Implement frame synchronization

There is an issue somewhere between the mod and demod, since frame
synchronization works on a direct path.

4 files changed, 127 insertions, 36 deletions

diff --git a/src/gr-fadingui/python/CMakeLists.txt b/src/gr-fadingui/python/CMakeLists.txt
index 1318857..6ee73d3 100644
--- a/src/gr-fadingui/python/CMakeLists.txt
+++ b/src/gr-fadingui/python/CMakeLists.txt
@@ -47,4 +47,4 @@ include(GrTest)
 
 set(GR_TEST_TARGET_DEPS gnuradio-fadingui)
 set(GR_TEST_PYTHON_DIRS ${CMAKE_BINARY_DIR}/swig)
-GR_ADD_TEST(qa_dearpygui_sink ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/qa_dearpygui_sink.py)
+GR_ADD_TEST(qa_xor_frame_sync ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/qa_xor_frame_sync.py)
diff --git a/src/gr-fadingui/python/datasource.py b/src/gr-fadingui/python/datasource.py
index 12573a8..38771c5 100644
--- a/src/gr-fadingui/python/datasource.py
+++ b/src/gr-fadingui/python/datasource.py
@@ -35,7 +35,7 @@ class datasource(gr.basic_block):
         # a frame has 5 id bits so, there can only be 2 ** 5 chunks per file
         # see docstring of frame_obj for more details
         nblocks = int(self.fsize / self.frame.payload_length)
-        log.debug(f"Loaded {self.fsize} bytes = {nblocks} blocks from {self.fname}")
+        log.debug(f"Loaded {self.fsize} bytes == {nblocks} blocks from {self.fname}")
         assert nblocks < 2 ** 5, "Payload size too small or file too big"
 
         self.fpos = 0
@@ -73,7 +73,7 @@ class datasource(gr.basic_block):
         self.outbuffer = frame_bytes[len(out):]
 
         log.debug(f"Sent frame nr={self.blocknr}")
-        log.debug(f"Set bytes {out}")
+        log.debug(f"Sent bytes {out}")
 
         self.fpos += self.frame.payload_length
         self.blocknr += 1
diff --git a/src/gr-fadingui/python/qa_xor_frame_sync.py b/src/gr-fadingui/python/qa_xor_frame_sync.py
new file mode 100644
index 0000000..280c694
--- /dev/null
+++ b/src/gr-fadingui/python/qa_xor_frame_sync.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+from gnuradio import gr, gr_unittest, blocks
+
+from xor_frame_sync import xor_frame_sync
+import numpy as np
+
+
+class test_xor_frame_sync(gr_unittest.TestCase):
+
+    def setUp(self):
+        self.tb = gr.top_block()
+
+    def tearDown(self):
+        self.tb = None
+
+    def test_001(self):
+        """Test a byte aligned delay"""
+        pattern = np.array([0xbe, 0xef], dtype=np.uint8)
+        testdata = np.packbits(np.concatenate([
+            np.unpackbits(np.arange(0, 10, dtype=np.uint8)),
+            np.random.randint(0, 2, size = 8 * 5), np.unpackbits(pattern),
+            np.random.randint(0, 2, size = 64)
+        ]))
+
+        src = blocks.vector_source_b(testdata)
+        op = xor_frame_sync(pattern, 2048)
+        dst = blocks.vector_sink_b()
+
+        self.tb.connect(src, op, dst)
+        self.tb.run()
+
+        self.assertEqual(op.synchronized, True)
+
+    # FIXME: implement feature
+    # def test_002(self):
+    #     """Test a byte unaligned delay"""
+    #     pattern = np.array([0xbe, 0xef], dtype=np.uint8)
+    #     testdata = np.packbits(np.concatenate([
+    #         np.unpackbits(np.arange(0, 10, dtype=np.uint8)),
+    #         np.random.randint(0, 2, size = (2 + 8 * 5)), np.unpackbits(pattern),
+    #         np.random.randint(0, 2, size = 64)
+    #     ]))
+
+    #     src = blocks.vector_source_b(testdata)
+    #     op = xor_frame_sync(pattern, 2048)
+    #     dst = blocks.vector_sink_b()
+
+    #     self.tb.connect(src, op, dst)
+    #     self.tb.run()
+
+    #     self.assertEqual(op.synchronized, True)
+
+
+if __name__ == "__main__":
+    gr_unittest.run(test_xor_frame_sync)
diff --git a/src/gr-fadingui/python/xor_frame_sync.py b/src/gr-fadingui/python/xor_frame_sync.py
index 51af35a..e52b493 100644
--- a/src/gr-fadingui/python/xor_frame_sync.py
+++ b/src/gr-fadingui/python/xor_frame_sync.py
@@ -25,23 +25,24 @@ class xor_frame_sync(gr.sync_block):
             out_sig=[np.byte])
 
         # binary pattern to match
-        self.pattern = np.unpackbits(np.array(sync_pattern, dtype=np.uint8))[::-1]
-        self.nbytes = len(sync_pattern)
-        self.nbits = len(self.pattern)
+        self.pattern = sync_pattern
+        self.nbytes = len(self.pattern)
 
