped.
* @param {boolean=} opt_isLikelyToContainHtmlChars Don't perform a check to see
* if the character needs replacing - use this option if you expect each of
* the characters to appear often. Leave false if you expect few html
* characters to occur in your strings, such as if you are escaping HTML.
* @return {string} An escaped copy of {@code str}.
*/
goog.string.htmlEscape = function(str, opt_isLikelyToContainHtmlChars) {
if (opt_isLikelyToContainHtmlChars) {
return str.replace(goog.string.amperRe_, '&')
.replace(goog.string.ltRe_, '<')
.replace(goog.string.gtRe_, '>')
.replace(goog.string.quotRe_, '"');
} else {
// quick test helps in the case when there are no chars to replace, in
// worst case this makes barely a difference to the time taken
if (!goog.string.allRe_.test(str)) return str;
// str.indexOf is faster than regex.test in this case
if (str.indexOf('&') != -1) {
str = str.replace(goog.string.amperRe_, '&');
}
if (str.indexOf('<') != -1) {
str = str.replace(goog.string.ltRe_, '<');
}
if (str.indexOf('>') != -1) {
str = str.replace(goog.string.gtRe_, '>');
}
if (str.indexOf('"') != -1) {
str = str.replace(goog.string.quotRe_, '"');
}
return str;
}
};
/**
* Regular expression that matches an ampersand, for use in escaping.
* @type {RegExp}
* @private
*/
goog.string.amperRe_ = /&/g;
/**
* Regular expression that matches a less than sign, for use in escaping.
* @type {RegExp}
* @private
*/
goog.string.ltRe_ = /</g;
/**
* Regular expression that matches a greater than sign, for use in escaping.
* @type {RegExp}
* @private
*/
goog.string.gtRe_ = />/g;
/**
* Regular expression that matches a double quote, for use in escaping.
* @type {RegExp}
* @private
*/
goog.string.quotRe_ = /\"/g;
/**
* Regular expression that matches any character that needs to be escaped.
* @type {RegExp}
* @private
*/
goog.string.allRe_ = /[&<>\"]/;
/**
* Unescapes an HTML string.
*
* @param {string} str The string to unescape.
* @return {string} An unescaped copy of {@code str}.
*/
goog.string.unescapeEntities = function(str) {
if (goog.string.contains(str, '&')) {
// We are careful not to use a DOM if we do not have one. We use the []
// notation so that the JSCompiler will not complain about these objects and
// fields in the case where we have no DOM.
if ('document' in goog.global) {
return goog.string.unescapeEntitiesUsingDom_(str);
} else {
// Fall back on pure XML entities
return goog.string.unescapePureXmlEntities_(str);
}
}
return str;
};
/**
* Unescapes an HTML string using a DOM to resolve non-XML, non-numeric
* entities. This function is XSS-safe and whitespace-preserving.
* @private
* @param {string} str The string to unescape.
* @return {string} The unescaped {@code str} string.
*/
goog.string.unescapeEntitiesUsingDom_ = function(str) {
var seen = {'&': '&', '<': '<', '>': '>', '"': '"'};
var div = document.createElement('div');
// Match as many valid entity characters as possible. If the actual entity
// happens to be shorter, it will still work as innerHTML will return the
// trailing characters unchanged. Since the entity characters do not include
// open angle bracket, there is no chance of XSS from the innerHTML use.
// Since no whitespace is passed to innerHTML, whitespace is preserved.
return str.replace(goog.string.HTML_ENTITY_PATTERN_, function(s, entity) {
// Check for cached entity.
var value = seen[s];
if (value) {
return value;
}
// Check for numeric entity.
if (entity.charAt(0) == '#') {
// Prefix with 0 so that hex entities (e.g. ) parse as hex numbers.
var n = Number('0' + entity.substr(1));
if (!isNaN(n)) {
value = String.fromCharCode(n);
}
}
// Fall back to innerHTML otherwise.
if (!value) {
// Append a non-entity character to avoid a bug in Webkit that parses
// an invalid entity at the end of innerHTML text as the empty string.
div.innerHTML = s + ' ';
// Then remove the trailing character from the result.
value = div.firstChild.nodeValue.slice(0, -1);
}
// Cache and return.
return seen[s] = value;
});
};
/**
* Unescapes XML entities.
* @private
* @param {string} str The string to unescape.
* @return {string} An unescaped copy of {@code str}.
