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Add experimental, disabled XOR mode, leaving all compression to ZSTD. Seems to perform worse.

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Henrik Rydgård 2023-02-13 15:22:28 +01:00
parent f6e5249327
commit 7f6e6ae985
1 changed files with 59 additions and 32 deletions
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91
Core/SaveState.cpp
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@ -103,9 +103,14 @@ namespace SaveState
}
struct StateBuffer {
void Clear() {
zstd_compressed.clear();
decompressed_size = 0;
compressed_size = 0;
}
std::vector<u8> zstd_compressed;
size_t decompressed_size;
size_t compressed_size;
size_t decompressed_size = 0;
size_t compressed_size = 0;
};
// This ring buffer of states is for rewind save states, which are kept in RAM.
@ -196,6 +201,8 @@ namespace SaveState
});
}
const bool USE_XOR = false;
void Compress(StateBuffer *result, std::vector<u8> &state, const std::vector<u8> &base)
{
std::lock_guard<std::mutex> guard(lock_);
@ -205,26 +212,36 @@ namespace SaveState
double start_time = time_now_d();
std::vector<u8> compressed;
compressed.reserve(512 * 1024);
for (size_t i = 0; i < state.size(); i += BLOCK_SIZE)
{
int blockSize = std::min(BLOCK_SIZE, (int)(state.size() - i));
if (i + blockSize > base.size() || memcmp(&state[i], &base[i], blockSize) != 0)
{
compressed.push_back(1);
compressed.insert(compressed.end(), state.begin() + i, state.begin() + i + blockSize);
if (USE_XOR) {
compressed.resize(state.size());
for (size_t i = 0; i < state.size(); i++) {
if (i >= base.size()) {
compressed[i] = state[i];
} else {
compressed[i] = base[i] ^ state[i];
}
}
} else {
compressed.reserve(512 * 1024);
for (size_t i = 0; i < state.size(); i += BLOCK_SIZE)
{
int blockSize = std::min(BLOCK_SIZE, (int)(state.size() - i));
if (i + blockSize > base.size() || memcmp(&state[i], &base[i], blockSize) != 0)
{
compressed.push_back(1);
compressed.insert(compressed.end(), state.begin() + i, state.begin() + i + blockSize);
} else {
compressed.push_back(0);
}
}
else
compressed.push_back(0);
}
double taken_s = time_now_d() - start_time;
DEBUG_LOG(SAVESTATE, "Rewind: Compressed save from %d bytes to %d in %0.2f ms.", (int)state.size(), (int)compressed.size(), taken_s * 1000.0);
// Temporarily allocate a buffer to do decompression in.
// Temporarily allocate a buffer to do compression in.
size_t compressCapacity = ZSTD_compressBound(compressed.size());
u8 *compress_buf = (u8 *)malloc(compressCapacity);
result->compressed_size = ZSTD_compress(compress_buf, compressCapacity, compressed.data(), compressed.size(), 0);
if (result->compressed_size) {
result->zstd_compressed = std::vector<u8>(result->compressed_size, 0);
@ -247,25 +264,35 @@ namespace SaveState
std::vector<u8> compressed = std::vector<u8>(buffer.decompressed_size, 0);
ZSTD_decompress(&compressed[0], compressed.size(), buffer.zstd_compressed.data(), buffer.zstd_compressed.size());
for (size_t i = 0; i < compressed.size(); )
{
if (compressed[i] == 0)
{
++i;
int blockSize = std::min(BLOCK_SIZE, (int)(base.size() - result.size()));
result.insert(result.end(), basePos, basePos + blockSize);
basePos += blockSize;
if (USE_XOR) {
result.resize(compressed.size());
for (size_t i = 0; i < compressed.size(); i++) {
if (i < base.size()) {
result[i] = compressed[i] ^ base[i];
} else {
result[i] = compressed[i];
}
}
else
{
++i;
int blockSize = std::min(BLOCK_SIZE, (int)(compressed.size() - i));
result.insert(result.end(), compressed.begin() + i, compressed.begin() + i + blockSize);
i += blockSize;
// This check is to avoid advancing basePos out of range, which MSVC catches.
// When this happens, we're at the end of decoding anyway.
if (base.end() - basePos >= blockSize) {
} else {
for (size_t i = 0; i < compressed.size(); ) {
if (compressed[i] == 0) {
++i;
int blockSize = std::min(BLOCK_SIZE, (int)(base.size() - result.size()));
_dbg_assert_(blockSize >= 0);
result.insert(result.end(), basePos, basePos + blockSize);
basePos += blockSize;
} else {
++i;
int blockSize = std::min(BLOCK_SIZE, (int)(compressed.size() - i));
if (blockSize > 0) {
result.insert(result.end(), compressed.begin() + i, compressed.begin() + i + blockSize);
i += blockSize;
// This check is to avoid advancing basePos out of range, which MSVC catches.
// When this happens, we're at the end of decoding anyway.
if (base.end() - basePos >= blockSize) {
basePos += blockSize;
}
}
}
}
}
@ -286,7 +313,7 @@ namespace SaveState
baseMapping_.clear();
baseMapping_.resize(size_);
for (auto &s : states_) {
s.clear();
s.Clear();
}
buffer_.clear();
base_ = -1;