Support integer LUTs.

[libdcp.git] / src / transfer_function.cc

diff --git a/src/transfer_function.cc b/src/transfer_function.cc
index dd3512ec3d498fdeb58a312ef8fc883f15100d44..39c8db0a9d8c5a358592f832dcccaea1f771ffc4 100644 (file)
--- a/src/transfer_function.cc
+++ b/src/transfer_function.cc
@@ -42,7 +42,6 @@
 
 
 using std::make_pair;
-using std::map;
 using std::pair;
 using std::pow;
 using std::shared_ptr;
@@ -51,15 +50,74 @@ using namespace dcp;
 
 
 vector<double> const&
-TransferFunction::lut (int bit_depth, bool inverse) 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];
+}
+
+
+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 = _luts.find (make_pair (bit_depth, inverse));
-       if (i != _luts.end ()) {
+       auto i = _int_luts.find(descriptor);
+       if (i != _int_luts.end()) {
                return i->second;
        }
 
-       _luts[make_pair(bit_depth, inverse)] = make_lut (bit_depth, inverse);
-       return _luts[make_pair(bit_depth, inverse)];
+       _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 && scale == other.scale;
+}
+
+
+std::size_t
+TransferFunction::LUTDescriptorHasher::operator()(TransferFunction::LUTDescriptor const& desc) const
+{
+       return std::hash<double>()(desc.from) ^
+               std::hash<double>()(desc.to) ^
+               std::hash<int>()(desc.bit_depth) ^
+               std::hash<bool>()(desc.inverse) ^
+               std::hash<int>()(desc.scale);
+}
+