logicsegment.cpp: Minor whitespace fix.
[pulseview.git] / pv / data / logicsegment.cpp
index 38f4bf246c21a619e531be955af26075678c2569..b9e57caa9e797725ed5532e226353cef527b7649 100644 (file)
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "config.h" // For HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
+
 #include <extdef.h>
 
 #include <cassert>
 #include <cmath>
 #include <cstdlib>
 #include <cstring>
+#include <cstdint>
 
 #include "logic.hpp"
 #include "logicsegment.hpp"
@@ -46,11 +49,13 @@ const int LogicSegment::MipMapScaleFactor = 1 << MipMapScalePower;
 const float LogicSegment::LogMipMapScaleFactor = logf(MipMapScaleFactor);
 const uint64_t LogicSegment::MipMapDataUnit = 64 * 1024; // bytes
 
-LogicSegment::LogicSegment(pv::data::Logic& owner, unsigned int unit_size,
-       uint64_t samplerate) :
-       Segment(samplerate, unit_size),
+LogicSegment::LogicSegment(pv::data::Logic& owner, uint32_t segment_id,
+       unsigned int unit_size, uint64_t samplerate) :
+       Segment(segment_id, samplerate, unit_size),
        owner_(owner),
-       last_append_sample_(0)
+       last_append_sample_(0),
+       last_append_accumulator_(0),
+       last_append_extra_(0)
 {
        memset(mip_map_, 0, sizeof(mip_map_));
 }
@@ -62,7 +67,184 @@ LogicSegment::~LogicSegment()
                free(l.data);
 }
 