*/
goog.string.unescapePureXmlEntities_ = function(str) {
return str.replace(/&([^;]+);/g, function(s, entity) {
switch (entity) {
case 'amp':
return '&';
case 'lt':
return '<';
case 'gt':
return '>';
case 'quot':
return '"';
default:
if (entity.charAt(0) == '#') {
// Prefix with 0 so that hex entities (e.g. ) parse as hex.
var n = Number('0' + entity.substr(1));
if (!isNaN(n)) {
return String.fromCharCode(n);
}
}
// For invalid entities we just return the entity
return s;
}
});
};
/**
* Regular expression that matches an HTML entity.
* See also HTML5: Tokenization / Tokenizing character references.
* @private
* @type {!RegExp}
*/
goog.string.HTML_ENTITY_PATTERN_ = /&([^;\s<&]+);?/g;
/**
* Do escaping of whitespace to preserve spatial formatting. We use character
* entity #160 to make it safer for xml.
* @param {string} str The string in which to escape whitespace.
* @param {boolean=} opt_xml Whether to use XML compatible tags.
* @return {string} An escaped copy of {@code str}.
*/
goog.string.whitespaceEscape = function(str, opt_xml) {
return goog.string.newLineToBr(str.replace(/ /g, '  '), opt_xml);
};
/**
* Strip quote characters around a string. The second argument is a string of
* characters to treat as quotes. This can be a single character or a string of
* multiple character and in that case each of those are treated as possible
* quote characters. For example:
*
* <pre>
* goog.string.stripQuotes('"abc"', '"`') --> 'abc'
* goog.string.stripQuotes('`abc`', '"`') --> 'abc'
* </pre>
*
* @param {string} str The string to strip.
* @param {string} quoteChars The quote characters to strip.
* @return {string} A copy of {@code str} without the quotes.
*/
goog.string.stripQuotes = function(str, quoteChars) {
var length = quoteChars.length;
for (var i = 0; i < length; i++) {
var quoteChar = length == 1 ? quoteChars : quoteChars.charAt(i);
if (str.charAt(0) == quoteChar && str.charAt(str.length - 1) == quoteChar) {
return str.substring(1, str.length - 1);
}
}
return str;
};
/**
* Truncates a string to a certain length and adds '...' if necessary. The
* length also accounts for the ellipsis, so a maximum length of 10 and a string
* 'Hello World!' produces 'Hello W...'.
* @param {string} str The string to truncate.
* @param {number} chars Max number of characters.
* @param {boolean=} opt_protectEscapedCharacters Whether to protect escaped
* characters from being cut off in the middle.
* @return {string} The truncated {@code str} string.
*/
goog.string.truncate = function(str, chars, opt_protectEscapedCharacters) {
if (opt_protectEscapedCharacters) {
str = goog.string.unescapeEntities(str);
}
if (str.length > chars) {
str = str.substring(0, chars - 3) + '...';
}
if (opt_protectEscapedCharacters) {
str = goog.string.htmlEscape(str);
}
return str;
};
/**
* Truncate a string in the middle, adding "..." if necessary,
* and favoring the beginning of the string.
* @param {string} str The string to truncate the middle of.
* @param {number} chars Max number of characters.
* @param {boolean=} opt_protectEscapedCharacters Whether to protect escaped
* characters from being cutoff in the middle.
* @param {number=} opt_trailingChars Optional number of trailing characters to
* leave at the end of the string, instead of truncating as close to the
* middle as possible.
* @return {string} A truncated copy of {@code str}.
*/
goog.string.truncateMiddle = function(str, chars,
opt_protectEscapedCharacters, opt_trailingChars) {
if (opt_protectEscapedCharacters) {
str = goog.string.unescapeEntities(str);
}
if (opt_trailingChars && str.length > chars) {
if (opt_trailingChars > chars) {
opt_trailingChars = chars;
}
var endPoint = str.length - opt_trailingChars;
var startPoint = chars - opt_trailingChars;
str = str.substring(0, startPoint) + '...' + str.substring(endPoint);
} else if (str.length > chars) {
// Favor the beginning of the string:
var half = Math.floor(chars / 2);
var endPos = str.length - half;
half += chars % 2;
str = str.substring(0, half) + '...' + str.substring(endPos);
}
if (opt_protectEscapedCharacters) {
str = goog.string.htmlEscape(str);
}
return str;
};
/**
* Special chars that need to be escaped for goog.string.quote.
* @private
* @type {Object}
*/
goog.string.specialEscapeChars_ = {
'\0': '\\0',
'\b': '\\b',
'\f': '\\f',
'\n': '\\n',
'\r': '\\r',
'\t': '\\t',
'\x0B': '\\x0B', // '\v' is not supported in JScript
'"': '\\"',
'\\': '\\\\'
};
/**
* Character mappings used internally for goog.string.escapeChar.
