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AS3 String Utils

/ Published in: ActionScript 3

This handy String Utils class was written by Ryan Matsikas at gSkinner.com
I take no credit for it.

A ZIP file containing 'StringUtils.as' can be downloaded from here ...
http://www.gskinner.com/products/downloads/AS3StringUtils.zip

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package {

/**
	* 	String Utilities class by Ryan Matsikas, Feb 10 2006
	*
	*	Visit www.gskinner.com for documentation, updates and more free code.
	* 	You may distribute this code freely, as long as this comment block remains intact.
	*/

public class StringUtils {

/**
		*	Returns everything after the first occurrence of the provided character in the string.
		*
		*	@param p_string The string.
		*
		*	@param p_begin The character or sub-string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function afterFirst(p_string:String, p_char:String):String {
			if (p_string == null) { return ''; }
			var idx:int = p_string.indexOf(p_char);
			if (idx == -1) { return ''; }
			idx += p_char.length;
			return p_string.substr(idx);
		}

/**
		*	Returns everything after the last occurence of the provided character in p_string.
		*
		*	@param p_string The string.
		*
		*	@param p_char The character or sub-string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function afterLast(p_string:String, p_char:String):String {
			if (p_string == null) { return ''; }
			var idx:int = p_string.lastIndexOf(p_char);
			if (idx == -1) { return ''; }
			idx += p_char.length;
			return p_string.substr(idx);
		}

/**
		*	Determines whether the specified string begins with the specified prefix.
		*
		*	@param p_string The string that the prefix will be checked against.
		*
		*	@param p_begin The prefix that will be tested against the string.
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function beginsWith(p_string:String, p_begin:String):Boolean {
			if (p_string == null) { return false; }
			return p_string.indexOf(p_begin) == 0;
		}

/**
		*	Returns everything before the first occurrence of the provided character in the string.
		*
		*	@param p_string The string.
		*
		*	@param p_begin The character or sub-string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function beforeFirst(p_string:String, p_char:String):String {
			if (p_string == null) { return ''; }
			var idx:int = p_string.indexOf(p_char);
        	if (idx == -1) { return ''; }
        	return p_string.substr(0, idx);
		}

/**
		*	Returns everything before the last occurrence of the provided character in the string.
		*
		*	@param p_string The string.
		*
		*	@param p_begin The character or sub-string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function beforeLast(p_string:String, p_char:String):String {
			if (p_string == null) { return ''; }
			var idx:int = p_string.lastIndexOf(p_char);
        	if (idx == -1) { return ''; }
        	return p_string.substr(0, idx);
		}

/**
		*	Returns everything after the first occurance of p_start and before
		*	the first occurrence of p_end in p_string.
		*
		*	@param p_string The string.
		*
		*	@param p_start The character or sub-string to use as the start index.
		*
		*	@param p_end The character or sub-string to use as the end index.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function between(p_string:String, p_start:String, p_end:String):String {
			var str:String = '';
			if (p_string == null) { return str; }
			var startIdx:int = p_string.indexOf(p_start);
			if (startIdx != -1) {
				startIdx += p_start.length; // RM: should we support multiple chars? (or ++startIdx);
				var endIdx:int = p_string.indexOf(p_end, startIdx);
				if (endIdx != -1) { str = p_string.substr(startIdx, endIdx-startIdx); }
			}
			return str;
		}

/**
		*	Description, Utility method that intelligently breaks up your string,
		*	allowing you to create blocks of readable text.
		*	This method returns you the closest possible match to the p_delim paramater,
		*	while keeping the text length within the p_len paramter.
		*	If a match can't be found in your specified length an  '...' is added to that block,
		*	and the blocking continues untill all the text is broken apart.
		*
		*	@param p_string The string to break up.
		*
		*	@param p_len Maximum length of each block of text.
		*
		*	@param p_delim delimter to end text blocks on, default = '.'
		*
		*	@returns Array
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function block(p_string:String, p_len:uint, p_delim:String = "."):Array {
			var arr:Array = new Array();
			if (p_string == null || !contains(p_string, p_delim)) { return arr; }
			var chrIndex:uint = 0;
			var strLen:uint = p_string.length;
			var replPatt:RegExp = new RegExp("[^"+escapePattern(p_delim)+"]+$");
			while (chrIndex <  strLen) {
				var subString:String = p_string.substr(chrIndex, p_len);
				if (!contains(subString, p_delim)){
					arr.push(truncate(subString, subString.length));
					chrIndex += subString.length;
				}
				subString = subString.replace(replPatt, '');
				arr.push(subString);
				chrIndex += subString.length;
			}
			return arr;
		}

/**
		*	Capitallizes the first word in a string or all words..
		*
		*	@param p_string The string.
		*
		*	@param p_all (optional) Boolean value indicating if we should
		*	capitalize all words or only the first.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function capitalize(p_string:String, ...args):String {
			var str:String = trimLeft(p_string);
			trace('capl', args[0])
			if (args[0] === true) { return str.replace(/^.|\b./g, _upperCase);}
			else { return str.replace(/(^\w)/, _upperCase); }
		}

