From 5bc27a128dc5fb6ec65591c0f0632973ce9e8116 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Thu, 24 Nov 2022 13:30:12 -0700
Subject: [PATCH] [machinery] Comment

---
 src/hb-machinery.hh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/hb-machinery.hh b/src/hb-machinery.hh
index 56669b970..5884872e4 100644
--- a/src/hb-machinery.hh
+++ b/src/hb-machinery.hh
@@ -136,6 +136,13 @@ static inline Type& StructAfter(TObject &X)
 
 /*
  * Lazy loaders.
+ *
+ * The lazy-loaders are thread-safe pointer-like objects that create their
+ * instead on-demand.  They also support access to a "data" object that is
+ * necessary for creating their instance.  The data object, if specified,
+ * is accessed via pointer math, located at a location before the position
+ * of the loader itself.  This avoids having to store a pointer to data
+ * for every lazy-loader.  Multiple lazy-loaders can access the same data.
  */
 
 template <typename Data, unsigned int WheresData>