Support integer LUTs.

diff --git a/src/transfer_function.cc b/src/transfer_function.cc
index be507af1f4c968a084a7d09ff61a77754181ff5d..39c8db0a9d8c5a358592f832dcccaea1f771ffc4 100644 (file)
--- a/src/transfer_function.cc
+++ b/src/transfer_function.cc
@@ -53,23 +53,61 @@ vector<double> const&
 TransferFunction::double_lut(double from, double to, int bit_depth, bool inverse) const
 {
        boost::mutex::scoped_lock lm (_mutex);
+       return double_lut_unlocked(from, to, bit_depth, inverse);
+}
+
+
+vector<double> const&
+TransferFunction::double_lut_unlocked(double from, double to, int bit_depth, bool inverse) const
+{
+       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse, 1};
+
+       auto i = _double_luts.find(descriptor);
+       if (i != _double_luts.end()) {
+               return i->second;
+       }
+
+       _double_luts[descriptor] = make_double_lut(from, to, bit_depth, inverse);
+       return _double_luts[descriptor];
+}
 
-       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse};
 
-       auto i = _luts.find(descriptor);
-       if (i != _luts.end()) {
+vector<int> const&
+TransferFunction::int_lut(double from, double to, int bit_depth, bool inverse, int scale) const
+{
+       boost::mutex::scoped_lock lm (_mutex);
+
+       auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse, scale};
+
+       auto i = _int_luts.find(descriptor);
+       if (i != _int_luts.end()) {
                return i->second;
        }
 
-       _luts[descriptor] = make_double_lut(from, to, bit_depth, inverse);
-       return _luts[descriptor];
+       _int_luts[descriptor] = make_int_lut(from, to, bit_depth, inverse, scale);
+       return _int_luts[descriptor];
+}
+
+
+/* Caller must hold lock on _mutex */
+vector<int>
+TransferFunction::make_int_lut(double from, double to, int bit_depth, bool inverse, int scale) const
+{
+       auto source_lut = double_lut_unlocked(from, to, bit_depth, inverse);
+       auto const size = source_lut.size();
+       vector<int> lut(size);
+       for (size_t i = 0; i < size; ++i) {
+               lut[i] = lrint(source_lut[i] * scale);
+       }
+
+       return lut;
 }
 
 
 bool
 TransferFunction::LUTDescriptor::operator==(TransferFunction::LUTDescriptor const& other) const
 {
-       return from == other.from && to == other.to && bit_depth == other.bit_depth && inverse == other.inverse;
+       return from == other.from && to == other.to && bit_depth == other.bit_depth && inverse == other.inverse && scale == other.scale;
 }
 
 
@@ -79,6 +117,7 @@ TransferFunction::LUTDescriptorHasher::operator()(TransferFunction::LUTDescripto
        return std::hash<double>()(desc.from) ^
                std::hash<double>()(desc.to) ^
                std::hash<int>()(desc.bit_depth) ^
-               std::hash<bool>()(desc.inverse);
+               std::hash<bool>()(desc.inverse) ^
+               std::hash<int>()(desc.scale);
 }
 

diff --git a/src/transfer_function.h b/src/transfer_function.h
index 033c30454e25ebf835deb3514b451029c81df6c5..2340ebfde855d7181f43a5e8564c1bfc656d15b3 100644 (file)
--- a/src/transfer_function.h
+++ b/src/transfer_function.h
@@ -62,6 +62,7 @@ public:
 
        /** @return A look-up table (of size 2^bit_depth) */
        std::vector<double> const& double_lut(double from, double to, int bit_depth, bool inverse) const;
+       std::vector<int> const& int_lut(double from, double to, int bit_depth, bool inverse, int scale) const;
 
        virtual bool about_equal (std::shared_ptr<const TransferFunction> other, double epsilon) const = 0;
 
@@ -69,11 +70,15 @@ protected:
        virtual std::vector<double> make_double_lut(double from, double to, int bit_depth, bool inverse) const = 0;
 
 private:
+       std::vector<int> make_int_lut(double from, double to, int bit_depth, bool inverse, int scale) const;
+       std::vector<double> const& double_lut_unlocked(double from, double to, int bit_depth, bool inverse) const;
+
        struct LUTDescriptor {
                double from;
                double to;
                int bit_depth;
                bool inverse;
+               int scale;
 
                bool operator==(LUTDescriptor const& other) const;
        };
@@ -82,8 +87,9 @@ private:
                std::size_t operator()(LUTDescriptor const& desc) const;
        };
 
-       mutable std::unordered_map<LUTDescriptor, std::vector<double>, LUTDescriptorHasher> _luts;
-       /** mutex to protect _luts */
+       mutable std::unordered_map<LUTDescriptor, std::vector<double>, LUTDescriptorHasher> _double_luts;
+       mutable std::unordered_map<LUTDescriptor, std::vector<int>, LUTDescriptorHasher> _int_luts;
+       /** mutex to protect _double_luts and _int_luts */
        mutable boost::mutex _mutex;
 };