/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   sha256.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: charles <me@cacharle.xyz>                  +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2020/08/02 16:36:43 by charles           #+#    #+#             */
/*   Updated: 2020/08/03 13:46:07 by charles          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "ft_ssl.h"

static const uint32_t	g_cube_roots[64] = {
   0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
   0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
   0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
   0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
   0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
   0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
   0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
   0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

void	*sha256_compression_func(void *v_state, uint8_t *chunk)
{
	uint32_t	buf[64] = {0};
	uint32_t	*state = v_state;
	uint32_t	a, b, c, d, e, f, g, h, s0, s1, ch, temp1, temp2, maj;
	size_t		i;

	for (i = 0; i < 16; i++)
		buf[i] = reverse_bytes32(((uint32_t*)chunk)[i]);
	for (i = 16; i < 64; i++)
	{
		s0 = rotate_right(buf[i - 15], 7) ^ rotate_right(buf[i - 15], 18) ^ (buf[i - 15] >> 3);
		s1 = rotate_right(buf[i - 2], 17) ^ rotate_right(buf[i - 2], 19) ^ (buf[i - 2] >> 10);
		buf[i] = buf[i - 16] + s0 + buf[i - 7] + s1;
	}

	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];
	e = state[4];
	f = state[5];
	g = state[6];
	h = state[7];

	for (i = 0; i < 64; i++)
	{
		s1 = rotate_right(e, 6) ^ rotate_right(e, 11) ^ rotate_right(e, 25);
		ch = (e & f) ^ (~e & g);
		temp1 = h + s1 + ch + g_cube_roots[i] + buf[i];
		s0 = rotate_right(a, 2) ^ rotate_right(a, 13) ^ rotate_right(a, 22);
		maj = (a & b) ^ (a & c) ^ (b & c);
		temp2 = s0 + maj;

		h = g;
		g = f;
		f = e;
		e = d + temp1;
		d = c;
		c = b;
		b = a;
		a = temp1 + temp2;
	}

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	state[5] += f;
	state[6] += g;
	state[7] += h;
	return (state);
}