From 369b314c57bb7fd7d32949fe5f47c307468913eb Mon Sep 17 00:00:00 2001
From: Andrew Podner <a.podner@me.com>
Date: Mon, 17 Dec 2012 22:32:02 -0500
Subject: Issue #2078: refinement of the minify function for CSS and scripts.

---
 system/core/Output.php | 215 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 142 insertions(+), 73 deletions(-)

diff --git a/system/core/Output.php b/system/core/Output.php
index 0ba0a5743..1fafa848b 100644
--- a/system/core/Output.php
+++ b/system/core/Output.php
@@ -705,103 +705,172 @@ class CI_Output {
 	 * @return	string	Minified output
 	 */
 	public function minify($output, $type = 'text/html')
-	{
-		switch ($type)
-		{
-			case 'text/html':
+    {
+        switch ($type)
+        {
+            case 'text/html':
 
-				$size_before = strlen($output);
+                $size_before = strlen($output);
 
-				if ($size_before === 0)
-				{
-					return '';
-				}
+                if ($size_before === 0)
+                {
+                    return '';
+                }
 
-				// Find all the <pre>,<code>,<textarea>, and <javascript> tags
-				// We'll want to return them to this unprocessed state later.
-				preg_match_all('{<pre.+</pre>}msU', $output, $pres_clean);
-				preg_match_all('{<code.+</code>}msU', $output, $codes_clean);
-				preg_match_all('{<textarea.+</textarea>}msU', $output, $textareas_clean);
-				preg_match_all('{<script.+</script>}msU', $output, $javascript_clean);
+                // Find all the <pre>,<code>,<textarea>, and <javascript> tags
+                // We'll want to return them to this unprocessed state later.
+                preg_match_all('{<pre.+</pre>}msU', $output, $pres_clean);
+                preg_match_all('{<code.+</code>}msU', $output, $codes_clean);
+                preg_match_all('{<textarea.+</textarea>}msU', $output, $textareas_clean);
+                preg_match_all('{<script.+</script>}msU', $output, $javascript_clean);
 
-				// Minify the CSS in all the <style> tags.
-				preg_match_all('{<style.+</style>}msU', $output, $style_clean);
-				foreach ($style_clean[0] as $s)
-				{
-					$output = str_replace($s, $this->minify($s, 'text/css'), $output);
-				}
+                // Minify the CSS in all the <style> tags.
+                preg_match_all('{<style.+</style>}msU', $output, $style_clean);
+                foreach ($style_clean[0] as $s)
+                {
+                    $output = str_replace($s, $this->_minify_script_style($s, $type), $output);
+                }
 
-				// Minify the javascript in <script> tags.
-				foreach ($javascript_clean[0] as $s)
-				{
-					$javascript_mini[] = $this->minify($s, 'text/javascript');
-				}
+                // Minify the javascript in <script> tags.
+                foreach ($javascript_clean[0] as $s)
+                {
+                    $javascript_mini[] = $this->_minify_script_style($s, $type);
+                }
 
-				// Replace multiple spaces with a single space.
-				$output = preg_replace('!\s{2,}!', ' ', $output);
+                // Replace multiple spaces with a single space.
+                $output = preg_replace('!\s{2,}!', ' ', $output);
 
-				// Remove comments (non-MSIE conditionals)
-				$output = preg_replace('{\s*<!--[^\[].*-->\s*}msU', '', $output);
+                // Remove comments (non-MSIE conditionals)
+                $output = preg_replace('{\s*<!--[^\[].*-->\s*}msU', '', $output);
 
-				// Remove spaces around block-level elements.
-				$output = preg_replace('/\s*(<\/?(html|head|title|meta|script|link|style|body|h[1-6]|div|p|br)[^>]*>)\s*/is', '$1', $output);
+                // Remove spaces around block-level elements.
+                $output = preg_replace('/\s*(<\/?(html|head|title|meta|script|link|style|body|h[1-6]|div|p|br)[^>]*>)\s*/is', '$1', $output);
 
-				// Replace mangled <pre> etc. tags with unprocessed ones.
+                // Replace mangled <pre> etc. tags with unprocessed ones.
 
-				if ( ! empty($pres_clean))
-				{
-					preg_match_all('{<pre.+</pre>}msU', $output, $pres_messed);
-					$output = str_replace($pres_messed[0], $pres_clean[0], $output);
-				}
+                if ( ! empty($pres_clean))
+                {
+                    preg_match_all('{<pre.+</pre>}msU', $output, $pres_messed);
+                    $output = str_replace($pres_messed[0], $pres_clean[0], $output);
+                }
 
-				if ( ! empty($codes_clean))
-				{
-					preg_match_all('{<code.+</code>}msU', $output, $codes_messed);
-					$output = str_replace($codes_messed[0], $codes_clean[0], $output);
-				}
+                if ( ! empty($codes_clean))
+                {
+                    preg_match_all('{<code.+</code>}msU', $output, $codes_messed);
+                    $output = str_replace($codes_messed[0], $codes_clean[0], $output);
+                }
 
