/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

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/>.

Additional permissions under GNU GPL version 3 section 7

If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
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containing parts covered by the terms of the Bink SDK EULA, 3ds Max EULA,
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 or by snail mail at:
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*==LICENSE==*/
/*****************************************************************************
*
*   $/Plasma20/Sources/Plasma/NucleusLib/pnUtils/Private/pnUtCrypt.cpp
*   
***/

#include "pnUtCrypt.h"
#include "pnUtStr.h"
#include "pnUtTime.h"

#include <openssl/rc4.h>

/*****************************************************************************
*
*   Opaque types
*
***/

struct CryptKey {
    ECryptAlgorithm algorithm;
    void *          handle;
};


/*****************************************************************************
*
*   Private
*
***/

namespace Crypt {


/*****************************************************************************
*
*   Internal functions
*
***/

/*****************************************************************************
*
*   RC4
*
***/

//============================================================================
static void Rc4Codec (
    CryptKey *      key,
    bool            encrypt,
    ARRAY(uint8_t) *   dest,
    unsigned        sourceBytes,
    const void *    sourceData
) {
    // RC4 uses the same algorithm to both encrypt and decrypt
    dest->SetCount(sourceBytes);
    RC4((RC4_KEY *)key->handle, sourceBytes, (const unsigned char *)sourceData, dest->Ptr());
}

//============================================================================
static void Rc4Codec (
    CryptKey *      key,
    bool            encrypt,
    unsigned        bytes,
    void *          data
) {
    // RC4 uses the same algorithm to both encrypt and decrypt
    uint8_t * temp = (uint8_t *)malloc(bytes);
    RC4((RC4_KEY *)key->handle, bytes, (const unsigned char *)data, temp);
    memcpy(data, temp, bytes);

    free(temp);
}

} using namespace Crypt;


/*****************************************************************************
*
*   Exports
*
***/

//============================================================================
CryptKey * CryptKeyCreate (
    ECryptAlgorithm algorithm,
    unsigned        bytes,
    const void *    data
) {
    CryptKey * key = nil;
    switch (algorithm) {
        case kCryptRc4: {
            RC4_KEY * rc4 = new RC4_KEY;
            RC4_set_key(rc4, bytes, (const unsigned char *)data);
            key = new CryptKey;
            key->algorithm = kCryptRc4;
            key->handle = rc4;
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//      break;

        DEFAULT_FATAL(algorithm);
    }

    return key;
}

//============================================================================
void CryptKeyClose (
    CryptKey *      key
) {
    if (!key)
        return;

    delete key->handle;
    delete key;
}

//============================================================================
unsigned CryptKeyGetBlockSize (
    CryptKey *      key
) {
    switch (key->algorithm) {
        case kCryptRc4: {
            return 1;
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//            return RsaGetBlockSize(key);

        DEFAULT_FATAL(algorithm);
    }
}

//============================================================================
void CryptEncrypt (
    CryptKey *      key,
    ARRAY(uint8_t) *   dest,
    unsigned        sourceBytes,
    const void *    sourceData
) {
    switch (key->algorithm) {
        case kCryptRc4: {
            Rc4Codec(key, true, dest, sourceBytes, sourceData);
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//          RsaCodec(key, true, dest, sourceBytes, sourceData);
//      break;

        DEFAULT_FATAL(key->algorithm);
    }
}

//============================================================================
void CryptEncrypt (
    CryptKey *      key,
    unsigned        bytes,
    void *          data
) {
    ASSERT(1 == CryptKeyGetBlockSize(key));

    switch (key->algorithm) {
        case kCryptRc4: {
            Rc4Codec(key, true, bytes, data);
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//          RsaCodec(key, true, dest, sourceBytes, sourceData);
//      break;

        DEFAULT_FATAL(key->algorithm);
    }
}

//============================================================================
void CryptDecrypt (
    CryptKey *      key,
    ARRAY(uint8_t) *   dest,
    unsigned        sourceBytes,
    const void *    sourceData
) {
    switch (key->algorithm) {
        case kCryptRc4: {
            Rc4Codec(key, false, dest, sourceBytes, sourceData);
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//          RsaCodec(key, false, dest, sourceBytes, sourceData);
//      break;

        DEFAULT_FATAL(key->algorithm);
    }
}

//============================================================================
void CryptDecrypt (
    CryptKey *      key,
    unsigned        bytes,
    void *          data
) {
    ASSERT(1 == CryptKeyGetBlockSize(key));

    switch (key->algorithm) {
        case kCryptRc4: {
            Rc4Codec(key, false, bytes, data);
        }
        break;

        case kCryptRsa: // Not implemented; fall-thru to FATAL
//          RsaCodec(key, false, dest, sourceBytes, sourceData);
//      break;

        DEFAULT_FATAL(key->algorithm);
    }
}