/* blake_small.c */
/*
 This file is part of the AVR-Crypto-Lib.
 Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/*
 * \file    blake_small.c
 * \author  Daniel Otte
 * \email   bg@nerilex.org
 * \date    2009-05-04
 * \license GPLv3 or later
 *
 */

#include <stdint.h>
#include <string.h>
#include <avr/pgmspace.h>
#include "memxor.h"
#include "blake_small.h"
#include "blake_common.h"

static const uint32_t blake_c[] PROGMEM = {
        0x243F6A88, 0x85A308D3,
        0x13198A2E, 0x03707344,
        0xA4093822, 0x299F31D0,
        0x082EFA98, 0xEC4E6C89,
        0x452821E6, 0x38D01377,
        0xBE5466CF, 0x34E90C6C,
        0xC0AC29B7, 0xC97C50DD,
        0x3F84D5B5, 0xB5470917
};

#define ROTL32(a, n) (((a)<<(n))|((a)>>(32-(n))))
#define ROTR32(a, n) (((a)>>(n))|((a)<<(32-(n))))
#define CHANGE_ENDIAN32(a) (((a)<<24)| \
                            ((0x0000ff00&(a))<<8)| \
						    ((0x00ff0000&(a))>>8)| \
						    (a)>>24 )
static
void blake_small_expand(uint32_t *v, const blake_small_ctx_t *ctx)
{
    uint8_t i;
    memcpy(v, ctx->h, 8 * 4);
    for (i = 0; i < 8; ++i) {
        v[8 + i] = pgm_read_dword(&(blake_c[i]));
    }
    memxor((uint8_t*) v + 8, ctx->s, 4 * 4);

}

static
void blake_small_changeendian(void *dest, const void *src)
{
    uint8_t i;
    for (i = 0; i < 16; ++i) {
        ((uint32_t*) dest)[i] = CHANGE_ENDIAN32(((uint32_t* )src)[i]);
    }
}

static
void blake_small_compress(uint32_t *v, const void *m)
{
    uint8_t r, i;
    uint8_t a, b, c, d, s0, s1, sigma_idx = 0;
    uint32_t lv[4];
    for (r = 0; r < 14; ++r) {
        for (i = 0; i < 8; ++i) {
            a = pgm_read_byte(blake_index_lut + 4 * i + 0);
            b = pgm_read_byte(blake_index_lut + 4 * i + 1);
            c = pgm_read_byte(blake_index_lut + 4 * i + 2);
            d = pgm_read_byte(blake_index_lut + 4 * i + 3);
            s0 = pgm_read_byte(blake_sigma + sigma_idx);
            s1 = s0 & 0xf;
            s0 >>= 4;
            ++sigma_idx;
            if (sigma_idx >= 80) {
                sigma_idx -= 80;
            }
            lv[0] = v[a];
            lv[1] = v[b];
            lv[2] = v[c];
            lv[3] = v[d];

            lv[0] += lv[1]
                    + (((uint32_t*) m)[s0] ^ pgm_read_dword(&(blake_c[s1])));
            lv[3] = ROTR32(lv[3] ^ lv[0], 16);
            lv[2] += lv[3];
            lv[1] = ROTR32(lv[1] ^ lv[2], 12);
            lv[0] += lv[1]
                    + (((uint32_t*) m)[s1] ^ pgm_read_dword(&(blake_c[s0])));
            lv[3] = ROTR32(lv[3] ^ lv[0], 8);
            lv[2] += lv[3];
            lv[1] = ROTR32(lv[1] ^ lv[2], 7);

            v[a] = lv[0];
            v[b] = lv[1];
            v[c] = lv[2];
            v[d] = lv[3];
        }
    }
}

static
void blake_small_collapse(blake_small_ctx_t *ctx, uint32_t *v)
{
    uint8_t i;
    for (i = 0; i < 8; ++i) {
        ctx->h[i] ^= ctx->s[i % 4] ^ v[i] ^ v[8 + i];
    }
}

void blake_small_nextBlock(blake_small_ctx_t *ctx, const void *msg)
{
    uint32_t v[16];
    uint32_t m[16];
    union {
        uint64_t v64;
        uint32_t v32[2];
    } ctr;
    blake_small_expand(v, ctx);
    ctx->counter++;
    ctr.v64 = ctx->counter * 512;
    v[12] ^= ctr.v32[0];
    v[13] ^= ctr.v32[0];
    v[14] ^= ctr.v32[1];
    v[15] ^= ctr.v32[1];
    blake_small_changeendian(m, msg);
    blake_small_compress(v, m);
    blake_small_collapse(ctx, v);
}

