Added subsampling for fast lookup
authorJoel Holdsworth <joel@airwebreathe.org.uk>
Mon, 16 Jul 2012 19:45:19 +0000 (20:45 +0100)
committerJoel Holdsworth <joel@airwebreathe.org.uk>
Mon, 3 Sep 2012 13:00:02 +0000 (14:00 +0100)
CMakeLists.txt
logicdatasnapshot.cpp
logicdatasnapshot.h
test/logicdatasnapshot.cpp [new file with mode: 0644]
test/test.cpp

index e0edfbc3d86132fc66d2beafce24b8914e589e87..2d62dfcbe1bee3da5b63da4d5ed9381e3401e6b4 100644 (file)
@@ -46,6 +46,7 @@ set(sigrok-qt2_RESOURCES
 )
 
 set(sigrok-qt2_TEST_SOURCES
 )
 
 set(sigrok-qt2_TEST_SOURCES
+       test/logicdatasnapshot.cpp
        test/test.cpp
        datasnapshot.cpp
        logicdatasnapshot.cpp
        test/test.cpp
        datasnapshot.cpp
        logicdatasnapshot.cpp
index e29a866e5fea444b735e5219835c1278b746bef5..8f7e9922bb50b3ccf74815d2c2200b00fbefe329 100644 (file)
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
-#include "logicdatasnapshot.h"
+#include "extdef.h"
 
 #include <assert.h>
 
 #include <assert.h>
+#include <string.h>
+#include <math.h>
+
+#include <boost/foreach.hpp>
+
+#include "logicdatasnapshot.h"
 
 using namespace std;
 
 
 using namespace std;
 
+const int LogicDataSnapshot::MipMapScalePower = 4;
+const int LogicDataSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
+const uint64_t LogicDataSnapshot::MipMapDataUnit = 64*1024;    // bytes
+
 LogicDataSnapshot::LogicDataSnapshot(
        const sr_datafeed_logic &logic) :
 LogicDataSnapshot::LogicDataSnapshot(
        const sr_datafeed_logic &logic) :
-       DataSnapshot(logic.unitsize)
+       DataSnapshot(logic.unitsize),
+       _last_append_sample(0)
 {
 {
+       memset(_mip_map, 0, sizeof(_mip_map));
        append_payload(logic);
 }
 
        append_payload(logic);
 }
 
+LogicDataSnapshot::~LogicDataSnapshot()
+{
+       BOOST_FOREACH(MipMapLevel &l, _mip_map)
+               free(l.data);
+}
+
 void LogicDataSnapshot::append_payload(
        const sr_datafeed_logic &logic)
 {
        assert(_unit_size == logic.unitsize);
 
 void LogicDataSnapshot::append_payload(
        const sr_datafeed_logic &logic)
 {
        assert(_unit_size == logic.unitsize);
 
