Adding upstream version 4:24.2.0.upstream/4%24.2.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 269 insertions, 0 deletions

diff --git a/include/o3tl/unit_conversion.hxx b/include/o3tl/unit_conversion.hxx
new file mode 100644
index 0000000000..54eb8cd246
--- /dev/null
+++ b/include/o3tl/unit_conversion.hxx
@@ -0,0 +1,269 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <o3tl/safeint.hxx>
+#include <sal/types.h>
+
+#include <array>
+#include <cassert>
+#include <numeric>
+#include <utility>
+#include <type_traits>
+
+namespace o3tl
+{
+// Length units
+enum class Length
+{
+    mm100 = 0, // 1/100th mm
+    mm10, // 1/10 mm, corresponds to MapUnit::Map10thMM
+    mm, // millimeter
+    cm, // centimeter
+    m, // meter
+    km, // kilometer
+    emu, // English Metric Unit: 1/360000 cm, 1/914400 in
+    twip, // "Twentieth of a point" aka "dxa": 1/20 pt
+    pt, // Point: 1/72 in
+    pc, // Pica: 1/6 in, corresponds to FieldUnit::PICA and MeasureUnit::PICA
+    in1000, // 1/1000 in, corresponds to MapUnit::Map1000thInch
+    in100, // 1/100 in, corresponds to MapUnit::Map100thInch
+    in10, // 1/10 in, corresponds to MapUnit::Map10thInch
+    in, // inch
+    ft, // foot
+    mi, // mile
+    master, // PPT Master Unit: 1/576 in
+    px, // "pixel" unit: 15 twip (96 ppi), corresponds to MeasureUnit::PIXEL
+    ch, // "char" unit: 210 twip (14 px), corresponds to FieldUnit::CHAR
+    line, // "line" unit: 312 twip, corresponds to FieldUnit::LINE
+    count, // <== add new units above this last entry
+    invalid = -1
+};
+
+// If other categories of units would be needed (like time), a separate scoped enum
+// should be created, respective conversion array prepared in detail namespace, and
+// respective md(NewUnit, NewUnit) overload introduced, which would allow using
+// o3tl::convert(), o3tl::convertSaturate() and o3tl::getConversionMulDiv() with the
+// new category in a type-safe way, without mixing unrelated units.
+
+namespace detail
+{
+// Common utilities
+
+// A special function to avoid compiler warning comparing signed and unsigned values
+template <typename I> constexpr bool isBetween(I n, sal_Int64 min, sal_Int64 max)
+{
+    assert(max > 0 && min < 0);
+    if constexpr (std::is_signed_v<I>)
+        return n >= min && n <= max;
+    else
+        return n <= sal_uInt64(max);
+}
+
+// Ensure correct rounding for both positive and negative integers
+template <typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0>
+constexpr sal_Int64 MulDiv(I n, sal_Int64 m, sal_Int64 d)
+{
+    assert(m > 0 && d > 0);
+    assert(isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m));
+    return (n >= 0 ? (n * m + d / 2) : (n * m - d / 2)) / d;
+}
+template <typename F, std::enable_if_t<std::is_floating_point_v<F>, int> = 0>
+constexpr double MulDiv(F f, sal_Int64 m, sal_Int64 d)
+{
+    assert(m > 0 && d > 0);
+    return f * (double(m) / d);
+}
+
+template <typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0>
+constexpr sal_Int64 MulDiv(I n, sal_Int64 m, sal_Int64 d, bool& bOverflow, sal_Int64 nDefault)
