From a977abe622de37bf7fc84e9996f1ea2a68b883e1 Mon Sep 17 00:00:00 2001
From: Sven Augustin <sven.augustin@psi.ch>
Date: Mon, 18 Jul 2022 21:46:25 +0200
Subject: [PATCH] allow record(n=None); renamed Buffer -> BufferFinite; added
 deque-based BufferInfinite

---
 slic/devices/general/detectors/buffer.py      | 26 +++++++++++++++++--
 .../general/detectors/pvdatastream2.py        | 11 +++++---
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/slic/devices/general/detectors/buffer.py b/slic/devices/general/detectors/buffer.py
index bfc660b0..14906f1e 100644
--- a/slic/devices/general/detectors/buffer.py
+++ b/slic/devices/general/detectors/buffer.py
@@ -1,8 +1,31 @@
+from collections import deque
 import numpy as np
 from slic.utils import get_dtype, get_shape
 
 
-class Buffer:
+class BufferInfinite:
+
+    def __init__(self, maxlen=None):
+        self._buffer = b = deque(maxlen=maxlen)
+
+    @property
+    def data(self):
+        return np.array(self._buffer)
+
+    is_full = False
+
+    def append(self, value):
+        self._buffer.append(value)
+
+    def __len__(self):
+        return len(self._buffer)
+
+    def __repr__(self):
+        return repr(self.data)
+
+
+
+class BufferFinite:
 
     def __init__(self, n, shape, dtype):
         self.n = n
@@ -22,7 +45,6 @@ class Buffer:
 
     @property
     def is_full(self):
-#        return self._index == len(self._buffer)
         return self._index == self.n
 
     def append(self, value):
diff --git a/slic/devices/general/detectors/pvdatastream2.py b/slic/devices/general/detectors/pvdatastream2.py
index b83af1bf..bc984a9d 100644
--- a/slic/devices/general/detectors/pvdatastream2.py
+++ b/slic/devices/general/detectors/pvdatastream2.py
@@ -1,7 +1,7 @@
 from time import sleep
 from slic.utils.hastyepics import get_pv as PV
 
-from .buffer import Buffer
+from .buffer import BufferInfinite, BufferFinite
 from .timer import Timer
 
 
@@ -14,11 +14,14 @@ class PVDataStream:
         self.running = False
 
 
-    def record(self, n, seconds=None):
+    def record(self, n=None, seconds=None):
         pv = self.pv
 
-        current = pv.get()
-        buf = Buffer.from_example(n, current)
+        if n is None:
+            buf = BufferInfinite()
+        else:
+            current = pv.get()
+            buf = BufferFinite.from_example(n, current)
 
         def on_value_change(value=None, **kwargs):
             buf.append(value)