Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1407 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-algs.hh b/gfx/harfbuzz/src/hb-algs.hh
new file mode 100644
index 0000000000..da383e050a
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-algs.hh
@@ -0,0 +1,1407 @@
+/*
+ * Copyright © 2017  Google, Inc.
+ * Copyright © 2019  Facebook, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Behdad Esfahbod
+ * Facebook Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_ALGS_HH
+#define HB_ALGS_HH
+
+#include "hb.hh"
+#include "hb-meta.hh"
+#include "hb-null.hh"
+#include "hb-number.hh"
+
+#include <algorithm>
+#include <initializer_list>
+#include <functional>
+#include <new>
+
+/*
+ * Flags
+ */
+
+/* Enable bitwise ops on enums marked as flags_t */
+/* To my surprise, looks like the function resolver is happy to silently cast
+ * one enum to another...  So this doesn't provide the type-checking that I
+ * originally had in mind... :(.
+ *
+ * For MSVC warnings, see: https://github.com/harfbuzz/harfbuzz/pull/163
+ */
+#ifdef _MSC_VER
+# pragma warning(disable:4200)
+# pragma warning(disable:4800)
+#endif
+#define HB_MARK_AS_FLAG_T(T) \
+	extern "C++" { \
+	  static inline constexpr T operator | (T l, T r) { return T ((unsigned) l | (unsigned) r); } \
+	  static inline constexpr T operator & (T l, T r) { return T ((unsigned) l & (unsigned) r); } \
+	  static inline constexpr T operator ^ (T l, T r) { return T ((unsigned) l ^ (unsigned) r); } \
+	  static inline constexpr unsigned operator ~ (T r) { return (~(unsigned) r); } \
+	  static inline T& operator |= (T &l, T r) { l = l | r; return l; } \
+	  static inline T& operator &= (T& l, T r) { l = l & r; return l; } \
+	  static inline T& operator ^= (T& l, T r) { l = l ^ r; return l; } \
+	} \
+	static_assert (true, "")
+
+/* Useful for set-operations on small enums.
+ * For example, for testing "x ∈ {x1, x2, x3}" use:
+ * (FLAG_UNSAFE(x) & (FLAG(x1) | FLAG(x2) | FLAG(x3)))
+ */
+#define FLAG(x) (static_assert_expr ((unsigned)(x) < 32) + (((uint32_t) 1U) << (unsigned)(x)))
+#define FLAG_UNSAFE(x) ((unsigned)(x) < 32 ? (((uint32_t) 1U) << (unsigned)(x)) : 0)
+#define FLAG_RANGE(x,y) (static_assert_expr ((x) < (y)) + FLAG(y+1) - FLAG(x))
+#define FLAG64(x) (static_assert_expr ((unsigned)(x) < 64) + (((uint64_t) 1ULL) << (unsigned)(x)))
+#define FLAG64_UNSAFE(x) ((unsigned)(x) < 64 ? (((uint64_t) 1ULL) << (unsigned)(x)) : 0)
+
+
+/*
+ * Big-endian integers.
+ */
+
+/* Endian swap, used in Windows related backends */
+static inline constexpr uint16_t hb_uint16_swap (uint16_t v)
+{ return (v >> 8) | (v << 8); }
+static inline constexpr uint32_t hb_uint32_swap (uint32_t v)
+{ return (hb_uint16_swap (v) << 16) | hb_uint16_swap (v >> 16); }
+
+template <typename Type, int Bytes = sizeof (Type)>
+struct BEInt;
+template <typename Type>
+struct BEInt<Type, 1>
+{
+  public:
+  BEInt () = default;
+  constexpr BEInt (Type V) : v {uint8_t (V)} {}
+  constexpr operator Type () const { return v; }
+  private: uint8_t v;
+};
+template <typename Type>
+struct BEInt<Type, 2>
+{
+  public:
+  BEInt () = default;
+  constexpr BEInt (Type V) : v {uint8_t ((V >>  8) & 0xFF),
+			        uint8_t ((V      ) & 0xFF)} {}
+
+  struct __attribute__((packed)) packed_uint16_t { uint16_t v; };
+  constexpr operator Type () const
+  {
+#if defined(__OPTIMIZE__) && !defined(HB_NO_PACKED) && \
+    defined(__BYTE_ORDER) && \
+    (__BYTE_ORDER == __BIG_ENDIAN || \
+     (__BYTE_ORDER == __LITTLE_ENDIAN && \
+      hb_has_builtin(__builtin_bswap16)))
+    /* Spoon-feed the compiler a big-endian integer with alignment 1.
+     * https://github.com/harfbuzz/harfbuzz/pull/1398 */
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+    return __builtin_bswap16 (((packed_uint16_t *) v)->v);
+#else /* __BYTE_ORDER == __BIG_ENDIAN */
+    return ((packed_uint16_t *) v)->v;
+#endif
+#else
+    return (v[0] <<  8)
+	 + (v[1]      );
+#endif
+  }
+  private: uint8_t v[2];
+};
+template <typename Type>
+struct BEInt<Type, 3>
+{
+  static_assert (!std::is_signed<Type>::value, "");
+  public:
+  BEInt () = default;
+  constexpr BEInt (Type V) : v {uint8_t ((V >> 16) & 0xFF),
+				uint8_t ((V >>  8) & 0xFF),
+				uint8_t ((V      ) & 0xFF)} {}
+
+  constexpr operator Type () const { return (v[0] << 16)
+					  + (v[1] <<  8)
+					  + (v[2]      ); }
+  private: uint8_t v[3];
+};
+template <typename Type>
+struct BEInt<Type, 4>
+{
+  public:
+  BEInt () = default;
+  constexpr BEInt (Type V) : v {uint8_t ((V >> 24) & 0xFF),
+			        uint8_t ((V >> 16) & 0xFF),
+			        uint8_t ((V >>  8) & 0xFF),
+			        uint8_t ((V      ) & 0xFF)} {}
+
+  struct __attribute__((packed)) packed_uint32_t { uint32_t v; };
+  constexpr operator Type () const {
+#if defined(__OPTIMIZE__) && !defined(HB_NO_PACKED) && \
+    defined(__BYTE_ORDER) && \
+    (__BYTE_ORDER == __BIG_ENDIAN || \
+     (__BYTE_ORDER == __LITTLE_ENDIAN && \
+      hb_has_builtin(__builtin_bswap32)))
+    /* Spoon-feed the compiler a big-endian integer with alignment 1.