* @private
* @type {Object}
*/
goog.string.jsEscapeCache_ = {
'\'': '\\\''
};
/**
* Encloses a string in double quotes and escapes characters so that the
* string is a valid JS string.
* @param {string} s The string to quote.
* @return {string} A copy of {@code s} surrounded by double quotes.
*/
goog.string.quote = function(s) {
s = String(s);
if (s.quote) {
return s.quote();
} else {
var sb = ['"'];
for (var i = 0; i < s.length; i++) {
var ch = s.charAt(i);
var cc = ch.charCodeAt(0);
sb[i + 1] = goog.string.specialEscapeChars_[ch] ||
((cc > 31 && cc < 127) ? ch : goog.string.escapeChar(ch));
}
sb.push('"');
return sb.join('');
}
};
/**
* Takes a string and returns the escaped string for that character.
* @param {string} str The string to escape.
* @return {string} An escaped string representing {@code str}.
*/
goog.string.escapeString = function(str) {
var sb = [];
for (var i = 0; i < str.length; i++) {
sb[i] = goog.string.escapeChar(str.charAt(i));
}
return sb.join('');
};
/**
* Takes a character and returns the escaped string for that character. For
* example escapeChar(String.fromCharCode(15)) -> "\\x0E".
* @param {string} c The character to escape.
* @return {string} An escaped string representing {@code c}.
*/
goog.string.escapeChar = function(c) {
if (c in goog.string.jsEscapeCache_) {
return goog.string.jsEscapeCache_[c];
}
if (c in goog.string.specialEscapeChars_) {
return goog.string.jsEscapeCache_[c] = goog.string.specialEscapeChars_[c];
}
var rv = c;
var cc = c.charCodeAt(0);
if (cc > 31 && cc < 127) {
rv = c;
} else {
// tab is 9 but handled above
if (cc < 256) {
rv = '\\x';
if (cc < 16 || cc > 256) {
rv += '0';
}
} else {
rv = '\\u';
if (cc < 4096) { // \u1000
rv += '0';
}
}
rv += cc.toString(16).toUpperCase();
}
return goog.string.jsEscapeCache_[c] = rv;
};
/**
* Takes a string and creates a map (Object) in which the keys are the
* characters in the string. The value for the key is set to true. You can
* then use goog.object.map or goog.array.map to change the values.
* @param {string} s The string to build the map from.
* @return {Object} The map of characters used.
*/
// TODO(arv): It seems like we should have a generic goog.array.toMap. But do
// we want a dependency on goog.array in goog.string?
goog.string.toMap = function(s) {
var rv = {};
for (var i = 0; i < s.length; i++) {
rv[s.charAt(i)] = true;
}
return rv;
};
/**
* Checks whether a string contains a given character.
* @param {string} s The string to test.
* @param {string} ss The substring to test for.
* @return {boolean} True if {@code s} contains {@code ss}.
*/
goog.string.contains = function(s, ss) {
return s.indexOf(ss) != -1;
};
/**
* Returns the non-overlapping occurrences of ss in s.
* If either s or ss evalutes to false, then returns zero.
* @param {string} s The string to look in.
* @param {string} ss The string to look for.
* @return {number} Number of occurrences of ss in s.
*/
goog.string.countOf = function(s, ss) {
return s && ss ? s.split(ss).length - 1 : 0;
};
/**
* Removes a substring of a specified length at a specific
* index in a string.
* @param {string} s The base string from which to remove.
* @param {number} index The index at which to remove the substring.
* @param {number} stringLength The length of the substring to remove.
* @return {string} A copy of {@code s} with the substring removed or the full
* string if nothing is removed or the input is invalid.
*/
goog.string.removeAt = function(s, index, stringLength) {
var resultStr = s;
// If the index is greater or equal to 0 then remove substring
if (index >= 0 && index < s.length && stringLength > 0) {
resultStr = s.substr(0, index) +
s.substr(index + stringLength, s.length - index - stringLength);
}
return resultStr;
};
/**
* Removes the first occurrence of a substring from a string.
* @param {string} s The base string from which to remove.
* @param {string} ss The string to remove.
* @return {string} A copy of {@code s} with {@code ss} removed or the full
* string if nothing is removed.
*/
goog.string.remove = function(s, ss) {
var re = new RegExp(goog.string.regExpEscape(ss), '');
return s.replace(re, '');
};
/**
* Removes all occurrences of a substring from a string.
* @param {string} s The base string from which to remove.
* @param {string} ss The string to remove.
* @return {string} A copy of {@code s} with {@code ss} removed or the full
* string if nothing is removed.
