util.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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include "util.hpp"

#include <extdef.h>

#include <assert.h>

#include <algorithm>
#include <sstream>

#include <QTextStream>
#include <QDebug>

using namespace Qt;

namespace pv {
namespace util {

static QTextStream& operator<<(QTextStream& stream, SIPrefix prefix)
{
    switch (prefix) {
    case SIPrefix::yocto: return stream << 'y';
    case SIPrefix::zepto: return stream << 'z';
    case SIPrefix::atto:  return stream << 'a';
    case SIPrefix::femto: return stream << 'f';
    case SIPrefix::pico:  return stream << 'p';
    case SIPrefix::nano:  return stream << 'n';
    case SIPrefix::micro: return stream << QChar(0x03BC);
    case SIPrefix::milli: return stream << 'm';
    case SIPrefix::kilo:  return stream << 'k';
    case SIPrefix::mega:  return stream << 'M';
    case SIPrefix::giga:  return stream << 'G';
    case SIPrefix::tera:  return stream << 'T';
    case SIPrefix::peta:  return stream << 'P';
    case SIPrefix::exa:   return stream << 'E';
    case SIPrefix::zetta: return stream << 'Z';
    case SIPrefix::yotta: return stream << 'Y';

    default: return stream;
    }
}

int exponent(SIPrefix prefix)
{
    return 3 * (static_cast<int>(prefix) - static_cast<int>(SIPrefix::none));
}

static SIPrefix successor(SIPrefix prefix)
{
    assert(prefix != SIPrefix::yotta);
    return static_cast<SIPrefix>(static_cast<int>(prefix) + 1);
}

// Insert the timestamp value into the stream in fixed-point notation
// (and honor the precision)
static QTextStream& operator<<(QTextStream& stream, const Timestamp& t)
{
    // The multiprecision types already have a function and a stream insertion
    // operator to convert them to a string, however these functions abuse a
    // precision value of zero to print all available decimal places instead of
    // none, and the boost authors refuse to fix this because they don't want
    // to break buggy code that relies on this bug.
    // (https://svn.boost.org/trac/boost/ticket/10103)
    // Therefore we have to work around the case where precision is zero.

    int precision = stream.realNumberPrecision();

    std::ostringstream ss;
    ss << std::fixed;

    if (stream.numberFlags() & QTextStream::ForceSign)
        ss << std::showpos;

    if (0 == precision)
        ss << std::setprecision(1) << round(t);
    else
        ss << std::setprecision(precision) << t;

    std::string str(ss.str());
    if (0 == precision) {
        // remove the separator and the unwanted decimal place
        str.resize(str.size() - 2);
    }

    return stream << QString::fromStdString(str);
}

QString format_time_si(
    const Timestamp& v,
    SIPrefix prefix,
    unsigned int precision,
    QString unit,
    bool sign)
{
    if (prefix == SIPrefix::unspecified) {
        // No prefix given, calculate it

        if (v.is_zero()) {
            prefix = SIPrefix::none;
        } else {
            int exp = exponent(SIPrefix::yotta);
            prefix = SIPrefix::yocto;
            while ((fabs(v) * pow(Timestamp(10), exp)) > 999 &&
                    prefix < SIPrefix::yotta) {
                prefix = successor(prefix);
                exp -= 3;
            }
        }
    }

    assert(prefix >= SIPrefix::yocto);
    assert(prefix <= SIPrefix::yotta);

    const Timestamp multiplier = pow(Timestamp(10), -exponent(prefix));

    QString s;
    QTextStream ts(&s);
    if (sign && !v.is_zero())
        ts << forcesign;
    ts
        << qSetRealNumberPrecision(precision)
        << (v * multiplier)
        << ' '
        << prefix
        << unit;

    return s;
}

QString format_time_si_adjusted(
    const Timestamp& t,
    SIPrefix prefix,
    unsigned precision,
    QString unit,
    bool sign)
{
    // The precision is always given without taking the prefix into account
    // so we need to deduct the number of decimals the prefix might imply
    const int prefix_order = -exponent(prefix);

    const unsigned int relative_prec =
        (prefix >= SIPrefix::none) ? precision :
        std::max((int)(precision - prefix_order), 0);

    return format_time_si(t, prefix, relative_prec, unit, sign);
}


// Helper for 'format_time_minutes()'.
static QString pad_number(unsigned int number, int length)
{
    return QString("%1").arg(number, length, 10, QChar('0'));
}

QString format_time_minutes(const Timestamp& t, signed precision, bool sign)
{
    const Timestamp whole_seconds = floor(abs(t));
    const Timestamp days = floor(whole_seconds / (60 * 60 * 24));
    const unsigned int hours = fmod(whole_seconds / (60 * 60), 24).convert_to<uint>();
    const unsigned int minutes = fmod(whole_seconds / 60, 60).convert_to<uint>();
    const unsigned int seconds = fmod(whole_seconds, 60).convert_to<uint>();

    QString s;
    QTextStream ts(&s);

    if (t < 0)
        ts << "-";
    else if (sign)
        ts << "+";

    bool use_padding = false;

    // DD
    if (days) {
        ts << days.str().c_str() << ":";
        use_padding = true;
    }

    // HH
    if (hours || days) {
        ts << pad_number(hours, use_padding ? 2 : 0) << ":";
        use_padding = true;
    }

    // MM
    ts << pad_number(minutes, use_padding ? 2 : 0);

    ts << ":";

    // SS
    ts << pad_number(seconds, 2);

    if (precision) {
        ts << ".";

        const Timestamp fraction = fabs(t) - whole_seconds;

        std::ostringstream ss;
        ss
            << std::fixed
            << std::setprecision(precision)
            << std::setfill('0')
            << fraction;
        std::string fs = ss.str();

        // Copy all digits, inserting spaces as unit separators
        for (int i = 1; i <= precision; i++) {
            // Start at index 2 to skip the "0." at the beginning
            ts << fs.at(1 + i);

            if ((i > 0) && (i % 3 == 0) && (i != precision))
                ts << " ";
        }
    }

    return s;
}

} // namespace util
} // namespace pv