From e05b522827f133335654619fe8d6c196d145dd45 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Wed, 1 Jan 2020 11:07:00 +1100
Subject: [PATCH] endian: add `readbe` to complement `readle` and `readhe`

---
 endian.hpp | 76 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 41 insertions(+), 35 deletions(-)

diff --git a/endian.hpp b/endian.hpp
index 405bc557..c16ba65b 100644
--- a/endian.hpp
+++ b/endian.hpp
@@ -73,41 +73,6 @@ namespace cruft {
     }
 
 
-    template <
-        typename T,
-        typename = std::enable_if_t<
-            std::is_integral_v<T>
-        >
-    >
-    T readle (const void *_data)
-    {
-        auto data = reinterpret_cast<const uint8_t*> (_data);
-
-        T value = 0;
-
-        for (size_t i = 0; i < sizeof (value); ++i)
-            value |= T{data[i]} << (i * 8);
-
-        return value;
-    }
-
-
-    /// read bytes from a supplied data pointer and return an integer using
-    /// host endian layout.
-    template <
-        typename T,
-        typename = std::enable_if_t<
-            std::is_integral_v<T>
-        >
-    >
-    T readhe (const std::uint8_t *data)
-    {
-        std::aligned_union_t <sizeof (T), T> buffer;
-        memcpy (reinterpret_cast<char *> (&buffer), data, sizeof (T));
-        return *reinterpret_cast<const T*> (&buffer);
-    }
-
-
     //-------------------------------------------------------------------------
 #if defined(WORDS_BIGENDIAN)
     template <typename T> constexpr T hton (T v) { return v; }
@@ -132,6 +97,47 @@ namespace cruft {
     template <typename T> T btol (T t) { return bswap (t); }
     template <typename T> T ltob (T t) { return bswap (t); }
 
+
+    /// read bytes from a supplied data pointer and return an integer using
+    /// host endian layout.
+    template <
+        typename T,
+        typename = std::enable_if_t<
+            std::is_integral_v<T>
+        >
+    >
+    T readhe (u08 const *data)
+    {
+        std::aligned_union_t <sizeof (T), T> buffer;
+        memcpy (reinterpret_cast<char *> (&buffer), data, sizeof (T));
+        return *reinterpret_cast<const T*> (&buffer);
+    }
+
+
+    template <
+        typename T,
+        typename = std::enable_if_t<
+            std::is_integral_v<T>
+        >
+    >
+    T readle (u08 const* ptr)
+    {
+        return ltoh (readhe<T> (ptr));
+    }
+
+
+    template <
+        typename T,
+        typename = std::enable_if_t<
+            std::is_integral_v<T>
+        >
+    >
+    T readbe (u08 const* ptr)
+    {
+        return btoh (readhe<T> (ptr));
+    }
+
+
     namespace endian {
         //---------------------------------------------------------------------
         // Uses the TIFF header values. Just because. Don't rely on this.