-uint64_t LogicSegment::unpack_sample(const uint8_t *ptr) const
+template <class T>
+void LogicSegment::downsampleTmain(const T*&in, T &acc, T &prev)
+{
+       // Accumulate one sample at a time
+       for (uint64_t i = 0; i < MipMapScaleFactor; i++) {
+               T sample = *in++;
+               acc |= prev ^ sample;
+               prev = sample;
+       }
+}
+
+template <>
+void LogicSegment::downsampleTmain<uint8_t>(const uint8_t*&in, uint8_t &acc, uint8_t &prev)
+{
+       // Handle 8 bit samples in 32 bit steps
+       uint32_t prev32 = prev | prev << 8 | prev << 16 | prev << 24;
+       uint32_t acc32 = acc;
+       const uint32_t *in32 = (const uint32_t*)in;
+       for (uint64_t i = 0; i < MipMapScaleFactor; i += 4) {
+               uint32_t sample32 = *in32++;
+               acc32 |= prev32 ^ sample32;
+               prev32 = sample32;
+       }
+       // Reduce result back to uint8_t
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+       prev = (prev32 >> 24) & 0xff; // MSB is last
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+       prev = prev32 & 0xff; // LSB is last
+#else
+#error Endianness unknown
+#endif
+       acc |= acc32 & 0xff;
+       acc |= (acc32 >> 8) & 0xff;
+       acc |= (acc32 >> 16) & 0xff;
+       acc |= (acc32 >> 24) & 0xff;
+       in = (const uint8_t*)in32;
+}
+
+template <>
+void LogicSegment::downsampleTmain<uint16_t>(const uint16_t*&in, uint16_t &acc, uint16_t &prev)
+{
+       // Handle 16 bit samples in 32 bit steps
+       uint32_t prev32 = prev | prev << 16;
+       uint32_t acc32 = acc;
+       const uint32_t *in32 = (const uint32_t*)in;
+       for (uint64_t i = 0; i < MipMapScaleFactor; i += 2) {
+               uint32_t sample32 = *in32++;
+               acc32 |= prev32 ^ sample32;
+               prev32 = sample32;
+       }
+       // Reduce result back to uint16_t
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+       prev = (prev32 >> 16) & 0xffff; // MSB is last
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+       prev = prev32 & 0xffff; // LSB is last
+#else
+#error Endian unknown
+#endif
+       acc |= acc32 & 0xffff;
+       acc |= (acc32 >> 16) & 0xffff;
+       in = (const uint16_t*)in32;
+}
+
+template <class T>
+void LogicSegment::downsampleT(const uint8_t *in_, uint8_t *&out_, uint64_t len)
+{
+       const T *in = (const T*)in_;
+       T *out = (T*)out_;
+       T prev = last_append_sample_;
+       T acc = last_append_accumulator_;
+
+       // Try to complete the previous downsample
+       if (last_append_extra_) {
+               while (last_append_extra_ < MipMapScaleFactor && len > 0) {
+                       T sample = *in++;
+                       acc |= prev ^ sample;
+                       prev = sample;
+                       last_append_extra_++;
+                       len--;
+               }
+               if (!len) {
+                       // Not enough samples available to complete downsample
+                       last_append_sample_ = prev;
+                       last_append_accumulator_ = acc;
+                       return;
+               }
+               // We have a complete downsample
+               *out++ = acc;
+               acc = 0;
+               last_append_extra_ = 0;
+       }
+
+       // Handle complete blocks of MipMapScaleFactor samples
+       while (len >= MipMapScaleFactor) {
+               downsampleTmain<T>(in, acc, prev);
+               len -= MipMapScaleFactor;
+               // Output downsample
+               *out++ = acc;
+               acc = 0;
+       }
+
+       // Process remainder, not enough for a complete sample
+       while (len > 0) {
+               T sample = *in++;
+               acc |= prev ^ sample;
+               prev = sample;
+               last_append_extra_++;
+               len--;
+       }
+
+       // Update context
+       last_append_sample_ = prev;
+       last_append_accumulator_ = acc;
+       out_ = (uint8_t *)out;
+}
+
+void LogicSegment::downsampleGeneric(const uint8_t *in, uint8_t *&out, uint64_t len)
+{
+       // Downsample using the generic unpack_sample()
+       // which can handle any width between 1 and 8 bytes
+       uint64_t prev = last_append_sample_;
+       uint64_t acc = last_append_accumulator_;
+
+       // Try to complete the previous downsample
+       if (last_append_extra_) {
+               while (last_append_extra_ < MipMapScaleFactor && len > 0) {
+                       const uint64_t sample = unpack_sample(in);
+                       in += unit_size_;
+                       acc |= prev ^ sample;
+                       prev = sample;
+                       last_append_extra_++;
+                       len--;
+               }
+               if (!len) {
+                       // Not enough samples available to complete downsample
+                       last_append_sample_ = prev;
+                       last_append_accumulator_ = acc;
+                       return;
+               }
+               // We have a complete downsample
+               pack_sample(out, acc);
+               out += unit_size_;
+               acc = 0;
+               last_append_extra_ = 0;
+       }
+
+       // Handle complete blocks of MipMapScaleFactor samples
+       while (len >= MipMapScaleFactor) {
+               // Accumulate one sample at a time
+               for (uint64_t i = 0; i < MipMapScaleFactor; i++) {
+                       const uint64_t sample = unpack_sample(in);
+                       in += unit_size_;
+                       acc |= prev ^ sample;
+                       prev = sample;
+               }
+               len -= MipMapScaleFactor;
+               // Output downsample
+               pack_sample(out, acc);
+               out += unit_size_;
+               acc = 0;
+       }
+
+       // Process remainder, not enough for a complete sample
+       while (len > 0) {
+               const uint64_t sample = unpack_sample(in);
+               in += unit_size_;
+               acc |= prev ^ sample;
+               prev = sample;
+               last_append_extra_++;
+               len--;
+       }
+
+       // Update context
+       last_append_sample_ = prev;
+       last_append_accumulator_ = acc;
+}
+
+inline uint64_t LogicSegment::unpack_sample(const uint8_t *ptr) const
 {
 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
        return *(uint64_t*)ptr;
@@ -100,7 +282,7 @@ uint64_t LogicSegment::unpack_sample(const uint8_t *ptr) const
 #endif
 }
 
-void LogicSegment::pack_sample(uint8_t *ptr, uint64_t value)
+inline void LogicSegment::pack_sample(uint8_t *ptr, uint64_t value)
 {
 #ifdef HAVE_UNALIGNED_LITTLE_ENDIAN_ACCESS
        *(uint64_t*)ptr = value;
@@ -150,8 +332,8 @@ void LogicSegment::append_payload(void *data, uint64_t data_size)
 
        lock_guard<recursive_mutex> lock(mutex_);
 
-       uint64_t prev_sample_count = sample_count_;
-       uint64_t sample_count = data_size / unit_size_;
+       const uint64_t prev_sample_count = sample_count_;
+       const uint64_t sample_count = data_size / unit_size_;
 
        append_samples(data, sample_count);
 
@@ -167,7 +349,7 @@ void LogicSegment::append_payload(void *data, uint64_t data_size)
 }
 
 void LogicSegment::get_samples(int64_t start_sample,
-       int64_t end_sample,     uint8_t* dest) const
+       int64_t end_sample, uint8_t* dest) const
 {
        assert(start_sample >= 0);
        assert(start_sample <= (int64_t)sample_count_);
@@ -181,134 +363,10 @@ void LogicSegment::get_samples(int64_t start_sample,
        get_raw_samples(start_sample, (end_sample - start_sample), dest);
 }
 
-SegmentLogicDataIterator* LogicSegment::begin_sample_iteration(uint64_t start)
-{
-       return (SegmentLogicDataIterator*)begin_raw_sample_iteration(start);
-}
-
-void LogicSegment::continue_sample_iteration(SegmentLogicDataIterator* it, uint64_t increase)
-{
-       Segment::continue_raw_sample_iteration((SegmentRawDataIterator*)it, increase);
-}
-
-void LogicSegment::end_sample_iteration(SegmentLogicDataIterator* it)
-{
-       Segment::end_raw_sample_iteration((SegmentRawDataIterator*)it);
-}
-
-void LogicSegment::reallocate_mipmap_level(MipMapLevel &m)
-{
-       lock_guard<recursive_mutex> lock(mutex_);
-
-       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;
-
-               // Padding is added to allow for the uint64_t write word
-               m.data = realloc(m.data, new_data_length * unit_size_ +
-                       sizeof(uint64_t));
-       }
-}
-
-void LogicSegment::append_payload_to_mipmap()
-{
-       MipMapLevel &m0 = mip_map_[0];
-       uint64_t prev_length;
-       uint8_t *dest_ptr;
-       SegmentRawDataIterator* it;
-       uint64_t accumulator;
-       unsigned int diff_counter;
-
-       // Expand the data buffer to fit the new samples
-       prev_length = m0.length;
-       m0.length = sample_count_ / MipMapScaleFactor;
-
-       // Break off if there are no new samples to compute
-       if (m0.length == prev_length)
-               return;
-
-       reallocate_mipmap_level(m0);
-
-       dest_ptr = (uint8_t*)m0.data + prev_length * unit_size_;
-
-       // Iterate through the samples to populate the first level mipmap
-       uint64_t start_sample = prev_length * MipMapScaleFactor;
-       uint64_t end_sample = m0.length * MipMapScaleFactor;
-
-       it = begin_raw_sample_iteration(start_sample);
-       for (uint64_t i = start_sample; i < end_sample;) {
-               // Accumulate transitions which have occurred in this sample
-               accumulator = 0;
-               diff_counter = MipMapScaleFactor;
-               while (diff_counter-- > 0) {
-                       const uint64_t sample = unpack_sample(it->value);
-                       accumulator |= last_append_sample_ ^ sample;
-                       last_append_sample_ = sample;
-                       continue_raw_sample_iteration(it, 1);
-                       i++;
-               }
-
-               pack_sample(dest_ptr, accumulator);
-               dest_ptr += unit_size_;
-       }
-       end_raw_sample_iteration(it);
-
-       // Compute higher level mipmaps
-       for (unsigned 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 be computed
-               if (m.length == prev_length)
-                       break;
-
-               reallocate_mipmap_level(m);
-
-               // Subsample the lower level
-               const uint8_t* src_ptr = (uint8_t*)ml.data +
-                       unit_size_ * prev_length * MipMapScaleFactor;
-               const uint8_t *const 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 |= unpack_sample(src_ptr);
-                               src_ptr += unit_size_;
-                       }
-
-                       pack_sample(dest_ptr, accumulator);
-               }
-       }
-}
-
-uint64_t LogicSegment::get_unpacked_sample(uint64_t index) const
-{
-       assert(index < sample_count_);
-
-       assert(unit_size_ <= 8);  // 8 * 8 = 64 channels
-       uint8_t data[8];
-
-       get_raw_samples(index, 1, data);
-       uint64_t sample = unpack_sample(data);
-
-       return sample;
-}
-
 void LogicSegment::get_subsampled_edges(
        vector<EdgePair> &edges,
        uint64_t start, uint64_t end,
-       float min_length, int sig_index)
+       float min_length, int sig_index, bool first_change_only)
 {
        uint64_t index = start;
        unsigned int level;
@@ -333,27 +391,27 @@ void LogicSegment::get_subsampled_edges(
 
