/*
 * Copyright (C) 2015 Southern Storm Software, Pty Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/*
This example runs tests on the SHA256 implementation to verify correct behaviour.
*/

#include <Crypto.h>
#include <SHA256.h>
#include <string.h>

#define HASH_SIZE 32

struct TestHashVector
{
    const char *name;
    const char *data;
    uint8_t hash[HASH_SIZE];
};

static TestHashVector const testVectorSHA256_1 = {
    "SHA-256 #1",
    "abc",
    {0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea,
     0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23,
     0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c,
     0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad}
};
static TestHashVector const testVectorSHA256_2 = {
    "SHA-256 #2",
    "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
    {0x24, 0x8d, 0x6a, 0x61, 0xd2, 0x06, 0x38, 0xb8,
     0xe5, 0xc0, 0x26, 0x93, 0x0c, 0x3e, 0x60, 0x39,
     0xa3, 0x3c, 0xe4, 0x59, 0x64, 0xff, 0x21, 0x67,
     0xf6, 0xec, 0xed, 0xd4, 0x19, 0xdb, 0x06, 0xc1}
};

SHA256 sha256;

byte buffer[128];

bool testHash_N(Hash *hash, const struct TestHashVector *test, size_t inc)
{
    size_t size = strlen(test->data);
    size_t posn, len;
    uint8_t value[HASH_SIZE];

    hash->reset();
    for (posn = 0; posn < size; posn += inc) {
        len = size - posn;
        if (len > inc)
            len = inc;
        hash->update(test->data + posn, len);
    }
    hash->finalize(value, sizeof(value));
    if (memcmp(value, test->hash, sizeof(value)) != 0)
        return false;

    return true;
}

void testHash(Hash *hash, const struct TestHashVector *test)
{
    bool ok;

    Serial.print(test->name);
    Serial.print(" ... ");

    ok  = testHash_N(hash, test, strlen(test->data));
    ok &= testHash_N(hash, test, 1);
    ok &= testHash_N(hash, test, 2);
    ok &= testHash_N(hash, test, 5);
    ok &= testHash_N(hash, test, 8);
    ok &= testHash_N(hash, test, 13);
    ok &= testHash_N(hash, test, 16);
    ok &= testHash_N(hash, test, 24);
    ok &= testHash_N(hash, test, 63);
    ok &= testHash_N(hash, test, 64);

    if (ok)
        Serial.println("Passed");
    else
        Serial.println("Failed");
}

void perfHash(Hash *hash)
{
    unsigned long start;
    unsigned long elapsed;
    int count;

    Serial.print("Hashing ... ");

    for (size_t posn = 0; posn < sizeof(buffer); ++posn)
        buffer[posn] = (uint8_t)posn;

    hash->reset();
    start = micros();
    for (count = 0; count < 500; ++count) {
        hash->update(buffer, sizeof(buffer));
    }
    elapsed = micros() - start;

    Serial.print(elapsed / (sizeof(buffer) * 500.0));
    Serial.print("us per byte, ");
    Serial.print((sizeof(buffer) * 500.0 * 1000000.0) / elapsed);
    Serial.println(" bytes per second");
}

void setup()
{
    Serial.begin(9600);

    Serial.println();

    Serial.println("Test Vectors:");
    testHash(&sha256, &testVectorSHA256_1);
    testHash(&sha256, &testVectorSHA256_2);

    Serial.println();

    Serial.println("Performance Tests:");
    perfHash(&sha256);
}

void loop()
{
}