/**
		*	Determines whether the specified string contains any instances of p_char.
		*
		*	@param p_string The string.
		*
		*	@param p_char The character or sub-string we are looking for.
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function contains(p_string:String, p_char:String):Boolean {
			if (p_string == null) { return false; }
			return p_string.indexOf(p_char) != -1;
		}

/**
		*	Determines the number of times a charactor or sub-string appears within the string.
		*
		*	@param p_string The string.
		*
		*	@param p_char The character or sub-string to count.
		*
		*	@param p_caseSensitive (optional, default is true) A boolean flag to indicate if the
		*	search is case sensitive.
		*
		*	@returns uint
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function countOf(p_string:String, p_char:String, p_caseSensitive:Boolean = true):uint {
			if (p_string == null) { return 0; }
			var char:String = escapePattern(p_char);
			var flags:String = (!p_caseSensitive) ? 'ig' : 'g';
			return p_string.match(new RegExp(char, flags)).length;
		}

/**
		*	Levenshtein distance (editDistance) is a measure of the similarity between two strings,
		*	The distance is the number of deletions, insertions, or substitutions required to
		*	transform p_source into p_target.
		*
		*	@param p_source The source string.
		*
		*	@param p_target The target string.
		*
		*	@returns uint
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function editDistance(p_source:String, p_target:String):uint {
			var i:uint;

if (p_source == null) { p_source = ''; }
			if (p_target == null) { p_target = ''; }

if (p_source == p_target) { return 0; }

var d:Array = new Array();
			var cost:uint;
			var n:uint = p_source.length;
			var m:uint = p_target.length;
			var j:uint;

if (n == 0) { return m; }
			if (m == 0) { return n; }

for (i=0; i<=n; i++) { d[i] = new Array(); }
			for (i=0; i<=n; i++) { d[i][0] = i; }
			for (j=0; j<=m; j++) { d[0][j] = j; }

for (i=1; i<=n; i++) {

var s_i:String = p_source.charAt(i-1);
				for (j=1; j<=m; j++) {

var t_j:String = p_target.charAt(j-1);

if (s_i == t_j) { cost = 0; }
					else { cost = 1; }

d[i][j] = _minimum(d[i-1][j]+1, d[i][j-1]+1, d[i-1][j-1]+cost);
				}
			}
			return d[n][m];
		}

/**
		*	Determines whether the specified string ends with the specified suffix.
		*
		*	@param p_string The string that the suffic will be checked against.
		*
		*	@param p_end The suffix that will be tested against the string.
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function endsWith(p_string:String, p_end:String):Boolean {
			return p_string.lastIndexOf(p_end) == p_string.length - p_end.length;
		}

/**
		*	Determines whether the specified string contains text.
		*
		*	@param p_string The string to check.
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function hasText(p_string:String):Boolean {
			var str:String = removeExtraWhitespace(p_string);
			return !!str.length;
		}

/**
		*	Determines whether the specified string contains any characters.
		*
		*	@param p_string The string to check
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function isEmpty(p_string:String):Boolean {
			if (p_string == null) { return true; }
			return !p_string.length;
		}

/**
		*	Determines whether the specified string is numeric.
		*
		*	@param p_string The string.
		*
		*	@returns Boolean
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function isNumeric(p_string:String):Boolean {
			if (p_string == null) { return false; }
			var regx:RegExp = /^[-+]?\d*\.?\d+(?:[eE][-+]?\d+)?$/;
			return regx.test(p_string);
		}

/**
		* Pads p_string with specified character to a specified length from the left.
		*
		*	@param p_string String to pad
		*
		*	@param p_padChar Character for pad.
		*
		*	@param p_length Length to pad to.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function padLeft(p_string:String, p_padChar:String, p_length:uint):String {
			var s:String = p_string;
			while (s.length < p_length) { s = p_padChar + s; }
			return s;
		}

/**
		* Pads p_string with specified character to a specified length from the right.
		*
		*	@param p_string String to pad
		*
		*	@param p_padChar Character for pad.
		*
		*	@param p_length Length to pad to.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function padRight(p_string:String, p_padChar:String, p_length:uint):String {
			var s:String = p_string;
			while (s.length < p_length) { s += p_padChar; }
			return s;
		}

/**
		*	Properly cases' the string in "sentence format".
		*
		*	@param p_string The string to check
		*
		*	@returns String.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function properCase(p_string:String):String {
			if (p_string == null) { return ''; }
			var str:String = p_string.toLowerCase().replace(/\b([^.?;!]+)/, capitalize);
			return str.replace(/\b[i]\b/, "I");
		}

/**
		*	Escapes all of the characters in a string to create a friendly "quotable" sting
		*
		*	@param p_string The string that will be checked for instances of remove
		*	string
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function quote(p_string:String):String {
			var regx:RegExp = /[\\"
]/g;
			return '"'+ p_string.replace(regx, _quote) +'"'; //"
		}