+     * https://github.com/harfbuzz/harfbuzz/pull/1398 */
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+    return __builtin_bswap32 (((packed_uint32_t *) v)->v);
+#else /* __BYTE_ORDER == __BIG_ENDIAN */
+    return ((packed_uint32_t *) v)->v;
+#endif
+#else
+    return (v[0] << 24)
+	 + (v[1] << 16)
+	 + (v[2] <<  8)
+	 + (v[3]      );
+#endif
+  }
+  private: uint8_t v[4];
+};
+
+/* Floats. */
+
+/* We want our rounding towards +infinity. */
+static inline float
+_hb_roundf (float x) { return floorf (x + .5f); }
+#define roundf(x) _hb_roundf(x)
+
+
+/* Encodes three unsigned integers in one 64-bit number.  If the inputs have more than 21 bits,
+ * values will be truncated / overlap, and might not decode exactly. */
+#define HB_CODEPOINT_ENCODE3(x,y,z) (((uint64_t) (x) << 42) | ((uint64_t) (y) << 21) | (uint64_t) (z))
+#define HB_CODEPOINT_DECODE3_1(v) ((hb_codepoint_t) ((v) >> 42))
+#define HB_CODEPOINT_DECODE3_2(v) ((hb_codepoint_t) ((v) >> 21) & 0x1FFFFFu)
+#define HB_CODEPOINT_DECODE3_3(v) ((hb_codepoint_t) (v) & 0x1FFFFFu)
+
+/* Custom encoding used by hb-ucd. */
+#define HB_CODEPOINT_ENCODE3_11_7_14(x,y,z) (((uint32_t) ((x) & 0x07FFu) << 21) | (((uint32_t) (y) & 0x007Fu) << 14) | (uint32_t) ((z) & 0x3FFFu))
+#define HB_CODEPOINT_DECODE3_11_7_14_1(v) ((hb_codepoint_t) ((v) >> 21))
+#define HB_CODEPOINT_DECODE3_11_7_14_2(v) ((hb_codepoint_t) (((v) >> 14) & 0x007Fu) | 0x0300)
+#define HB_CODEPOINT_DECODE3_11_7_14_3(v) ((hb_codepoint_t) (v) & 0x3FFFu)
+
+
+struct
+{
+  /* Note.  This is dangerous in that if it's passed an rvalue, it returns rvalue-reference. */
+  template <typename T> constexpr auto
+  operator () (T&& v) const HB_AUTO_RETURN ( std::forward<T> (v) )
+}
+HB_FUNCOBJ (hb_identity);
+struct
+{
+  /* Like identity(), but only retains lvalue-references.  Rvalues are returned as rvalues. */
+  template <typename T> constexpr T&
+  operator () (T& v) const { return v; }
+
+  template <typename T> constexpr hb_remove_reference<T>
+  operator () (T&& v) const { return v; }
+}
+HB_FUNCOBJ (hb_lidentity);
+struct
+{
+  /* Like identity(), but always returns rvalue. */
+  template <typename T> constexpr hb_remove_reference<T>
+  operator () (T&& v) const { return v; }
+}
+HB_FUNCOBJ (hb_ridentity);
+
+struct
+{
+  template <typename T> constexpr bool
+  operator () (T&& v) const { return bool (std::forward<T> (v)); }
+}
+HB_FUNCOBJ (hb_bool);
+
+struct
+{
+  private:
+
+  template <typename T> constexpr auto
+  impl (const T& v, hb_priority<1>) const HB_RETURN (uint32_t, hb_deref (v).hash ())
+
+  template <typename T> constexpr auto
+  impl (const T& v, hb_priority<0>) const HB_RETURN (uint32_t, std::hash<hb_decay<decltype (hb_deref (v))>>{} (hb_deref (v)))
+
+  public:
+
+  template <typename T> constexpr auto
+  operator () (const T& v) const HB_RETURN (uint32_t, impl (v, hb_prioritize))
+}
+HB_FUNCOBJ (hb_hash);
+
+
+struct
+{
+  private:
+
+  /* Pointer-to-member-function. */
+  template <typename Appl, typename T, typename ...Ts> auto
+  impl (Appl&& a, hb_priority<2>, T &&v, Ts&&... ds) const HB_AUTO_RETURN
+  ((hb_deref (std::forward<T> (v)).*std::forward<Appl> (a)) (std::forward<Ts> (ds)...))
+
+  /* Pointer-to-member. */
+  template <typename Appl, typename T> auto
+  impl (Appl&& a, hb_priority<1>, T &&v) const HB_AUTO_RETURN
+  ((hb_deref (std::forward<T> (v))).*std::forward<Appl> (a))
+
+  /* Operator(). */
+  template <typename Appl, typename ...Ts> auto
+  impl (Appl&& a, hb_priority<0>, Ts&&... ds) const HB_AUTO_RETURN
+  (hb_deref (std::forward<Appl> (a)) (std::forward<Ts> (ds)...))
+
+  public:
+
+  template <typename Appl, typename ...Ts> auto
+  operator () (Appl&& a, Ts&&... ds) const HB_AUTO_RETURN
+  (
+    impl (std::forward<Appl> (a),
+	  hb_prioritize,
+	  std::forward<Ts> (ds)...)
+  )
+}
+HB_FUNCOBJ (hb_invoke);
+
+template <unsigned Pos, typename Appl, typename V>
+struct hb_partial_t
+{
+  hb_partial_t (Appl a, V v) : a (a), v (v) {}
+
+  static_assert (Pos > 0, "");
+
+  template <typename ...Ts,
+	    unsigned P = Pos,
+	    hb_enable_if (P == 1)> auto
+  operator () (Ts&& ...ds) -> decltype (hb_invoke (hb_declval (Appl),
+						   hb_declval (V),
+						   hb_declval (Ts)...))
+  {
+    return hb_invoke (std::forward<Appl> (a),
+		      std::forward<V> (v),
+		      std::forward<Ts> (ds)...);
+  }
+  template <typename T0, typename ...Ts,
+	    unsigned P = Pos,
+	    hb_enable_if (P == 2)> auto
+  operator () (T0&& d0, Ts&& ...ds) -> decltype (hb_invoke (hb_declval (Appl),
+							    hb_declval (T0),
+							    hb_declval (V),
+							    hb_declval (Ts)...))
