Function dngHdrDecodingFunction

src/imageio/TiffImageLoader.cpp:366–366

// https://helpx.adobe.com/content/dam/help/en/photoshop/pdf/DNG_Spec_1_7_0_0.pdf page 94
float dngHdrEncodingFunction(const float x) { return x * (256.0f + x) / (256.0f * (1 + x)); }
float dngHdrDecodingFunction(const float x) { return 16.0f * (8.0f * x - 8.0f + sqrt(64.0f * x * x - 127.0f * x + 64.0f)); }

template <trivially_copyable T>
void unpackBits(