+{
+    if (!isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m))
+    {
+        bOverflow = true;
+        return nDefault;
+    }
+    bOverflow = false;
+    return MulDiv(n, m, d);
+}
+
+template <typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0>
+constexpr sal_Int64 MulDivSaturate(I n, sal_Int64 m, sal_Int64 d)
+{
+    if (sal_Int64 d_2 = d / 2; !isBetween(n, (SAL_MIN_INT64 + d_2) / m, (SAL_MAX_INT64 - d_2) / m))
+    {
+        if (n >= 0)
+        {
+            if (m > d && std::make_unsigned_t<I>(n) > sal_uInt64(SAL_MAX_INT64 / m * d - d_2))
+                return SAL_MAX_INT64; // saturate
+            return saturating_add<sal_uInt64>(n, d_2) / d * m; // divide before multiplication
+        }
+        else if constexpr (std::is_signed_v<I>) // n < 0; don't compile for unsigned n
+        {
+            if (m > d && n < SAL_MIN_INT64 / m * d + d_2)
+                return SAL_MIN_INT64; // saturate
+            return saturating_sub<sal_Int64>(n, d_2) / d * m; // divide before multiplication
+        }
+    }
+    return MulDiv(n, m, d);
+}
+
+template <class M, class N> constexpr std::common_type_t<M, N> asserting_gcd(M m, N n)
+{
+    auto ret = std::gcd(m, n);
+    assert(ret != 0);
+    return ret;
+}
+
+// Packs integral multiplier and divisor for conversion from one unit to another
+struct m_and_d
+{
+    sal_Int64 m; // multiplier
+    sal_Int64 d; // divisor
+    constexpr m_and_d(sal_Int64 _m, sal_Int64 _d)
+        : m(_m / asserting_gcd(_m, _d)) // make sure to use smallest quotients here because
+        , d(_d / asserting_gcd(_m, _d)) // they will be multiplied when building final table
+    {
+        assert(_m > 0 && _d > 0);
+    }
+};
+
+// Resulting static array N x N of all quotients to convert between all units. The
+// quotients are minimal to allow largest range of converted numbers without overflow.
+// Maybe o3tl::enumarray could be used here, but it's not constexpr yet.
+template <int N> constexpr auto prepareMDArray(const m_and_d (&mdBase)[N])
+{
+    std::array<std::array<sal_Int64, N>, N> a{};
+    for (int i = 0; i < N; ++i)
+    {
+        a[i][i] = 1;
+        for (int j = 0; j < i; ++j)
+        {
+            assert(mdBase[i].m < SAL_MAX_INT64 / mdBase[j].d);
+            assert(mdBase[i].d < SAL_MAX_INT64 / mdBase[j].m);
+            const sal_Int64 m = mdBase[i].m * mdBase[j].d, d = mdBase[i].d * mdBase[j].m;
+            const sal_Int64 g = asserting_gcd(m, d);
+            a[i][j] = m / g;
+            a[j][i] = d / g;
+        }
+    }
+    return a;
+}
+
+// A generic template used for fundamental arithmetic types
+template <typename U> constexpr sal_Int64 md(U i, U /*j*/) { return i; }
+
+// Length units implementation
+
+// Array of conversion quotients for mm, used to build final conversion table. Entries
+// are { multiplier, divider } to convert respective unit *to* mm. Order of elements
+// corresponds to order in o3tl::Length enum (Length::count and Length::invalid omitted).