+  {
+    return hb_invoke (std::forward<Appl> (a),
+		      std::forward<T0> (d0),
+		      std::forward<V> (v),
+		      std::forward<Ts> (ds)...);
+  }
+
+  private:
+  hb_reference_wrapper<Appl> a;
+  V v;
+};
+template <unsigned Pos=1, typename Appl, typename V>
+auto hb_partial (Appl&& a, V&& v) HB_AUTO_RETURN
+(( hb_partial_t<Pos, Appl, V> (a, v) ))
+
+/* The following, HB_PARTIALIZE, macro uses a particular corner-case
+ * of C++11 that is not particularly well-supported by all compilers.
+ * What's happening is that it's using "this" in a trailing return-type
+ * via decltype().  Broken compilers deduce the type of "this" pointer
+ * in that context differently from what it resolves to in the body
+ * of the function.
+ *
+ * One probable cause of this is that at the time of trailing return
+ * type declaration, "this" points to an incomplete type, whereas in
+ * the function body the type is complete.  That doesn't justify the
+ * error in any way, but is probably what's happening.
+ *
+ * In the case of MSVC, we get around this by using C++14 "decltype(auto)"
+ * which deduces the type from the actual return statement.  For gcc 4.8
+ * we use "+this" instead of "this" which produces an rvalue that seems
+ * to be deduced as the same type with this particular compiler, and seem
+ * to be fine as default code path as well.
+ */
+#ifdef _MSC_VER
+/* https://github.com/harfbuzz/harfbuzz/issues/1730 */ \
+#define HB_PARTIALIZE(Pos) \
+  template <typename _T> \
+  decltype(auto) operator () (_T&& _v) const \
+  { return hb_partial<Pos> (this, std::forward<_T> (_v)); } \
+  static_assert (true, "")
+#else
+/* https://github.com/harfbuzz/harfbuzz/issues/1724 */
+#define HB_PARTIALIZE(Pos) \
+  template <typename _T> \
+  auto operator () (_T&& _v) const HB_AUTO_RETURN \
+  (hb_partial<Pos> (+this, std::forward<_T> (_v))) \
+  static_assert (true, "")
+#endif
+
+
+struct
+{
+  private:
+
+  template <typename Pred, typename Val> auto
+  impl (Pred&& p, Val &&v, hb_priority<1>) const HB_AUTO_RETURN
+  (
+    hb_deref (std::forward<Pred> (p)).has (std::forward<Val> (v))
+  )
+
+  template <typename Pred, typename Val> auto
+  impl (Pred&& p, Val &&v, hb_priority<0>) const HB_AUTO_RETURN
+  (
+    hb_invoke (std::forward<Pred> (p),
+	       std::forward<Val> (v))
+  )
+
+  public:
+
+  template <typename Pred, typename Val> auto
+  operator () (Pred&& p, Val &&v) const HB_RETURN (bool,
+    impl (std::forward<Pred> (p),
+	  std::forward<Val> (v),
+	  hb_prioritize)
+  )
+}
+HB_FUNCOBJ (hb_has);
+
+struct
+{
+  private:
+
+  template <typename Pred, typename Val> auto
+  impl (Pred&& p, Val &&v, hb_priority<1>) const HB_AUTO_RETURN
+  (
+    hb_has (std::forward<Pred> (p),
+	    std::forward<Val> (v))
+  )
+
+  template <typename Pred, typename Val> auto
+  impl (Pred&& p, Val &&v, hb_priority<0>) const HB_AUTO_RETURN
+  (
+    std::forward<Pred> (p) == std::forward<Val> (v)
+  )
+
+  public:
+
+  template <typename Pred, typename Val> auto
+  operator () (Pred&& p, Val &&v) const HB_RETURN (bool,
+    impl (std::forward<Pred> (p),
+	  std::forward<Val> (v),
+	  hb_prioritize)
+  )
+}
+HB_FUNCOBJ (hb_match);
+
+struct
+{
+  private:
+
+  template <typename Proj, typename Val> auto
+  impl (Proj&& f, Val &&v, hb_priority<2>) const HB_AUTO_RETURN
+  (
+    hb_deref (std::forward<Proj> (f)).get (std::forward<Val> (v))
+  )
+
+  template <typename Proj, typename Val> auto
+  impl (Proj&& f, Val &&v, hb_priority<1>) const HB_AUTO_RETURN
+  (
+    hb_invoke (std::forward<Proj> (f),
+	       std::forward<Val> (v))
+  )
+
+  template <typename Proj, typename Val> auto
+  impl (Proj&& f, Val &&v, hb_priority<0>) const HB_AUTO_RETURN
+  (
+    std::forward<Proj> (f)[std::forward<Val> (v)]
+  )
+
+  public:
+
+  template <typename Proj, typename Val> auto
+  operator () (Proj&& f, Val &&v) const HB_AUTO_RETURN
+  (
+    impl (std::forward<Proj> (f),
+	  std::forward<Val> (v),
+	  hb_prioritize)
+  )
+}
+HB_FUNCOBJ (hb_get);
+
+struct
+{
+  private:
+
+  template <typename T1, typename T2> auto
+  impl (T1&& v1, T2 &&v2, hb_priority<3>) const HB_AUTO_RETURN
+  (
+    std::forward<T2> (v2).cmp (std::forward<T1> (v1)) == 0
+  )
+
+  template <typename T1, typename T2> auto
+  impl (T1&& v1, T2 &&v2, hb_priority<2>) const HB_AUTO_RETURN
+  (
+    std::forward<T1> (v1).cmp (std::forward<T2> (v2)) == 0
+  )
+
+  template <typename T1, typename T2> auto
+  impl (T1&& v1, T2 &&v2, hb_priority<1>) const HB_AUTO_RETURN
+  (
+    std::forward<T1> (v1) == std::forward<T2> (v2)
+  )
+
+  template <typename T1, typename T2> auto
+  impl (T1&& v1, T2 &&v2, hb_priority<0>) const HB_AUTO_RETURN
+  (
+    std::forward<T2> (v2) == std::forward<T1> (v1)
+  )
+
+  public:
+
+  template <typename T1, typename T2> auto
+  operator () (T1&& v1, T2 &&v2) const HB_AUTO_RETURN
+  (
+    impl (std::forward<T1> (v1),
+	  std::forward<T2> (v2),
+	  hb_prioritize)
+  )
+}
+HB_FUNCOBJ (hb_equal);
+
+struct
+{
+  template <typename T> void
+  operator () (T& a, T& b) const
+  {