void blake_small_lastBlock(blake_small_ctx_t *ctx, const void *msg,
        uint16_t length_b)
{
    while (length_b >= BLAKE_SMALL_BLOCKSIZE) {
        blake_small_nextBlock(ctx, msg);
        msg = (uint8_t*) msg + BLAKE_SMALL_BLOCKSIZE_B;
        length_b -= BLAKE_SMALL_BLOCKSIZE;
    }
    union {
        uint8_t v8[64];
        uint32_t v32[16];
    } buffer;
    uint32_t v[16];
    union {
        uint64_t v64;
        uint32_t v32[2];
    } ctr;
    ctr.v64 = ctx->counter * 512 + length_b;
    memset(buffer.v8, 0, 64);
    memcpy(buffer.v8, msg, (length_b + 7) / 8);
    buffer.v8[length_b / 8] |= 0x80 >> (length_b & 0x7);
    blake_small_changeendian(buffer.v8, buffer.v8);
    blake_small_expand(v, ctx);
    if (length_b > 512 - 64 - 2) {
        v[12] ^= ctr.v32[0];
        v[13] ^= ctr.v32[0];
        v[14] ^= ctr.v32[1];
        v[15] ^= ctr.v32[1];
        blake_small_compress(v, buffer.v8);
        blake_small_collapse(ctx, v);
        memset(buffer.v8, 0, 64 - 8);
        blake_small_expand(v, ctx);
    } else {
        if (length_b) {
            v[12] ^= ctr.v32[0];
            v[13] ^= ctr.v32[0];
            v[14] ^= ctr.v32[1];
            v[15] ^= ctr.v32[1];
        }
    }
    if (ctx->appendone)
        buffer.v8[64 - 8 - 4] |= 0x01;
    buffer.v32[14] = ctr.v32[1];
    buffer.v32[15] = ctr.v32[0];
    blake_small_compress(v, buffer.v8);
    blake_small_collapse(ctx, v);

}

const uint32_t blake256_iv[] PROGMEM = {
        0x6A09E667L, 0xBB67AE85,
        0x3C6EF372L, 0xA54FF53A,
        0x510E527FL, 0x9B05688C,
        0x1F83D9ABL, 0x5BE0CD19
};

void blake256_init(blake256_ctx_t *ctx)
{
    uint8_t i;
    for (i = 0; i < 8; ++i) {
        ctx->h[i] = pgm_read_dword(&(blake256_iv[i]));
    }
    memset(ctx->s, 0, 4 * 4);
    ctx->counter = 0;
    ctx->appendone = 1;
}

const uint32_t blake224_iv[] PROGMEM = {
        0xC1059ED8, 0x367CD507,
        0x3070DD17, 0xF70E5939,
        0xFFC00B31, 0x68581511,
        0x64F98FA7, 0xBEFA4FA4
};

void blake224_init(blake224_ctx_t *ctx)
{
    uint8_t i;
    for (i = 0; i < 8; ++i) {
        ctx->h[i] = pgm_read_dword(&(blake224_iv[i]));
    }
    memset(ctx->s, 0, 4 * 4);
    ctx->counter = 0;
    ctx->appendone = 0;
}

void blake256_ctx2hash(void *dest, const blake256_ctx_t *ctx)
{
    uint8_t i;
    for (i = 0; i < 8; ++i) {
        ((uint32_t*) dest)[i] = CHANGE_ENDIAN32(ctx->h[i]);
    }
}

void blake224_ctx2hash(void *dest, const blake224_ctx_t *ctx)
{
    uint8_t i;
    for (i = 0; i < 7; ++i) {
        ((uint32_t*) dest)[i] = CHANGE_ENDIAN32(ctx->h[i]);
    }
}

void blake256_nextBlock(blake256_ctx_t *ctx, const void *block)
{
    blake_small_nextBlock(ctx, block);
}

void blake224_nextBlock(blake224_ctx_t *ctx, const void *block)
{
    blake_small_nextBlock(ctx, block);
}

void blake256_lastBlock(blake256_ctx_t *ctx, const void *block,
        uint16_t length_b)
{
    blake_small_lastBlock(ctx, block, length_b);
}

void blake224_lastBlock(blake224_ctx_t *ctx, const void *block,
        uint16_t length_b)
{
    blake_small_lastBlock(ctx, block, length_b);
}

void blake256(void *dest, const void *msg, uint32_t length_b)
{
    blake_small_ctx_t ctx;
    blake256_init(&ctx);
    while (length_b >= BLAKE_SMALL_BLOCKSIZE) {
        blake_small_nextBlock(&ctx, msg);
        msg = (uint8_t*) msg + BLAKE_SMALL_BLOCKSIZE_B;
        length_b -= BLAKE_SMALL_BLOCKSIZE;
    }
    blake_small_lastBlock(&ctx, msg, length_b);
    blake256_ctx2hash(dest, &ctx);
}

void blake224(void *dest, const void *msg, uint32_t length_b)
{
    blake_small_ctx_t ctx;
    blake224_init(&ctx);
    while (length_b >= BLAKE_SMALL_BLOCKSIZE) {
        blake_small_nextBlock(&ctx, msg);
        msg = (uint8_t*) msg + BLAKE_SMALL_BLOCKSIZE_B;
        length_b -= BLAKE_SMALL_BLOCKSIZE;
    }
    blake_small_lastBlock(&ctx, msg, length_b);
    blake224_ctx2hash(dest, &ctx);
}