Update the file link code to add both the basename and relative filename within

the document tree, and to put the target at the top of the page that actually
contains the start of the HTML file (Issue #534)

Author: michaelrsweet

CHANGES.md

@@ -2,6 +2,7 @@
 
 - Fixed a regression that caused spaces to disappear between some words
   (Issue #533)
+- Fixed broken links to HTML files in the document (Issue #534)
 
 
 # Changes in HTMLDOC v1.9.19

htmldoc/ps-pdf.cxx

@@ -4126,23 +4126,37 @@ parse_doc(tree_t *t,		/* I - Tree to parse */
     }
     else if (t->markup == MARKUP_FILE)
     {
-     /*
-      * Add a file link...
-      */
+      // Add file links, stripping any trailing HTTP GET parameters...
+      uchar	newname[256],	// New filename
+		*sep;		// "?" separator in links
+      int	linkpage;	// Link page
+
+      // Figure out what page the file will actually start on...
+      linkpage = *page;
+
+      if ((chapter > 0 && OutputType == OUTPUT_BOOK) ||
+          ((linkpage > 0 || *y < *top) && OutputType == OUTPUT_WEBPAGES))
+      {
+        if (*y < *top)
+          linkpage ++;
 
-      uchar	newname[256],	/* New filename */
-		*sep;		/* "?" separator in links */
+        if (PageDuplex && (linkpage & 1))
+          linkpage ++;
+      }
 
+      // Base filename link...
+      strlcpy((char *)newname, (char *)htmlGetVariable(t, (uchar *)"_HD_FILENAME"), sizeof(newname));
+      if ((sep = (uchar *)strchr((char *)newname, '?')) != NULL)
+        *sep = '\0';
 
-      // Strip any trailing HTTP GET data stuff...
-      strlcpy((char *)newname, (char *)htmlGetVariable(t, (uchar *)"_HD_FILENAME"),
-              sizeof(newname));
+      add_link(NULL, newname, linkpage, (int)*top);
 
+      // Relative filename link...
+      strlcpy((char *)newname, (char *)htmlGetVariable(t, (uchar *)"_HD_URL"), sizeof(newname));
       if ((sep = (uchar *)strchr((char *)newname, '?')) != NULL)
         *sep = '\0';
 
-      // Add the link
-      add_link(NULL, newname, *page, (int)*y);
+      add_link(NULL, newname, linkpage, (int)*top);
     }
 
     if (chapter == 0 && !title_page)