+    using std::swap; // allow ADL
+    swap (a, b);
+  }
+}
+HB_FUNCOBJ (hb_swap);
+
+
+template <typename T1, typename T2>
+struct hb_pair_t
+{
+  typedef T1 first_t;
+  typedef T2 second_t;
+  typedef hb_pair_t<T1, T2> pair_t;
+
+  template <typename U1 = T1, typename U2 = T2,
+	    hb_enable_if (std::is_default_constructible<U1>::value &&
+			  std::is_default_constructible<U2>::value)>
+  hb_pair_t () : first (), second () {}
+  hb_pair_t (T1 a, T2 b) : first (std::forward<T1> (a)), second (std::forward<T2> (b)) {}
+
+  template <typename Q1, typename Q2,
+	    hb_enable_if (hb_is_convertible (T1, Q1) &&
+			  hb_is_convertible (T2, Q2))>
+  operator hb_pair_t<Q1, Q2> () { return hb_pair_t<Q1, Q2> (first, second); }
+
+  hb_pair_t<T1, T2> reverse () const
+  { return hb_pair_t<T1, T2> (second, first); }
+
+  bool operator == (const pair_t& o) const { return first == o.first && second == o.second; }
+  bool operator != (const pair_t& o) const { return !(*this == o); }
+  bool operator < (const pair_t& o) const { return first < o.first || (first == o.first && second < o.second); }
+  bool operator >= (const pair_t& o) const { return !(*this < o); }
+  bool operator > (const pair_t& o) const { return first > o.first || (first == o.first && second > o.second); }
+  bool operator <= (const pair_t& o) const { return !(*this > o); }
+
+  static int cmp (const void *pa, const void *pb)
+  {
+    pair_t *a = (pair_t *) pa;
+    pair_t *b = (pair_t *) pb;
+
+    if (a->first < b->first) return -1;
+    if (a->first > b->first) return +1;
+    if (a->second < b->second) return -1;
+    if (a->second > b->second) return +1;
+    return 0;
+  }
+
+  friend void swap (hb_pair_t& a, hb_pair_t& b)
+  {
+    hb_swap (a.first, b.first);
+    hb_swap (a.second, b.second);
+  }
+
+
+  T1 first;
+  T2 second;
+};
+template <typename T1, typename T2> static inline hb_pair_t<T1, T2>
+hb_pair (T1&& a, T2&& b) { return hb_pair_t<T1, T2> (a, b); }
+
+struct
+{
+  template <typename Pair> constexpr typename Pair::first_t
+  operator () (const Pair& pair) const { return pair.first; }
+}
+HB_FUNCOBJ (hb_first);
+
+struct
+{
+  template <typename Pair> constexpr typename Pair::second_t
+  operator () (const Pair& pair) const { return pair.second; }
+}
+HB_FUNCOBJ (hb_second);
+
+/* Note.  In min/max impl, we can use hb_type_identity<T> for second argument.
+ * However, that would silently convert between different-signedness integers.
+ * Instead we accept two different types, such that compiler can err if
+ * comparing integers of different signedness. */
+struct
+{
+  template <typename T, typename T2> constexpr auto
+  operator () (T&& a, T2&& b) const HB_AUTO_RETURN
+  (a <= b ? a : b)
+}
+HB_FUNCOBJ (hb_min);
+struct
+{
+  template <typename T, typename T2> constexpr auto
+  operator () (T&& a, T2&& b) const HB_AUTO_RETURN
+  (a >= b ? a : b)
+}
+HB_FUNCOBJ (hb_max);
+struct
+{
+  template <typename T, typename T2, typename T3> constexpr auto
+  operator () (T&& x, T2&& min, T3&& max) const HB_AUTO_RETURN
+  (hb_min (hb_max (std::forward<T> (x), std::forward<T2> (min)), std::forward<T3> (max)))
+}
+HB_FUNCOBJ (hb_clamp);
+
+/*
+ * Bithacks.
+ */
+
+/* Return the number of 1 bits in v. */
+template <typename T>
+static inline unsigned int
+hb_popcount (T v)
+{
+#if hb_has_builtin(__builtin_popcount)
+  if (sizeof (T) <= sizeof (unsigned int))
+    return __builtin_popcount (v);
+#endif
+
+#if hb_has_builtin(__builtin_popcountl)
+  if (sizeof (T) <= sizeof (unsigned long))
+    return __builtin_popcountl (v);
+#endif
+
+#if hb_has_builtin(__builtin_popcountll)
+  if (sizeof (T) <= sizeof (unsigned long long))
+    return __builtin_popcountll (v);
+#endif
+
+  if (sizeof (T) <= 4)
+  {
+    /* "HACKMEM 169" */
+    uint32_t y;
+    y = (v >> 1) &033333333333;
+    y = v - y - ((y >>1) & 033333333333);
+    return (((y + (y >> 3)) & 030707070707) % 077);
+  }
+
+  if (sizeof (T) == 8)
+  {
+    uint64_t y = (uint64_t) v;
+    y -= ((y >> 1) & 0x5555555555555555ull);
+    y = (y & 0x3333333333333333ull) + (y >> 2 & 0x3333333333333333ull);
+    return ((y + (y >> 4)) & 0xf0f0f0f0f0f0f0full) * 0x101010101010101ull >> 56;
+  }
+
+  if (sizeof (T) == 16)
+  {
+    unsigned int shift = 64;
+    return hb_popcount<uint64_t> ((uint64_t) v) + hb_popcount ((uint64_t) (v >> shift));
+  }
+
+  assert (0);
+  return 0; /* Shut up stupid compiler. */
+}
+
+/* Returns the number of bits needed to store number */
+template <typename T>
+static inline unsigned int
+hb_bit_storage (T v)
+{
+  if (unlikely (!v)) return 0;
+
+#if hb_has_builtin(__builtin_clz)
+  if (sizeof (T) <= sizeof (unsigned int))
+    return sizeof (unsigned int) * 8 - __builtin_clz (v);
+#endif
+
+#if hb_has_builtin(__builtin_clzl)
+  if (sizeof (T) <= sizeof (unsigned long))
+    return sizeof (unsigned long) * 8 - __builtin_clzl (v);
+#endif
+
+#if hb_has_builtin(__builtin_clzll)
+  if (sizeof (T) <= sizeof (unsigned long long))
+    return sizeof (unsigned long long) * 8 - __builtin_clzll (v);
+#endif
+
