1 files changed, 90 insertions, 0 deletions
diff --git a/demo/utils.py b/demo/utils.py
new file mode 100644
index 0000000..03b1b3a
--- /dev/null
+++ b/demo/utils.py
@@ -0,0 +1,90 @@
+import time 
+import sys
+
+PY_MAJOR_VERSION = sys.version_info[0]
+
+if PY_MAJOR_VERSION > 2:
+    NULL_CHAR = 0
+else:
+    NULL_CHAR = '\0'
+
+def raise_error(error, message):
+    # I have to exec() this code because the Python 2 syntax is invalid
+    # under Python 3 and vice-versa.
+    s = "raise "
+    s += "error, message" if (PY_MAJOR_VERSION == 2) else "error(message)" 
+        
+    exec(s)
+
+
+def say(s):
+    """Prints a timestamped, self-identified message"""
+    who = sys.argv[0]
+    if who.endswith(".py"):
+        who = who[:-3]
+        
+    s = "%s@%1.6f: %s" % (who, time.time(), s)
+    print (s)
+
+
+def write_to_memory(mapfile, s):
+    """Writes the string s to the mapfile"""
+    say("writing %s " % s)
+    mapfile.seek(0)
+    # I append a trailing NULL in case I'm communicating with a C program.
+    s += '\0'
+    if PY_MAJOR_VERSION > 2:
+        s = s.encode()
+    mapfile.write(s)
+
+
+def read_from_memory(mapfile):
+    """Reads a string from the mapfile and returns that string"""
+    mapfile.seek(0)
+    s = [ ]
+    c = mapfile.read_byte()
+    while c != NULL_CHAR:
+        s.append(c)
+        c = mapfile.read_byte()
+            
+    if PY_MAJOR_VERSION > 2:
+        s = [chr(c) for c in s]
+    s = ''.join(s)
+    
+    say("read %s" % s)
+    
+    return s
+
+
+def read_params():
+    """Reads the contents of params.txt and returns them as a dict"""
+    params = { }
+    
+    f = open("params.txt")
+    
+    for line in f:
+        line = line.strip()
+        if line:
+            if line.startswith('#'):
+                pass # comment in input, ignore
+            else:
+                name, value = line.split('=')
+                name = name.upper().strip()
+            
+                if name == "PERMISSIONS":
+                    # Think octal, young man!
+                    value = int(value, 8)
+                elif "NAME" in name:
+                    # This is a string; leave it alone.
+                    pass
+                else:
+                    value = int(value)
+                
+                #print "name = %s, value = %d" % (name, value)
+            
+                params[name] = value
+
+    f.close()
+    
+    return params
+