From 1ed2582247129fca2a907d4e986a0a2020be58bd Mon Sep 17 00:00:00 2001
From: Mike Naberezny <mike@naberezny.com>
Date: Sat, 4 Apr 2009 19:40:22 -0700
Subject: [PATCH] Changed ObservableMemory interface. (offe)

---
 src/py65/memory.py | 63 +++++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

diff --git a/src/py65/memory.py b/src/py65/memory.py
index 3cf42b1..e5f42df 100644
--- a/src/py65/memory.py
+++ b/src/py65/memory.py
@@ -1,44 +1,45 @@
-class ObservableMemory:
-    READ  = 0
-    WRITE = 1
-    RW    = 2
+from collections import defaultdict
 
+class ObservableMemory:
     def __init__(self, subject=None):
         if subject is None:
-            subject = []
-            for addr in range(0x0000, 0xFFFF+1):
-                subject.insert(addr, 0x00)
+            subject = 0x10000 * [0x00]
         self._subject = subject
-        self._observers = []
+
+        self._listeners = defaultdict(list)
+        self._providers = defaultdict(list)        
 
     def __setitem__(self, address, value):
-        for oper, addr_range, callback in self._observers:
-            if address in addr_range:
-                if (oper == self.RW) or (oper == self.WRITE):
-                    result = callback(self.WRITE, address, value)        
-                    if result is not None:
-                        value = result
-        self._subject[address] = value
+        callbacks = self._listeners[address]
+        for callback in callbacks:
+            result = callback(address, value)
+            if result is not None:
+                value = result
 
     def __getitem__(self, address):
-        for oper, addr_range, callback in self._observers:
-            if address in addr_range:
-                if (oper == self.RW) or (oper == self.READ):
-                    result = callback(self.READ, address, None)
-                    if result is not None:
-                        return result
-        return self._subject[address]
+        callbacks = self._providers[address]
+        final_result = None
+
+        for callback in callbacks:
+            result = callback(address)
+            if result is not None:
+                final_result = result
+
+        if final_result:
+            return final_result
+        else:
+            return self._subject[address]
     
     def __getattr__(self, address):
         return getattr(self._subject, address)
 
-    def subscribe(self, operation, addr_range, callback):
-        if operation not in (self.READ, self.WRITE, self.RW):
-            raise ValueError("Unsupported operation")
-        self._observers.append([operation, addr_range, callback])
+    def register_provider(self, address_range, callback):
+        for address in address_range:
+            self._providers[address].append(callback)
 
-    def dma_read(self, key):
-        return self._subject[key]
-    
-    def dma_write(self, key, value):
-        self._subject[key] = value
+    def register_listener(self, address_range, callback):
+        for address in address_range:
+            self._listeners[address].append(callback)
+
+    def write(self, start_address, bytes):
+        self._subject[start_address:start_address+len(bytes)] = bytes