        // Store the initial state
        last_sample = (get_unpacked_sample(start) & sig_mask) != 0;
-       edges.emplace_back(index++, last_sample);
+       if (!first_change_only)
+               edges.emplace_back(index++, last_sample);
 
        while (index + block_length <= end) {
                //----- Continue to search -----//
                level = min_level;
 
                // We cannot fast-forward if there is no mip-map data at
-               // at the minimum level.
+               // the minimum level.
                fast_forward = (mip_map_[level].data != nullptr);
 
                if (min_length < MipMapScaleFactor) {
                        // Search individual samples up to the beginning of
                        // the next first level mip map block
-                       const uint64_t final_index = min(end,
-                               pow2_ceil(index, MipMapScalePower));
+                       const uint64_t final_index = min(end, pow2_ceil(index, MipMapScalePower));
 
                        for (; index < final_index &&
                                        (index & ~((uint64_t)(~0) << MipMapScalePower)) != 0;
                                        index++) {
-                               const bool sample =
-                                       (get_unpacked_sample(index) & sig_mask) != 0;
+
+                               const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
 
                                // If there was a change we cannot fast forward
                                if (sample != last_sample) {
@@ -365,15 +423,13 @@ void LogicSegment::get_subsampled_edges(
                        // If resolution is less than a mip map block,
                        // round up to the beginning of the mip-map block
                        // for this level of detail
-                       const int min_level_scale_power =
-                               (level + 1) * MipMapScalePower;
+                       const int min_level_scale_power = (level + 1) * MipMapScalePower;
                        index = pow2_ceil(index, min_level_scale_power);
                        if (index >= end)
                                break;
 
                        // We can fast forward only if there was no change
-                       const bool sample =
-                               (get_unpacked_sample(index) & sig_mask) != 0;
+                       const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
                        if (last_sample != sample)
                                fast_forward = false;
                }
@@ -388,32 +444,27 @@ void LogicSegment::get_subsampled_edges(
                        // Slide right and zoom out at the beginnings of mip-map
                        // blocks until we encounter a change
                        while (true) {
-                               const int level_scale_power =
-                                       (level + 1) * MipMapScalePower;
-                               const uint64_t offset =
-                                       index >> level_scale_power;
+                               const int level_scale_power = (level + 1) * MipMapScalePower;
+                               const uint64_t offset = index >> level_scale_power;
 
                                // Check if we reached the last block at this
                                // level, or if there was a change in this block
                                if (offset >= mip_map_[level].length ||
-                                       (get_subsample(level, offset) &
-                                               sig_mask))
+                                       (get_subsample(level, offset) & sig_mask))
                                        break;
 
                                if ((offset & ~((uint64_t)(~0) << MipMapScalePower)) == 0) {
                                        // If we are now at the beginning of a
                                        // higher level mip-map block ascend one
                                        // level
-                                       if (level + 1 >= ScaleStepCount ||
-                                               !mip_map_[level + 1].data)
+                                       if ((level + 1 >= ScaleStepCount) || (!mip_map_[level + 1].data))
                                                break;
 