+#if (defined(_MSC_VER) && _MSC_VER >= 1500) || (defined(__MINGW32__) && (__GNUC__ < 4))
+  if (sizeof (T) <= sizeof (unsigned int))
+  {
+    unsigned long where;
+    _BitScanReverse (&where, v);
+    return 1 + where;
+  }
+# if defined(_WIN64)
+  if (sizeof (T) <= 8)
+  {
+    unsigned long where;
+    _BitScanReverse64 (&where, v);
+    return 1 + where;
+  }
+# endif
+#endif
+
+  if (sizeof (T) <= 4)
+  {
+    /* "bithacks" */
+    const unsigned int b[] = {0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000};
+    const unsigned int S[] = {1, 2, 4, 8, 16};
+    unsigned int r = 0;
+    for (int i = 4; i >= 0; i--)
+      if (v & b[i])
+      {
+	v >>= S[i];
+	r |= S[i];
+      }
+    return r + 1;
+  }
+  if (sizeof (T) <= 8)
+  {
+    /* "bithacks" */
+    const uint64_t b[] = {0x2ULL, 0xCULL, 0xF0ULL, 0xFF00ULL, 0xFFFF0000ULL, 0xFFFFFFFF00000000ULL};
+    const unsigned int S[] = {1, 2, 4, 8, 16, 32};
+    unsigned int r = 0;
+    for (int i = 5; i >= 0; i--)
+      if (v & b[i])
+      {
+	v >>= S[i];
+	r |= S[i];
+      }
+    return r + 1;
+  }
+  if (sizeof (T) == 16)
+  {
+    unsigned int shift = 64;
+    return (v >> shift) ? hb_bit_storage<uint64_t> ((uint64_t) (v >> shift)) + shift :
+			  hb_bit_storage<uint64_t> ((uint64_t) v);
+  }
+
+  assert (0);
+  return 0; /* Shut up stupid compiler. */
+}
+
+/* Returns the number of zero bits in the least significant side of v */
+template <typename T>
+static inline unsigned int
+hb_ctz (T v)
+{
+  if (unlikely (!v)) return 8 * sizeof (T);
+
+#if hb_has_builtin(__builtin_ctz)
+  if (sizeof (T) <= sizeof (unsigned int))
+    return __builtin_ctz (v);
+#endif
+
+#if hb_has_builtin(__builtin_ctzl)
+  if (sizeof (T) <= sizeof (unsigned long))
+    return __builtin_ctzl (v);
+#endif
+
+#if hb_has_builtin(__builtin_ctzll)
+  if (sizeof (T) <= sizeof (unsigned long long))
+    return __builtin_ctzll (v);
+#endif
+
+#if (defined(_MSC_VER) && _MSC_VER >= 1500) || (defined(__MINGW32__) && (__GNUC__ < 4))
+  if (sizeof (T) <= sizeof (unsigned int))
+  {
+    unsigned long where;
+    _BitScanForward (&where, v);
+    return where;
+  }
+# if defined(_WIN64)
+  if (sizeof (T) <= 8)
+  {
+    unsigned long where;
+    _BitScanForward64 (&where, v);
+    return where;
+  }
+# endif
+#endif
+
+  if (sizeof (T) <= 4)
+  {
+    /* "bithacks" */
+    unsigned int c = 32;
+    v &= - (int32_t) v;
+    if (v) c--;
+    if (v & 0x0000FFFF) c -= 16;
+    if (v & 0x00FF00FF) c -= 8;
+    if (v & 0x0F0F0F0F) c -= 4;
+    if (v & 0x33333333) c -= 2;
+    if (v & 0x55555555) c -= 1;
+    return c;
+  }
+  if (sizeof (T) <= 8)
+  {
+    /* "bithacks" */
+    unsigned int c = 64;
+    v &= - (int64_t) (v);
+    if (v) c--;
+    if (v & 0x00000000FFFFFFFFULL) c -= 32;
+    if (v & 0x0000FFFF0000FFFFULL) c -= 16;
+    if (v & 0x00FF00FF00FF00FFULL) c -= 8;
+    if (v & 0x0F0F0F0F0F0F0F0FULL) c -= 4;
+    if (v & 0x3333333333333333ULL) c -= 2;
+    if (v & 0x5555555555555555ULL) c -= 1;
+    return c;
+  }
+  if (sizeof (T) == 16)
+  {
+    unsigned int shift = 64;
+    return (uint64_t) v ? hb_bit_storage<uint64_t> ((uint64_t) v) :
+			  hb_bit_storage<uint64_t> ((uint64_t) (v >> shift)) + shift;
+  }
+
+  assert (0);
+  return 0; /* Shut up stupid compiler. */
+}
+
+
+/*
+ * Tiny stuff.
+ */
+
+/* ASCII tag/character handling */
+static inline bool ISALPHA (unsigned char c)
+{ return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); }
+static inline bool ISALNUM (unsigned char c)
+{ return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9'); }
+static inline bool ISSPACE (unsigned char c)
+{ return c == ' ' || c =='\f'|| c =='\n'|| c =='\r'|| c =='\t'|| c =='\v'; }
+static inline unsigned char TOUPPER (unsigned char c)
+{ return (c >= 'a' && c <= 'z') ? c - 'a' + 'A' : c; }
+static inline unsigned char TOLOWER (unsigned char c)
+{ return (c >= 'A' && c <= 'Z') ? c - 'A' + 'a' : c; }
+static inline bool ISHEX (unsigned char c)
+{ return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'); }
+static inline unsigned char TOHEX (uint8_t c)
+{ return (c & 0xF) <= 9 ? (c & 0xF) + '0' : (c & 0xF) + 'a' - 10; }
+static inline uint8_t FROMHEX (unsigned char c)
+{ return (c >= '0' && c <= '9') ? c - '0' : TOLOWER (c) - 'a' + 10; }
+
+static inline unsigned int DIV_CEIL (const unsigned int a, unsigned int b)
+{ return (a + (b - 1)) / b; }
+
+
+#undef  ARRAY_LENGTH
+template <typename Type, unsigned int n>
+static inline unsigned int ARRAY_LENGTH (const Type (&)[n]) { return n; }
+/* A const version, but does not detect erratically being called on pointers. */
+#define ARRAY_LENGTH_CONST(__array) ((signed int) (sizeof (__array) / sizeof (__array[0])))
+
+
+static inline void *
+hb_memcpy (void *__restrict dst, const void *__restrict src, size_t len)
+{
+  /* It's illegal to pass 0 as size to memcpy. */
+  if (unlikely (!len)) return dst;
+  return memcpy (dst, src, len);
+}
+
+static inline int
+hb_memcmp (const void *a, const void *b, unsigned int len)
+{
+  /* It's illegal to pass NULL to memcmp(), even if len is zero.