-        log.debug(f"Loaded pattern {self.pattern} length={self.nbits}")
+        self.pattern_bits = np.unpackbits(np.array(self.pattern, dtype=np.uint8))[::-1]
+        self.nbits = len(self.pattern_bits)
+
+        log.debug(f"Loaded pattern {self.pattern_bits} length={self.nbits}")
         assert(self.nbits % 8 == 0)
 
         # packed buffer to delay the data
         self.delaybuf = RingBuffer(buffer_size, dtype=np.uint8)
         self.delay = 0
 
-        # unpacked buffer to compute correlation values, initially filled with zeros
-        self.corrbuf = RingBuffer(self.nbits)
-        self.corrbuf.extend(np.zeros(self.nbits))
+        log.debug(f"Created delay ring buffer of size {self.delaybuf.maxlen}")
 
-        # buffer to store correlation values
-        self.xcorrs = RingBuffer(buffer_size)
+        # unpacked buffer to compute correlation values, initially filled with zeros
+        self.corrbuf = RingBuffer(self.nbits, dtype=np.uint8)
+        self.corrbuf.extend(np.zeros(self.corrbuf.maxlen))
 
         # synchronization state
         self.synchronized = False
@@ -53,11 +54,21 @@ class xor_frame_sync(gr.sync_block):
 
         Binary correlation between two bit vectors is just size of the
         vector(s) minus the number of bits that differ.
+
+        @return: Number of bits of v that were shifted into the buffer
+                 when the correlation matched. If no match is found
+                 the return value is None.
         """
-        v_arr = np.array(v, dtype=np.uint8)
-        for b in np.unpackbits(v_arr):
+        # this could be much faster with shifts, bitwise or and xor
+        # but this should do alright for the moment
+        v_bits = np.unpackbits(np.array(v, dtype=np.uint8))
+        for bitnr, b in enumerate(v_bits):
             self.corrbuf.appendleft(b)
-            yield self.nbits - np.sum(np.logical_xor(self.corrbuf, self.pattern))
+            if (np.bitwise_xor(self.corrbuf, self.pattern_bits) == 0).all():
+                return bitnr
+
+        # no cross correlation found
+        return None
 
     def work(self, input_items, output_items):
         """
@@ -68,35 +79,59 @@ class xor_frame_sync(gr.sync_block):
 
             - If the buffer is not synchronized, compute a binary cross
               correlation to find how much the stream should be delayed.
-
-        Notes:
-
-            - Even though the block input is of type np.byte, inp is an array
-              of 255 bytes, probably for performance reasons.
-              TODO: block processing
         """
         inp = input_items[0]
         out = output_items[0]
 
-        if not self.synchronized:
-            for v in inp:
-                # compute the cross correlation
-                xcs = self.xcorrelation(v)
+        inp_len = len(inp)
 
-                # add cross correlations to buffer and save value
-                self.xcorrs.extend(list(xcs))
-                self.delaybuf.appendleft(v)
+        if not self.synchronized:
+            if inp_len > self.delaybuf.maxlen:
+                log.error("Input is bigger than delay buffer")
 
-            peak = np.argmax(self.xcorrs)
-            if self.xcorrs[peak] == self.nbits:
-                self.delay = peak
-                self.synchronized = True
-                log.debug(f"Synchronized with delay={peak}")
+                # FIXME: Makes the QA hang for some reason
+                # raise NotImplemented
 
-            else:
-                self.synchronized = False
-                log.warning(f"Did not find a peak (max={self.xcorrs[peak]}, should be {self.nbits})")
+            for bytenr, value in enumerate(inp):
+                # save value in the buffer
+                self.delaybuf.appendleft(value)
 
+                # compute the cross correlation
+                bitnr = self.xcorrelation(value)
+                if bitnr is not None:
+                    # correlation was found
+                    delay_bits = 8 * bytenr + bitnr
+
+                    # FIXME: add bit delay
+                    self.delay = bytenr
+                    self.synchronized = True
+                    log.debug(f"Synchronized with delay={self.delay} delay_bits={delay_bits}")
+
+                    # Not aligned to bytes
+                    if bitnr != 7:
+                        log.error("Not implemented: byte unaligned delay")
+                        self.synchronized = False
+                        self.delay = 0
+
+                        # FIXME: Makes the QA hang for some reason
+                        # raise NotImplemented
+
+                    # bigger than buffer
+                    if bytenr > self.delaybuf.maxlen:
+                        log.error("Too too long to synchronize, ran out of buffer memory")
+                        self.synchronized = False
+                        self.delay = 0
+
+                        # FIXME: Makes the QA hang for some reason
+                        # raise NotImplemented
+
+                    # stop processing inputs
+                    break
+
+            if not self.synchronized:
+                log.warning(f"Processed {inp_len} samples but could not synchronize")
+        else:
+            self.delaybuf.extendleft(inp)
 
         # return data with delay
         out[:] = self.delaybuf[self.delay]