[glib] GDBusMessage: simplify byteswapping

[Ryan Lortie <desrt src gnome org>]

commit d108ada4b98cb50fb1517f55c4f09acdaf3de471
Author: Ryan Lortie <desrt desrt ca>
Date:   Fri Jul 4 14:59:17 2014 -0400

    GDBusMessage: simplify byteswapping
    
    Remove some duplication by simplifying our byteswap checks.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=732754

 gio/gdbusmessage.c |  108 +++++++++++++++++-----------------------------------
 1 files changed, 35 insertions(+), 73 deletions(-)
---
diff --git a/gio/gdbusmessage.c b/gio/gdbusmessage.c
index dade2b9..b41f649 100644
--- a/gio/gdbusmessage.c
+++ b/gio/gdbusmessage.c
@@ -64,6 +64,16 @@ struct _GMemoryBuffer
   GDataStreamByteOrder byte_order;
 };
 
+static gboolean
+g_memory_buffer_is_byteswapped (GMemoryBuffer *mbuf)
+{
+#if G_BYTE_ORDER == G_LITTLE_ENDIAN
+  return mbuf->byte_order == G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN;
+#else
+  return mbuf->byte_order == G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN;
+#endif
+}
+
 static guchar
 g_memory_buffer_read_byte (GMemoryBuffer  *mbuf)
 {
@@ -85,18 +95,10 @@ g_memory_buffer_read_int16 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 2);
   mbuf->pos += 2;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GINT16_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GINT16_FROM_LE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-    default:
-      break;
-    }
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT16_SWAP_LE_BE (v);
+
   return v;
 }
 
@@ -113,18 +115,10 @@ g_memory_buffer_read_uint16 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 2);
   mbuf->pos += 2;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GINT16_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GINT16_FROM_LE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-    default:
-      break;
-    }
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT16_SWAP_LE_BE (v);
+
   return v;
 }
 
@@ -141,18 +135,10 @@ g_memory_buffer_read_int32 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 4);
   mbuf->pos += 4;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GINT32_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GINT32_FROM_LE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-    default:
-      break;
-    }
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT32_SWAP_LE_BE (v);
+
   return v;
 }
 
@@ -169,18 +155,10 @@ g_memory_buffer_read_uint32 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 4);
   mbuf->pos += 4;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GUINT32_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GUINT32_FROM_LE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-    default:
-      break;
-    }
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT32_SWAP_LE_BE (v);
+
   return v;
 }
 
@@ -197,18 +175,10 @@ g_memory_buffer_read_int64 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 8);
   mbuf->pos += 8;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GINT64_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GINT64_FROM_LE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-    default:
-      break;
-    }
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT64_SWAP_LE_BE (v);
+
   return v;
 }
 
@@ -225,19 +195,11 @@ g_memory_buffer_read_uint64 (GMemoryBuffer  *mbuf)
 
   memcpy (&v, mbuf->data + mbuf->pos, 8);
   mbuf->pos += 8;
-  switch (mbuf->byte_order)
-    {
-    case G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN:
-      v = GUINT64_FROM_BE (v);
-      break;
-    case G_DATA_STREAM_BYTE_ORDER_LITTLE_ENDIAN:
-      v = GUINT64_FROM_LE (v);
-      break;
-       case G_DATA_STREAM_BYTE_ORDER_HOST_ENDIAN:
-       default:
-         break;
-       }
-      return v;
+
+  if (g_memory_buffer_is_byteswapped (mbuf))
+    v = GUINT64_SWAP_LE_BE (v);
+
+  return v;
 }
 
 #define MIN_ARRAY_SIZE  128