+   * So, wrap it.
+   * https://sourceware.org/bugzilla/show_bug.cgi?id=23878 */
+  if (unlikely (!len)) return 0;
+  return memcmp (a, b, len);
+}
+
+static inline void *
+hb_memset (void *s, int c, unsigned int n)
+{
+  /* It's illegal to pass NULL to memset(), even if n is zero. */
+  if (unlikely (!n)) return 0;
+  return memset (s, c, n);
+}
+
+static inline unsigned int
+hb_ceil_to_4 (unsigned int v)
+{
+  return ((v - 1) | 3) + 1;
+}
+
+template <typename T> static inline bool
+hb_in_range (T u, T lo, T hi)
+{
+  static_assert (!std::is_signed<T>::value, "");
+
+  /* The casts below are important as if T is smaller than int,
+   * the subtract results will become a signed int! */
+  return (T)(u - lo) <= (T)(hi - lo);
+}
+template <typename T> static inline bool
+hb_in_ranges (T u, T lo1, T hi1)
+{
+  return hb_in_range (u, lo1, hi1);
+}
+template <typename T, typename ...Ts> static inline bool
+hb_in_ranges (T u, T lo1, T hi1, Ts... ds)
+{
+  return hb_in_range<T> (u, lo1, hi1) || hb_in_ranges<T> (u, ds...);
+}
+
+
+/*
+ * Overflow checking.
+ */
+
+static inline bool
+hb_unsigned_mul_overflows (unsigned int count, unsigned int size, unsigned *result = nullptr)
+{
+#if hb_has_builtin(__builtin_mul_overflow)
+  unsigned stack_result;
+  if (!result)
+    result = &stack_result;
+  return __builtin_mul_overflow (count, size, result);
+#endif
+
+  if (result)
+    *result = count * size;
+  return (size > 0) && (count >= ((unsigned int) -1) / size);
+}
+
+
+/*
+ * Sort and search.
+ */
+
+template <typename K, typename V, typename ...Ts>
+static int
+_hb_cmp_method (const void *pkey, const void *pval, Ts... ds)
+{
+  const K& key = * (const K*) pkey;
+  const V& val = * (const V*) pval;
+
+  return val.cmp (key, ds...);
+}
+
+template <typename V, typename K, typename ...Ts>
+static inline bool
+hb_bsearch_impl (unsigned *pos, /* Out */
+		 const K& key,
+		 V* base, size_t nmemb, size_t stride,
+		 int (*compar)(const void *_key, const void *_item, Ts... _ds),
+		 Ts... ds)
+{
+  /* This is our *only* bsearch implementation. */
+
+  int min = 0, max = (int) nmemb - 1;
+  while (min <= max)
+  {
+    int mid = ((unsigned int) min + (unsigned int) max) / 2;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-align"
+    V* p = (V*) (((const char *) base) + (mid * stride));
+#pragma GCC diagnostic pop
+    int c = compar ((const void *) std::addressof (key), (const void *) p, ds...);
+    if (c < 0)
+      max = mid - 1;
+    else if (c > 0)
+      min = mid + 1;
+    else
+    {
+      *pos = mid;
+      return true;
+    }
+  }
+  *pos = min;
+  return false;
+}
+
+template <typename V, typename K>
+static inline V*
+hb_bsearch (const K& key, V* base,
+	    size_t nmemb, size_t stride = sizeof (V),
+	    int (*compar)(const void *_key, const void *_item) = _hb_cmp_method<K, V>)
+{
+  unsigned pos;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-align"
+  return hb_bsearch_impl (&pos, key, base, nmemb, stride, compar) ?
+	 (V*) (((const char *) base) + (pos * stride)) : nullptr;
+#pragma GCC diagnostic pop
+}
+template <typename V, typename K, typename ...Ts>
+static inline V*
+hb_bsearch (const K& key, V* base,
+	    size_t nmemb, size_t stride,
+	    int (*compar)(const void *_key, const void *_item, Ts... _ds),
+	    Ts... ds)
+{
+  unsigned pos;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-align"
+  return hb_bsearch_impl (&pos, key, base, nmemb, stride, compar, ds...) ?
+	 (V*) (((const char *) base) + (pos * stride)) : nullptr;
+#pragma GCC diagnostic pop
+}
+
+
+/* From https://github.com/noporpoise/sort_r
+   Feb 5, 2019 (c8c65c1e)
+   Modified to support optional argument using templates */
+
+/* Isaac Turner 29 April 2014 Public Domain */
+
+/*
+hb_qsort function to be exported.
+Parameters:
+  base is the array to be sorted
+  nel is the number of elements in the array
+  width is the size in bytes of each element of the array
+  compar is the comparison function
+  arg (optional) is a pointer to be passed to the comparison function
+
+void hb_qsort(void *base, size_t nel, size_t width,
+              int (*compar)(const void *_a, const void *_b, [void *_arg]),
+              [void *arg]);
+*/
+
+#define SORT_R_SWAP(a,b,tmp) ((void) ((tmp) = (a)), (void) ((a) = (b)), (b) = (tmp))
+
+/* swap a and b */
+/* a and b must not be equal! */
+static inline void sort_r_swap(char *__restrict a, char *__restrict b,
+                               size_t w)
+{
+  char tmp, *end = a+w;
+  for(; a < end; a++, b++) { SORT_R_SWAP(*a, *b, tmp); }
+}
+
+/* swap a, b iff a>b */
+/* a and b must not be equal! */
+/* __restrict is same as restrict but better support on old machines */
+template <typename ...Ts>
+static inline int sort_r_cmpswap(char *__restrict a,
+                                 char *__restrict b, size_t w,
+                                 int (*compar)(const void *_a,
+                                               const void *_b,
+                                               Ts... _ds),
+                                 Ts... ds)
+{
+  if(compar(a, b, ds...) > 0) {
+    sort_r_swap(a, b, w);
+    return 1;
+  }
+  return 0;
+}
+
+/*
+Swap consecutive blocks of bytes of size na and nb starting at memory addr ptr,
+with the smallest swap so that the blocks are in the opposite order. Blocks may
+be internally re-ordered e.g.
