analogsegment.cpp

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/*
 * This file is part of the PulseView 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, see <http://www.gnu.org/licenses/>.
 */

#include <extdef.h>

#include <cassert>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <memory>

#include <algorithm>

#include "analog.hpp"
#include "analogsegment.hpp"

using std::lock_guard;
using std::recursive_mutex;
using std::make_pair;
using std::max;
using std::max_element;
using std::min;
using std::min_element;
using std::pair;
using std::unique_ptr;

namespace pv {
namespace data {

const int AnalogSegment::EnvelopeScalePower = 4;
const int AnalogSegment::EnvelopeScaleFactor = 1 << EnvelopeScalePower;
const float AnalogSegment::LogEnvelopeScaleFactor = logf(EnvelopeScaleFactor);
const uint64_t AnalogSegment::EnvelopeDataUnit = 64 * 1024; // bytes

AnalogSegment::AnalogSegment(Analog& owner, uint32_t segment_id, uint64_t samplerate) :
    Segment(segment_id, samplerate, sizeof(float)),
    owner_(owner),
    min_value_(0),
    max_value_(0)
{
    lock_guard<recursive_mutex> lock(mutex_);
    memset(envelope_levels_, 0, sizeof(envelope_levels_));
}

AnalogSegment::~AnalogSegment()
{
    lock_guard<recursive_mutex> lock(mutex_);
    for (Envelope &e : envelope_levels_)
        free(e.samples);
}

void AnalogSegment::append_interleaved_samples(const float *data,
    size_t sample_count, size_t stride)
{
    assert(unit_size_ == sizeof(float));

    lock_guard<recursive_mutex> lock(mutex_);

    uint64_t prev_sample_count = sample_count_;

    // Deinterleave the samples and add them
    unique_ptr<float[]> deint_data(new float[sample_count]);
    float *deint_data_ptr = deint_data.get();
    for (uint32_t i = 0; i < sample_count; i++) {
        *deint_data_ptr = (float)(*data);
        deint_data_ptr++;
        data += stride;
    }

    append_samples(deint_data.get(), sample_count);

    // Generate the first mip-map from the data
    append_payload_to_envelope_levels();

    if (sample_count > 1)
        owner_.notify_samples_added(shared_ptr<Segment>(shared_from_this()),
            prev_sample_count + 1, prev_sample_count + 1 + sample_count);
    else
        owner_.notify_samples_added(shared_ptr<Segment>(shared_from_this()),
            prev_sample_count + 1, prev_sample_count + 1);
}

float AnalogSegment::get_sample(int64_t sample_num) const
{
    assert(sample_num >= 0);
    assert(sample_num <= (int64_t)sample_count_);

    lock_guard<recursive_mutex> lock(mutex_);  // Because of free_unused_memory()

    return *((const float*)get_raw_sample(sample_num));
}

void AnalogSegment::get_samples(int64_t start_sample, int64_t end_sample,
    float* dest) const
{
    assert(start_sample >= 0);
    assert(start_sample < (int64_t)sample_count_);
    assert(end_sample >= 0);
    assert(end_sample <= (int64_t)sample_count_);
    assert(start_sample <= end_sample);
    assert(dest != nullptr);

    lock_guard<recursive_mutex> lock(mutex_);

    get_raw_samples(start_sample, (end_sample - start_sample), (uint8_t*)dest);
}

const pair<float, float> AnalogSegment::get_min_max() const
{
    return make_pair(min_value_, max_value_);
}

float* AnalogSegment::get_iterator_value_ptr(SegmentDataIterator* it)
{
    assert(it->sample_index <= (sample_count_ - 1));

    return (float*)(it->chunk + it->chunk_offs);
}

void AnalogSegment::get_envelope_section(EnvelopeSection &s,
    uint64_t start, uint64_t end, float min_length) const
{
    assert(end <= get_sample_count());
    assert(start <= end);
    assert(min_length > 0);

    lock_guard<recursive_mutex> lock(mutex_);

    const unsigned int min_level = max((int)floorf(logf(min_length) /
        LogEnvelopeScaleFactor) - 1, 0);
    const unsigned int scale_power = (min_level + 1) *
        EnvelopeScalePower;
    start >>= scale_power;
    end >>= scale_power;

