APK.cpp

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// ReSharper disable CppRedundantQualifier
 
#include <vpkpp/format/APK.h>
 
#include <filesystem>
 
#include <FileStream.h>
 
using namespace sourcepp;
using namespace vpkpp;
 
std::unique_ptr<PackFile> APK::create(const std::string& path) {
    {
        FileStream stream{path, FileStream::OPT_TRUNCATE | FileStream::OPT_CREATE_IF_NONEXISTENT};
        stream
            .write(APK_SIGNATURE)
            .write<uint32_t>(sizeof(uint32_t) * 4)
            .write<uint32_t>(0)
            .write<uint32_t>(sizeof(uint32_t) * 4)
            .pad<uint32_t>();
    }
    return APK::open(path);
}
 
std::unique_ptr<PackFile> APK::open(const std::string& path, const EntryCallback& callback) {
    if (!std::filesystem::exists(path)) {
        // File does not exist
        return nullptr;
    }
 
    auto* apk = new APK{path};
    auto packFile = std::unique_ptr<PackFile>(apk);
 
    FileStream reader{apk->fullFilePath};
    reader.seek_in(0);
 
    if (
        reader.read<uint32_t>() != APK_SIGNATURE ||
        reader.read<uint32_t>() != sizeof(uint32_t) * 4
    ) {
        // File is not an APK
        return nullptr;
    }
 
    const auto entryCount = reader.read<uint32_t>();
 
    auto nextEntryOffset = reader.read<uint32_t>();
    for (uint32_t i = 0; i < entryCount; i++) {
        reader.seek_in(nextEntryOffset);
 
        Entry entry = createNewEntry();
 
        auto entryPath = apk->cleanEntryPath(reader.read_string(reader.read<uint32_t>() + 1));
 
        entry.offset = reader.read<uint32_t>();
        entry.length = reader.read<uint32_t>();
 
        reader
            .read(nextEntryOffset)
            .skip_in<uint32_t>();
 
        apk->entries.emplace(entryPath, entry);
 
        if (callback) {
            callback(entryPath, entry);
        }
    }
 
    return packFile;
}
 
std::optional<std::vector<std::byte>> APK::readEntry(const std::string& path_) const {
    const auto path = this->cleanEntryPath(path_);
    const auto entry = this->findEntry(path);
    if (!entry) {
        return std::nullopt;
    }
    if (entry->unbaked) {
        return readUnbakedEntry(*entry);
    }
 
    // It's baked into the file on disk
    FileStream stream{this->fullFilePath};
    if (!stream) {
        return std::nullopt;
    }
    stream.seek_in_u(entry->offset);
    return stream.read_bytes(entry->length);
}
 
void APK::addEntryInternal(Entry& entry, const std::string& path, std::vector<std::byte>& buffer, EntryOptions options) {
    entry.length = buffer.size();
 
    // Offset will be reset when it's baked
    entry.offset = 0;
}
 
bool APK::bake(const std::string& outputDir_, BakeOptions options, const EntryCallback& callback) {
    // Get the proper file output folder
    const std::string outputDir = this->getBakeOutputDir(outputDir_);
    const std::string outputPath = outputDir + '/' + this->getFilename();
 
    // Reconstruct data for ease of access
    std::vector<std::pair<std::string, Entry*>> entriesToBake;
    this->runForAllEntriesInternal([&entriesToBake](const std::string& path, Entry& entry) {
        entriesToBake.emplace_back(path, &entry);
    });
 
    // Read data before overwriting, we don't know if we're writing to ourself
    std::vector<std::byte> fileData;
    for (auto& [path, entry] : entriesToBake) {
        if (auto binData = this->readEntry(path)) {
            entry->offset = fileData.size();
 
            fileData.insert(fileData.end(), binData->begin(), binData->end());
        } else {
            entry->offset = 0;
            entry->length = 0;
        }
    }
 
    {
        FileStream stream{outputPath, FileStream::OPT_TRUNCATE | FileStream::OPT_CREATE_IF_NONEXISTENT};
        stream.seek_out(0);
 
        // Signature + header size
        stream
            .write(APK_SIGNATURE)
            .write<uint32_t>(sizeof(uint32_t) * 4);
 
        // Offset and size of directory
        static constexpr auto HEADER_OFFSET = sizeof(uint32_t) * 5;
        stream
            .write<uint32_t>(entriesToBake.size())
            .write<uint32_t>(HEADER_OFFSET + fileData.size())
            .pad<uint32_t>();
 
        // File data
        stream.write(fileData);
 
        // Directory
        for (const auto& [path, entry] : entriesToBake) {
            stream
                .write<uint32_t>(path.size())
                .write(path)
                .write<uint32_t>(entry->offset + HEADER_OFFSET)
                .write<uint32_t>(entry->length)
                .write<uint32_t>(stream.tell_out() + sizeof(uint32_t) * 2)
                .pad<uint32_t>();
 
            if (callback) {
                callback(path, *entry);
            }
        }
    }
 
    // Clean up
    this->mergeUnbakedEntries();
    PackFile::setFullFilePath(outputDir);
    return true;
}
 
Attribute APK::getSupportedEntryAttributes() const {
    using enum Attribute;
    return LENGTH;
}