don't copy values in asn1parse if not necessary

Author: tomato42

tlslite/utils/asn1parser.py

@@ -85,9 +85,9 @@ def getChildCount(self):
         while True:
             if p.getRemainingLength() == 0:
                 break
-            p.get(1)  # skip Type
+            p.skip_bytes(1)  # skip Type
             length = self._getASN1Length(p)
-            p.getFixBytes(length)  # skip value
+            p.skip_bytes(length)  # skip value
             count += 1
         return count
 
@@ -104,9 +104,9 @@ def getChildBytes(self, which):
         p = Parser(self.value)
         for _ in range(which+1):
             markIndex = p.index
-            p.get(1) #skip Type
+            p.skip_bytes(1)  # skip Type
             length = self._getASN1Length(p)
-            p.getFixBytes(length)
+            p.skip_bytes(length)
         return p.bytes[markIndex : p.index]
 
     @staticmethod

tlslite/utils/codec.py

@@ -324,6 +324,12 @@ def getFixBytes(self, lengthBytes):
         self.index += lengthBytes
         return bytes
 
+    def skip_bytes(self, length):
+        """Move the internal pointer ahead length bytes."""
+        if self.index + length > len(self.bytes):
+            raise DecodeError("Read past end of buffer")
+        self.index += length
+
     def getVarBytes(self, lengthLength):
         """
         Read a variable length string with a fixed length.