From 26b3f53398c9546e11b09f1ebc4cf576871f12eb Mon Sep 17 00:00:00 2001
From: Dominique Fournier <dominique@fournier38.fr>
Date: Thu, 1 Jun 2017 20:46:48 +0000
Subject: [PATCH] markdown: manage correctely the backslashes and the emphasis
 and the HR separators

git-svn-id: https://svn.fournier38.fr/svn/ProgSVN/trunk@3744 bf3deb0d-5f1a-0410-827f-c0cc1f45334c
---
 markdown.php | 110 +++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 93 insertions(+), 17 deletions(-)

diff --git a/markdown.php b/markdown.php
index b0bceca..a4a47f2 100644
--- a/markdown.php
+++ b/markdown.php
@@ -59,6 +59,91 @@ class markdown
       echo "CALL searchReplace ($line)\n";
     // REMEMBER : THE $line is already in HTML ENTITIES !
     // Quotes : &quot;
+    $res = $line;
+    // Manage the <hr/> separators
+    $search = array ("***", "---", "___", "* * *", "- - -", "_ _ _");
+    foreach ($search as $key=>$pattern)
+    {
+      $start = 0;
+      while (1)
+      {
+        $start = strpos ($res, $pattern, $start);
+        if ($start === false)
+          break;
+        if ($res[$start+1] === $pattern)
+        {
+          // Pattern too long, not this test : skip it
+          $start += strlen ($pattern) + 1;
+          continue;
+        }
+        if ($start > 1 && $res[$start-1] === "\\")
+        {
+          // Search the ending pattern to skip it. Remove the backslash
+          $res = substr ($res, 0, $start - 1) . substr ($res, $start);
+        }
+        else
+        {
+          $res = substr ($res, 0, $start) . "<hr/>" .
+                 substr ($res, $start+strlen ($pattern));
+        }
+      }
+    }
+
+    // Manage the emphasis and code correctely with the backslash
+    $search = array ();
+    $replace = array ();
+    $search[] = "__";
+    $replace[] = "<strong>\\1</strong>";
+    $search[] = "_";
+    $replace[] = "<em>\\1</em>";
+    $search[] = "**";
+    $replace[] = "<strong>\\1</strong>";
+    $search[] = "*";
+    $replace[] = "<em>\\1</em>";
+    $search[] = "`";
+    $replace[] = "<code>\\1</code>";
+
+    foreach ($search as $key=>$pattern)
+    {
+      $start = 0;
+      while (1)
+      {
+        $start = strpos ($res, $pattern, $start);
+        if ($start === false)
+          break;
+        $end = strpos ($res, $pattern, $start + strlen ($pattern));
+        if ($end === false)
+          break;
+        if ($res[$start+1] === $pattern)
+        {
+          // Pattern too long, not this test : skip it
+          $start += strlen ($pattern) + strspn ($res, $pattern, $start+1);
+          continue;
+        }
+        if ($start > 1 && $res[$start-1] === "\\")
+        {
+          // Search the ending pattern to skip it. Remove the backslash
+          $res = substr ($res, 0, $start - 1) . substr ($res, $start);
+        }
+        else
+        {
+          // It is the real pattern found, without backslash. Replace by the
+          // $replace value
+          $content = substr ($res, $start + strlen ($pattern),
+                             $end - $start - strlen ($pattern));
+          if (trim ($content) !== "")
+          {
+            $first = substr ($replace[$key], 0, strpos ($replace[$key], "\\1"));
+            $second = substr ($replace[$key], strpos ($replace[$key], "\\1")+2);
+            $res = substr ($res, 0, $start).$first.$content.$second.
+                   substr ($res, $end + strlen ($pattern));
+          }
+        }
+        $start = $end + strlen ($pattern);
+      }
+    }
+
+    // Manage the others cases
     $search = array ();
     $replace = array ();
     // Titles short
@@ -69,25 +154,10 @@ class markdown
     $search[] = '~^([^\\\\]|^)(--+ (.+)( --+)?)$~Um';
     $replace[] = '</p>\n<h2>\3</h2>\n<p>';
 
-    // EMPHASIS : _ or * for normal, __ or ** for strong
-    $search[] = '~([^\\\\]|^)(__(.+)__)~U';
-    $replace[] = '\1<strong>\3</strong>';
-    $search[] = '~([^\\\\_]|^)(_(.+)_)~U';
-    $replace[] = '\1<em>\3</em>';
-
-    $search[] = '~([^\\\\]|^)(\*\*(.+)\*\*)~U';
-    $replace[] = '\1<strong>\3</strong>';
-    $search[] = '~([^\\\\*]|^)(\*(.+)\*)~U';
-    $replace[] = '\1<em>\3</em>';
-
-    // CODE : `code` -> <code>
-    $search[] = "~\\n?([^\\\\]|^)(\`((\\n|.)+)\`)~Um";
-    $replace[] = '\1<code>\3</code>';
-
     // LINKS (can be relative)
     // images
     $search[] = '~([^\\\\]|^)(!\[(.+)\]\((.+)\))~';
-    $replace[] = '<img src=\'\4\' alt=\'\3\'/>';
+    $replace[] = '\1<img src=\'\4\' alt=\'\3\'/>';
     // [Google Site](http://google.fr/ "With help bubble")
     $search[] = '~([^\\\\!]|^)(\[(.+)\]\((.+) &quot;(.+)&quot;\))~';
     $replace[] = '\1<a href=\'\4\' title=\'\5\'>\3</a>';
@@ -140,7 +210,13 @@ class markdown
       $search[] = $s;
       $replace[] = '\2';
     }
-    $res =  preg_replace ($search, $replace, $line);
+/*foreach ($search as $key=>$s)
+{
+echo "$key => $s\n";
+  $res =  preg_replace ($s, $replace[$key], $res);
+echo "$res\n";
+}*/
+    $res =  preg_replace ($search, $replace, $res);
     return $res;
   }