*/
goog.string.removeAll = function(s, ss) {
var re = new RegExp(goog.string.regExpEscape(ss), 'g');
return s.replace(re, '');
};
/**
* Escapes characters in the string that are not safe to use in a RegExp.
* @param {*} s The string to escape. If not a string, it will be casted
* to one.
* @return {string} A RegExp safe, escaped copy of {@code s}.
*/
goog.string.regExpEscape = function(s) {
return String(s).replace(/([-()\[\]{}+?*.$\^|,:#<!\\])/g, '\\$1').
replace(/\x08/g, '\\x08');
};
/**
* Repeats a string n times.
* @param {string} string The string to repeat.
* @param {number} length The number of times to repeat.
* @return {string} A string containing {@code length} repetitions of
* {@code string}.
*/
goog.string.repeat = function(string, length) {
return new Array(length + 1).join(string);
};
/**
* Pads number to given length and optionally rounds it to a given precision.
* For example:
* <pre>padNumber(1.25, 2, 3) -> '01.250'
* padNumber(1.25, 2) -> '01.25'
* padNumber(1.25, 2, 1) -> '01.3'
* padNumber(1.25, 0) -> '1.25'</pre>
*
* @param {number} num The number to pad.
* @param {number} length The desired length.
* @param {number=} opt_precision The desired precision.
* @return {string} {@code num} as a string with the given options.
*/
goog.string.padNumber = function(num, length, opt_precision) {
var s = goog.isDef(opt_precision) ? num.toFixed(opt_precision) : String(num);
var index = s.indexOf('.');
if (index == -1) {
index = s.length;
}
return goog.string.repeat('0', Math.max(0, length - index)) + s;
};
/**
* Returns a string representation of the given object, with
* null and undefined being returned as the empty string.
*
* @param {*} obj The object to convert.
* @return {string} A string representation of the {@code obj}.
*/
goog.string.makeSafe = function(obj) {
return obj == null ? '' : String(obj);
};
/**
* Concatenates string expressions. This is useful
* since some browsers are very inefficient when it comes to using plus to
* concat strings. Be careful when using null and undefined here since
* these will not be included in the result. If you need to represent these
* be sure to cast the argument to a String first.
* For example:
* <pre>buildString('a', 'b', 'c', 'd') -> 'abcd'
* buildString(null, undefined) -> ''
* </pre>
* @param {...*} var_args A list of strings to concatenate. If not a string,
* it will be casted to one.
* @return {string} The concatenation of {@code var_args}.
*/
goog.string.buildString = function(var_args) {
return Array.prototype.join.call(arguments, '');
};
/**
* Returns a string with at least 64-bits of randomness.
*
* Doesn't trust Javascript's random function entirely. Uses a combination of
* random and current timestamp, and then encodes the string in base-36 to
* make it shorter.
*
* @return {string} A random string, e.g. sn1s7vb4gcic.
*/
goog.string.getRandomString = function() {
var x = 2147483648;
return Math.floor(Math.random() * x).toString(36) +
Math.abs(Math.floor(Math.random() * x) ^ goog.now()).toString(36);
};
/**
* Compares two version numbers.
*
* @param {string|number} version1 Version of first item.
* @param {string|number} version2 Version of second item.
*
* @return {number} 1 if {@code version1} is higher.
* 0 if arguments are equal.
* -1 if {@code version2} is higher.
*/
goog.string.compareVersions = function(version1, version2) {
var order = 0;
// Trim leading and trailing whitespace and split the versions into
// subversions.
var v1Subs = goog.string.trim(String(version1)).split('.');
var v2Subs = goog.string.trim(String(version2)).split('.');
var subCount = Math.max(v1Subs.length, v2Subs.length);
// Iterate over the subversions, as long as they appear to be equivalent.
for (var subIdx = 0; order == 0 && subIdx < subCount; subIdx++) {
var v1Sub = v1Subs[subIdx] || '';
var v2Sub = v2Subs[subIdx] || '';
// Split the subversions into pairs of numbers and qualifiers (like 'b').
