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Change mask to a vector

This commit is contained in:
Ted John 2020-07-10 19:07:46 +01:00
parent 06f1b58004
commit 2b962577b9
1 changed files with 9 additions and 22 deletions
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31
src/openrct2/rct2/SeaDecrypt.cpp
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@ -42,33 +42,22 @@ static EncryptionKey GetEncryptionKey(const std::string_view& fileName)
return EncryptionKey{ s0, s1 };
}
static std::unique_ptr<uint8_t[]> CreateMask(const EncryptionKey& key)
static std::vector<uint8_t> CreateMask(const EncryptionKey& key)
{
auto result = std::make_unique<uint8_t[]>(MASK_SIZE);
auto dst8 = result.get();
std::vector<uint8_t> result;
result.resize(MASK_SIZE);
uint32_t seed0 = key.Seed0;
uint32_t seed1 = key.Seed1;
int32_t i = MASK_SIZE;
while (i > 0)
for (size_t i = 0; i < MASK_SIZE; i += 4)
{
uint32_t s0 = seed0;
uint32_t s1 = seed1 ^ 0xF7654321;
seed0 = rol32(s1, 25) + s0;
seed1 = rol32(s0, 29);
*dst8++ = (s0 >> 3) & 0xFF;
if (i >= 2)
{
*dst8++ = (s0 >> 11) & 0xFF;
if (i >= 3)
{
*dst8++ = (s0 >> 19) & 0xFF;
if (i >= 4)
{
*dst8++ = (seed1 >> 24) & 0xFF;
i -= 4;
}
}
}
result[i + 0] = (s0 >> 3) & 0xFF;
result[i + 1] = (s0 >> 11) & 0xFF;
result[i + 2] = (s0 >> 19) & 0xFF;
result[i + 3] = (seed1 >> 24) & 0xFF;
}
return result;
}
@ -76,8 +65,6 @@ static std::unique_ptr<uint8_t[]> CreateMask(const EncryptionKey& key)
static void Decrypt(std::vector<uint8_t>& data, const EncryptionKey& key)
{
auto mask = CreateMask(key);
const uint8_t* mask8 = (const uint8_t*)mask.get();
uint32_t b = 0;
uint32_t c = 0;
for (size_t i = 0; i < data.size(); i++)
@ -86,7 +73,7 @@ static void Decrypt(std::vector<uint8_t>& data, const EncryptionKey& key)
c = c % MASK_SIZE;
b = (a + 1) % MASK_SIZE;
data[i] = (((data[i] - mask8[b]) ^ mask8[c]) + mask8[a]) & 0xFF;
data[i] = (((data[i] - mask[b]) ^ mask[c]) + mask[a]) & 0xFF;
c += 3;
b = a + 7;