Implementation of a multiple replace class based on Dict substitutions. Very fast for large dictionnaries.

src/calibre/utils/mreplace.py

@@ -0,0 +1,32 @@
+#multiple replace from dictionnary : http://code.activestate.com/recipes/81330/
+__license__   = 'GPL v3'
+__copyright__ = '2010, sengian <sengian1 @ gmail.com>'
+__docformat__ = 'restructuredtext en'
+
+import re
+from UserDict import UserDict
+
+class MReplace(UserDict):
+    def __init__(self, dict = None):
+        UserDict.__init__(self, dict)
+        self.re = None
+        self.regex = None
+        self.compile_regex()
+
+    def compile_regex(self): 
+        if len(self.data) > 0:
+            keys = sorted(self.data.keys(), key=len)
+            keys.reverse()
+            tmp = "(%s)" % "|".join([re.escape(item) for item in keys])
+            if self.re != tmp:
+                self.re = tmp
+                self.regex = re.compile(self.re)
+
+    def __call__(self, mo): 
+        return self[mo.string[mo.start():mo.end()]]
+
+    def mreplace(self, text): 
+        #Replace without regex compile
+        if len(self.data) < 1 or self.re is None:
+            return text
+        return self.regex.sub(self, text)