/* bcal-basic.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/>.
 */

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <avr/pgmspace.h>
#include "blockcipher_descriptor.h"
#include "keysize_descriptor.h"

uint8_t bcal_cipher_init(const bcdesc_t *cipher_descriptor,
        const void *key, uint16_t keysize_b, bcgen_ctx_t *ctx)
{
    if (!is_valid_keysize_P((PGM_VOID_P) pgm_read_word(&(cipher_descriptor->valid_keysize_desc)),
            keysize_b)) {
        return 1;
    }
    uint8_t flags;
    bc_init_fpt init_fpt;
    ctx->desc_ptr = (bcdesc_t*) cipher_descriptor;
    ctx->keysize = keysize_b;
    flags = pgm_read_byte(cipher_descriptor->flags);
    init_fpt.initvoid =
            (void_fpt) (pgm_read_word(&(cipher_descriptor->init.initvoid)));
    if (init_fpt.initvoid == NULL) {
        if (!(ctx->ctx = malloc((keysize_b + 7) / 8))) {
            return 2;
        }
        memcpy(ctx->ctx, key, (keysize_b + 7) / 8);
        return 0;
    }
    if (!(ctx->ctx = malloc(pgm_read_word(&(cipher_descriptor->ctxsize_B))))) {
        return 3;
    }
    if ((flags & BC_INIT_TYPE) == BC_INIT_TYPE_1) {
        init_fpt.init1((void*) key, (ctx->ctx));
    } else {
        init_fpt.init2((void*) key, keysize_b, (ctx->ctx));
    }
    return 0;
}

void bcal_cipher_free(bcgen_ctx_t *ctx)
{
    if (!ctx)
        return;
    bc_free_fpt free_fpt;
    free_fpt = (bc_free_fpt) (pgm_read_word(&(ctx->desc_ptr->free)));
    if (free_fpt)
        free_fpt((ctx->ctx));
    free(ctx->ctx);
}

void bcal_cipher_enc(void *block, const bcgen_ctx_t *ctx)
{
    bc_enc_fpt enc_fpt;
    enc_fpt.encvoid = (void_fpt) pgm_read_word(&(ctx->desc_ptr->enc.encvoid));
    if (!enc_fpt.encvoid) {
        /* very bad error, no enciphering function specified */
        return;
    }
    enc_fpt.enc1(block, (ctx->ctx));

}

void bcal_cipher_dec(void *block, const bcgen_ctx_t *ctx)
{
    bc_dec_fpt dec_fpt;
    dec_fpt.decvoid = (void_fpt) pgm_read_word(&(ctx->desc_ptr->dec.decvoid));
    if (!dec_fpt.decvoid) {
        /* very bad error, no deciphering function specified */
        return;
    }
    dec_fpt.dec1(block, (ctx->ctx));
}

uint16_t bcal_cipher_getBlocksize_b(const bcdesc_t *desc)
{
    return pgm_read_word(&(desc->blocksize_b));
}

PGM_VOID_P bcal_cipher_getKeysizeDesc(const bcdesc_t *desc) {
    return (PGM_VOID_P)pgm_read_word(&(desc->valid_keysize_desc));
}