Implementation of YUI rules

README

@@ -1,7 +1,9 @@
 This is a node module that minimize CSS files (cssmin).
 
-I used most rules for minimizing from Isaac Z. Schlueter cssmin git
+I used most rules for minimizing from Isaac Schlueter cssmin git
 	http://github.com/isaacs/cssmin
+
+And I also used YUICompressor source code for CSS minification.
 
 ------------------------------------------------------------------------------
 

cssmin.js

@@ -1,8 +1,5 @@
 /*
- node-cssmin - a css minifier
-
-
-
+ node-cssmin - a simple css minifier
 */
 
 
@@ -14,22 +11,75 @@ function cssmin(input, linebreak) {
 		linebreak = 0;
 	}
 
-	// normalize whitespace
+	/*
+	 * Normalize whitespace by removing \t, \n, ... 
+	 */
 	output = input.replace(/\s+/g, " ");
 
-	// Remove comments
-	output = output.replace(/\/\*(.*?)\*\//g, "");
-
-	// Remove extra whitespace
+	/**
+	 * Remove comments from source
+	 * Comments starting with ! are preserved 
+	 */
+	output = output.replace(/\/\*[^!](.*?)\*\//g, "");
+
+	/**
+	 * Remove extra whitespace on blocks
+	 */
 	output = output.replace(/([!{}:;>+\(\[,])\s+/g, "$1");
+
+	/**
+	 * Restore certain space for @webkit that would fail
+	 * 
+	 */
+	output = output.replace(/(@media[^{]*[^\s])\(/, "$1 (");
+
+	/**
+	 * Remove unnecessary 0px, 0em,... Turning them into 0
+	 */
+	output = output.replace(/([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)/g, "$1$2");
+
+	/** 
+	 * Combine multiple 0 into one
+	 */
+		output = output.replace(/:0 0 0 0(;|})/, ":0$1");
+		output = output.replace(/:0 0 0(;|})/, ":0$1");
+		output = output.replace(/:0 0(;|})/, ":0$1");
+	/* Restore background-position:0; with background-position:0 0; */
+		output =output.replace(/background-position:0(;|})/, "background-position:0 0$1");
+
+	/**
+	 * Remove multiple semi-colon in a row
+	 */
+	output = output.replace(/;;+/g,";")
 
+	/**
+	 * Remove the final semi-colon of block
+	 */
+	output = output.replace(/;(})/g, "}");
+
+	/**
+	 * Remove empty rules
+	 */
+	output = output.replace(/[^}{;]+{}/, "");
+
+	/**
+	 * Removing first white if exist
+	 */
+	output = output.replace(/^ /, "");
+
+	/**
+	 * Removing last white space if exist
+	 */
+	output = output.replace(/ /, "");
+
+	/**
+	 * Linebreak is an option that generate one block per line.
+	 * Could be useful for debug.
+	 */
 	if(linebreak == 1){
 		// Option for debug, that adds a linebreak after each rule
-		output = output.replace(/(})/g, "$1\n");
+		output = output.replace(/(\*\/|})( ?)/g, "$1\n");
 	}
-
-	// Remove unnecessary 0px, 0em,... Turning them into 0;
-	output = output.replace(/([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)/g, "$1$2");
 
 	return output;
 }