                                        level++;
                                } else {
                                        // Slide right to the beginning of the
                                        // next mip map block
-                                       index = pow2_ceil(index + 1,
-                                               level_scale_power);
+                                       index = pow2_ceil(index + 1, level_scale_power);
                                }
                        }
 
@@ -422,16 +473,13 @@ void LogicSegment::get_subsampled_edges(
                        while (true) {
                                assert(mip_map_[level].data);
 
-                               const int level_scale_power =
-                                       (level + 1) * MipMapScalePower;
-                               const uint64_t offset =
-                                       index >> level_scale_power;
+                               const int level_scale_power = (level + 1) * MipMapScalePower;
+                               const uint64_t offset = index >> level_scale_power;
 
                                // Check if we reached the last block at this
                                // level, or if there was a change in this block
                                if (offset >= mip_map_[level].length ||
-                                               (get_subsample(level, offset) &
-                                               sig_mask)) {
+                                               (get_subsample(level, offset) & sig_mask)) {
                                        // Zoom in unless we reached the minimum
                                        // zoom
                                        if (level == min_level)
@@ -441,8 +489,7 @@ void LogicSegment::get_subsampled_edges(
                                } else {
                                        // Slide right to the beginning of the
                                        // next mip map block
-                                       index = pow2_ceil(index + 1,
-                                               level_scale_power);
+                                       index = pow2_ceil(index + 1, level_scale_power);
                                }
                        }
 
@@ -451,8 +498,7 @@ void LogicSegment::get_subsampled_edges(
                        // block
                        if (min_length < MipMapScaleFactor) {
                                for (; index < end; index++) {
-                                       const bool sample = (get_unpacked_sample(index) &
-                                               sig_mask) != 0;
+                                       const bool sample = (get_unpacked_sample(index) & sig_mask) != 0;
                                        if (sample != last_sample)
                                                break;
                                }
@@ -467,19 +513,177 @@ void LogicSegment::get_subsampled_edges(
                        break;
 
                // Store the final state
-               const bool final_sample =
-                       (get_unpacked_sample(final_index - 1) & sig_mask) != 0;
+               const bool final_sample = (get_unpacked_sample(final_index - 1) & sig_mask) != 0;
                edges.emplace_back(index, final_sample);
 
                index = final_index;
                last_sample = final_sample;
+
+               if (first_change_only)
+                       break;
        }
 