/**
		*	Removes all instances of the remove string in the input string.
		*
		*	@param p_string The string that will be checked for instances of remove
		*	string
		*
		*	@param p_remove The string that will be removed from the input string.
		*
		*	@param p_caseSensitive An optional boolean indicating if the replace is case sensitive. Default is true.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function remove(p_string:String, p_remove:String, p_caseSensitive:Boolean = true):String {
			if (p_string == null) { return ''; }
			var rem:String = escapePattern(p_remove);
			var flags:String = (!p_caseSensitive) ? 'ig' : 'g';
			return p_string.replace(new RegExp(rem, flags), '');
		}

/**
		*	Removes extraneous whitespace (extra spaces, tabs, line breaks, etc) from the
		*	specified string.
		*
		*	@param p_string The String whose extraneous whitespace will be removed.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function removeExtraWhitespace(p_string:String):String {
			if (p_string == null) { return ''; }
			var str:String = trim(p_string);
			return str.replace(/\s+/g, ' ');
		}

/**
		*	Returns the specified string in reverse character order.
		*
		*	@param p_string The String that will be reversed.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function reverse(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.split('').reverse().join('');
		}

/**
		*	Returns the specified string in reverse word order.
		*
		*	@param p_string The String that will be reversed.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function reverseWords(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.split(/\s+/).reverse().join('');
		}

/**
		*	Determines the percentage of similiarity, based on editDistance
		*
		*	@param p_source The source string.
		*
		*	@param p_target The target string.
		*
		*	@returns Number
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function similarity(p_source:String, p_target:String):Number {
			var ed:uint = editDistance(p_source, p_target);
			var maxLen:uint = Math.max(p_source.length, p_target.length);
			if (maxLen == 0) { return 100; }
			else { return (1 - ed/maxLen) * 100; }
		}

/**
		*	Remove's all < and > based tags from a string
		*
		*	@param p_string The source string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function stripTags(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.replace(/<\/?[^>]+>/igm, '');
		}

/**
		*	Swaps the casing of a string.
		*
		*	@param p_string The source string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function swapCase(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.replace(/(\w)/, _swapCase);
		}

/**
		*	Removes whitespace from the front and the end of the specified
		*	string.
		*
		*	@param p_string The String whose beginning and ending whitespace will
		*	will be removed.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function trim(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.replace(/^\s+|\s+$/g, '');
		}

/**
		*	Removes whitespace from the front (left-side) of the specified string.
		*
		*	@param p_string The String whose beginning whitespace will be removed.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function trimLeft(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.replace(/^\s+/, '');
		}

/**
		*	Removes whitespace from the end (right-side) of the specified string.
		*
		*	@param p_string The String whose ending whitespace will be removed.
		*
		*	@returns String	.
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function trimRight(p_string:String):String {
			if (p_string == null) { return ''; }
			return p_string.replace(/\s+$/, '');
		}

/**
		*	Determins the number of words in a string.
		*
		*	@param p_string The string.
		*
		*	@returns uint
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function wordCount(p_string:String):uint {
			if (p_string == null) { return 0; }
			return p_string.match(/\b\w+\b/g).length;
		}

/**
		*	Returns a string truncated to a specified length with optional suffix
		*
		*	@param p_string The string.
		*
		*	@param p_len The length the string should be shortend to
		*
		*	@param p_suffix (optional, default=...) The string to append to the end of the truncated string.
		*
		*	@returns String
		*
		* 	@langversion ActionScript 3.0
		*	@playerversion Flash 9.0
		*	@tiptext
		*/
		public static function truncate(p_string:String, p_len:uint, p_suffix:String = "..."):String {
			if (p_string == null) { return ''; }
			p_len -= p_suffix.length;
			var trunc:String = p_string;
			if (trunc.length > p_len) {
				trunc = trunc.substr(0, p_len);
				if (/[^\s]/.test(p_string.charAt(p_len))) {
					trunc = trimRight(trunc.replace(/\w+$|\s+$/, ''));
				}
				trunc += p_suffix;
			}

return trunc;
		}

/* **************************************************************** */
		/*	These are helper methods used by some of the above methods.		*/
		/* **************************************************************** */
		private static function escapePattern(p_pattern:String):String {
			// RM: might expose this one, I've used it a few times already.
			return p_pattern.replace(/(\]|\[|\{|\}|$|$|\*|\+|\?|\.|\\)/g, '\\$1');
		}

private static function _minimum(a:uint, b:uint, c:uint):uint {
			return Math.min(a, Math.min(b, Math.min(c,a)));
		}

private static function _quote(p_string:String, ...args):String {
			switch (p_string) {
				case "\\":
					return "\\\\";
				case "\r":
					return "\\r";
				case "\n":
					return "\\n";
				case '"':
					return '\\"';
				default:
					return '';
			}
		}

private static function _upperCase(p_char:String, ...args):String {
			trace('cap latter ',p_char)
			return p_char.toUpperCase();
		}

private static function _swapCase(p_char:String, ...args):String {
			var lowChar:String = p_char.toLowerCase();
			var upChar:String = p_char.toUpperCase();
			switch (p_char) {
				case lowChar:
					return upChar;
				case upChar:
					return lowChar;
				default:
					return p_char;
			}
		}

}
}

URL: http://www.gskinner.com/blog/archives/2007/04/free_extension.html

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