+  12345ab  ->   ab34512
+  123abc   ->   abc123
+  12abcde  ->   deabc12
+*/
+static inline void sort_r_swap_blocks(char *ptr, size_t na, size_t nb)
+{
+  if(na > 0 && nb > 0) {
+    if(na > nb) { sort_r_swap(ptr, ptr+na, nb); }
+    else { sort_r_swap(ptr, ptr+nb, na); }
+  }
+}
+
+/* Implement recursive quicksort ourselves */
+/* Note: quicksort is not stable, equivalent values may be swapped */
+template <typename ...Ts>
+static inline void sort_r_simple(void *base, size_t nel, size_t w,
+                                 int (*compar)(const void *_a,
+                                               const void *_b,
+                                               Ts... _ds),
+                                 Ts... ds)
+{
+  char *b = (char *)base, *end = b + nel*w;
+
+  /* for(size_t i=0; i<nel; i++) {printf("%4i", *(int*)(b + i*sizeof(int)));}
+  printf("\n"); */
+
+  if(nel < 10) {
+    /* Insertion sort for arbitrarily small inputs */
+    char *pi, *pj;
+    for(pi = b+w; pi < end; pi += w) {
+      for(pj = pi; pj > b && sort_r_cmpswap(pj-w,pj,w,compar,ds...); pj -= w) {}
+    }
+  }
+  else
+  {
+    /* nel > 9; Quicksort */
+
+    int cmp;
+    char *pl, *ple, *pr, *pre, *pivot;
+    char *last = b+w*(nel-1), *tmp;
+
+    /*
+    Use median of second, middle and second-last items as pivot.
+    First and last may have been swapped with pivot and therefore be extreme
+    */
+    char *l[3];
+    l[0] = b + w;
+    l[1] = b+w*(nel/2);
+    l[2] = last - w;
+
+    /* printf("pivots: %i, %i, %i\n", *(int*)l[0], *(int*)l[1], *(int*)l[2]); */
+
+    if(compar(l[0],l[1],ds...) > 0) { SORT_R_SWAP(l[0], l[1], tmp); }
+    if(compar(l[1],l[2],ds...) > 0) {
+      SORT_R_SWAP(l[1], l[2], tmp);
+      if(compar(l[0],l[1],ds...) > 0) { SORT_R_SWAP(l[0], l[1], tmp); }
+    }
+
+    /* swap mid value (l[1]), and last element to put pivot as last element */
+    if(l[1] != last) { sort_r_swap(l[1], last, w); }
+
+    /*
+    pl is the next item on the left to be compared to the pivot
+    pr is the last item on the right that was compared to the pivot
+    ple is the left position to put the next item that equals the pivot
+    ple is the last right position where we put an item that equals the pivot
+                                           v- end (beyond the array)
+      EEEEEELLLLLLLLuuuuuuuuGGGGGGGEEEEEEEE.
+      ^- b  ^- ple  ^- pl   ^- pr  ^- pre ^- last (where the pivot is)
+    Pivot comparison key:
+      E = equal, L = less than, u = unknown, G = greater than, E = equal
+    */
+    pivot = last;
+    ple = pl = b;
+    pre = pr = last;
+
+    /*
+    Strategy:
+    Loop into the list from the left and right at the same time to find:
+    - an item on the left that is greater than the pivot
+    - an item on the right that is less than the pivot
+    Once found, they are swapped and the loop continues.
+    Meanwhile items that are equal to the pivot are moved to the edges of the
+    array.
+    */
+    while(pl < pr) {
+      /* Move left hand items which are equal to the pivot to the far left.
+         break when we find an item that is greater than the pivot */
+      for(; pl < pr; pl += w) {
+        cmp = compar(pl, pivot, ds...);
+        if(cmp > 0) { break; }
+        else if(cmp == 0) {
+          if(ple < pl) { sort_r_swap(ple, pl, w); }
+          ple += w;
+        }
+      }
+      /* break if last batch of left hand items were equal to pivot */
+      if(pl >= pr) { break; }
+      /* Move right hand items which are equal to the pivot to the far right.
