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connector/native/zip.cpp

@@ -0,0 +1,136 @@
+#include "zip.hpp"
+
+#include <array>
+#include <chrono>
+#include <ctime>
+#include <filesystem>
+#include <stdexcept>
+
+namespace connector {
+namespace {
+
+void append_u16(std::vector<std::uint8_t>& output, std::uint16_t value) {
+  output.push_back(static_cast<std::uint8_t>(value));
+  output.push_back(static_cast<std::uint8_t>(value >> 8));
+}
+
+void append_u32(std::vector<std::uint8_t>& output, std::uint32_t value) {
+  append_u16(output, static_cast<std::uint16_t>(value));
+  append_u16(output, static_cast<std::uint16_t>(value >> 16));
+}
+
+std::uint32_t crc32(const std::vector<std::uint8_t>& data) {
+  static const std::array<std::uint32_t, 256> table = [] {
+    std::array<std::uint32_t, 256> values{};
+    for (std::uint32_t value = 0; value < values.size(); ++value) {
+      std::uint32_t crc = value;
+      for (int bit = 0; bit < 8; ++bit) crc = (crc & 1) ? 0xedb88320U ^ (crc >> 1) : crc >> 1;
+      values[value] = crc;
+    }
+    return values;
+  }();
+  std::uint32_t crc = 0xffffffffU;
+  for (const auto byte : data) crc = table[(crc ^ byte) & 0xff] ^ (crc >> 8);
+  return crc ^ 0xffffffffU;
+}
+
+std::string archive_path(const std::string& raw) {
+  std::string value = raw;
+  for (char& c : value) if (c == '\\') c = '/';
+  while (value.rfind("./", 0) == 0) value.erase(0, 2);
+  if (value.empty() || value.front() == '/' || value == ".." || value.rfind("../", 0) == 0 ||
+      value.find("/../") != std::string::npos) {
+    throw std::runtime_error("ZIP 文件路径无效");
+  }
+  return value;
+}
+
+struct Timestamp {
+  std::uint16_t time;
+  std::uint16_t date;
+};
+
+Timestamp dos_timestamp() {
+  const std::time_t now = std::time(nullptr);
+  std::tm local{};
+#ifdef _WIN32
+  localtime_s(&local, &now);
+#else
+  localtime_r(&now, &local);
+#endif
+  const int year = std::max(1980, local.tm_year + 1900);
+  return {
+      static_cast<std::uint16_t>((local.tm_hour << 11) | (local.tm_min << 5) | (local.tm_sec / 2)),
+      static_cast<std::uint16_t>(((year - 1980) << 9) | ((local.tm_mon + 1) << 5) | local.tm_mday),
+  };
+}
+
+}  // namespace
+
+std::vector<std::uint8_t> create_zip(const std::vector<ArchiveFile>& files) {
+  if (files.size() > 65535) throw std::runtime_error("ZIP 文件数量过多");
+  struct CentralRecord {
+    std::string name;
+    std::uint32_t crc;
+    std::uint32_t size;
+    std::uint32_t offset;
+  };
+  std::vector<std::uint8_t> output;
+  std::vector<CentralRecord> records;
+  const Timestamp timestamp = dos_timestamp();
+  for (const auto& file : files) {
+    const std::string name = archive_path(file.name);
+    if (name.size() > 65535 || file.data.size() > 0xffffffffULL || output.size() > 0xffffffffULL) {
+      throw std::runtime_error("ZIP 文件超过 Store 格式限制");
+    }
+    const auto checksum = crc32(file.data);
+    records.push_back({name, checksum, static_cast<std::uint32_t>(file.data.size()),
+                       static_cast<std::uint32_t>(output.size())});
+    append_u32(output, 0x04034b50);
+    append_u16(output, 20);
+    append_u16(output, 0x0800);
+    append_u16(output, 0);
+    append_u16(output, timestamp.time);
+    append_u16(output, timestamp.date);
+    append_u32(output, checksum);
+    append_u32(output, static_cast<std::uint32_t>(file.data.size()));
+    append_u32(output, static_cast<std::uint32_t>(file.data.size()));
+    append_u16(output, static_cast<std::uint16_t>(name.size()));
+    append_u16(output, 0);
+    output.insert(output.end(), name.begin(), name.end());
+    output.insert(output.end(), file.data.begin(), file.data.end());
+  }
+  const auto central_offset = static_cast<std::uint32_t>(output.size());
+  for (const auto& record : records) {
+    append_u32(output, 0x02014b50);
+    append_u16(output, 20);
+    append_u16(output, 20);
+    append_u16(output, 0x0800);
+    append_u16(output, 0);
+    append_u16(output, timestamp.time);
+    append_u16(output, timestamp.date);
+    append_u32(output, record.crc);
+    append_u32(output, record.size);
+    append_u32(output, record.size);
+    append_u16(output, static_cast<std::uint16_t>(record.name.size()));
+    append_u16(output, 0);
+    append_u16(output, 0);
+    append_u16(output, 0);
+    append_u16(output, 0);
+    append_u32(output, 0);
+    append_u32(output, record.offset);
+    output.insert(output.end(), record.name.begin(), record.name.end());
+  }
+  const auto central_size = static_cast<std::uint32_t>(output.size()) - central_offset;
+  append_u32(output, 0x06054b50);
+  append_u16(output, 0);
+  append_u16(output, 0);
+  append_u16(output, static_cast<std::uint16_t>(records.size()));
+  append_u16(output, static_cast<std::uint16_t>(records.size()));
+  append_u32(output, central_size);
+  append_u32(output, central_offset);
+  append_u16(output, 0);
+  return output;
+}
+
+}  // namespace connector