ggml-guided-diffusion/src/zip_archive.cpp at main · vecnode/ggml-guided-diffusion · GitHub

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#include "zip_archive.h"

#include <algorithm>
#include <fstream>
#include <iostream>

namespace gd {
namespace {

uint8_t read_u8(std::istream & input) {
    char byte = 0;
    input.read(&byte, 1);
    return static_cast<uint8_t>(byte);
}

uint16_t read_u16(std::istream & input) {
    uint8_t bytes[2] = {0, 0};
    input.read(reinterpret_cast<char *>(bytes), sizeof(bytes));
    return static_cast<uint16_t>(bytes[0]) |
           (static_cast<uint16_t>(bytes[1]) << 8);
}

uint32_t read_u32(std::istream & input) {
    uint8_t bytes[4] = {0, 0, 0, 0};
    input.read(reinterpret_cast<char *>(bytes), sizeof(bytes));
    return static_cast<uint32_t>(bytes[0]) |
           (static_cast<uint32_t>(bytes[1]) << 8) |
           (static_cast<uint32_t>(bytes[2]) << 16) |
           (static_cast<uint32_t>(bytes[3]) << 24);
}

}  // namespace

std::optional<uint64_t> find_end_of_central_directory(std::ifstream & input, uint64_t file_size) {
    const uint64_t max_scan = 65535 + 22;
    const uint64_t read_size = std::min<uint64_t>(file_size, max_scan);
    std::vector<uint8_t> tail(read_size);

    input.seekg(static_cast<std::streamoff>(file_size - read_size), std::ios::beg);
    input.read(reinterpret_cast<char *>(tail.data()), static_cast<std::streamsize>(tail.size()));
    if (!input) {
        return std::nullopt;
    }

    for (int64_t index = static_cast<int64_t>(tail.size()) - 22; index >= 0; --index) {
        const size_t i = static_cast<size_t>(index);
        if (tail[i + 0] == 0x50 && tail[i + 1] == 0x4b && tail[i + 2] == 0x05 && tail[i + 3] == 0x06) {
            return file_size - read_size + static_cast<uint64_t>(index);
        }
    }

    return std::nullopt;
}

std::optional<std::vector<ZipEntry>> read_zip_entries(const fs::path & archive_path) {
    std::ifstream input(archive_path, std::ios::binary);
    if (!input) {
        std::cerr << "Failed to open archive: " << archive_path << '\n';
        return std::nullopt;
    }

    input.seekg(0, std::ios::end);
    const uint64_t file_size = static_cast<uint64_t>(input.tellg());
    if (file_size < 22) {
        std::cerr << "Archive is too small to be a valid zip file: " << archive_path << '\n';
        return std::nullopt;
    }

    const std::optional<uint64_t> eocd_offset = find_end_of_central_directory(input, file_size);
    if (!eocd_offset.has_value()) {
        std::cerr << "Could not locate zip central directory: " << archive_path << '\n';
        return std::nullopt;
    }

    input.seekg(static_cast<std::streamoff>(*eocd_offset), std::ios::beg);
    if (read_u32(input) != 0x06054b50U) {
        std::cerr << "Invalid EOCD signature in: " << archive_path << '\n';
        return std::nullopt;
    }

    (void) read_u16(input);
    (void) read_u16(input);
    (void) read_u16(input);
    const uint16_t total_entries = read_u16(input);
    (void) read_u32(input);
    const uint32_t central_directory_offset = read_u32(input);
    (void) read_u16(input);

    std::vector<ZipEntry> entries;
    entries.reserve(total_entries);

    input.seekg(static_cast<std::streamoff>(central_directory_offset), std::ios::beg);
    for (uint16_t index = 0; index < total_entries; ++index) {
        if (read_u32(input) != 0x02014b50U) {
            std::cerr << "Invalid central directory header in: " << archive_path << '\n';
            return std::nullopt;
        }

        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u16(input);

        ZipEntry entry;
        entry.compression_method = read_u16(input);
        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u32(input);
        entry.compressed_size = read_u32(input);
        entry.uncompressed_size = read_u32(input);

        const uint16_t file_name_length = read_u16(input);
        const uint16_t extra_field_length = read_u16(input);
        const uint16_t file_comment_length = read_u16(input);

        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u32(input);
        entry.local_header_offset = read_u32(input);

        entry.name.resize(file_name_length);
        input.read(entry.name.data(), static_cast<std::streamsize>(file_name_length));

        std::streampos central_resume = input.tellg();
        input.seekg(static_cast<std::streamoff>(entry.local_header_offset), std::ios::beg);
        if (read_u32(input) != 0x04034b50U) {
            std::cerr << "Invalid local header for entry: " << entry.name << '\n';
            return std::nullopt;
        }

        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u16(input);
        (void) read_u32(input);
        (void) read_u32(input);
        (void) read_u32(input);
        const uint16_t local_name_length = read_u16(input);
        const uint16_t local_extra_length = read_u16(input);
        entry.data_offset = static_cast<uint64_t>(entry.local_header_offset) + 30 + local_name_length + local_extra_length;

        input.seekg(central_resume + static_cast<std::streamoff>(extra_field_length + file_comment_length), std::ios::beg);
        entries.push_back(std::move(entry));
    }

    return entries;
}

std::optional<std::vector<uint8_t>> read_stored_zip_entry(const fs::path & archive_path, const ZipEntry & entry) {
    if (entry.compression_method != 0) {
        std::cerr << "Unsupported compression method " << entry.compression_method << " for entry: " << entry.name << '\n';
        return std::nullopt;
    }

    std::ifstream input(archive_path, std::ios::binary);
    if (!input) {
        std::cerr << "Failed to reopen archive: " << archive_path << '\n';
        return std::nullopt;
    }

    input.seekg(static_cast<std::streamoff>(entry.data_offset), std::ios::beg);
    std::vector<uint8_t> data(entry.uncompressed_size);
    input.read(reinterpret_cast<char *>(data.data()), static_cast<std::streamsize>(data.size()));
    if (!input) {
        std::cerr << "Failed to read payload for entry: " << entry.name << '\n';
        return std::nullopt;
    }

    return data;
}

}  // namespace gd