new pack system

src/PackLib/Pack.cpp

@@ -0,0 +1,71 @@
+#include "Pack.h"
+#include <zstd.h>
+
+bool CPack::Open(const std::string& path, TPackFileMap& entries)
+{
+	std::error_code ec;
+	m_file.map(path, ec);
+	
+	if (ec) {
+		return false;
+	}
+
+	size_t file_size = m_file.size();
+	if (file_size < sizeof(TPackFileHeader)) {
+		return false;
+	}
+
+	memcpy(&m_header, m_file.data(), sizeof(TPackFileHeader));
+	m_decryption.SetKeyWithIV(PACK_KEY.data(), PACK_KEY.size(), m_header.iv, CryptoPP::Camellia::BLOCKSIZE);
+
+	if (file_size < sizeof(TPackFileHeader) + m_header.entry_num * sizeof(TPackFileEntry)) {
+		return false;
+	}
+
+	for (size_t i = 0; i < m_header.entry_num; i++) {
+		TPackFileEntry entry;
+		memcpy(&entry, m_file.data() + sizeof(TPackFileHeader) + i * sizeof(TPackFileEntry), sizeof(TPackFileEntry));
+		m_decryption.ProcessData((CryptoPP::byte*)&entry, (CryptoPP::byte*)&entry, sizeof(TPackFileEntry));
+
+		entries[entry.file_name] = std::make_pair(shared_from_this(), entry);
+
+		if (file_size < m_header.data_begin + entry.offset + entry.compressed_size) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+bool CPack::GetFile(const TPackFileEntry& entry, TPackFile& result)
+{
+	result.resize(entry.file_size);
+
+	size_t offset = m_header.data_begin + entry.offset;
+	switch (entry.encryption)
+	{
+		case 0: {
+			size_t decompressed_size = ZSTD_decompress(result.data(), result.size(), m_file.data() + offset, entry.compressed_size);
+			if (decompressed_size != entry.file_size) {
+				return false;
+			}
+		} break;
+
+		case 1: {
+			std::vector<uint8_t> compressed_data(entry.compressed_size);
+			memcpy(compressed_data.data(), m_file.data() + offset, entry.compressed_size);
+
+			m_decryption.Resynchronize(entry.iv, sizeof(entry.iv));
+			m_decryption.ProcessData(compressed_data.data(), compressed_data.data(), entry.compressed_size);
+
+			size_t decompressed_size = ZSTD_decompress(result.data(), result.size(), compressed_data.data(), compressed_data.size());
+			if (decompressed_size != entry.file_size) {
+				return false;
+			}
+		} break;
+
+		default: return false;
+	}
+
+	return true;
+}