Minor code cleanup

Author: Jisk Attema

README.md

@@ -3,7 +3,7 @@ Python3 bindings to the ringbuffer implementation in [PSRDada](http://psrdada.so
 
 It allows you to connect to a ringbuffer, read header info, and read/write ringbuffer pages as numpy arrays.
 I aim to be interoperable, and bug-for-bug compattible, with PSRDADA.
-It also supports reading multiple datasets form a ringbuffer for connecting to dada\_dbevent.
+It also supports reading multiple datasets from a ringbuffer for connecting to dada\_dbevent.
 
 This is a proof-of-concept implementation, only functions from PSRDADA immediately necessary for my project will be implemented.
 The code is inspired by the example code in the [cython userguide](http://cython.readthedocs.io/en/latest/src/userguide/buffer.html)

examples/read_eod_iterators.py

@@ -9,9 +9,7 @@
 from psrdada import Reader
 
 
-reader = Reader()
-
-reader.connect(0xdbda)
+reader = Reader(0xdbda)
 
 nheader = 0
 done = False

examples/read_eod_no_iterators.py

@@ -8,9 +8,7 @@
 
 from psrdada import Reader
 
-reader = Reader()
-
-reader.connect(0xdbda)
+reader = Reader(0xdbda)
 
 nheader = 0
 while True:

examples/sum_no_iterator.py

@@ -6,11 +6,8 @@
 
 def read_untill_end():
     """Connect, read all pages, and disconnect from a ringbuffer."""
-    # Create a reader instace
-    reader = Reader()
-
-    # Connect to a running ringbuffer with key 'dada'
-    reader.connect(0xdada)
+    # Create a reader instace and connect to a running ringbuffer
+    reader = Reader(0xdada)
 
     # loop over the pages until EOD is encountered
     while not reader.isEndOfData:

examples/sum_with_iterator.py

@@ -6,11 +6,8 @@
 
 def read_untill_end():
     """Connect, read all pages, and disconnect from a ringbuffer."""
-    # Create a reader instace
-    reader = Reader()
-
-    # Connect to a running ringbuffer with key 'dada'
-    reader.connect(0xdada)
+    # Create a reader instace and connect to a running ringbuffer
+    reader = Reader(0xdada)
 
     # loop over the pages
     for page in reader:

examples/write_eod_iterators.py

@@ -17,9 +17,7 @@ def random_string(length=10):
     return ''.join(choice(ascii_lowercase) for i in range(length))
 
 
-writer = Writer()
-
-writer.connect(0xdbda)
+writer = Writer(0xdbda)
 
 # send 10 datasets, separated by an EOD
 for ndataset in range(10):

examples/write_eod_no_iterators.py

@@ -17,9 +17,7 @@ def random_string(length=10):
     return ''.join(choice(ascii_lowercase) for i in range(length))
 
 
-writer = Writer()
-
-writer.connect(0xdbda)
+writer = Writer(0xdbda)
 
 # send 10 datasets, separated by an EOD
 for ndataset in range(10):

psrdada/reader.pyx

@@ -3,6 +3,14 @@
 Reader class.
 
 Implements reading header and data from a running PSRDada ringbuffer.
+Create a new reader instance::
+
+    reader = Reader()
+
+Create a new reader instance, and connect it directly to a running ringbuffer::
+
+    reader = Reader(0xdada)
+
 """
 from cpython.buffer cimport PyBUF_READ
 cimport dada_hdu
@@ -23,9 +31,14 @@ cdef class Reader(Ringbuffer):
 
     Implements reading header and data from a running PSRDada ringbuffer.
     """
-    def __init__(self):
-        self.isEndOfData = False
-        self.isHoldingPage = False
+    def __init__(self, key=None):
+        """
+        Creates a new Reader instance, and optionally connects to a ringbuffer.
+
+        :param key: Optional. Identifier of the ringbuffer, typically 0xdada
+        """
+        if key:
+            self.connect(key)
 
     def connect(self, key):
         """

psrdada/ringbuffer.pyx

@@ -12,6 +12,9 @@ cdef class Ringbuffer:
 
         self._c_dada_hdu = dada_hdu.dada_hdu_create(self._multilog)
         self._key = 0xdada
+        self.isConnected = False
+        self.isHoldingPage = False
+        self.isEndOfData = False
         self.header = dict()
 
     def __dealloc__(self):

psrdada/writer.pyx

@@ -3,6 +3,13 @@
 Writer class.
 
 Implements writing header and data from a running PSRDada ringbuffer.
+Create a new writer instance::
+
+    writer = Writer()
+
+Create a new reader instance, and connect it directly to a running ringbuffer::
+
+    writer = Writer(0xdada)
 """
 
 from cpython.buffer cimport PyBUF_WRITE
@@ -25,6 +32,15 @@ cdef class Writer(Ringbuffer):
 
     Implements writing header and data to a running PSRDada ringbuffer.
     """
+    def __init__(self, key=None):
+        """
+        Creates a new Reader instance, and optionally connects to a ringbuffer.
+
+        :param key: Optional. Identifier of the ringbuffer, typically 0xdada
+        """
+        if key:
+            self.connect(key)
+
     def connect(self, key):
         """
         Connect to a PSR DADA ringbuffer with the specified key, and lock it for writing