+constexpr m_and_d mdBaseLen[] = {
+    { 1, 100 }, // mm100 => mm
+    { 1, 10 }, // mm10 => mm
+    { 1, 1 }, // mm => mm
+    { 10, 1 }, // cm => mm
+    { 1000, 1 }, // m => mm
+    { 1000000, 1 }, // km => mm
+    { 1, 36000 }, // emu => mm
+    { 254, 10 * 1440 }, // twip => mm
+    { 254, 10 * 72 }, // pt => mm
+    { 254, 10 * 6 }, // pc => mm
+    { 254, 10000 }, // in1000 => mm
+    { 254, 1000 }, // in100 => mm
+    { 254, 100 }, // in10 => mm
+    { 254, 10 }, // in => mm
+    { 254 * 12, 10 }, // ft => mm
+    { 254 * 12 * 5280, 10 }, // mi => mm
+    { 254, 10 * 576 }, // master => mm
+    { 254 * 15, 10 * 1440 }, // px => mm
+    { 254 * 210, 10 * 1440 }, // ch => mm
+    { 254 * 312, 10 * 1440 }, // line => mm
+};
+static_assert(std::size(mdBaseLen) == static_cast<int>(Length::count),
+              "mdBaseL must have an entry for each unit in o3tl::Length");
+
+// The resulting multipliers and divisors array
+constexpr auto aLengthMDArray = prepareMDArray(mdBaseLen);
+
+// an overload taking Length
+constexpr sal_Int64 md(Length i, Length j)
+{
+    const int nI = static_cast<int>(i), nJ = static_cast<int>(j);
+    assert(nI >= 0 && o3tl::make_unsigned(nI) < aLengthMDArray.size());
+    assert(nJ >= 0 && o3tl::make_unsigned(nJ) < aLengthMDArray.size());
+    return aLengthMDArray[nI][nJ];
+}
+
+// here might go overloads of md() taking other units ...
+}
+
+// Unchecked conversion. Takes a number value, multiplier and divisor
+template <typename N> constexpr auto convert(N n, sal_Int64 mul, sal_Int64 div)
+{
+    return detail::MulDiv(n, mul, div);
+}
+
+// Unchecked conversion. Takes a number value and units defined in this header
+template <typename N, typename U> constexpr auto convert(N n, U from, U to)
+{
+    return convert(n, detail::md(from, to), detail::md(to, from));
+}
+
+// Convert to twips - for convenience as we do this a lot
+template <typename N> constexpr auto toTwips(N number, Length from)
+{
+    return convert(number, from, Length::twip);
+}
+
+// Returns nDefault if intermediate multiplication overflows sal_Int64 (only for integral types).
+// On return, bOverflow indicates if overflow happened. nDefault is returned when overflow occurs.
+template <typename N, typename U>
+constexpr auto convert(N n, U from, U to, bool& bOverflow, sal_Int64 nDefault = 0)
+{
+    return detail::MulDiv(n, detail::md(from, to), detail::md(to, from), bOverflow, nDefault);
+}
+
+// Conversion with saturation (only for integral types). For too large input returns SAL_MAX_INT64.
+// When intermediate multiplication would overflow, but the end result is in sal_Int64 range, the
+// precision is decreased because of inversion of multiplication and division.
+template <typename N, typename U> constexpr auto convertSaturate(N n, U from, U to)
+{
+    return detail::MulDivSaturate(n, detail::md(from, to), detail::md(to, from));
+}
+
+// Conversion with saturation (only for integral types), optimized for return types smaller than
+// sal_Int64. In this case, it's easier to clamp input values to known bounds, than to do some
+// preprocessing to handle too large input values, just to clamp the result anyway. Use it like:
+//
+//     sal_Int32 n = convertNarrowing<sal_Int32, o3tl::Length::mm100, o3tl::Length::emu>(m);
+template <typename Out, auto from, auto to, typename N,
+          std::enable_if_t<
+              std::is_integral_v<N> && std::is_integral_v<Out> && sizeof(Out) < sizeof(sal_Int64),
+              int> = 0>
+constexpr Out convertNarrowing(N n)
+{
+    constexpr sal_Int64 nMin = convertSaturate(std::numeric_limits<Out>::min(), to, from);
+    constexpr sal_Int64 nMax = convertSaturate(std::numeric_limits<Out>::max(), to, from);
+    if (static_cast<sal_Int64>(n) > nMax)
+        return std::numeric_limits<Out>::max();
+    if (static_cast<sal_Int64>(n) < nMin)
+        return std::numeric_limits<Out>::min();
+    return convert(n, from, to);
+}
+
+// Return a pair { multiplier, divisor } for a given conversion
+template <typename U> constexpr std::pair<sal_Int64, sal_Int64> getConversionMulDiv(U from, U to)
+{
+    return { detail::md(from, to), detail::md(to, from) };
+}
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */