diff options
Diffstat (limited to 'common/bsinc_tables.cpp')
| -rw-r--r-- | common/bsinc_tables.cpp | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/common/bsinc_tables.cpp b/common/bsinc_tables.cpp index 853fe605..460462cd 100644 --- a/common/bsinc_tables.cpp +++ b/common/bsinc_tables.cpp @@ -2,6 +2,7 @@ #include "bsinc_tables.h" #include <algorithm> +#include <array> #include <cassert> #include <cmath> #include <limits> @@ -198,25 +199,19 @@ constexpr BSincHeader GenerateBSincHeader(int Rejection, int Order) } /* 11th and 23rd order filters (12 and 24-point respectively) with a 60dB drop - * at nyquist. Each filter will scale up the order when downsampling, to 23 and - * 47th order respectively. + * at nyquist. Each filter will scale up the order when downsampling, to 23rd + * and 47th order respectively. */ constexpr BSincHeader bsinc12_hdr{GenerateBSincHeader(60, 11)}; constexpr BSincHeader bsinc24_hdr{GenerateBSincHeader(60, 23)}; -/* std::array is missing constexpr for several methods. */ -template<typename T, size_t N> -struct Array { - T data[N]; -}; - -/* FIXME: This should be constexpr, but the temporary filter table is apparently too big - * (~200K) for some systems. This requires using heap space, which is not - * allowed in a constexpr function. +/* FIXME: This should be constexpr, but the temporary filter arrays are too + * big. This requires using heap space, which is not allowed in a constexpr + * function (maybe in C++20). */ template<size_t total_size> -auto GenerateBSincCoeffs(const BSincHeader &hdr) +std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr) { auto filter = std::make_unique<double[][BSincPhaseCount+1][BSincPointsMax]>(BSincScaleCount); @@ -248,7 +243,7 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) } } - Array<float,total_size> ret{}; + auto ret = std::make_unique<std::array<float,total_size>>(); size_t idx{0}; for(unsigned int si{0};si < BSincScaleCount-1;++si) @@ -262,7 +257,7 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) * scale deltas. */ for(int i{0};i < m;++i) - ret.data[idx++] = static_cast<float>(filter[si][pi][o+i]); + (*ret)[idx++] = static_cast<float>(filter[si][pi][o+i]); /* Linear interpolation between phases is simplified by pre- * calculating the delta (b - a) in: x = a + f (b - a) @@ -270,7 +265,7 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) for(int i{0};i < m;++i) { const double phDelta{filter[si][pi+1][o+i] - filter[si][pi][o+i]}; - ret.data[idx++] = static_cast<float>(phDelta); + (*ret)[idx++] = static_cast<float>(phDelta); } /* Linear interpolation between scales is also simplified. @@ -281,7 +276,7 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) for(int i{0};i < m;++i) { const double scDelta{filter[si+1][pi][o+i] - filter[si][pi][o+i]}; - ret.data[idx++] = static_cast<float>(scDelta); + (*ret)[idx++] = static_cast<float>(scDelta); } /* This last simplification is done to complete the bilinear @@ -291,7 +286,7 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) { const double spDelta{(filter[si+1][pi+1][o+i] - filter[si+1][pi][o+i]) - (filter[si][pi+1][o+i] - filter[si][pi][o+i])}; - ret.data[idx++] = static_cast<float>(spDelta); + (*ret)[idx++] = static_cast<float>(spDelta); } } } @@ -304,24 +299,26 @@ auto GenerateBSincCoeffs(const BSincHeader &hdr) for(int pi{0};pi < BSincPhaseCount;++pi) { for(int i{0};i < m;++i) - ret.data[idx++] = static_cast<float>(filter[si][pi][o+i]); + (*ret)[idx++] = static_cast<float>(filter[si][pi][o+i]); for(int i{0};i < m;++i) { const double phDelta{filter[si][pi+1][o+i] - filter[si][pi][o+i]}; - ret.data[idx++] = static_cast<float>(phDelta); + (*ret)[idx++] = static_cast<float>(phDelta); } for(int i{0};i < m;++i) - ret.data[idx++] = 0.0f; + (*ret)[idx++] = 0.0f; for(int i{0};i < m;++i) - ret.data[idx++] = 0.0f; + (*ret)[idx++] = 0.0f; } } assert(idx == total_size); - return ret; + return *ret; } -/* FIXME: These can't be constexpr due to reaching the step limit. */ +/* FIXME: These can't be constexpr due to the calls reaching the compiler's + * step limit. + */ alignas(16) const auto bsinc12_table = GenerateBSincCoeffs<bsinc12_hdr.total_size>(bsinc12_hdr); alignas(16) const auto bsinc24_table = GenerateBSincCoeffs<bsinc24_hdr.total_size>(bsinc24_hdr); @@ -342,5 +339,5 @@ constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab } // namespace -const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, bsinc12_table.data)}; -const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, bsinc24_table.data)}; +const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, &bsinc12_table.front())}; +const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, &bsinc24_table.front())}; |