Correctly parse CIP BOOL in all Python version

Author: pjkundert

server/enip/parser.py

@@ -143,10 +143,7 @@ class words( words_base, cpppo.state ):
 # 
 # USINT		-- Parse an 8-bit EtherNet/IP unsigned int 
 # USINT.produce	--   and convert a value back to a 8-bit EtherNet/IP unsigned int
-# INT		-- Parse a 16-bit EtherNet/IP   signed int 
-# UINT		-- Parse a 16-bit EtherNet/IP unsigned int 
-# DINT		-- Parse a 32-bit EtherNet/IP   signed int 
-# UDINT		-- Parse a 32-bit EtherNet/IP unsigned int 
+# ...
 # 
 #     You must provide either a name or a context; if you provide neither, then both default to the
 # name of the class.  An instance of any of these types "is" a parser state machine, and has a
@@ -172,10 +169,29 @@ def produce( cls, value ):
         return struct.pack( cls.struct_format, value )
 
 class BOOL( TYPE ):
+    """An EtherNet/IP BOOL; 8-bit boolean
+
+    Surprisingly, the struct '?' format does *not* work as you might expect.  the value b'\x00'
+    converts to False reliably.  However, only b'\x01' converts to True reliably; any other value
+    may or may not result in True, depending on the version of Python being used!  Python 2.7/3.9
+    return False for eg. b'\x02', while Pypy 3.6.9 return True.
+
+    Therefore, we will convert octets to unsigned integer via 'B', and then post-process to bool.
+    """
     tag_type                    = 0x00c1 # 193
-    struct_format               = '?'
+    struct_format               = 'B' # do not use '?'!
     struct_calcsize             = struct.calcsize( struct_format )
 
+    def terminate( self, exception, machine=None, path=None, data=None ):
+        super( BOOL, self ).terminate( exception=exception, machine=machine, path=path, data=data )
+        if exception is not None:
+            return
+        ours			= self.context( path=path )
+        if cpppo.is_listlike( data[ours] ):
+            data[ours]		= list( map( bool, data[ours] ))
+        else:
+            data[ours]		= bool( data[ours] )
+
     @classmethod
     def produce( cls, value ):
         """Historically, a 0xFF has been used to represent an EtherNet/IP CIP BOOL Truthy value."""

server/enip_test.py

@@ -301,6 +301,41 @@ def test_enip_TYPES_numeric():
     assert data.typed_data.data == [2**63]
 
 
+def test_enip_TYPES_bool():
+    """Disappointingly, the struct '?' format in Python2 """
+    pkt				= b'\x00\x01\x02\x04\x08\x10\x20\x40\x80\xff\x00'
+    pkt_truths			= [ False, True, True, True, True, True, True, True, True, True, False ]
+    data			= cpppo.dotdict()
+    source			= cpppo.chainable( pkt )
+    with enip.BOOL() as machine:
+        for i,(m,s) in enumerate( machine.run( source=source, data=data )):
+            log.info( "%s #%3d -> %10.10s; next byte %3d: %-10.10r: %r", m.name_centered(),
+                      i, s, source.sent, source.peek(), data )
+        assert i == 0
+    assert data.BOOL == False
+
+    data			= cpppo.dotdict()
+    with enip.BOOL() as machine:
+        for i,(m,s) in enumerate( machine.run( source=source, data=data )):
+            log.info( "%s #%3d -> %10.10s; next byte %3d: %-10.10r: %r", m.name_centered(),
+                      i, s, source.sent, source.peek(), data )
+        assert i == 0
+    assert data.BOOL == True
+
+    data			= cpppo.dotdict()
+    source			= cpppo.chainable( pkt )
+    with enip.typed_data( tag_type=enip.BOOL.tag_type, terminal=True ) as machine:
+        for i,(m,s) in enumerate( machine.run( source=source, data=data )):
+            log.info( "%s #%3d -> %10.10s; next byte %3d: %-10.10r: %r", m.name_centered(),
+                      i, s, source.sent, source.peek(), data )
+        assert i == 48
+    assert data.typed_data.data == pkt_truths
+
+    pkt_produced		= b'\x00\xff\xff\xff\xff\xff\xff\xff\xff\x00'
+    enip.typed_data.produce( {'data': pkt_truths}, tag_type=enip.BOOL.tag_type ) == pkt_produced
+
+    
+
 # pkt4
 # "4","0.000863000","192.168.222.128","10.220.104.180","ENIP","82","Register Session (Req)"
 rss_004_request 		= bytes(bytearray([

version.py

@@ -1,2 +1,2 @@
-__version_info__		= ( 4, 3, 2 )
+__version_info__		= ( 4, 3, 4 )
 __version__			= '.'.join( map( str, __version_info__ ))