Implemented mapfiles

1 files changed, 99 insertions, 0 deletions

diff --git a/libbe/mapfile.py b/libbe/mapfile.py
new file mode 100644
index 0000000..b1fab20
--- /dev/null
+++ b/libbe/mapfile.py
@@ -0,0 +1,99 @@
+class FileString(object):
+    """Bare-bones pseudo-file class"""
+    def __init__(self, str=""):
+        object.__init__(self)
+        self.str = str
+
+    def __iter__(self):
+        for line in self.str.splitlines(True):
+            yield line
+
+    def write(self, line):
+        self.str += line
+
+
+def parse(f):
+    """Parses a mapfile, returns a Dictionary
+
+    >>> f = FileString("1:q\\n2:q\\n3:q\\n>p\\n4:q\\n5:q\\n6:q\\n")
+    >>> parse(f)["q"]
+    'p'
+    >>> parse("1:q\\n2:q\\n3:q\\n>r\\n4:q\\n5:q\\n6:q\\n")["q"]
+    'r'
+    >>> parse("1:q:5\\n>s\\n2:q:5\\n")["q:5"]
+    's'
+    >>> parse("1:q\\n>s\\n2:q\\n1:q\\n>s\\n2:q\\n")
+    Traceback (most recent call last):
+      File "<stdin>", line 1, in ?
+      File "libbe/mapfile.py", line 41, in parse
+        assert (lnum == prev_num + 1)
+    AssertionError
+    >>> parse("1:q\\n>s\\n2:q\\n1:l\\n>s\\n2:l\\n1:q\\n>s\\n2:q\\n")
+    Traceback (most recent call last):
+    AssertionError
+    >>> parse("1:q\\n>s\\n>s\\n2:q\\n")
+    Traceback (most recent call last):
+    AssertionError
+    """
+    if isinstance(f, basestring):
+        f = FileString(f)
+    result = {}
+    name = None
+    prev_num = None
+    for line in f:
+        value = None
+        # Handle values
+        if line.startswith(">"):
+            assert (name is not None)
+            assert (not result.has_key(name))
+            result[name] = line[1:].rstrip("\n")
+        # Handle names
+        else:
+            lname = ":".join(line.split(":")[1:]).rstrip("\n")
+            lnum = int(line.split(":")[0])
+
+            #special-case the first execution
+            if name is None:
+                name = lname 
+
+            #ensure sequential operation
+            elif lname == name:
+                assert (lnum == prev_num + 1)
+            #if name changes, start over at 1
+            else:
+                if lnum != 1:
+                    assert(lname != name)
+                    raise "%i %s %s" % (lnum, lname, name)
+                assert (lnum == 1)
+                name = lname
+            prev_num = lnum
+    return result
+ 
+
+def generate(f, map, context=3):
+    """
+    >>> f = FileString()
+    >>> generate(f, {"q":"p"})
+    >>> f.str
+    '1:q\\n2:q\\n3:q\\n>p\\n4:q\\n5:q\\n6:q\\n'
+    >>> parse(f)["q"]
+    'p'
+    >>> f = FileString()
+    >>> generate(f, {"a":"b", "c":"d", "e":"f"})
+    >>> dict = parse(f)
+    >>> dict["a"]
+    'b'
+    >>> dict["c"]
+    'd'
+    >>> dict["e"]
+    'f'
+    """
+    assert(context > 0)
+    keys = map.keys()
+    keys.sort()
+    for key in keys:
+        for i in range(context):
+            f.write("%i:%s\n" % (i+1, key))
+        f.write(">%s\n" % map[key])
+        for i in range(context):
+            f.write("%i:%s\n" % (i+context+1, key))