/*
 * Copyright (C) 2006-2009 Vincent Hanquez <vincent@snarc.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <string.h>
#include "bitfn.h"
#include "sha512.h"

void _mc_sha384_init(struct sha512_ctx *ctx)
{
	memset(ctx, 0, sizeof(*ctx));

	ctx->h[0] = 0xcbbb9d5dc1059ed8ULL;
	ctx->h[1] = 0x629a292a367cd507ULL;
	ctx->h[2] = 0x9159015a3070dd17ULL;
	ctx->h[3] = 0x152fecd8f70e5939ULL;
	ctx->h[4] = 0x67332667ffc00b31ULL;
	ctx->h[5] = 0x8eb44a8768581511ULL;
	ctx->h[6] = 0xdb0c2e0d64f98fa7ULL;
	ctx->h[7] = 0x47b5481dbefa4fa4ULL;
}

void _mc_sha512_init(struct sha512_ctx *ctx)
{
	memset(ctx, 0, sizeof(*ctx));

	ctx->h[0] = 0x6a09e667f3bcc908ULL;
	ctx->h[1] = 0xbb67ae8584caa73bULL;
	ctx->h[2] = 0x3c6ef372fe94f82bULL;
	ctx->h[3] = 0xa54ff53a5f1d36f1ULL;
	ctx->h[4] = 0x510e527fade682d1ULL;
	ctx->h[5] = 0x9b05688c2b3e6c1fULL;
	ctx->h[6] = 0x1f83d9abfb41bd6bULL;
	ctx->h[7] = 0x5be0cd19137e2179ULL;
}

/* 232 times the cube root of the first 64 primes 2..311 */
static const uint64_t k[] = {
	0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL, 0xb5c0fbcfec4d3b2fULL,
	0xe9b5dba58189dbbcULL, 0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
	0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL, 0xd807aa98a3030242ULL,
	0x12835b0145706fbeULL, 0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
	0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL, 0x9bdc06a725c71235ULL,
	0xc19bf174cf692694ULL, 0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
	0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL, 0x2de92c6f592b0275ULL,
	0x4a7484aa6ea6e483ULL, 0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
	0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL, 0xb00327c898fb213fULL,
	0xbf597fc7beef0ee4ULL, 0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
	0x06ca6351e003826fULL, 0x142929670a0e6e70ULL, 0x27b70a8546d22ffcULL,
	0x2e1b21385c26c926ULL, 0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
	0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL, 0x81c2c92e47edaee6ULL,
	0x92722c851482353bULL, 0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
	0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL, 0xd192e819d6ef5218ULL,
	0xd69906245565a910ULL, 0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
	0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL, 0x2748774cdf8eeb99ULL,
	0x34b0bcb5e19b48a8ULL, 0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
	0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL, 0x748f82ee5defb2fcULL,
	0x78a5636f43172f60ULL, 0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
	0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL, 0xbef9a3f7b2c67915ULL,
	0xc67178f2e372532bULL, 0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
	0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL, 0x06f067aa72176fbaULL,
	0x0a637dc5a2c898a6ULL, 0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
	0x28db77f523047d84ULL, 0x32caab7b40c72493ULL, 0x3c9ebe0a15c9bebcULL,
	0x431d67c49c100d4cULL, 0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
	0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL,
};

#define e0(x)       (ror64(x, 28) ^ ror64(x, 34) ^ ror64(x, 39))
#define e1(x)       (ror64(x, 14) ^ ror64(x, 18) ^ ror64(x, 41))
#define s0(x)       (ror64(x, 1) ^ ror64(x, 8) ^ (x >> 7))
#define s1(x)       (ror64(x, 19) ^ ror64(x, 61) ^ (x >> 6))

static void sha512_do_chunk(struct sha512_ctx *ctx, uint64_t *buf)
{
	uint64_t a, b, c, d, e, f, g, h, t1, t2;
	int i;
	uint64_t w[80];

	cpu_to_be64_array(w, buf, 16);

	for (i = 16; i < 80; i++)
		w[i] = s1(w[i - 2]) + w[i - 7] + s0(w[i - 15]) + w[i - 16];

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

#define R(a, b, c, d, e, f, g, h, k, w)			\
	t1 = h + e1(e) + (g ^ (e & (f ^ g))) + k + w;	\
	t2 = e0(a) + ((a & b) | (c & (a | b)));		\
	d += t1;					\
	h = t1 + t2

	for (i = 0; i < 80; i += 8) {
		R(a, b, c, d, e, f, g, h, k[i + 0], w[i + 0]);
		R(h, a, b, c, d, e, f, g, k[i + 1], w[i + 1]);
		R(g, h, a, b, c, d, e, f, k[i + 2], w[i + 2]);
		R(f, g, h, a, b, c, d, e, k[i + 3], w[i + 3]);
		R(e, f, g, h, a, b, c, d, k[i + 4], w[i + 4]);
		R(d, e, f, g, h, a, b, c, k[i + 5], w[i + 5]);
		R(c, d, e, f, g, h, a, b, k[i + 6], w[i + 6]);
		R(b, c, d, e, f, g, h, a, k[i + 7], w[i + 7]);
	}

