1 files changed, 226 insertions, 0 deletions
diff --git a/FreeFileSync/Source/base/speed_test.cpp b/FreeFileSync/Source/base/speed_test.cpp
new file mode 100644
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+++ b/FreeFileSync/Source/base/speed_test.cpp
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+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#include "speed_test.h"
+#include <zen/basic_math.h>
+#include <zen/i18n.h>
+#include <zen/format_unit.h>
+
+using namespace zen;
+using namespace fff;
+
+
+void SpeedTest::addSample(std::chrono::nanoseconds timeElapsed, int itemsCurrent, int64_t bytesCurrent)
+{
+    //time expected to be monotonously ascending
+    assert(samples_.empty() || samples_.back().timeElapsed <= timeElapsed);
+
+    samples_.push_back(Sample{timeElapsed, itemsCurrent, bytesCurrent});
+
+    //remove old records outside of "window"
+    std::optional<Sample> lastPop;
+    while (!samples_.empty() && samples_.front().timeElapsed <= timeElapsed - windowSize_)
+    {
+        lastPop = samples_.front();
+        samples_.pop_front();
+    }
+    if (lastPop) //keep one point before new start to handle gaps
+        samples_.push_front(*lastPop);
+}
+
+
+std::optional<double> SpeedTest::getRemainingSec(int /*itemsRemaining*/, int64_t bytesRemaining) const
+{
+    if (!samples_.empty())
+    {
+        const double timeDelta = std::chrono::duration<double>(samples_.back().timeElapsed - samples_.front().timeElapsed).count();
+        const int64_t bytesDelta = samples_.back().bytes - samples_.front().bytes;
+
+        //"items" counts logical operations *NOT* disk accesses, so we better play safe and use "bytes" only!
+
+        if (bytesDelta != 0) //sign(dataRemaining) != sign(bytesDelta) usually an error, so show it!
+            return bytesRemaining * timeDelta / bytesDelta;
+    }
+    return std::nullopt;
+}
+
+
+std::optional<double> SpeedTest::getBytesPerSec() const
+{
+    if (!samples_.empty())
+    {
+        const double timeDelta = std::chrono::duration<double>(samples_.back().timeElapsed - samples_.front().timeElapsed).count();
+        const int64_t bytesDelta = samples_.back().bytes - samples_.front().bytes;
+
+        if (!numeric::isNull(timeDelta))
+            return bytesDelta / timeDelta;
+    }
+    return std::nullopt;
+}
+
+
+std::optional<double> SpeedTest::getItemsPerSec() const
+{
+    if (!samples_.empty())
+    {
+        const double timeDelta = std::chrono::duration<double>(samples_.back().timeElapsed - samples_.front().timeElapsed).count();
+        const int itemsDelta = samples_.back().items - samples_.front().items;
+
+        if (!numeric::isNull(timeDelta))
+            return itemsDelta / timeDelta;
+    }
+    return std::nullopt;
+}
+
+
+std::wstring SpeedTest::getBytesPerSecFmt() const
+{
+    if (const std::optional<double> bps = getBytesPerSec())
+        return replaceCpy(_("%x/sec"), L"%x", formatFilesizeShort(std::llround(*bps)));
+    return {};
+}
+
+
+std::wstring SpeedTest::getItemsPerSecFmt() const
+{
+    if (const std::optional<double> ips = getItemsPerSec())
+        return replaceCpy(_("%x/sec"), L"%x", replaceCpy(_("%x items"), L"%x", formatTwoDigitPrecision(*ips)));
+    return {};
+}
+
+
+/*
+class for calculation of remaining time:
+----------------------------------------
+"filesize |-> time" is an affine linear function f(x) = z_1 + z_2 x
+
+For given n measurements, sizes x_0, ..., x_n and times f_0, ..., f_n, the function f (as a polynom of degree 1) can be lineary approximated by
+
+z_1 = (r - s * q / p) / ((n + 1) - s * s / p)
+z_2 = (q - s * z_1) / p = (r - (n + 1) z_1) / s
+
+with
+p := x_0^2 + ... + x_n^2
+q := f_0 x_0 + ... + f_n x_n
+r := f_0 + ... + f_n
+s := x_0 + ... + x_n
+
+=> the time to process N files with amount of data D is:    N * z_1 + D * z_2
+
+Problem:
+--------
+Times f_0, ..., f_n can be very small so that precision of the PC clock is poor.