-				if ( ! empty($codes_clean))
-				{
-					preg_match_all('{<textarea.+</textarea>}msU', $output, $textareas_messed);
-					$output = str_replace($textareas_messed[0], $textareas_clean[0], $output);
-				}
+                if ( ! empty($codes_clean))
+                {
+                    preg_match_all('{<textarea.+</textarea>}msU', $output, $textareas_messed);
+                    $output = str_replace($textareas_messed[0], $textareas_clean[0], $output);
+                }
 
-				if (isset($javascript_mini))
-				{
-					preg_match_all('{<script.+</script>}msU', $output, $javascript_messed);
-					$output = str_replace($javascript_messed[0], $javascript_mini, $output);
-				}
+                if (isset($javascript_mini))
+                {
+                    preg_match_all('{<script.+</script>}msU', $output, $javascript_messed);
+                    $output = str_replace($javascript_messed[0], $javascript_mini, $output);
+                }
 
-				$size_removed = $size_before - strlen($output);
-				$savings_percent = round(($size_removed / $size_before * 100));
+                $size_removed = $size_before - strlen($output);
+                $savings_percent = round(($size_removed / $size_before * 100));
 
-				log_message('debug', 'Minifier shaved '.($size_removed / 1000).'KB ('.$savings_percent.'%) off final HTML output.');
+                log_message('debug', 'Minifier shaved '.($size_removed / 1000).'KB ('.$savings_percent.'%) off final HTML output.');
 
-			break;
+            break;
 
-			case 'text/css':
-			case 'text/javascript':
+            case 'text/css':
+            case 'text/javascript':
 
-				//Remove CSS comments
-				$output = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $output);
+                $output = $this->_minify_scripts_css($output, $type);
 
-				// Remove spaces around curly brackets, colons,
-				// semi-colons, parenthesis, commas
-				$output = preg_replace('!\s*(:|;|,|}|{|\(|\))\s*!', '$1', $output);
+            break;
 
-				// Remove spaces
-			        $output =  preg_replace('/  /s', ' ', $output);
+            default: break;
+        }
 
-			        // Remove breaklines and tabs
-			        $output =  preg_replace('/[\r\n\t]/', '', $output);
+        return $output;
+    }
 
-			break;
 
-			default: break;
-		}
+    // --------------------------------------------------------------------
 
-		return $output;
-	}
+	/**
+	 * Minify Style and Script
+	 *
+	 * Reduce excessive size of CSS/JavaScript content.  To remove spaces this
+     * script walks the string as an array and determines if the pointer is inside
+     * a string created by single quotes or double quotes.  spaces inside those
+     * strings are not stripped.  Opening and closing tags are severed from
+     * the string initially and saved without stripping whitespace to preserve
+     * the tags and any associated properties if tags are present
+	 *
+	 * @param	string	$output	Output to minify
+     * @param   string  $type Output content MIME type
+	 * @return	string	Minified output
+	 */
+    protected function _minify_script_style($output, $type = 'text/html')
+    {
+        // We only need this if there are tags in the file
+        if ($type == 'text/html')
+        {
+            // Remove opening tag and save for later
+            $pos = strpos($output, '>');
+            $open_tag = substr($output, 0, $pos);
+            $output = substr_replace($output, '', 0, $pos);
+
+            // Remove closing tag and save it for later
+            $end_pos = strlen($output);
+            $pos = strpos($output, '</');
+            $closing_tag = substr($output, $pos, $end_pos);
+            $output = substr_replace($output, '', $pos);
+        }
+
+        // Remove CSS comments
+        $output = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $output);
+
+        // Remove spaces around curly brackets, colons,
+        // semi-colons, parenthesis, commas
+        $output = preg_replace('!\s*(:|;|,|}|{|\(|\))\s*!', '$1', $output);
+
+        // Remove spaces
+        $in_string = FALSE;
+        $in_dstring = FALSE;
+        $array_output = str_split($output);
+        foreach ($array_output as $key => $value)
+        {
+            if ($in_string === FALSE and $in_dstring === FALSE)
+            {
+                if ($value == ' ')
+                {
+                    unset($array_output[$key]);
+                }
+            }
+
+            if ($value == "'")
+            {
+                $in_string = !$in_string;
+            }
+
+            if ($value == '"')
+            {
+                $in_dstring = !$in_dstring;
+            }
+        }
+
+        $output =  implode($array_output);
+
+        // Remove breaklines and tabs
+        $output =  preg_replace('/[\r\n\t]/', '', $output);
+
+        // Put the opening and closing tags back if applicable
+        if (isset($open_tag))
+        {
+            $output = $open_tag . $output . $closing_tag;
+        }
+
+        return $output;
+    }
 
 }
 
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