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openmw/components/bsa/compressedbsafile.cpp
elsid 796202f435
Use fail function to verify stream state in BSA 
If there is a failure to read the file like unexpected EOF, bad returns
false, but fail returns true. Important for reading number of items more
than the file actually has.
2025-10-06 00:02:32 +02:00

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/*
OpenMW - The completely unofficial reimplementation of Morrowind
Copyright (C) 2008-2010 Nicolay Korslund
Email: < korslund@gmail.com >
WWW: http://openmw.sourceforge.net/
This file (compressedbsafile.cpp) is part of the OpenMW package.
OpenMW is distributed as free software: you can redistribute it
and/or modify it under the terms of the GNU General Public License
version 3, as published by the Free Software Foundation.
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
version 3 along with this program. If not, see
http://www.gnu.org/licenses/ .
Compressed BSA stuff added by cc9cii 2018
*/
#include "compressedbsafile.hpp"
#include <algorithm>
#include <cassert>
#include <cerrno>
#include <filesystem>
#include <format>
#include <fstream>
#include <system_error>
#include <lz4frame.h>
#include <zlib.h>
#include <components/files/constrainedfilestream.hpp>
#include <components/files/conversion.hpp>
#include <components/misc/strings/lower.hpp>
#include "memorystream.hpp"
namespace Bsa
{
/// Read header information from the input source
void CompressedBSAFile::readHeader()
{
assert(!mIsLoaded);
std::ifstream input(mFilepath, std::ios_base::binary);
// Total archive size
std::streamoff fsize = 0;
if (input.seekg(0, std::ios_base::end))
{
fsize = input.tellg();
input.seekg(0);
}
if (fsize < 36) // Header is 36 bytes
fail("File too small to be a valid BSA archive");
input.read(reinterpret_cast<char*>(&mHeader), sizeof(mHeader));
if (mHeader.mFormat != static_cast<std::uint32_t>(BsaVersion::Compressed)) // BSA
fail("Unrecognized compressed BSA format");
if (mHeader.mVersion != Version_TES4 && mHeader.mVersion != Version_FO3 && mHeader.mVersion != Version_SSE)
fail("Unrecognized compressed BSA version");
if (mHeader.mVersion == Version_TES4)
mHeader.mFlags &= (~ArchiveFlag_EmbeddedNames);
input.seekg(mHeader.mFoldersOffset);
if (input.fail())
fail("Failed to read compressed BSA folder record offset: " + std::generic_category().message(errno));
struct FlatFolderRecord
{
std::uint64_t mHash;
std::string mName;
std::uint32_t mCount;
std::int64_t mOffset;
};
std::vector<std::pair<FlatFolderRecord, std::vector<FileRecord>>> folders;
folders.reserve(mHeader.mFolderCount);
for (std::uint32_t i = 0; i < mHeader.mFolderCount; ++i)
{
FlatFolderRecord folder;
input.read(reinterpret_cast<char*>(&folder.mHash), 8);
input.read(reinterpret_cast<char*>(&folder.mCount), 4);
if (mHeader.mVersion == Version_SSE) // SSE
{
std::uint32_t unknown = 0;
input.read(reinterpret_cast<char*>(&unknown), 4);
input.read(reinterpret_cast<char*>(&folder.mOffset), 8);
}
else
{
input.read(reinterpret_cast<char*>(&folder.mOffset), 4);
}
if (input.fail())
fail(std::format(
"Failed to read compressed BSA folder record: {}", std::generic_category().message(errno)));
folders.emplace_back(std::move(folder), std::vector<FileRecord>());
}
// file record blocks
if ((mHeader.mFlags & ArchiveFlag_FolderNames) == 0)
mHeader.mFolderCount = 1; // TODO: not tested - unit test necessary
for (auto& [folder, filelist] : folders)
{
if ((mHeader.mFlags & ArchiveFlag_FolderNames) != 0)
{
uint8_t size = 0;
input.read(reinterpret_cast<char*>(&size), 1);
if (size > 0)
{
folder.mName.resize(size);