+         break when we find an item that is less than the pivot */
+      for(; pl < pr; ) {
+        pr -= w; /* Move right pointer onto an unprocessed item */
+        cmp = compar(pr, pivot, ds...);
+        if(cmp == 0) {
+          pre -= w;
+          if(pr < pre) { sort_r_swap(pr, pre, w); }
+        }
+        else if(cmp < 0) {
+          if(pl < pr) { sort_r_swap(pl, pr, w); }
+          pl += w;
+          break;
+        }
+      }
+    }
+
+    pl = pr; /* pr may have gone below pl */
+
+    /*
+    Now we need to go from: EEELLLGGGGEEEE
+                        to: LLLEEEEEEEGGGG
+    Pivot comparison key:
+      E = equal, L = less than, u = unknown, G = greater than, E = equal
+    */
+    sort_r_swap_blocks(b, ple-b, pl-ple);
+    sort_r_swap_blocks(pr, pre-pr, end-pre);
+
+    /*for(size_t i=0; i<nel; i++) {printf("%4i", *(int*)(b + i*sizeof(int)));}
+    printf("\n");*/
+
+    sort_r_simple(b, (pl-ple)/w, w, compar, ds...);
+    sort_r_simple(end-(pre-pr), (pre-pr)/w, w, compar, ds...);
+  }
+}
+
+static inline void
+hb_qsort (void *base, size_t nel, size_t width,
+	  int (*compar)(const void *_a, const void *_b))
+{
+#if defined(__OPTIMIZE_SIZE__) && !defined(HB_USE_INTERNAL_QSORT)
+  qsort (base, nel, width, compar);
+#else
+  sort_r_simple (base, nel, width, compar);
+#endif
+}
+
+static inline void
+hb_qsort (void *base, size_t nel, size_t width,
+	  int (*compar)(const void *_a, const void *_b, void *_arg),
+	  void *arg)
+{
+#ifdef HAVE_GNU_QSORT_R
+  qsort_r (base, nel, width, compar, arg);
+#else
+  sort_r_simple (base, nel, width, compar, arg);
+#endif
+}
+
+
+template <typename T, typename T2, typename T3 = int> static inline void
+hb_stable_sort (T *array, unsigned int len, int(*compar)(const T2 *, const T2 *), T3 *array2 = nullptr)
+{
+  static_assert (hb_is_trivially_copy_assignable (T), "");
+  static_assert (hb_is_trivially_copy_assignable (T3), "");
+
+  for (unsigned int i = 1; i < len; i++)
+  {
+    unsigned int j = i;
+    while (j && compar (&array[j - 1], &array[i]) > 0)
+      j--;
+    if (i == j)
+      continue;
+    /* Move item i to occupy place for item j, shift what's in between. */
+    {
+      T t = array[i];
+      memmove (&array[j + 1], &array[j], (i - j) * sizeof (T));
+      array[j] = t;
+    }
+    if (array2)
+    {
+      T3 t = array2[i];
+      memmove (&array2[j + 1], &array2[j], (i - j) * sizeof (T3));
+      array2[j] = t;
+    }
+  }
+}
+
+static inline hb_bool_t
+hb_codepoint_parse (const char *s, unsigned int len, int base, hb_codepoint_t *out)
+{
+  unsigned int v;
+  const char *p = s;
+  const char *end = p + len;
+  if (unlikely (!hb_parse_uint (&p, end, &v, true/* whole buffer */, base)))
+    return false;
+
+  *out = v;
+  return true;
+}
+
+
+/* Operators. */
+
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (a & b)
+}
+HB_FUNCOBJ (hb_bitwise_and);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (a | b)
+}
+HB_FUNCOBJ (hb_bitwise_or);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (a ^ b)
+}
+HB_FUNCOBJ (hb_bitwise_xor);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (~a & b)
+}
+HB_FUNCOBJ (hb_bitwise_lt);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (a & ~b)
+}
+HB_FUNCOBJ (hb_bitwise_gt); // aka sub
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (~a | b)
+}
+HB_FUNCOBJ (hb_bitwise_le);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T> constexpr auto
+  operator () (const T &a, const T &b) const HB_AUTO_RETURN (a | ~b)
+}
+HB_FUNCOBJ (hb_bitwise_ge);
+struct
+{
+  template <typename T> constexpr auto
+  operator () (const T &a) const HB_AUTO_RETURN (~a)
+}
+HB_FUNCOBJ (hb_bitwise_neg);
+
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (a + b)
+}
+HB_FUNCOBJ (hb_add);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (a - b)
+}
+HB_FUNCOBJ (hb_sub);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (b - a)
+}
+HB_FUNCOBJ (hb_rsub);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (a * b)
+}
+HB_FUNCOBJ (hb_mul);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (a / b)
+}
+HB_FUNCOBJ (hb_div);
+struct
+{ HB_PARTIALIZE(2);
+  template <typename T, typename T2> constexpr auto
+  operator () (const T &a, const T2 &b) const HB_AUTO_RETURN (a % b)
+}
+HB_FUNCOBJ (hb_mod);
+struct
+{
+  template <typename T> constexpr auto
+  operator () (const T &a) const HB_AUTO_RETURN (+a)
+}
+HB_FUNCOBJ (hb_pos);
+struct
+{
+  template <typename T> constexpr auto
+  operator () (const T &a) const HB_AUTO_RETURN (-a)
+}
+HB_FUNCOBJ (hb_neg);
+struct
+{
+  template <typename T> constexpr auto
+  operator () (T &a) const HB_AUTO_RETURN (++a)
+}
+HB_FUNCOBJ (hb_inc);
+struct
+{
+  template <typename T> constexpr auto
+  operator () (T &a) const HB_AUTO_RETURN (--a)
+}
+HB_FUNCOBJ (hb_dec);
+
+
+/* Adapted from kurbo implementation with extra parameters added,
+ * and finding for a particular range instead of 0.
+ *
+ * For documentation and implementation see:
+ *
+ * [ITP method]: https://en.wikipedia.org/wiki/ITP_Method
+ * [An Enhancement of the Bisection Method Average Performance Preserving Minmax Optimality]: https://dl.acm.org/doi/10.1145/3423597
+ * https://docs.rs/kurbo/0.8.1/kurbo/common/fn.solve_itp.html
+ * https://github.com/linebender/kurbo/blob/fd839c25ea0c98576c7ce5789305822675a89938/src/common.rs#L162-L248
+ */
+template <typename func_t>
+double solve_itp (func_t f,
+		  double a, double b,
+		  double epsilon,
+		  double min_y, double max_y,
+		  double &ya, double &yb, double &y)
+{
+  unsigned n1_2 = (unsigned) (hb_max (ceil (log2 ((b - a) / epsilon)) - 1.0, 0.0));
+  const unsigned n0 = 1; // Hardwired
+  const double k1 = 0.2 / (b - a); // Hardwired.
+  unsigned nmax = n0 + n1_2;
+  double scaled_epsilon = epsilon * double (1llu << nmax);
+  double _2_epsilon = 2.0 * epsilon;
+  while (b - a > _2_epsilon)
+  {
+    double x1_2 = 0.5 * (a + b);
+    double r = scaled_epsilon - 0.5 * (b - a);
+    double xf = (yb * a - ya * b) / (yb - ya);
+    double sigma = x1_2 - xf;
+    double b_a = b - a;
+    // This has k2 = 2 hardwired for efficiency.
+    double b_a_k2 = b_a * b_a;
+    double delta = k1 * b_a_k2;
+    int sigma_sign = sigma >= 0 ? +1 : -1;
+    double xt = delta <= fabs (x1_2 - xf) ? xf + delta * sigma_sign : x1_2;
+    double xitp = fabs (xt - x1_2) <= r ? xt : x1_2 - r * sigma_sign;
+    double yitp = f (xitp);
+    if (yitp > max_y)
+    {
+      b = xitp;
+      yb = yitp;
+    }
+    else if (yitp < min_y)
+    {
+      a = xitp;
+      ya = yitp;
+    }
+    else
+    {
+      y = yitp;
+      return xitp;
+    }
+    scaled_epsilon *= 0.5;
+  }
+  return 0.5 * (a + b);
+}
+
+
+#endif /* HB_ALGS_HH */