+       const uint64_t prev_length = _data_length;
        append_data(logic.data, logic.length);
        append_data(logic.data, logic.length);
+
+       // Generate the first mip-map from the data
+       append_payload_to_mipmap();
+}
+
+void LogicDataSnapshot::reallocate_mip_map(MipMapLevel &m)
+{
+       const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
+               MipMapDataUnit) * MipMapDataUnit;
+       if(new_data_length > m.data_length)
+       {
+               m.data_length = new_data_length;
+               m.data = realloc(m.data, new_data_length * _unit_size);
+       }
+}
+
+void LogicDataSnapshot::append_payload_to_mipmap()
+{
+       MipMapLevel &m0 = _mip_map[0];
+       uint64_t prev_length;
+       const uint8_t *src_ptr;
+       uint8_t *dest_ptr;
+       uint64_t accumulator;
+       unsigned int diff_counter;
+
+       // Expand the data buffer to fit the new samples
+       prev_length = m0.length;
+       m0.length = _data_length / MipMapScaleFactor;
+
+       // Break off if there are no new samples to compute
+       if(m0.length == prev_length)
+               return;
+
+       reallocate_mip_map(m0);
+
+       dest_ptr = (uint8_t*)m0.data + prev_length * _unit_size;
+
+       // Iterate through the samples to populate the first level mipmap
+       accumulator = 0;
+       diff_counter = MipMapScaleFactor;
+       const uint8_t *end_src_ptr = (uint8_t*)_data +
+               m0.length * _unit_size * MipMapScaleFactor;
+       for(src_ptr = (uint8_t*)_data +
+               prev_length * _unit_size * MipMapScaleFactor;
+               src_ptr < end_src_ptr;)
+       {
+               // Accumulate transitions which have occurred in this sample
+               accumulator = 0;
+               diff_counter = MipMapScaleFactor;
+               while(diff_counter-- > 0)
+               {
+                       const uint64_t sample = *(uint64_t*)src_ptr;
+                       accumulator |= _last_append_sample ^ sample;
+                       _last_append_sample = sample;
+                       src_ptr += _unit_size;
+               }
+
+               *(uint64_t*)dest_ptr = accumulator;
+               dest_ptr += _unit_size;
+       }
+
+       // Compute higher level mipmaps
+       for(int level = 1; level < ScaleStepCount; level++)
+       {
+               MipMapLevel &m = _mip_map[level];
+               const MipMapLevel &ml = _mip_map[level-1];
+
+               // Expand the data buffer to fit the new samples
+               prev_length = m.length;
+               m.length = ml.length / MipMapScaleFactor;
+
+               // Break off if there are no more samples to computed
+               if(m.length == prev_length)
+                       break;
+
+               reallocate_mip_map(m);
+
+               // Subsample the level lower level
+               src_ptr = (uint8_t*)ml.data +
+                       _unit_size * prev_length * MipMapScaleFactor;
+               const uint8_t *end_dest_ptr =
+                       (uint8_t*)m.data + _unit_size * m.length;
+               for(dest_ptr = (uint8_t*)m.data +
+                       _unit_size * prev_length;
+                       dest_ptr < end_dest_ptr;
+                       dest_ptr += _unit_size)
+               {
+                       accumulator = 0;
+                       diff_counter = MipMapScaleFactor;
+                       while(diff_counter-- > 0)
+                       {
+                               accumulator |= *(uint64_t*)src_ptr;
+                               src_ptr += _unit_size;
+                       }
+
+                       *(uint64_t*)dest_ptr = accumulator;
+               }
+       }
 }
 
 uint64_t LogicDataSnapshot::get_sample(uint64_t index) const
 }
 
 uint64_t LogicDataSnapshot::get_sample(uint64_t index) const
index e6fee52bea70f88aad01ee18c8522636930c4bc7..c49d05d58ca2d032f84c28f045238be4ef12d120 100644 (file)
 
 class LogicDataSnapshot : public DataSnapshot
 {
 
 class LogicDataSnapshot : public DataSnapshot
 {
+private:
+       struct MipMapLevel
+       {
+               uint64_t length;
+               uint64_t data_length;
+               void *data;
+       };
+
+private:
+       static const int ScaleStepCount = 10;
+       static const int MipMapScalePower;
+       static const int MipMapScaleFactor;
+       static const uint64_t MipMapDataUnit;
+
 public:
        typedef std::pair<int64_t, bool> EdgePair;
 
 public:
        LogicDataSnapshot(const sr_datafeed_logic &logic);
 
 public:
        typedef std::pair<int64_t, bool> EdgePair;
 
 public:
        LogicDataSnapshot(const sr_datafeed_logic &logic);
 
+       virtual ~LogicDataSnapshot();
+
        void append_payload(const sr_datafeed_logic &logic);
 
        void append_payload(const sr_datafeed_logic &logic);
 
+private:
+       void reallocate_mip_map(MipMapLevel &m);
+
+       void append_payload_to_mipmap();
+
+public:
        uint64_t get_sample(uint64_t index) const;
 
        /**
        uint64_t get_sample(uint64_t index) const;
 
