Merge pull request #37 from mookerji/table-and-log

Moves JSON and pickle iterators into libsbp.

python/sbp/__init__.py

@@ -51,7 +51,7 @@
 
 def crc16(s, crc=0):
   """CRC16 implementation acording to CCITT standards.
-    
+
   """
   for ch in s:
     crc = ((crc<<8)&0xFFFF) ^ crc16_tab[ ((crc>>8)&0xFF) ^ (ord(ch)&0xFF) ]
@@ -60,9 +60,9 @@ def crc16(s, crc=0):
 
 class SBP(object):
   """Swift Binary Protocol container.
-    
+
   """
-  
+
   def __init__(self, msg_type=None, sender=None,
                length=None, payload=None, crc=None):
     self.preamble = SBP_PREAMBLE
@@ -71,11 +71,13 @@ def __init__(self, msg_type=None, sender=None,
     self.length = length
     self.payload = payload
     self.crc = crc
-
+
+  def __eq__(self, other):
+    return self.__dict__ == other.__dict__
+
   def pack(self):
     """Pack to framed binary message.
-      
-      
+
     """
     framed_msg = struct.pack('<BHHB',
                              self.preamble,
@@ -92,7 +94,7 @@ def __repr__(self):
          self.payload, self.crc)
     fmt = "<SBP (preamble=0x%X, msg_type=0x%X, sender=%s, length=%d, payload=%s, crc=0x%X)>"
     return fmt % p
-      
+
   @staticmethod
   def from_json_dict(data):
     msg_type = data['msg_type']

python/sbp/client/drivers/file_driver.py

@@ -8,7 +8,7 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
-from base_driver import BaseDriver
+from .base_driver import BaseDriver
 
 class FileDriver(BaseDriver):
   """
@@ -24,3 +24,40 @@ class FileDriver(BaseDriver):
   def __init__(self, filename):
     handle = open(filename, "r")
     super(FileDriver, self).__init__(handle)
+
+  def __iter__(self):
+    return self
+
+  def seek(self, pos, whence=0):
+    """
+    Wrapper around file seek.
+
+    Parameters
+    ----------
+    pos : int
+      Position of the read/write pointer within the file.
+    whence : int
+      Optional and defaults to 0 which means absolute file
+      positioning, other values are 1 which means seek relative to the
+      current position and 2 means seek relative to the file's end
+
+    """
+    self.handle.seek(pos, whence)
+
+  def next(self):
+    """
+    Call handle's iterator.
+
+    """
+    line = self.handle.readline()
+    if not line:
+      raise StopIteration
+    return line
+
+  def readline(self):
+    """
+    Readline wrapper: read a line which is terminated with end-of-line
+    (EOL) character ('\n' by default), or until timeout.
+
+    """
+    return self.handle.readline()

python/sbp/client/drivers/pyftdi_driver.py

@@ -8,11 +8,11 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
-from base_driver import BaseDriver
+from .base_driver import BaseDriver
 
 class PyFTDIDriver(BaseDriver):
   """
-  PyFTDIDriver 
+  PyFTDIDriver
 
   The :class:`PyFTDIDriver` class reads SBP messages from a serial port
   using the pyftdi driver.

python/sbp/client/drivers/pyserial_driver.py

@@ -8,7 +8,7 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
-from base_driver import BaseDriver
+from .base_driver import BaseDriver
 
 class PySerialDriver(BaseDriver):
   """

python/sbp/client/loggers/base_logger.py

@@ -8,6 +8,7 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
+from ...table import dispatch
 import calendar
 import time
 
@@ -21,6 +22,7 @@ class BaseLogger(object):
   ----------
   filename : string
     File to log to.
+
   """
   def __init__(self, filename):
     self.handle = open(filename, "w+")
@@ -47,3 +49,42 @@ def delta(self):
     """
     return int((time.time() - self.base_time) * 1000)
 
+
+class LogIterator(object):
+  """
+  LogIterator
+
+  The :class: `LogIterator` provides an abstract interface for reading
+  serialized logs of SBP data.
+
+  Parameters
+  ----------
+  handle : File-like handle
+    Any file-like handle providing SBP messages.
+
+  """
+  def __init__(self, handle, dispatcher=dispatch):
+    self.handle = handle
+    self.dispatcher = dispatcher
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, *args):
+    self.handle.close()
+
+  def __iter__(self):
+    return self
+
+  def next(self):
+    """Return the next record tuple from the log file. If an unknown SBP
+    message type is found, it'll return the raw SBP. If EOF, throws
+    exception and then returns to start of file.
+
+    Returns
+    -------
+    (float, float, object)
+      (elapsed msec since beginning of log, UTC timestamp, msg)
+
+    """
+    raise NotImplementedError("next() not implemented!")