// Two different RegExp objects are needed because they are both using
// the 'g' flag.
var v1CompParser = new RegExp('(\\d*)(\\D*)', 'g');
var v2CompParser = new RegExp('(\\d*)(\\D*)', 'g');
do {
var v1Comp = v1CompParser.exec(v1Sub) || ['', '', ''];
var v2Comp = v2CompParser.exec(v2Sub) || ['', '', ''];
// Break if there are no more matches.
if (v1Comp[0].length == 0 && v2Comp[0].length == 0) {
break;
}
// Parse the numeric part of the subversion. A missing number is
// equivalent to 0.
var v1CompNum = v1Comp[1].length == 0 ? 0 : parseInt(v1Comp[1], 10);
var v2CompNum = v2Comp[1].length == 0 ? 0 : parseInt(v2Comp[1], 10);
// Compare the subversion components. The number has the highest
// precedence. Next, if the numbers are equal, a subversion without any
// qualifier is always higher than a subversion with any qualifier. Next,
// the qualifiers are compared as strings.
order = goog.string.compareElements_(v1CompNum, v2CompNum) ||
goog.string.compareElements_(v1Comp[2].length == 0,
v2Comp[2].length == 0) ||
goog.string.compareElements_(v1Comp[2], v2Comp[2]);
// Stop as soon as an inequality is discovered.
} while (order == 0);
}
return order;
};
/**
* Compares elements of a version number.
*
* @param {string|number|boolean} left An element from a version number.
* @param {string|number|boolean} right An element from a version number.
*
* @return {number} 1 if {@code left} is higher.
* 0 if arguments are equal.
* -1 if {@code right} is higher.
* @private
*/
goog.string.compareElements_ = function(left, right) {
if (left < right) {
return -1;
} else if (left > right) {
return 1;
}
return 0;
};
/**
* Maximum value of #goog.string.hashCode, exclusive. 2^32.
* @type {number}
* @private
*/
goog.string.HASHCODE_MAX_ = 0x100000000;
/**
* String hash function similar to java.lang.String.hashCode().
* The hash code for a string is computed as
* s[0] * 31 ^ (n - 1) + s[1] * 31 ^ (n - 2) + ... + s[n - 1],
* where s[i] is the ith character of the string and n is the length of
* the string. We mod the result to make it between 0 (inclusive) and 2^32
* (exclusive).
* @param {string} str A string.
* @return {number} Hash value for {@code str}, between 0 (inclusive) and 2^32
* (exclusive). The empty string returns 0.
*/
goog.string.hashCode = function(str) {
var result = 0;
for (var i = 0; i < str.length; ++i) {
result = 31 * result + str.charCodeAt(i);
// Normalize to 4 byte range, 0 ... 2^32.
result %= goog.string.HASHCODE_MAX_;
}
return result;
};
/**
* The most recent unique ID. |0 is equivalent to Math.floor in this case.
* @type {number}
* @private
*/
goog.string.uniqueStringCounter_ = Math.random() * 0x80000000 | 0;
/**
* Generates and returns a string which is unique in the current document.
* This is useful, for example, to create unique IDs for DOM elements.
* @return {string} A unique id.
*/
goog.string.createUniqueString = function() {
return 'goog_' + goog.string.uniqueStringCounter_++;
};
/**
* Converts the supplied string to a number, which may be Ininity or NaN.
* This function strips whitespace: (toNumber(' 123') === 123)
* This function accepts scientific notation: (toNumber('1e1') === 10)
*
* This is better than Javascript's built-in conversions because, sadly:
* (Number(' ') === 0) and (parseFloat('123a') === 123)
*
* @param {string} str The string to convert.
* @return {number} The number the supplied string represents, or NaN.
*/
goog.string.toNumber = function(str) {
var num = Number(str);
if (num == 0 && goog.string.isEmpty(str)) {
return NaN;
}
return num;
};
/**
* A memoized cache for goog.string.toCamelCase.
* @type {Object.<string>}
* @private
*/
goog.string.toCamelCaseCache_ = {};
/**
* Converts a string from selector-case to camelCase (e.g. from
* "multi-part-string" to "multiPartString"), useful for converting
* CSS selectors and HTML dataset keys to their equivalent JS properties.
* @param {string} str The string in selector-case form.
* @return {string} The string in camelCase form.
*/
goog.string.toCamelCase = function(str) {
return goog.string.toCamelCaseCache_[str] ||
(goog.string.toCamelCaseCache_[str] =
String(str).replace(/\-([a-z])/g, function(all, match) {
return match.toUpperCase();
}));
};
/**
* A memoized cache for goog.string.toSelectorCase.
* @type {Object.<string>}
* @private
*/
goog.string.toSelectorCaseCache_ = {};
/**
* Converts a string from camelCase to selector-case (e.g. from
* "multiPartString" to "multi-part-string"), useful for converting JS
* style and dataset properties to equivalent CSS selectors and HTML keys.
* @param {string} str The string in camelCase form.
* @return {string} The string in selector-case form.
*/
goog.string.toSelectorCase = function(str) {
return goog.string.toSelectorCaseCache_[str] ||
(goog.string.toSelectorCaseCache_[str] =
String(str).replace(/([A-Z])/g, '-$1').toLowerCase());
};