    s.start = start << scale_power;
    s.scale = 1 << scale_power;
    s.length = end - start;
    s.samples = new EnvelopeSample[s.length];
    memcpy(s.samples, envelope_levels_[min_level].samples + start,
        s.length * sizeof(EnvelopeSample));
}

void AnalogSegment::reallocate_envelope(Envelope &e)
{
    const uint64_t new_data_length = ((e.length + EnvelopeDataUnit - 1) /
        EnvelopeDataUnit) * EnvelopeDataUnit;
    if (new_data_length > e.data_length) {
        e.data_length = new_data_length;
        e.samples = (EnvelopeSample*)realloc(e.samples,
            new_data_length * sizeof(EnvelopeSample));
    }
}

void AnalogSegment::append_payload_to_envelope_levels()
{
    Envelope &e0 = envelope_levels_[0];
    uint64_t prev_length;
    EnvelopeSample *dest_ptr;
    SegmentDataIterator* it;

    // Expand the data buffer to fit the new samples
    prev_length = e0.length;
    e0.length = sample_count_ / EnvelopeScaleFactor;

    // Calculate min/max values in case we have too few samples for an envelope
    const float old_min_value = min_value_, old_max_value = max_value_;
    if (sample_count_ < EnvelopeScaleFactor) {
        it = begin_sample_iteration(0);
        for (uint64_t i = 0; i < sample_count_; i++) {
            const float sample = *get_iterator_value_ptr(it);
            if (sample < min_value_)
                min_value_ = sample;
            if (sample > max_value_)
                max_value_ = sample;
            continue_sample_iteration(it, 1);
        }
        end_sample_iteration(it);
    }

    // Break off if there are no new samples to compute
    if (e0.length == prev_length)
        return;

    reallocate_envelope(e0);

    dest_ptr = e0.samples + prev_length;

    // Iterate through the samples to populate the first level mipmap
    uint64_t start_sample = prev_length * EnvelopeScaleFactor;
    uint64_t end_sample = e0.length * EnvelopeScaleFactor;

    it = begin_sample_iteration(start_sample);
    for (uint64_t i = start_sample; i < end_sample; i += EnvelopeScaleFactor) {
        const float* samples = get_iterator_value_ptr(it);

        const EnvelopeSample sub_sample = {
            *min_element(samples, samples + EnvelopeScaleFactor),
            *max_element(samples, samples + EnvelopeScaleFactor),
        };

        if (sub_sample.min < min_value_)
            min_value_ = sub_sample.min;
        if (sub_sample.max > max_value_)
            max_value_ = sub_sample.max;

        continue_sample_iteration(it, EnvelopeScaleFactor);
        *dest_ptr++ = sub_sample;
    }
    end_sample_iteration(it);

    // Compute higher level mipmaps
    for (unsigned int level = 1; level < ScaleStepCount; level++) {
        Envelope &e = envelope_levels_[level];
        const Envelope &el = envelope_levels_[level - 1];

        // Expand the data buffer to fit the new samples
        prev_length = e.length;
        e.length = el.length / EnvelopeScaleFactor;

        // Break off if there are no more samples to be computed
        if (e.length == prev_length)
            break;

        reallocate_envelope(e);

        // Subsample the lower level
        const EnvelopeSample *src_ptr =
            el.samples + prev_length * EnvelopeScaleFactor;
        const EnvelopeSample *const end_dest_ptr = e.samples + e.length;

        for (dest_ptr = e.samples + prev_length;
                dest_ptr < end_dest_ptr; dest_ptr++) {
            const EnvelopeSample *const end_src_ptr =
                src_ptr + EnvelopeScaleFactor;

            EnvelopeSample sub_sample = *src_ptr++;
            while (src_ptr < end_src_ptr) {
                sub_sample.min = min(sub_sample.min, src_ptr->min);;
                sub_sample.max = max(sub_sample.max, src_ptr->max);
                src_ptr++;
            }

            *dest_ptr = sub_sample;
        }
    }

    // Notify if the min or max value changed
    if ((old_min_value != min_value_) || (old_max_value != max_value_))
        owner_.min_max_changed(min_value_, max_value_);
}

} // namespace data
} // namespace pv