// Copyright Low Entry. Apache License, Version 2.0.

#include "LowEntryHashingSha512Library.h"


constexpr int64 ULowEntryHashingSha512Library::k[80] = {0x428a2f98d728ae22, 0x7137449123ef65cd, static_cast<int64>(0xb5c0fbcfec4d3b2f), static_cast<int64>(0xe9b5dba58189dbbc), 0x3956c25bf348b538, 0x59f111f1b605d019, static_cast<int64>(0x923f82a4af194f9b), static_cast<int64>(0xab1c5ed5da6d8118), static_cast<int64>(0xd807aa98a3030242), 0x12835b0145706fbe, 0x243185be4ee4b28c, 0x550c7dc3d5ffb4e2, 0x72be5d74f27b896f, static_cast<int64>(0x80deb1fe3b1696b1), static_cast<int64>(0x9bdc06a725c71235), static_cast<int64>(0xc19bf174cf692694), static_cast<int64>(0xe49b69c19ef14ad2), static_cast<int64>(0xefbe4786384f25e3), 0x0fc19dc68b8cd5b5, 0x240ca1cc77ac9c65, 0x2de92c6f592b0275, 0x4a7484aa6ea6e483, 0x5cb0a9dcbd41fbd4, 0x76f988da831153b5, static_cast<int64>(0x983e5152ee66dfab), static_cast<int64>(0xa831c66d2db43210), static_cast<int64>(0xb00327c898fb213f), static_cast<int64>(0xbf597fc7beef0ee4), static_cast<int64>(0xc6e00bf33da88fc2), static_cast<int64>(0xd5a79147930aa725), 0x06ca6351e003826f, 0x142929670a0e6e70, 0x27b70a8546d22ffc, 0x2e1b21385c26c926, 0x4d2c6dfc5ac42aed, 0x53380d139d95b3df, 0x650a73548baf63de, 0x766a0abb3c77b2a8, static_cast<int64>(0x81c2c92e47edaee6), static_cast<int64>(0x92722c851482353b), static_cast<int64>(0xa2bfe8a14cf10364), static_cast<int64>(0xa81a664bbc423001), static_cast<int64>(0xc24b8b70d0f89791), static_cast<int64>(0xc76c51a30654be30), static_cast<int64>(0xd192e819d6ef5218), static_cast<int64>(0xd69906245565a910), static_cast<int64>(0xf40e35855771202a), 0x106aa07032bbd1b8, 0x19a4c116b8d2d0c8, 0x1e376c085141ab53, 0x2748774cdf8eeb99, 0x34b0bcb5e19b48a8, 0x391c0cb3c5c95a63, 0x4ed8aa4ae3418acb, 0x5b9cca4f7763e373, 0x682e6ff3d6b2b8a3, 0x748f82ee5defb2fc, 0x78a5636f43172f60, static_cast<int64>(0x84c87814a1f0ab72), static_cast<int64>(0x8cc702081a6439ec), static_cast<int64>(0x90befffa23631e28), static_cast<int64>(0xa4506cebde82bde9), static_cast<int64>(0xbef9a3f7b2c67915), static_cast<int64>(0xc67178f2e372532b), static_cast<int64>(0xca273eceea26619c), static_cast<int64>(0xd186b8c721c0c207), static_cast<int64>(0xeada7dd6cde0eb1e), static_cast<int64>(0xf57d4f7fee6ed178), 0x06f067aa72176fba, 0x0a637dc5a2c898a6, 0x113f9804bef90dae, 0x1b710b35131c471b, 0x28db77f523047d84, 0x32caab7b40c72493, 0x3c9ebe0a15c9bebc, 0x431d67c49c100d4c, 0x4cc5d4becb3e42b6, 0x597f299cfc657e2a, 0x5fcb6fab3ad6faec, 0x6c44198c4a475817};


void ULowEntryHashingSha512Library::initialize()
{
	w.SetNum(80);
	buffer.SetNum(128);
}

void ULowEntryHashingSha512Library::update(const TArray<uint8>& b, const int64 offset, const int64 len)
{
	int32 n = count % BLOCK_SIZE;
	count += len;
	int64 partLen = BLOCK_SIZE - n;
	int64 i = 0;

	if (len >= partLen)
	{
		for (int32 index = 0; index < partLen; index++)
		{
			buffer[n + index] = b[offset + index];
		}
		sha(buffer, 0);
		for (i = partLen; ((i + BLOCK_SIZE) - 1) < len; i += BLOCK_SIZE)
		{
			sha(b, offset + i);
		}
		n = 0;
	}

	if (i < len)
	{
		for (int32 index = 0; index < len - i; index++)
		{
			buffer[n + index] = b[offset + i + index];
		}
	}
}

