/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   sl_md5.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: bchanot <bchanot@student.42.fr>            +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2018/09/24 00:10:37 by bchanot           #+#    #+#             */
/*   Updated: 2018/10/10 12:53:46 by bchanot          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "ft_ssl.h"
#include "sl_md5.h"

static const t_uint32	g_k[64] = {
	0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, \
	0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, \
	0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, \
	0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, \
	0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, \
	0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, \
	0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, \
	0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, \
	0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, \
	0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, \
	0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
};

static const t_uint32	g_r[64] = {
	7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, \
	5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, \
	4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, \
	6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21
};

static void	sl_md5_get_registers(t_process_md5 *t, size_t cpt,
		t_uint32 bytes[2])
{
	if (cpt < 16)
	{
		bytes[0] = (t->b & t->c) | ((~t->b) & t->d);
		bytes[1] = cpt;
	}
	else if (cpt < 32)
	{
		bytes[0] = (t->d & t->b) | ((~t->d) & t->c);
		bytes[1] = (5 * cpt + 1) % 16;
	}
	else if (cpt < 48)
	{
		bytes[0] = t->b ^ t->c ^ t->d;
		bytes[1] = (3 * cpt + 5) % 16;
	}
	else
	{
		bytes[0] = t->c ^ (t->b | (~t->d));
		bytes[1] = (7 * cpt) % 16;
	}
}

static void	sl_md5_process(t_md5 *ctx, t_uint32 *data)
{
	t_process_md5			t;
	t_uint32				bytes[2];
	size_t					cpt;

	t.a = ctx->state[0];
	t.b = ctx->state[1];
	t.c = ctx->state[2];
	t.d = ctx->state[3];
	cpt = -1;
	while (++cpt < 64)
	{
		sl_md5_get_registers(&t, cpt, bytes);
		bytes[0] = bytes[0] + t.a + g_k[cpt] + data[bytes[1]];
		t.a = t.d;
		t.d = t.c;
		t.c = t.b;
		t.b = t.b + ROL32(bytes[0], g_r[cpt]);
	}
	ctx->state[0] += t.a;
	ctx->state[1] += t.b;
	ctx->state[2] += t.c;
	ctx->state[3] += t.d;
}

void		sl_md5_update(t_md5 *ctx, const t_uint8 *data, size_t len)
{
	t_uint32	avail;

	avail = sizeof(ctx->buff) - (ctx->count & 0x3f);
	ctx->count += len;
	if (avail > len)
	{
		ft_memcpy((char *)ctx->buff + (sizeof(ctx->buff) - avail), data, len);
		return ;
	}
	ft_memcpy((char *)ctx->buff + (sizeof(ctx->buff) - avail), data, avail);
	sl_md5_process(ctx, ctx->buff);
	data += avail;
	len -= avail;
	while (len >= sizeof(ctx->buff))
	{
		ft_memcpy(ctx->buff, data, sizeof(ctx->buff));
		sl_md5_process(ctx, ctx->buff);
		data += sizeof(ctx->buff);
		len -= sizeof(ctx->buff);
	}
	ft_memcpy(ctx->buff, data, len);
}

void		sl_md5_final(t_md5 *ctx, t_uint8 *hash)
{
	size_t	offset;
	char	*padding;
	int		pad_len;

	offset = ctx->count & 0x3f;
	padding = (char *)ctx->buff + offset;
	pad_len = 56 - (offset + 1);
	*padding = 0x80;
	padding++;
	if (pad_len < 0)
	{
		ft_bzero(padding, pad_len + 8);
		sl_md5_process(ctx, ctx->buff);
		padding = (char *)ctx->buff;
		pad_len = 56;
	}
	ft_bzero(padding, pad_len);
	ctx->buff[14] = ctx->count << 3;
	ctx->buff[15] = ctx->count >> 29;
	sl_md5_process(ctx, ctx->buff);
	ft_memcpy(hash, ctx->state, sizeof(ctx->state));
}

void		sl_md5_init(t_md5 *ctx)
{
	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xefcdab89;
	ctx->state[2] = 0x98badcfe;
	ctx->state[3] = 0x10325476;
	ctx->count = 0;
}