From cbbb9e63b7ec7a5c34f186ceafe5da6be8faa739 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Thu, 5 May 2022 20:56:14 +0200
Subject: Allow LUTs to be created with a particular range.

---
 src/transfer_function.cc | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

(limited to 'src/transfer_function.cc')

diff --git a/src/transfer_function.cc b/src/transfer_function.cc
index dd3512ec..c1343ff2 100644
--- a/src/transfer_function.cc
+++ b/src/transfer_function.cc
@@ -51,15 +51,35 @@ using namespace dcp;
 
 
 vector<double> const&
-TransferFunction::lut (int bit_depth, bool inverse) const
+TransferFunction::lut (double from, double to, int bit_depth, bool inverse) const
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
-	auto i = _luts.find (make_pair (bit_depth, inverse));
-	if (i != _luts.end ()) {
+	auto const descriptor = LUTDescriptor{from, to, bit_depth, inverse};
+
+	auto i = _luts.find(descriptor);
+	if (i != _luts.end()) {
 		return i->second;
 	}
 
-	_luts[make_pair(bit_depth, inverse)] = make_lut (bit_depth, inverse);
-	return _luts[make_pair(bit_depth, inverse)];
+	_luts[descriptor] = make_lut(from, to, bit_depth, inverse);
+	return _luts[descriptor];
+}
+
+
+bool
+TransferFunction::LUTDescriptor::operator==(TransferFunction::LUTDescriptor const& other) const
+{
+	return from == other.from && to == other.to && bit_depth == other.bit_depth && inverse == other.inverse;
+}
+
+
+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);
 }
+
-- 
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