TArray<uint8> ULowEntryHashingSha512Library::digest()
{
	TArray<uint8> tail = padBuffer();
	update(tail, 0, tail.Num());
	return getResult();
}

TArray<uint8> ULowEntryHashingSha512Library::padBuffer()
{
	int32 n = count % BLOCK_SIZE;
	int32 padding = (n < 112) ? (112 - n) : (240 - n);
	TArray<uint8> result;
	result.SetNum(padding + 16);
	result[0] = static_cast<uint8>(0x80);
	uint64 bits = count << 3;
	padding += 8;
	result[padding + 0] = static_cast<uint8>(bits >> 56);
	result[padding + 1] = static_cast<uint8>(bits >> 48);
	result[padding + 2] = static_cast<uint8>(bits >> 40);
	result[padding + 3] = static_cast<uint8>(bits >> 32);
	result[padding + 4] = static_cast<uint8>(bits >> 24);
	result[padding + 5] = static_cast<uint8>(bits >> 16);
	result[padding + 6] = static_cast<uint8>(bits >> 8);
	result[padding + 7] = static_cast<uint8>(bits);
	return result;
}

TArray<uint8> ULowEntryHashingSha512Library::getResult()
{
	TArray<uint8> result;
	result.SetNum(64);

	result[0] = static_cast<uint8>(h0 >> 56);
	result[1] = static_cast<uint8>(h0 >> 48);
	result[2] = static_cast<uint8>(h0 >> 40);
	result[3] = static_cast<uint8>(h0 >> 32);
	result[4] = static_cast<uint8>(h0 >> 24);
	result[5] = static_cast<uint8>(h0 >> 16);
	result[6] = static_cast<uint8>(h0 >> 8);
	result[7] = static_cast<uint8>(h0);

	result[8] = static_cast<uint8>(h1 >> 56);
	result[9] = static_cast<uint8>(h1 >> 48);
	result[10] = static_cast<uint8>(h1 >> 40);
	result[11] = static_cast<uint8>(h1 >> 32);
	result[12] = static_cast<uint8>(h1 >> 24);
	result[13] = static_cast<uint8>(h1 >> 16);
	result[14] = static_cast<uint8>(h1 >> 8);
	result[15] = static_cast<uint8>(h1);

	result[16] = static_cast<uint8>(h2 >> 56);
	result[17] = static_cast<uint8>(h2 >> 48);
	result[18] = static_cast<uint8>(h2 >> 40);
	result[19] = static_cast<uint8>(h2 >> 32);
	result[20] = static_cast<uint8>(h2 >> 24);
	result[21] = static_cast<uint8>(h2 >> 16);
	result[22] = static_cast<uint8>(h2 >> 8);
	result[23] = static_cast<uint8>(h2);

	result[24] = static_cast<uint8>(h3 >> 56);
	result[25] = static_cast<uint8>(h3 >> 48);
	result[26] = static_cast<uint8>(h3 >> 40);
	result[27] = static_cast<uint8>(h3 >> 32);
	result[28] = static_cast<uint8>(h3 >> 24);
	result[29] = static_cast<uint8>(h3 >> 16);
	result[30] = static_cast<uint8>(h3 >> 8);
	result[31] = static_cast<uint8>(h3);

	result[32] = static_cast<uint8>(h4 >> 56);
	result[33] = static_cast<uint8>(h4 >> 48);
	result[34] = static_cast<uint8>(h4 >> 40);
	result[35] = static_cast<uint8>(h4 >> 32);
	result[36] = static_cast<uint8>(h4 >> 24);
	result[37] = static_cast<uint8>(h4 >> 16);
	result[38] = static_cast<uint8>(h4 >> 8);
	result[39] = static_cast<uint8>(h4);

	result[40] = static_cast<uint8>(h5 >> 56);
	result[41] = static_cast<uint8>(h5 >> 48);
	result[42] = static_cast<uint8>(h5 >> 40);
	result[43] = static_cast<uint8>(h5 >> 32);
	result[44] = static_cast<uint8>(h5 >> 24);
	result[45] = static_cast<uint8>(h5 >> 16);
	result[46] = static_cast<uint8>(h5 >> 8);
	result[47] = static_cast<uint8>(h5);