input.getline(folder.mName.data(), size, '\0');
if (input.gcount() != static_cast<std::streamsize>(size))
fail("Folder name size mismatch: " + std::to_string(input.gcount()) + " bytes read, expected "
+ std::to_string(size));
if (mHeader.mFolderNamesLength < size)
fail("Failed to read folder names: " + std::to_string(mHeader.mFolderNamesLength) + " < "
+ std::to_string(size));
folder.mName.resize(size - 1);
}
mHeader.mFolderNamesLength -= size;
}
filelist.reserve(folder.mCount);
for (std::uint32_t i = 0; i < folder.mCount; ++i)
{
FileRecord file;
input.read(reinterpret_cast<char*>(&file.mHash), 8);
input.read(reinterpret_cast<char*>(&file.mSize), 4);
input.read(reinterpret_cast<char*>(&file.mOffset), 4);
if (input.fail())
fail(std::format("Failed to read compressed BSA folder file record: {}",
std::generic_category().message(errno)));
filelist.push_back(std::move(file));
}
}
if (mHeader.mFolderNamesLength != 0)
input.ignore(mHeader.mFolderNamesLength);
if (input.fail())
fail(std::format("Failed to read compressed BSA file records: {}", std::generic_category().message(errno)));
if ((mHeader.mFlags & ArchiveFlag_FileNames) != 0)
{
for (auto& [folder, filelist] : folders)
{
for (auto& file : filelist)
{
auto& name = file.mName;
name.resize(256);
input.getline(name.data(), 256, '\0');
if (input.gcount() <= 1)
fail("Failed to read a filename: filename is empty");
if (mHeader.mFileNamesLength < input.gcount())
fail("Failed to read file names: " + std::to_string(mHeader.mFileNamesLength) + " < "
+ std::to_string(input.gcount()));
name.resize(input.gcount());
if (name.back() != '\0')
fail("Failed to read a filename: filename is too long");
mHeader.mFileNamesLength -= static_cast<std::uint32_t>(input.gcount());
file.mName.insert(file.mName.begin(), folder.mName.begin(), folder.mName.end());
file.mName.insert(file.mName.begin() + folder.mName.size(), '\\');
}
}
}
if (mHeader.mFileNamesLength != 0)
input.ignore(mHeader.mFileNamesLength);
if (input.fail())
fail(std::format("Failed to read compressed BSA filenames: {}", std::generic_category().message(errno)));
for (auto& [folder, filelist] : folders)
{
std::map<std::uint64_t, FileRecord> fileMap;
for (auto& file : filelist)
fileMap[file.mHash] = std::move(file);
mFolders[folder.mHash] = FolderRecord{ folder.mCount, folder.mOffset, folder.mName, std::move(fileMap) };
}
for (auto& [folderHash, folderRecord] : mFolders)
{
for (auto& [fileHash, fileRecord] : folderRecord.mFiles)
{
FileStruct fileStruct{};
fileStruct.mFileSize = fileRecord.mSize & (~FileSizeFlag_Compression);
fileStruct.mOffset = fileRecord.mOffset;
fileStruct.mNameOffset = 0;
fileStruct.mNameSize
= fileRecord.mName.empty() ? 0 : static_cast<uint32_t>(fileRecord.mName.size() - 1);
fileStruct.mNamesBuffer = &fileRecord.mName;
mFiles.push_back(fileStruct);
}
}
mIsLoaded = true;
}
CompressedBSAFile::FileRecord CompressedBSAFile::getFileRecord(std::string_view str) const
{
for (const auto c : str)
{
if (((static_cast<unsigned>(c) >> 7U) & 1U) != 0U)
{
fail(std::format("File record {} contains unicode characters, refusing to load.", str));
}
}
#ifdef _WIN32
const auto& path = str;
#else
// Force-convert the path into something UNIX can handle first
// to make sure std::filesystem::path doesn't think the entire path is the filename on Linux
// and subsequently purge it to determine the file folder.
std::string path(str);
std::replace(path.begin(), path.end(), '\\', '/');
#endif
const auto p = std::filesystem::path{ path }; // Purposefully damage Unicode strings.
const auto stem = p.stem();
const auto ext = p.extension().string(); // Purposefully damage Unicode strings.