#undef R

	ctx->h[0] += a; ctx->h[1] += b; ctx->h[2] += c; ctx->h[3] += d;
	ctx->h[4] += e; ctx->h[5] += f; ctx->h[6] += g; ctx->h[7] += h;
}

void _mc_sha384_update(struct sha384_ctx *ctx, uint8_t *data, uint32_t len)
{
	_mc_sha512_update(ctx, data, len);
}

void _mc_sha512_update(struct sha512_ctx *ctx, uint8_t *data, uint32_t len)
{
	unsigned int index, to_fill;

	/* check for partial buffer */
	index = (unsigned int) (ctx->sz[0] & 0x7f);
	to_fill = 128 - index;

	ctx->sz[0] += len;
	if (ctx->sz[0] < len)
		ctx->sz[1]++;

	/* process partial buffer if there's enough data to make a block */
	if (index && len >= to_fill) {
		memcpy(ctx->buf + index, data, to_fill);
		sha512_do_chunk(ctx, (uint64_t *) ctx->buf);
		len -= to_fill;
		data += to_fill;
		index = 0;
	}

	/* process as much 128-block as possible */
	for (; len >= 128; len -= 128, data += 128)
		sha512_do_chunk(ctx, (uint64_t *) data);

	/* append data into buf */
	if (len)
		memcpy(ctx->buf + index, data, len);
}

void _mc_sha384_finalize(struct sha384_ctx *ctx, uint8_t *out)
{
	uint8_t intermediate[SHA512_DIGEST_SIZE];

	_mc_sha512_finalize(ctx, intermediate);
	memcpy(out, intermediate, SHA384_DIGEST_SIZE);
}

void _mc_sha512_finalize(struct sha512_ctx *ctx, uint8_t *out)
{
	static uint8_t padding[128] = { 0x80, };
	uint32_t i, index, padlen;
	uint64_t bits[2];
	uint64_t *p = (uint64_t *) out;

	/* cpu -> big endian */
	bits[0] = cpu_to_be64((ctx->sz[1] << 3 | ctx->sz[0] >> 61));
	bits[1] = cpu_to_be64((ctx->sz[0] << 3));

	/* pad out to 56 */
	index = (unsigned int) (ctx->sz[0] & 0x7f);
	padlen = (index < 112) ? (112 - index) : ((128 + 112) - index);
	_mc_sha512_update(ctx, padding, padlen);

	/* append length */
	_mc_sha512_update(ctx, (uint8_t *) bits, sizeof(bits));

	/* store to digest */
	for (i = 0; i < 8; i++)
		p[i] = cpu_to_be64(ctx->h[i]);
}

// //  i don't wanna go to libc i said no no no
// #include <stdio.h>
// 
// void _mc_sha512_init_t(struct sha512_ctx *ctx, int t)
// {
// 	memset(ctx, 0, sizeof(*ctx));
// 	if (t >= 512)
// 		return;
// 
// 	switch (t) {
// 	case 224:
// 		ctx->h[0] = 0x8c3d37c819544da2ULL;
// 		ctx->h[1] = 0x73e1996689dcd4d6ULL;
// 		ctx->h[2] = 0x1dfab7ae32ff9c82ULL;
// 		ctx->h[3] = 0x679dd514582f9fcfULL;
// 		ctx->h[4] = 0x0f6d2b697bd44da8ULL;
// 		ctx->h[5] = 0x77e36f7304c48942ULL;
// 		ctx->h[6] = 0x3f9d85a86a1d36c8ULL;
// 		ctx->h[7] = 0x1112e6ad91d692a1ULL;
// 		break;
// 	case 256:
// 		ctx->h[0] = 0x22312194fc2bf72cULL;
// 		ctx->h[1] = 0x9f555fa3c84c64c2ULL;
// 		ctx->h[2] = 0x2393b86b6f53b151ULL;
// 		ctx->h[3] = 0x963877195940eabdULL;
// 		ctx->h[4] = 0x96283ee2a88effe3ULL;
// 		ctx->h[5] = 0xbe5e1e2553863992ULL;
// 		ctx->h[6] = 0x2b0199fc2c85b8aaULL;
// 		ctx->h[7] = 0x0eb72ddc81c52ca2ULL;
// 		break;
// 	default: {
// 		uint8_t buf[8+4];
// 		uint8_t out[64];
// 		int i;
// 
// 		_mc_sha512_init(ctx);
// 		for (i = 0; i < 8; i++)
// 			ctx->h[i] ^= 0xa5a5a5a5a5a5a5a5ULL;
// 
// 		i = sprintf((char *)buf, "SHA-512/%d", t);
// 		_mc_sha512_update(ctx, buf, i);
// 		_mc_sha512_finalize(ctx, out);
// 
// 		/* re-init the context, otherwise len is changed */
// 		memset(ctx, 0, sizeof(*ctx));
// 		for (i = 0; i < 8; i++)
// 			ctx->h[i] = cpu_to_be64(((uint64_t *) out)[i]);
// 		}
// 	}
// }