        // Add the final state
-       const bool end_sample = get_unpacked_sample(end) & sig_mask;
-       if (last_sample != end_sample)
-               edges.emplace_back(end, end_sample);
-       edges.emplace_back(end + 1, end_sample);
+       if (!first_change_only) {
+               const bool end_sample = get_unpacked_sample(end) & sig_mask;
+               if (last_sample != end_sample)
+                       edges.emplace_back(end, end_sample);
+               edges.emplace_back(end + 1, end_sample);
+       }
+}
+
+void LogicSegment::get_surrounding_edges(vector<EdgePair> &dest,
+       uint64_t origin_sample, float min_length, int sig_index)
+{
+       if (origin_sample >= sample_count_)
+               return;
+
+       // Put the edges vector on the heap, it can become quite big until we can
+       // use a get_subsampled_edges() implementation that searches backwards
+       vector<EdgePair>* edges = new vector<EdgePair>;
+
+       // Get all edges to the left of origin_sample
+       get_subsampled_edges(*edges, 0, origin_sample, min_length, sig_index, false);
+
+       // If we don't specify "first only", the first and last edge are the states
+       // at samples 0 and origin_sample. If only those exist, there are no edges
+       if (edges->size() == 2) {
+               delete edges;
+               return;
+       }
+
+       // Dismiss the entry for origin_sample so that back() gives us the
+       // real last entry
+       edges->pop_back();
+       dest.push_back(edges->back());
+       edges->clear();
+
+       // Get first edge to the right of origin_sample
+       get_subsampled_edges(*edges, origin_sample, sample_count_, min_length, sig_index, true);
+
+       // "first only" is specified, so nothing needs to be dismissed
+       if (edges->size() == 0) {
+               delete edges;
+               return;
+       }
+
+       dest.push_back(edges->front());
+
+       delete edges;
+}
+
+void LogicSegment::reallocate_mipmap_level(MipMapLevel &m)
+{
+       lock_guard<recursive_mutex> lock(mutex_);
+
+       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;
+
+               // Padding is added to allow for the uint64_t write word
+               m.data = realloc(m.data, new_data_length * unit_size_ +
+                       sizeof(uint64_t));
+       }
+}
+
+void LogicSegment::append_payload_to_mipmap()
+{
+       MipMapLevel &m0 = mip_map_[0];
+       uint64_t prev_length;
+       uint8_t *dest_ptr;
+       SegmentDataIterator* it;
+       uint64_t accumulator;
+       unsigned int diff_counter;
+
+       // Expand the data buffer to fit the new samples
+       prev_length = m0.length;
+       m0.length = sample_count_ / MipMapScaleFactor;
+
+       // Break off if there are no new samples to compute
+       if (m0.length == prev_length)
+               return;
+
+       reallocate_mipmap_level(m0);
+
+       dest_ptr = (uint8_t*)m0.data + prev_length * unit_size_;
+
+       // Iterate through the samples to populate the first level mipmap
+       const uint64_t start_sample = prev_length * MipMapScaleFactor;
+       const uint64_t end_sample = m0.length * MipMapScaleFactor;
+       uint64_t len_sample = end_sample - start_sample;
+       it = begin_sample_iteration(start_sample);
+       while (len_sample > 0) {
+               // Number of samples available in this chunk
+               uint64_t count = get_iterator_valid_length(it);
+               // Reduce if less than asked for
+               count = std::min(count, len_sample);
+               uint8_t *src_ptr = get_iterator_value(it);
+               // Submit these contiguous samples to downsampling in bulk
+               if (unit_size_ == 1)
+                       downsampleT<uint8_t>(src_ptr, dest_ptr, count);
+               else if (unit_size_ == 2)
+                       downsampleT<uint16_t>(src_ptr, dest_ptr, count);
+               else if (unit_size_ == 4)
+                       downsampleT<uint32_t>(src_ptr, dest_ptr, count);
+               else if (unit_size_ == 8)
+                       downsampleT<uint8_t>(src_ptr, dest_ptr, count);
+               else
+                       downsampleGeneric(src_ptr, dest_ptr, count);
+               len_sample -= count;
+               // Advance iterator, should move to start of next chunk
+               continue_sample_iteration(it, count);
+       }
+       end_sample_iteration(it);
+
+       // Compute higher level mipmaps
+       for (unsigned 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 be computed
+               if (m.length == prev_length)
+                       break;
+
+               reallocate_mipmap_level(m);
+
+               // Subsample the lower level
+               const uint8_t* src_ptr = (uint8_t*)ml.data +
+                       unit_size_ * prev_length * MipMapScaleFactor;
+               const uint8_t *const 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 |= unpack_sample(src_ptr);
+                               src_ptr += unit_size_;
+                       }
+
+                       pack_sample(dest_ptr, accumulator);
+               }
+       }
+}
+
+uint64_t LogicSegment::get_unpacked_sample(uint64_t index) const
+{
+       assert(index < sample_count_);
+
+       assert(unit_size_ <= 8);  // 8 * 8 = 64 channels
+       uint8_t data[8];
+
+       get_raw_samples(index, 1, data);
+
+       return unpack_sample(data);
 }
 
 uint64_t LogicSegment::get_subsample(int level, uint64_t offset) const
@@ -492,7 +696,7 @@ uint64_t LogicSegment::get_subsample(int level, uint64_t offset) const
 
 uint64_t LogicSegment::pow2_ceil(uint64_t x, unsigned int power)
 {
-       const uint64_t p = 1 << power;
+       const uint64_t p = UINT64_C(1) << power;
        return (x + p - 1) / p * p;
 }