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/*
* OpenTyrian: A modern cross-platform port of Tyrian
* Copyright (C) 2007-2009 The OpenTyrian Development Team
*
* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "editship.h"
#include "file.h"
#include "opentyr.h"
#define SAS (sizeof(JE_ShipsType) - 4)
const JE_byte extraCryptKey[10] = { 58, 23, 16, 192, 254, 82, 113, 147, 62, 99 };
JE_boolean extraAvail;
JE_ShipsType extraShips;
void *extraShapes;
JE_word extraShapeSize;
void JE_decryptShips( void )
{
JE_boolean correct = true;
JE_ShipsType s2;
JE_byte y;
for (int x = SAS - 1; x >= 0; x--)
{
s2[x] = extraShips[x] ^ extraCryptKey[(x + 1) % 10];
if (x > 0)
s2[x] ^= extraShips[x - 1];
} /* <= Key Decryption Test (Reversed key) */
y = 0;
for (uint x = 0; x < SAS; x++)
y += s2[x];
if (extraShips[SAS + 0] != y)
correct = false;
y = 0;
for (uint x = 0; x < SAS; x++)
y -= s2[x];
if (extraShips[SAS + 1] != y)
correct = false;
y = 1;
for (uint x = 0; x < SAS; x++)
y = y * s2[x] + 1;
if (extraShips[SAS + 2] != y)
correct = false;
y = 0;
for (uint x = 0; x < SAS; x++)
y ^= s2[x];
if (extraShips[SAS + 3] != y)
correct = false;
if (!correct)
exit(255);
memcpy(extraShips, s2, sizeof(extraShips));
}
void JE_loadExtraShapes( void )
{
FILE *f = dir_fopen(get_user_directory(), "newsh$.shp", "rb");
if (f)
{
extraAvail = true;
extraShapeSize = ftell_eof(f) - sizeof(extraShips);
extraShapes = malloc(extraShapeSize);
efread(extraShapes, extraShapeSize, 1, f);
efread(extraShips, sizeof(extraShips), 1, f);
JE_decryptShips();
fclose(f);
}
}
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