        /**
@@ -48,4 +70,10 @@ public:
        void get_subsampled_edges(std::vector<EdgePair> &edges,
                int64_t start, int64_t end,
                int64_t quantization_length, int sig_index);
        void get_subsampled_edges(std::vector<EdgePair> &edges,
                int64_t start, int64_t end,
                int64_t quantization_length, int sig_index);
+
+private:
+       struct MipMapLevel _mip_map[ScaleStepCount];
+       uint64_t _last_append_sample;
+
+       friend class LogicDataSnapshotTest;
 };
 };
diff --git a/test/logicdatasnapshot.cpp b/test/logicdatasnapshot.cpp
new file mode 100644 (file)
index 0000000..67e7dc1
--- /dev/null
@@ -0,0 +1,104 @@
+/*
+ * This file is part of the sigrok project.
+ *
+ * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <boost/test/unit_test.hpp>
+
+#include "../logicdatasnapshot.h"
+
+void push_logic(LogicDataSnapshot &s, unsigned int length, uint8_t value)
+{
+       sr_datafeed_logic logic;
+       logic.unitsize = 1;
+       logic.length = length;
+       logic.data = new uint8_t[length];
+       memset(logic.data, value, length * logic.unitsize);
+       s.append_payload(logic);
+       delete[] (uint8_t*)logic.data;
+}
+
+BOOST_AUTO_TEST_CASE(LogicDataSnapshotTest)
+{
+       // Create an empty LogicDataSnapshot object
+       sr_datafeed_logic logic;
+       logic.length = 0;
+       logic.unitsize = 1;
+       logic.data = NULL;
+
+       LogicDataSnapshot s(logic);
+
+       BOOST_CHECK(s.get_sample_count() == 0);
+       for(int i = 0; i < LogicDataSnapshot::ScaleStepCount; i++)
+       {
+               const LogicDataSnapshot::MipMapLevel &m = s._mip_map[i];
+               BOOST_CHECK_EQUAL(m.length, 0);
+               BOOST_CHECK_EQUAL(m.data_length, 0);
+               BOOST_CHECK(m.data == NULL);
+       }
+
+       // Push 8 samples of all zeros
+       push_logic(s, 8, 0);
+
+       BOOST_CHECK(s.get_sample_count() == 8);
+
+       // There should not be enough samples to have a single mip map sample
+       for(int i = 0; i < LogicDataSnapshot::ScaleStepCount; i++)
+       {
+               const LogicDataSnapshot::MipMapLevel &m = s._mip_map[i];
+               BOOST_CHECK_EQUAL(m.length, 0);
+               BOOST_CHECK_EQUAL(m.data_length, 0);
+               BOOST_CHECK(m.data == NULL);
+       }
+
+       // Push 8 samples of 0x11s to bring the total up to 16
+       push_logic(s, 8, 0x11);
+
+       // There should now be enough data for exactly one sample
+       // in mip map level 0, and that sample should be 0
+       const LogicDataSnapshot::MipMapLevel &m0 = s._mip_map[0];
+       BOOST_CHECK_EQUAL(m0.length, 1);
+       BOOST_CHECK_EQUAL(m0.data_length, LogicDataSnapshot::MipMapDataUnit);
+       BOOST_REQUIRE(m0.data != NULL);
+       BOOST_CHECK_EQUAL(((uint8_t*)m0.data)[0], 0x11);
+
+       // The higher levels should still be empty
+       for(int i = 1; i < LogicDataSnapshot::ScaleStepCount; i++)
+       {
+               const LogicDataSnapshot::MipMapLevel &m = s._mip_map[i];
+               BOOST_CHECK_EQUAL(m.length, 0);
+               BOOST_CHECK_EQUAL(m.data_length, 0);
+               BOOST_CHECK(m.data == NULL);
+       }
+
+       // Push 240 samples of all zeros to bring the total up to 256
+       push_logic(s, 240, 0);
+
+       BOOST_CHECK_EQUAL(m0.length, 16);
+       BOOST_CHECK_EQUAL(m0.data_length, LogicDataSnapshot::MipMapDataUnit);
+
+       BOOST_CHECK_EQUAL(((uint8_t*)m0.data)[1], 0x11);
+       for(int i = 2; i < m0.length; i++)
+               BOOST_CHECK_EQUAL(((uint8_t*)m0.data)[i], 0);
+
+       const LogicDataSnapshot::MipMapLevel &m1 = s._mip_map[1];
+       BOOST_CHECK_EQUAL(m1.length, 1);
+       BOOST_CHECK_EQUAL(m1.data_length, LogicDataSnapshot::MipMapDataUnit);
+       BOOST_REQUIRE(m1.data != NULL);
+       BOOST_CHECK_EQUAL(((uint8_t*)m1.data)[0], 0x11);
+}
index acb3c963dcfb8a1488440c1f7165fe2f07a6a81a..2c278c04e650a1eb9b090eff0e5c4d254510ad7c 100644 (file)
 
 #define BOOST_TEST_MAIN
 #include <boost/test/unit_test.hpp>
 
 #define BOOST_TEST_MAIN
 #include <boost/test/unit_test.hpp>
-
-#include "../logicdatasnapshot.h"
-
-BOOST_AUTO_TEST_CASE(LogicDataSnapshotTest)
-{
-       // Create an empty LogicDataSnapshot object
-       sr_datafeed_logic logic;
-       logic.length = 0;
-       logic.unitsize = 1;
-       logic.data = NULL;
-
-       LogicDataSnapshot s(logic);
-
-       BOOST_CHECK(s.get_sample_count() == 0);
-}