Source Code for Module envi.util

 1   
 2 -class CopyOnWrite: 
 3      """ 
 4      A memory object wrapper you can use to do copy-on-write memory 
 5      use and be able to simply reset it. 
 6      """ 
 7   
 8 -    def __init__(self, memobj): 
 9          self.writes = [] 
10          self.memobj = memobj 
11   
12 -    def reset(self): 
13          """ 
14          Throw away the current writes and be fresh... 
15          """ 
16          self.writes = [] 
17   
18 -    def writeMemory(self, va, bytes): 
19          # FIXME for now, allow any writes, but soon, do more 
20          self.writes.append((va,va+len(bytes),bytes)) 
21   
22 -    def readMemory(self, va, size): 
23          for memva,nextva,bytes in self.writes: 
24              if memva <= va and va+size <= nextva: 
25                  offset = va-memva 
26                  return bytes[offset:offset+size] 
27          return self.memobj.readMemory(va, size) 
28