diff options
Diffstat (limited to 'include/tools')
| -rw-r--r-- | include/tools/UnitConversion.hxx | 66 |
1 files changed, 40 insertions, 26 deletions
diff --git a/include/tools/UnitConversion.hxx b/include/tools/UnitConversion.hxx index 57f8e39119f0..7aac3f36ebd0 100644 --- a/include/tools/UnitConversion.hxx +++ b/include/tools/UnitConversion.hxx @@ -12,46 +12,60 @@ #include <sal/types.h> #include <cassert> -#include <limits> +#include <type_traits> -constexpr sal_Int64 convertTwipToMm100(sal_Int64 n) +template <typename I> constexpr bool isBetween(I n, sal_Int64 min, sal_Int64 max) { - assert(n < std::numeric_limits<sal_Int64>::max() / 127 - && n > std::numeric_limits<sal_Int64>::min() / 127); - return (n >= 0) ? (n * 127 + 36) / 72 : (n * 127 - 36) / 72; + assert(max > 0 && min < 0); + if constexpr (std::is_signed_v<I>) + return n >= min && n <= max; + else + return n <= sal_uInt64(max); } -constexpr sal_Int64 convertMm100ToTwip(sal_Int64 n) +constexpr int actualMul(int m, int d) { return (m % d == 0) ? m / d : (d % m == 0) ? 1 : m; } +constexpr int actualDiv(int m, int d) { return (m % d == 0) ? 1 : (d % m == 0) ? d / m : d; } + +// Ensure correct rounding for both positive and negative integers +template <int mul, int div, typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0> +constexpr sal_Int64 MulDiv(I n) { - assert(n < std::numeric_limits<sal_Int64>::max() / 72 - && n > std::numeric_limits<sal_Int64>::min() / 72); - return (n >= 0) ? (n * 72 + 63) / 127 : (n * 72 - 63) / 127; + static_assert(mul > 0 && div > 0); + constexpr int m = actualMul(mul, div), d = actualDiv(mul, div); + assert(isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m)); + return (n >= 0 ? (sal_Int64(n) * m + d / 2) : (sal_Int64(n) * m - d / 2)) / d; } - -constexpr sal_Int64 sanitiseMm100ToTwip(sal_Int64 n) +template <int mul, int div, typename F, std::enable_if_t<std::is_floating_point_v<F>, int> = 0> +constexpr double MulDiv(F f) { - if (n >= std::numeric_limits<sal_Int64>::max() / 72 - || n <= std::numeric_limits<sal_Int64>::min() / 72) - return n / 127 * 72; // do without correction; can not overflow here - else - return convertMm100ToTwip(n); + static_assert(mul > 0 && div > 0); + return f * (double(mul) / div); } -constexpr sal_Int64 convertPointToTwip(sal_Int64 nNumber) { return nNumber * 20; } - -constexpr sal_Int64 convertPointToMm100(sal_Int64 nNumber) +template <int mul, int div, typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0> +constexpr sal_Int64 sanitizeMulDiv(I n) { - return convertTwipToMm100(convertPointToTwip(nNumber)); + constexpr int m = actualMul(mul, div), d = actualDiv(mul, div); + if constexpr (m > d) + if (!isBetween(n, SAL_MIN_INT64 / m * d + d / 2, SAL_MAX_INT64 / m * d - d / 2)) + return n > 0 ? SAL_MAX_INT64 : SAL_MIN_INT64; // saturate + if (!isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m)) + return (n >= 0 ? n + d / 2 : n - d / 2) / d * m; // divide before multiplication + return MulDiv<mul, div>(n); } -constexpr double convertPointToTwip(double fNumber) { return fNumber * 20.0; } +template <typename N> constexpr auto convertTwipToMm100(N n) { return MulDiv<127, 72>(n); } +template <typename N> constexpr auto convertMm100ToTwip(N n) { return MulDiv<72, 127>(n); } + +constexpr sal_Int64 sanitiseMm100ToTwip(sal_Int64 n) { return sanitizeMulDiv<72, 127>(n); } -constexpr double convertPointToMm100(double fNumber) { return fNumber * (2540.0 / 72.0); } +template <typename N> constexpr auto convertPointToTwip(N n) { return MulDiv<20, 1>(n); } -// Convert PPT's "master unit" (1/576 inch) to mm/100 -constexpr sal_Int64 convertMasterUnitToMm100(sal_Int64 n) { return n * (2540.0 / 576.0); } +template <typename N> constexpr auto convertPointToMm100(N n) { return MulDiv<2540, 72>(n); } +template <typename N> constexpr auto convertMm100ToPoint(N n) { return MulDiv<72, 2540>(n); } -// Convert mm/100 to PPT's "master unit" -constexpr sal_Int64 convertMm100ToMasterUnit(sal_Int64 n) { return n / (2540.0 / 576.0); } +// PPT's "master unit" (1/576 inch) <=> mm/100 +template <typename N> constexpr auto convertMasterUnitToMm100(N n) { return MulDiv<2540, 576>(n); } +template <typename N> constexpr auto convertMm100ToMasterUnit(N n) { return MulDiv<576, 2540>(n); } /* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |