Move the bsinc tables out of common

3 files changed, 0 insertions, 373 deletions

diff --git a/common/bsinc_defs.h b/common/bsinc_defs.h
deleted file mode 100644
index 30d1219e..00000000
--- a/common/bsinc_defs.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#ifndef BSINC_DEFS_H
-#define BSINC_DEFS_H
-
-/* The number of distinct scale and phase intervals within the filter table. */
-#define BSINC_SCALE_BITS  4
-#define BSINC_SCALE_COUNT (1<<BSINC_SCALE_BITS)
-#define BSINC_PHASE_BITS  5
-#define BSINC_PHASE_COUNT (1<<BSINC_PHASE_BITS)
-
-/* The maximum number of sample points for the bsinc filters. */
-#define BSINC_POINTS_MAX 48
-
-#endif /* BSINC_DEFS_H */
diff --git a/common/bsinc_tables.cpp b/common/bsinc_tables.cpp
deleted file mode 100644
index 460462cd..00000000
--- a/common/bsinc_tables.cpp
+++ /dev/null
@@ -1,343 +0,0 @@
-
-#include "bsinc_tables.h"
-
-#include <algorithm>
-#include <array>
-#include <cassert>
-#include <cmath>
-#include <limits>
-#include <memory>
-#include <stdexcept>
-
-#include "math_defs.h"
-#include "vector.h"
-
-
-namespace {
-
-/* The max points includes the doubling for downsampling, so the maximum number
- * of base sample points is 24, which is 23rd order.
- */
-constexpr int BSincPointsMax{BSINC_POINTS_MAX};
-constexpr int BSincPointsHalf{BSincPointsMax / 2};
-
-constexpr int BSincPhaseCount{BSINC_PHASE_COUNT};
-constexpr int BSincScaleCount{BSINC_SCALE_COUNT};
-
-
-template<typename T>
-constexpr std::enable_if_t<std::is_floating_point<T>::value,T> sqrt(T x)
-{
-    if(!(x >= 0 && x < std::numeric_limits<double>::infinity()))
-        throw std::domain_error{"Invalid sqrt value"};
-
-    T cur{x}, prev{0};
-    while(cur != prev)
-    {
-        prev = cur;
-        cur = 0.5f*(cur + x/cur);
-    }
-    return cur;
-}
-
-template<typename T>
-constexpr std::enable_if_t<std::is_floating_point<T>::value,T> sin(T x)
-{
-    if(x >= al::MathDefs<T>::Tau())
-    {
-        if(!(x < 65536))
-            throw std::domain_error{"Invalid sin value"};
-        do {
-            x -= al::MathDefs<T>::Tau();
-        } while(x >= al::MathDefs<T>::Tau());
-    }
-    else if(x < 0)
-    {
-        if(!(x > -65536))
-            throw std::domain_error{"Invalid sin value"};
-        do {
-            x += al::MathDefs<T>::Tau();
-        } while(x < 0);
-    }
-
-    T prev{x}, n{6};
-    int i{4}, s{-1};
-    const T xx{x*x};
-    T t{xx*x};
-
-    T cur{prev + t*s/n};
-    while(prev != cur)
-    {
-        prev = cur;
-        n *= i*(i+1);
-        i += 2;
-        s = -s;
-        t *= xx;
-
-        cur += t*s/n;
-    }
-    return cur;
-}
-
-
-/* This is the normalized cardinal sine (sinc) function.
- *
- *   sinc(x) = { 1,                   x = 0
- *             { sin(pi x) / (pi x),  otherwise.
- */
-constexpr double Sinc(const double x)
-{
-    if(!(x > 1e-15 || x < -1e-15))
-        return 1.0;
-    return sin(al::MathDefs<double>::Pi()*x) / (al::MathDefs<double>::Pi()*x);
-}
-
-/* The zero-order modified Bessel function of the first kind, used for the
- * Kaiser window.
- *
- *   I_0(x) = sum_{k=0}^inf (1 / k!)^2 (x / 2)^(2 k)
- *          = sum_{k=0}^inf ((x / 2)^k / k!)^2
- */
-constexpr double BesselI_0(const double x)
-{
-    /* Start at k=1 since k=0 is trivial. */
-    const double x2{x / 2.0};
-    double term{1.0};
-    double sum{1.0};
-    double last_sum{};
-    int k{1};
-
-    /* Let the integration converge until the term of the sum is no longer
-     * significant.
-     */
-    do {
-        const double y{x2 / k};
-        ++k;
-        last_sum = sum;
-        term *= y * y;
-        sum += term;
-    } while(sum != last_sum);
-
-    return sum;
-}
-
-/* Calculate a Kaiser window from the given beta value and a normalized k
- * [-1, 1].
- *
- *   w(k) = { I_0(B sqrt(1 - k^2)) / I_0(B),  -1 <= k <= 1
- *          { 0,                              elsewhere.
- *
- * Where k can be calculated as:
- *
- *   k = i / l,         where -l <= i <= l.
- *
- * or:
- *
- *   k = 2 i / M - 1,   where 0 <= i <= M.
- */
-constexpr double Kaiser(const double beta, const double k, const double besseli_0_beta)
-{
-    if(!(k >= -1.0 && k <= 1.0))
-        return 0.0;
-    return BesselI_0(beta * sqrt(1.0 - k*k)) / besseli_0_beta;
-}
-
-/* Calculates the (normalized frequency) transition width of the Kaiser window.
- * Rejection is in dB.
- */
-constexpr double CalcKaiserWidth(const double rejection, const int order)
-{
-    if(rejection > 21.19)
-       return (rejection - 7.95) / (order * 2.285 * al::MathDefs<double>::Tau());
-    /* This enforces a minimum rejection of just above 21.18dB */
-    return 5.79 / (order * al::MathDefs<double>::Tau());
-}
-
-/* Calculates the beta value of the Kaiser window. Rejection is in dB. */
-constexpr double CalcKaiserBeta(const double rejection)
-{
-    if(rejection > 50.0)
-       return 0.1102 * (rejection-8.7);
-    else if(rejection >= 21.0)
-       return (0.5842 * std::pow(rejection-21.0, 0.4)) + (0.07886 * (rejection-21.0));
-    return 0.0;
-}
-
-
-struct BSincHeader {
-    double width;
-    double beta;
-    double scaleBase;
-    double scaleRange;
-    double besseli_0_beta;
-
-    int a[BSINC_SCALE_COUNT];
-    int total_size;
-};
-
-constexpr BSincHeader GenerateBSincHeader(int Rejection, int Order)
-{
-    BSincHeader ret{};
-    ret.width = CalcKaiserWidth(Rejection, Order);
-    ret.beta = CalcKaiserBeta(Rejection);
-    ret.scaleBase = ret.width / 2.0;
-    ret.scaleRange = 1.0 - ret.scaleBase;
-    ret.besseli_0_beta = BesselI_0(ret.beta);
-
-    int num_points{Order+1};
-    for(int si{0};si < BSincScaleCount;++si)
-    {
-        const double scale{ret.scaleBase + (ret.scaleRange * si / (BSincScaleCount - 1))};
-        const int a{std::min(static_cast<int>(num_points / 2.0 / scale), num_points)};
-        const int m{2 * a};
-
-        ret.a[si] = a;
-        ret.total_size += 4 * BSincPhaseCount * ((m+3) & ~3);
-    }
-
-    return ret;
-}
-
-/* 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 23rd
- * and 47th order respectively.
- */
-constexpr BSincHeader bsinc12_hdr{GenerateBSincHeader(60, 11)};
-constexpr BSincHeader bsinc24_hdr{GenerateBSincHeader(60, 23)};
-
-
-/* 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>
-std::array<float,total_size> GenerateBSincCoeffs(const BSincHeader &hdr)
-{
-    auto filter = std::make_unique<double[][BSincPhaseCount+1][BSincPointsMax]>(BSincScaleCount);
-
-    /* Calculate the Kaiser-windowed Sinc filter coefficients for each scale
-     * and phase index.
-     */
-    for(unsigned int si{0};si < BSincScaleCount;++si)
-    {
-        const int m{hdr.a[si] * 2};
-        const int o{BSincPointsHalf - (m/2)};
-        const int l{hdr.a[si] - 1};
-        const int a{hdr.a[si]};
-        const double scale{hdr.scaleBase + (hdr.scaleRange * si / (BSincScaleCount - 1))};
-        const double cutoff{scale - (hdr.scaleBase * std::max(0.5, scale) * 2.0)};
-
-        /* Do one extra phase index so that the phase delta has a proper target
-         * for its last index.
-         */
-        for(int pi{0};pi <= BSincPhaseCount;++pi)
-        {
-            const double phase{l + (pi/double{BSincPhaseCount})};
-
-            for(int i{0};i < m;++i)
-            {
-                const double x{i - phase};
-                filter[si][pi][o+i] = Kaiser(hdr.beta, x/a, hdr.besseli_0_beta) * cutoff *
-                    Sinc(cutoff*x);
-            }
-        }
-    }
-
-    auto ret = std::make_unique<std::array<float,total_size>>();
-    size_t idx{0};
-
-    for(unsigned int si{0};si < BSincScaleCount-1;++si)
-    {
-        const int m{((hdr.a[si]*2) + 3) & ~3};
-        const int o{BSincPointsHalf - (m/2)};
-
-        for(int pi{0};pi < BSincPhaseCount;++pi)
-        {
-            /* Write out the filter. Also calculate and write out the phase and
-             * scale deltas.
-             */
-            for(int i{0};i < m;++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)
-             */
-            for(int i{0};i < m;++i)
-            {
-                const double phDelta{filter[si][pi+1][o+i] - filter[si][pi][o+i]};
-                (*ret)[idx++] = static_cast<float>(phDelta);
-            }
-
-            /* Linear interpolation between scales is also simplified.
-             *
-             * Given a difference in points between scales, the destination
-             * points will be 0, thus: x = a + f (-a)
-             */
-            for(int i{0};i < m;++i)
-            {
-                const double scDelta{filter[si+1][pi][o+i] - filter[si][pi][o+i]};
-                (*ret)[idx++] = static_cast<float>(scDelta);
-            }
-
-            /* This last simplification is done to complete the bilinear
-             * equation for the combination of phase and scale.
-             */
-            for(int i{0};i < m;++i)
-            {
-                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)[idx++] = static_cast<float>(spDelta);
-            }
-        }
-    }
-    {
-        /* The last scale index doesn't have any scale or scale-phase deltas. */
-        const unsigned int si{BSincScaleCount - 1};
-        const int m{((hdr.a[si]*2) + 3) & ~3};
-        const int o{BSincPointsHalf - (m/2)};
-
-        for(int pi{0};pi < BSincPhaseCount;++pi)
-        {
-            for(int i{0};i < m;++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)[idx++] = static_cast<float>(phDelta);
-            }
-            for(int i{0};i < m;++i)
-                (*ret)[idx++] = 0.0f;
-            for(int i{0};i < m;++i)
-                (*ret)[idx++] = 0.0f;
-        }
-    }
-    assert(idx == total_size);
-
-    return *ret;
-}
-
-/* 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);
-
-
-constexpr BSincTable GenerateBSincTable(const BSincHeader &hdr, const float *tab)
-{
-    BSincTable ret{};
-    ret.scaleBase = static_cast<float>(hdr.scaleBase);
-    ret.scaleRange = static_cast<float>(1.0 / hdr.scaleRange);
-    for(int i{0};i < BSincScaleCount;++i)
-        ret.m[i] = static_cast<unsigned int>(((hdr.a[i]*2) + 3) & ~3);
-    ret.filterOffset[0] = 0;
-    for(int i{1};i < BSincScaleCount;++i)
-        ret.filterOffset[i] = ret.filterOffset[i-1] + ret.m[i-1]*4*BSincPhaseCount;
-    ret.Tab = tab;
-    return ret;
-}
-
-} // namespace
-
-const BSincTable bsinc12{GenerateBSincTable(bsinc12_hdr, &bsinc12_table.front())};
-const BSincTable bsinc24{GenerateBSincTable(bsinc24_hdr, &bsinc24_table.front())};
diff --git a/common/bsinc_tables.h b/common/bsinc_tables.h
deleted file mode 100644
index 2e2443e5..00000000
--- a/common/bsinc_tables.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef BSINC_TABLES_H
-#define BSINC_TABLES_H
-
-#include "bsinc_defs.h"
-
-
-struct BSincTable {
-    float scaleBase, scaleRange;
-    unsigned int m[BSINC_SCALE_COUNT];
-    unsigned int filterOffset[BSINC_SCALE_COUNT];
-    const float *Tab;
-};
-
-extern const BSincTable bsinc12;
-extern const BSincTable bsinc24;
-
-#endif /* BSINC_TABLES_H */