endianness

--HG--
branch : pmacs2

mode/hex.py

@@ -13,6 +13,12 @@ class Hex(mode.Fundamental):
     lmargin  = 12
     rmargin  = 18
     _ctrans  = ['.'] * 256
+    byteorder = 'native'
+    byteorders = {
+        'native': '=',
+        'little': '<',
+        'big':    '>',
+    }
     cgreen   = color.build('green', 'default', 'bold')
     ccyan    = color.build('cyan', 'default', 'bold')
     ccursor  = color.build('default', 'default', 'bold', 'reverse')
@@ -103,6 +109,8 @@ class Hex(mode.Fundamental):
         self.add_action_and_bindings(ShowX86Instruction(), ('C-c x',))
         self.add_action_and_bindings(GotoAddress(), ('C-c M-g',))
 
+        self.add_action(HexSetByteOrder())
+
         # create all the insert actions for the basic text input
         for c in string.letters + string.digits + string.punctuation:
             if c in string.hexdigits:
@@ -152,8 +160,20 @@ class Hex(mode.Fundamental):
         return s
     def read_struct(self, cy, ix, fmt, size):
         s = self.read_data(cy, ix, size)
+        fmt = '%s%s' % (self.byteorders[self.byteorder], fmt)
         return struct.unpack(fmt, s)[0]
 
+class HexSetByteOrder(Method):
+    '''Sets the byte-order to use to 'little', 'big', or 'native' order'''
+    args = [Argument("byteorder", type=type(''), prompt="Byte order: ")]
+    def _execute(self, w, **vargs):
+        order = vargs['byteorder']
+        if order in w.mode.byteorders:
+            w.mode.byteorder = order
+            w.set_error("byte-order set to %r" % w.mode.byteorder)
+        else:
+            w.set_error("invalid ordering %r (use 'little', 'big', or 'native'")
+
 class HexForward(Method):
     def _execute(self, w, **vargs):
         w.forward()
@@ -212,7 +232,8 @@ class HexRead(Method):
             if v is None:
                 w.set_error("not enough data to read %s" % self.type_)
             else:
-                w.set_error("%s at 0x%08x: %r" % (self.type_, addr, v))
+                end = '%s-endian' % w.mode.byteorder
+                w.set_error("%s %s at 0x%08x: %r" % (end, self.type_, addr, v))
         except Exception, e:
             w.set_error("%s could not be read at 0x%08x" % (self.type_, addr))
 class HexReadAligned(HexRead):