src/Common/Math.cpp

// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "Math.hpp"

#include "CPUID.hpp"

namespace sw
{
	inline uint64_t FNV_1a(uint64_t hash, unsigned char data)
	{
		return (hash ^ data) * 1099511628211;
	}

	uint64_t FNV_1a(const unsigned char *data, int size)
	{
		int64_t hash = 0xCBF29CE484222325;
   
		for(int i = 0; i < size; i++)
		{
			hash = FNV_1a(hash, data[i]);
		}

		return hash;
	}

	unsigned char sRGB8toLinear8(unsigned char value)
	{
		static unsigned char sRGBtoLinearTable[256] = { 255 };
		if(sRGBtoLinearTable[0] == 255)
		{
			for(int i = 0; i < 256; i++)
			{
				sRGBtoLinearTable[i] = static_cast<unsigned char>(sw::sRGBtoLinear(static_cast<float>(i) / 255.0f) * 255.0f + 0.5f);
			}
		}

		return sRGBtoLinearTable[value];
	}
}