python/sbp/client/loggers/byte_logger.py

@@ -10,12 +10,12 @@
 
 import struct
 
-from base_logger import BaseLogger
+from .base_logger import BaseLogger
 
 class ByteLogger(BaseLogger):
   """
   ByteLogger
-  
+
   The :class:`ByteLogger` logs SBP messages to bytes.
   """
   def __call__(self, msg):

python/sbp/client/loggers/json_logger.py

@@ -8,21 +8,63 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
+from ... import SBP
+from .base_logger import BaseLogger, LogIterator
 import json
 
-from base_logger import BaseLogger
-
 class JSONLogger(BaseLogger):
   """
   JSONLogger
-  
+
   The :class:`JSONLogger` logs JSON records.
   """
   def __call__(self, msg):
     self.call(msg)
 
   def fmt_msg(self, msg):
-    return {"delta": self.delta(), "timestamp": self.timestamp(), "data": msg.to_json_dict()}
-
+    return {"delta": self.delta(),
+            "timestamp": self.timestamp(),
+            "data": msg.to_json_dict()}
+
   def call(self, msg):
     self.handle.write(json.dumps(self.fmt_msg(msg)) + "\n")
+
+
+class JSONLogIterator(LogIterator):
+  """
+  JSONLogIterator
+
+  The :class:`JSONLogIterator` is an iterator for reading JSON logs
+  of SBP data.
+
+  Parameters
+  ----------
+  handle : File-like handle
+    Any file-like handle providing SBP messages.
+
+  """
+
+  def next(self):
+    """
+    Return the next record tuple from log file containing
+    JSON-serialized SBP. If an unknown SBP message type is found,
+    it'll return the raw SBP. If EOF, throws exception and then
+    returns to start of file.
+
+    Returns
+    -------
+    (float, float, object)
+      (elapsed msec since beginning of log, UTC timestamp, msg)
+
+    """
+    for line in self.handle:
+      data = json.loads(line)
+      delta = data['delta']
+      timestamp = data['timestamp']
+      item = SBP.from_json_dict(data['data'])
+      try:
+        yield (delta, timestamp, self.dispatcher(item))
+      except KeyError:
+        yield (delta, timestamp, item)
+    self.handle.seek(0, 0)
+    raise StopIteration

python/sbp/client/loggers/pickle_logger.py

@@ -8,14 +8,13 @@
 # EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 # WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 
+from .base_logger import BaseLogger, LogIterator
 import cPickle as pickle
 
-from base_logger import BaseLogger
-
 class PickleLogger(BaseLogger):
   """
   PickleLogger
-  
+
   The :class:`PickleLogger` logs pickled structures.
   """
   def __call__(self, msg):
@@ -26,3 +25,42 @@ def fmt_msg(self, msg):
 
   def call(self, msg):
     pickle.dump(self.fmt_msg(msg), self.handle, 2)
+
+
+class PickleLogIterator(LogIterator):
+  """
+  PickleLogIterator
+
+  The :class:`PickleLogIterator` is an iterator for reading pickled logs
+  of SBP data.
+
+  Parameters
+  ----------
+  handle : File-like handle
+    Any file-like handle providing SBP messages.
+
+  """
+
+  def next(self):
+    """
+    Return the next record tuple from log file containing
+    Pickle SBP. If an unknown SBP message type is found,
+    it'll return the raw SBP. If EOF, throws exception and then
+    returns to start of file.
+
+    Returns
+    -------
+    (float, float, object)
+      (elapsed msec since beginning of log, UTC timestamp, msg)
+
+    """
+    try:
+      while True:
+        delta, timestamp, item = pickle.load(self.handle)
+        try:
+          yield (delta, timestamp, self.dispatcher(item))
+        except KeyError:
+          yield (delta, timestamp, item)
+    except EOFError:
+      self.handle.seek(0, 0)
+      raise StopIteration

python/sbp/client/main.py

@@ -17,15 +17,15 @@
 import sys
 import time
 
-from ..piksi                 import SBP_MSG_PRINT
-from drivers.file_driver     import FileDriver
-from drivers.pyserial_driver import PySerialDriver
-from drivers.pyftdi_driver   import PyFTDIDriver
-from loggers.byte_logger     import ByteLogger
-from loggers.json_logger     import JSONLogger
-from loggers.null_logger     import NullLogger
-from loggers.pickle_logger   import PickleLogger
-from handler                 import Handler
+from ..piksi                  import SBP_MSG_PRINT
+from .drivers.file_driver     import FileDriver
+from .drivers.pyserial_driver import PySerialDriver
+from .drivers.pyftdi_driver   import PyFTDIDriver
+from .loggers.byte_logger     import ByteLogger
+from .loggers.json_logger     import JSONLogger
+from .loggers.null_logger     import NullLogger
+from .loggers.pickle_logger   import PickleLogger
+from .handler                 import Handler
 
 DEFAULT_PORT         = "/dev/ttyUSB0"
 DEFAULT_BAUD         = 1000000