	result[48] = static_cast<uint8>(h6 >> 56);
	result[49] = static_cast<uint8>(h6 >> 48);
	result[50] = static_cast<uint8>(h6 >> 40);
	result[51] = static_cast<uint8>(h6 >> 32);
	result[52] = static_cast<uint8>(h6 >> 24);
	result[53] = static_cast<uint8>(h6 >> 16);
	result[54] = static_cast<uint8>(h6 >> 8);
	result[55] = static_cast<uint8>(h6);

	result[56] = static_cast<uint8>(h7 >> 56);
	result[57] = static_cast<uint8>(h7 >> 48);
	result[58] = static_cast<uint8>(h7 >> 40);
	result[59] = static_cast<uint8>(h7 >> 32);
	result[60] = static_cast<uint8>(h7 >> 24);
	result[61] = static_cast<uint8>(h7 >> 16);
	result[62] = static_cast<uint8>(h7 >> 8);
	result[63] = static_cast<uint8>(h7);

	return result;
}

void ULowEntryHashingSha512Library::sha(const TArray<uint8>& in, int64 offset)
{
	int64 A = h0;
	int64 B = h1;
	int64 C = h2;
	int64 D = h3;
	int64 E = h4;
	int64 F = h5;
	int64 G = h6;
	int64 H = h7;
	uint64 T;
	uint64 T2;
	int32 r;
	for (r = 0; r < 16; r++)
	{
		w[r] = (static_cast<int64>(in[offset]) << 56) | ((static_cast<int64>(in[offset + 1]) & 0xFF) << 48) | ((static_cast<int64>(in[offset + 2]) & 0xFF) << 40) | ((static_cast<int64>(in[offset + 3]) & 0xFF) << 32) | ((static_cast<int64>(in[offset + 4]) & 0xFF) << 24) | ((static_cast<int64>(in[offset + 5]) & 0xFF) << 16) | ((static_cast<int64>(in[offset + 6]) & 0xFF) << 8) | (static_cast<int64>(in[offset + 7]) & 0xFF);
		offset += 8;
	}
	for (r = 16; r < 80; r++)
	{
		T = w[r - 2];
		T2 = w[r - 15];
		w[r] = ((s(T, 19) | (T << 45)) ^ (s(T, 61) | (T << 3)) ^ s(T, 6)) + w[r - 7] + ((s(T2, 1) | (T2 << 63)) ^ (s(T2, 8) | (T2 << 56)) ^ s(T2, 7)) + w[r - 16];
	}
	for (r = 0; r < 80; r++)
	{
		T = H + ((s(E, 14) | (E << 50)) ^ (s(E, 18) | (E << 46)) ^ (s(E, 41) | (E << 23))) + ((E & F) ^ ((~E) & G)) + k[r] + w[r];
		T2 = ((s(A, 28) | (A << 36)) ^ (s(A, 34) | (A << 30)) ^ (s(A, 39) | (A << 25))) + ((A & B) ^ (A & C) ^ (B & C));
		H = G;
		G = F;
		F = E;
		E = D + T;
		D = C;
		C = B;
		B = A;
		A = T + T2;
	}
	h0 += A;
	h1 += B;
	h2 += C;
	h3 += D;
	h4 += E;
	h5 += F;
	h6 += G;
	h7 += H;
}

int64 ULowEntryHashingSha512Library::s(const int64 a, const int32 b)
{
	const uint64 A = a;
	const uint32 B = b;
	return (A >> B);
}


TArray<uint8> ULowEntryHashingSha512Library::Hash(const TArray<uint8>& Bytes)
{
	ULowEntryHashingSha512Library instance = ULowEntryHashingSha512Library();
	instance.initialize();
	instance.update(Bytes, 0, Bytes.Num());
	return instance.digest();
}

TArray<uint8> ULowEntryHashingSha512Library::Hash(const TArray<uint8>& Bytes, int32 Index, int32 Length)
{
	if (Bytes.Num() <= 0)
	{
		ULowEntryHashingSha512Library instance = ULowEntryHashingSha512Library();
		instance.initialize();
		return instance.digest();
	}

	if (Index < 0)
	{
		Length += Index;
		Index = 0;
	}
	if (Length > (Bytes.Num() - Index))
	{
		Length = Bytes.Num() - Index;
	}

	if (Length <= 0)
	{
		ULowEntryHashingSha512Library instance = ULowEntryHashingSha512Library();
		instance.initialize();
		return instance.digest();
	}

	ULowEntryHashingSha512Library instance = ULowEntryHashingSha512Library();
	instance.initialize();
	instance.update(Bytes, Index, Length);
	return instance.digest();
}