From a642513db37b09b31057aea43429bd028cee0c30 Mon Sep 17 00:00:00 2001
From: Jeremy Rand <jeremy@rand-family.com>
Date: Wed, 21 Apr 2021 00:21:02 -0400
Subject: [PATCH] Add some basic support for HTML entities.  Just the copyright
 symbol is supported now but all characters from the extended set of the GS
 that exist in the HTML entities should be added.

---
 md2teach/main.c | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/md2teach/main.c b/md2teach/main.c
index 03231a8..f7cbf52 100644
--- a/md2teach/main.c
+++ b/md2teach/main.c
@@ -48,6 +48,12 @@ typedef struct tBlockListItem
     struct tBlockListItem * next;
 } tBlockListItem;
 
+typedef struct tEntity
+{
+    const char * entityString;
+    char entityChar;
+} tEntity;
+
 // Forward declarations
 
 static int enterBlockHook(MD_BLOCKTYPE type, void * detail, void * userdata);
@@ -82,6 +88,10 @@ tBlockListItem * blockList = NULL;
 
 FILE * outputFile;
 
+tEntity entities[] = {
+    { "&copy;", 0xa9 }
+    // GS_TODO - Add more to the entity table to fill out the extended character set of the GS.
+};
 
 // Implementation
 
@@ -395,6 +405,24 @@ static int leaveSpanHook(MD_SPANTYPE type, void * detail, void * userdata)
     return 0;
 }
 
+static void printEntity(const MD_CHAR * text, MD_SIZE size)
+{
+    int entityNum;
+    
+    for (entityNum = 0; entityNum < (sizeof(entities) / sizeof(entities[0])); entityNum++) {
+        int offset;
+        char * entityString = entities[entityNum].entityString;
+        
+        for (offset = 0; offset < size; offset++) {
+            if (tolower(text[offset]) != entityString[offset])
+                break;
+        }
+        if (offset >= size) {
+            fputc(entities[entityNum].entityChar, outputFile);
+            return;
+        }
+    }
+}
 
 static int textHook(MD_TEXTTYPE type, const MD_CHAR * text, MD_SIZE size, void * userdata)
 {
@@ -420,12 +448,12 @@ static int textHook(MD_TEXTTYPE type, const MD_CHAR * text, MD_SIZE size, void *
             return 0;
             
         case MD_TEXT_ENTITY:
-            if (debugEnabled)
+            if (debugEnabled) {
                 fprintf(stderr, "%*sEntity: \"", debugIndentLevel, "");
+                fwrite(text, sizeof(MD_CHAR), size, stderr);
+            }
             
-            // GS_TODO - For now, just skip printing anything but it would be best to look
-            // at the extended character map and do the "right thing" for special characters
-            // like the copyright symbol.
+            printEntity(text, size);
             text = "";
             size = 0;
             break;