I can't combine libjxl/experimental/fast_lossless and the github.com/veluca93/fpnge encoder code in the same program (e.g. to compare the two encoders' speeds), because both fjxl and fpnge declare struct BitWriter in the top-level namespace, with the same name (and both have a Write(uint32_t, uint64_t) method) but different field layout (see links below). Linking both of them leads to a crash, presumably because the fjxl code mistakenly calls the fpnge BitWriter or vice versa.

• libjxl/experimental/fast_lossless/fast_lossless.cc

  Line 46 in 506714e

  std::unique_ptr<uint8_t[], void (*)(void*)> data = {nullptr, free};

• https://github.com/veluca93/fpnge/blob/48020025e197318ab3c695903a4577e3d9565ddb/fpnge.cc#L374

I believe one solution would be to wrap a C++ "anonymous namespace" around all of fast_lossless.cc code except for the final FastLosslessEncode function.

@veluca93