std::uint64_t folderHash = generateHash(p.parent_path(), {});
auto it = mFolders.find(folderHash);
if (it == mFolders.end())
return FileRecord();
std::uint64_t fileHash = generateHash(stem, ext);
auto iter = it->second.mFiles.find(fileHash);
if (iter == it->second.mFiles.end())
return FileRecord();
return iter->second;
}
Files::IStreamPtr CompressedBSAFile::getFile(const FileStruct* file)
{
FileRecord fileRec = getFileRecord(file->name());
if (fileRec.mOffset == std::numeric_limits<uint32_t>::max())
{
fail("File not found: " + std::string(file->name()));
}
return getFile(fileRec);
}
void CompressedBSAFile::addFile(const std::string& filename, std::istream& file)
{
assert(false); // not implemented yet
fail("Add file is not implemented for compressed BSA: " + filename);
}
Files::IStreamPtr CompressedBSAFile::getFile(const char* file)
{
FileRecord fileRec = getFileRecord(file);
if (fileRec.mOffset == std::numeric_limits<uint32_t>::max())
{
fail("File not found: " + std::string(file));
}
return getFile(fileRec);
}
Files::IStreamPtr CompressedBSAFile::getFile(const FileRecord& fileRecord)
{
size_t size = fileRecord.mSize & (~FileSizeFlag_Compression);
size_t resultSize = size;
Files::IStreamPtr streamPtr = Files::openConstrainedFileStream(mFilepath, fileRecord.mOffset, size);
bool compressed = (fileRecord.mSize != size) == ((mHeader.mFlags & ArchiveFlag_Compress) == 0);
if ((mHeader.mFlags & ArchiveFlag_EmbeddedNames) != 0)
{
// Skip over the embedded file name
uint8_t length = 0;
streamPtr->read(reinterpret_cast<char*>(&length), 1);
streamPtr->ignore(length);
size -= length + sizeof(uint8_t);
}
if (compressed)
{
streamPtr->read(reinterpret_cast<char*>(&resultSize), sizeof(uint32_t));
size -= sizeof(uint32_t);
}
auto memoryStreamPtr = std::make_unique<MemoryInputStream>(resultSize);
if (compressed)
{
std::vector<char> buffer(size);
streamPtr->read(buffer.data(), size);
if (mHeader.mVersion != Version_SSE)
{
uLongf destSize = static_cast<uLongf>(resultSize);
int ec = ::uncompress(reinterpret_cast<Bytef*>(memoryStreamPtr->getRawData()), &destSize,
reinterpret_cast<Bytef*>(buffer.data()), static_cast<uLong>(buffer.size()));
if (ec != Z_OK)
{
std::string message = "zlib uncompress failed for file ";
message.append(fileRecord.mName.begin(), fileRecord.mName.end());
message += ": ";
message += ::zError(ec);
fail(message);
}
}
else
{
LZ4F_decompressionContext_t context = nullptr;
LZ4F_createDecompressionContext(&context, LZ4F_VERSION);
LZ4F_decompressOptions_t options = {};
LZ4F_errorCode_t errorCode = LZ4F_decompress(
context, memoryStreamPtr->getRawData(), &resultSize, buffer.data(), &size, &options);
if (LZ4F_isError(errorCode))
fail("LZ4 decompression error (file " + Files::pathToUnicodeString(mFilepath)
+ "): " + LZ4F_getErrorName(errorCode));
errorCode = LZ4F_freeDecompressionContext(context);
if (LZ4F_isError(errorCode))
fail("LZ4 decompression error (file " + Files::pathToUnicodeString(mFilepath)
+ "): " + LZ4F_getErrorName(errorCode));
}
}
else
{
streamPtr->read(memoryStreamPtr->getRawData(), size);
}
return std::make_unique<Files::StreamWithBuffer<MemoryInputStream>>(std::move(memoryStreamPtr));
}
std::uint64_t CompressedBSAFile::generateHash(const std::filesystem::path& stem, std::string extension)
{
auto str = stem.u8string();
size_t len = str.length();
if (len == 0)
return 0;
std::replace(str.begin(), str.end(), '/', '\\');
Misc::StringUtils::lowerCaseInPlace(str);
uint64_t result = str[len - 1];
if (len >= 3)
result |= str[len - 2] << 8;
result |= len << 16;
result |= static_cast<uint32_t>(str[0] << 24);
if (len >= 4)
{
uint32_t hash = 0;
for (size_t i = 1; i <= len - 3; ++i)
hash = hash * 0x1003f + str[i];
result += static_cast<uint64_t>(hash) << 32;
}
if (extension.empty())
return result;
Misc::StringUtils::lowerCaseInPlace(extension);
if (extension == ".kf")
result |= 0x80;
else if (extension == ".nif")
result |= 0x8000;
else if (extension == ".dds")
result |= 0x8080;
else if (extension == ".wav")
result |= 0x80000000;
uint32_t hash = 0;
for (const auto& c : extension)
hash = hash * 0x1003f + c;
result += static_cast<uint64_t>(hash) << 32;
return result;
}
} // namespace Bsa
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