From fc5914f2657f8d55c8ac33ff727ad526f7b24951 Mon Sep 17 00:00:00 2001
From: Bruce Flynn <brucef@ssec.wisc.edu>
Date: Tue, 20 Oct 2015 17:38:04 +0000
Subject: [PATCH] Support pipes as streams
---
edosl0util/stream.py | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/edosl0util/stream.py b/edosl0util/stream.py
index 2efd489..746d821 100644
--- a/edosl0util/stream.py
+++ b/edosl0util/stream.py
@@ -1,4 +1,5 @@
import os
+import errno
import logging
import ctypes as c
from collections import deque, defaultdict, namedtuple
@@ -40,12 +41,22 @@ class NonConsecutiveSeqId(Error):
class BasicStream(object):
+ """
+ Basic packet stream iterator that reads the primary and secondary headers and
+ maintains offsets and read sizes.
+ """
Tracker = namedtuple('Tracker', ['h1', 'h2', 'size', 'offset', 'data'])
def __init__(self, fobj, header_lookup=None, with_data=True):
self.file = fobj
self.header_lookup = header_lookup
self.with_data = with_data
+ try:
+ self._offset = self.file.tell()
+ except IOError as err: # handle illegal seek for pipes
+ if err.errno != errno.ESPIPE:
+ raise
+ self._offset = 0
def __iter__(self):
return self
@@ -61,6 +72,7 @@ class BasicStream(object):
raise PacketTooShort(
'expected to read {:d} bytes, got {:d}'
.format(size, len(buf)))
+ self._offset += size
return buf
def read_primary_header(self):
@@ -77,7 +89,7 @@ class BasicStream(object):
return H2Impl.from_buffer_copy(buf), h2size
def next(self):
- offset = self.file.tell()
+ offset = self._offset
h1, h1size = self.read_primary_header()
h2, h2size = self.read_secondary_header(h1)
# data length includes h2size
--
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