Add the operation type to the mutator types; add a dictionary append.

Knowing which type of mutators are in use helps to favour certain
kinds of operations. In particular, if you start with a small dictionary
of words and wish to generate longer strings, using just an option
that appends to the dictionary is useful.

The dictionary append operation has been added which allows the
values from the dictionary to be strung together in increasingly
longer sequences. It doesn't offer the option of appending multiple
values from the dictionary so the operation my end up in a local
minima, but such mutators could be added in the future.

pythonfuzz/corpus.py

@@ -78,7 +78,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorRemoveRange(Mutator):
     name = 'Remove a range of bytes'
-    types = set(['byte'])
+    types = set(['byte', 'remove'])
 
     def mutate(self, res):
         if len(res) < 2:
@@ -95,7 +95,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorInsertBytes(Mutator):
     name = 'Insert a range of random bytes'
-    types = set(['byte'])
+    types = set(['byte', 'insert'])
 
     def mutate(self, res):
         pos = self._rand(len(res) + 1)
@@ -111,7 +111,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorDuplicateBytes(Mutator):
     name = 'Duplicate a range of bytes'
-    types = set(['byte'])
+    types = set(['byte', 'duplicate'])
 
     def mutate(self, res):
         if len(res) <= 1:
@@ -134,7 +134,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorCopyBytes(Mutator):
     name = 'Copy a range of bytes'
-    types = set(['byte'])
+    types = set(['byte', 'copy'])
 
     def mutate(self, res):
         if len(res) <= 1:
@@ -151,7 +151,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorBitFlip(Mutator):
     name = 'Bit flip'
-    types = set(['bit'])
+    types = set(['bit', 'replace'])
 
     def mutate(self, res):
         if len(res) == 0:
@@ -164,7 +164,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorRandomiseByte(Mutator):
     name = 'Set a byte to a random value.'
-    types = set(['byte'])
+    types = set(['byte', 'replace'])
 
     def mutate(self, res):
         if len(res) == 0:
@@ -177,7 +177,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorSwapBytes(Mutator):
     name = 'Swap 2 bytes'
-    types = set(['byte'])
+    types = set(['byte', 'swap'])
 
     def mutate(self, res):
         if len(res) <= 1:
@@ -193,7 +193,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorAddSubByte(Mutator):
     name = 'Add/subtract from a byte'
-    types = set(['byte'])
+    types = set(['byte', 'addsub'])
 
     def mutate(self, res):
         if len(res) == 0:
@@ -210,7 +210,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorAddSubShort(Mutator):
     name = 'Add/subtract from a uint16'
-    types = set(['short'])
+    types = set(['short', 'addsub'])
 
     def mutate(self, res):
         if len(res) < 2:
@@ -232,7 +232,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorAddSubLong(Mutator):
     name = 'Add/subtract from a uint32'
-    types = set(['long'])
+    types = set(['long', 'addsub'])
 
     def mutate(self, res):
         if len(res) < 4:
@@ -254,7 +254,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorAddSubLongLong(Mutator):
     name = 'Add/subtract from a uint64'
-    types = set(['longlong'])
+    types = set(['longlong', 'addsub'])
 
     def mutate(self, res):
         if len(res) < 8:
@@ -276,7 +276,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorReplaceByte(Mutator):
     name = 'Replace a byte with an interesting value'
-    types = set(['byte'])
+    types = set(['byte', 'replace'])
 
     def mutate(self, res):
         if len(res) == 0:
@@ -289,7 +289,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorReplaceShort(Mutator):
     name = 'Replace an uint16 with an interesting value'
-    types = set(['short'])
+    types = set(['short', 'replace'])
 
     def mutate(self, res):
         if len(res) < 2:
@@ -309,7 +309,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorReplaceLong(Mutator):
     name = 'Replace an uint32 with an interesting value'
-    types = set(['long'])
+    types = set(['long', 'replace'])
 
     def mutate(self, res):
         if len(res) < 4:
@@ -329,7 +329,7 @@ def mutate(self, res):
 @register_mutator
 class MutatorReplaceDigit(Mutator):
     name = 'Replace an ascii digit with another digit'
-    types = set(['byte', 'ascii'])
+    types = set(['byte', 'ascii', 'replace'])
 
     def mutate(self, res):
         digits = []
@@ -365,6 +365,19 @@ def mutate(self, res):
         return res
 
 
+@register_mutator
+class MutatorDictionaryWordAppend(Mutator):
+    name = 'Append a word'
+    types = set(['dictionary', 'append'])
+
+    def mutate(self, res):
+        word = self.corpus._dict.get_word()
+        if not word:
+            return None
+        res.extend(word)
+        return res
+
+
 class CorpusError(Exception):
     pass