+=> Times have to be accumulated to enhance precision:
+Copying of m files with sizes x_i and times f_i (i = 1, ..., m) takes sum_i f(x_i) := m * z_1 + z_2 * sum x_i = sum f_i
+With X defined as the accumulated sizes and F the accumulated times this gives: (in theory...)
+m * z_1 + z_2 * X = F   <=>
+z_1 + z_2 * X / m = F / m
+
+=> we obtain a new (artificial) measurement with size X / m and time F / m to be used in the linear approximation above
+
+
+Statistics::Statistics(int totalObjectCount, double totalDataAmount, unsigned recordCount) :
+        itemsTotal(totalObjectCount),
+        bytesTotal(totalDataAmount),
+        recordsMax(recordCount),
+        objectsLast(0),
+        dataLast(0),
+        timeLast(wxGetLocalTimeMillis()),
+        z1_current(0),
+        z2_current(0),
+        dummyRecordPresent(false) {}
+
+
+wxString Statistics::getRemainingTime(int objectsCurrent, double dataCurrent)
+{
+    //add new measurement point
+    const int m = objectsCurrent - objectsLast;
+    if (m != 0)
+    {
+        objectsLast = objectsCurrent;
+
+        const double X = dataCurrent - dataLast;
+        dataLast = dataCurrent;
+
+        const int64_t timeCurrent = wxGetLocalTimeMillis();
+        const double F = (timeCurrent - timeLast).ToDouble();
+        timeLast = timeCurrent;
+
+        record newEntry;
+        newEntry.x_i = X / m;
+        newEntry.f_i = F / m;
+
+        //remove dummy record
+        if (dummyRecordPresent)
+        {
+            measurements.pop_back();
+            dummyRecordPresent = false;
+        }
+
+        //insert new record
+        measurements.push_back(newEntry);
+        if (measurements.size() > recordsMax)
+            measurements.pop_front();
+    }
+    else //dataCurrent increased without processing new objects:
+    {    //modify last measurement until m != 0
+        const double X = dataCurrent - dataLast; //do not set dataLast, timeLast variables here, but write dummy record instead
+        if (!isNull(X))
+        {
+            const int64_t timeCurrent = wxGetLocalTimeMillis();
+            const double F = (timeCurrent - timeLast).ToDouble();
+
+            record modifyEntry;
+            modifyEntry.x_i = X;
+            modifyEntry.f_i = F;
+
+            //insert dummy record
+            if (!dummyRecordPresent)
+            {
+                measurements.push_back(modifyEntry);
+                if (measurements.size() > recordsMax)
+                    measurements.pop_front();
+                dummyRecordPresent = true;
+            }
+            else //modify dummy record
+                measurements.back() = modifyEntry;
+        }
+    }
+
+    //calculate remaining time based on stored measurement points
+    double p = 0;
+    double q = 0;
+    double r = 0;
+    double s = 0;
+    for (const record& rec : measurements)
+    {
+        const double x_i = rec.x_i;
+        const double f_i = rec.f_i;
+        p += x_i * x_i;
+        q += f_i * x_i;
+        r += f_i;
+        s += x_i;
+    }
+
+    if (!isNull(p))
+    {
+        const double n   = measurements.size();
+        const double tmp = (n - s * s / p);
+
+        if (!isNull(tmp) && !isNull(s))
+        {
+            const double z1 = (r - s * q / p) / tmp;
+            const double z2 = (r - n * z1) / s;    //not (n + 1) here, since n already is the number of measurements
+
+            //refresh current values for z1, z2
+            z1_current = z1;
+            z2_current = z2;
+        }
+    }
+
+    return formatRemainingTime((itemsTotal - objectsCurrent) * z1_current + (bytesTotal - dataCurrent) * z2_current);
+}
+*/