From 6cd96ba1aca99b6eb31f8402d02c565dd4e96e03 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sun, 30 Dec 2018 20:51:31 -0500
Subject: [PATCH] [iter] Make is_random_access_iterator a constant

We cannot rely on constexpr functions...
---
 src/hb-array.hh  |  2 +-
 src/hb-iter.hh   | 11 ++++-------
 src/test-iter.cc |  2 +-
 3 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/hb-array.hh b/src/hb-array.hh
index c800dda96..ff93e1153 100644
--- a/src/hb-array.hh
+++ b/src/hb-array.hh
@@ -53,6 +53,7 @@ struct hb_array_t :
    * Iterator implementation.
    */
   typedef Type& __item_type__;
+  enum { is_random_access_iterator = true };
   Type& __item_at__ (unsigned i) const
   {
     if (unlikely (i >= length)) return CrapOrNull (Type);
@@ -72,7 +73,6 @@ struct hb_array_t :
     length -= n;
   }
   unsigned __len__ () const { return length; }
-  bool __random_access__ () const { return true; }
 
   /* Extra operators.
    */
diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index d00619840..93f79ef88 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -55,7 +55,8 @@ struct hb_iter_t
   typedef Iter iter_t;
   typedef Item item_t;
   enum { item_size = hb_static_size (Item) };
-  enum { is_iter = true };
+  enum { is_iterator = true };
+  enum { is_random_access_iterator = false };
 
   private:
   /* https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern */
@@ -80,7 +81,6 @@ struct hb_iter_t
   iter_t operator ++ (int) { iter_t c (*thiz()); ++*thiz(); return c; }
   iter_t operator - (unsigned count) const { iter_t c (*thiz()); c -= count; return c; }
   iter_t operator -- (int) { iter_t c (*thiz()); --*thiz(); return c; }
-  constexpr bool is_random_access () const { return thiz()->__random_access__ (); }
 
   protected:
   hb_iter_t () {}
@@ -92,7 +92,8 @@ struct hb_iter_t
   using typename Name::iter_t; \
   using typename Name::item_t; \
   using Name::item_size; \
-  using Name::is_iter; \
+  using Name::is_iterator; \
+  using Name::is_random_access_iterator; \
   using Name::iter; \
   using Name::operator bool; \
   using Name::len; \
@@ -105,7 +106,6 @@ struct hb_iter_t
   using Name::operator --; \
   using Name::operator +; \
   using Name::operator -; \
-  using Name::is_random_access; \
   static_assert (true, "")
 
 /* Base class for sorted iterators.  Does not enforce anything.
@@ -146,9 +146,6 @@ struct hb_iter_mixin_t
   void __prev__ () { *thiz() -= 1; }
   void __rewind__ (unsigned n) { while (n--) --*thiz(); }
 
-  /* Random access: Implement if __item_at__(), __len__(), __forward__() are. */
-  constexpr bool __random_access__ () const { return false; }
-
   protected:
   hb_iter_mixin_t () {}
   hb_iter_mixin_t (const hb_iter_mixin_t &o HB_UNUSED) {}
diff --git a/src/test-iter.cc b/src/test-iter.cc
index b4f056b0c..8b66737e1 100644
--- a/src/test-iter.cc
+++ b/src/test-iter.cc
@@ -40,11 +40,11 @@ struct array_iter_t :
   array_iter_t (hb_array_t<T> arr_) : arr (arr_) {}
 
   typedef T& __item_type__;
+  enum { is_random_access_iterator = true };
   T& __item_at__ (unsigned i) const { return arr[i]; }
   void __forward__ (unsigned n) { arr += n; }
   void __rewind__ (unsigned n) { arr -= n; }
   unsigned __len__ () const { return arr.length; }
-  bool __random_access__ () const { return true; }
 
   private:
   hb_array_t<T> arr;