Add ability to extract contents of zip archive to a file

This can be used to extract nested jar files to a temporary folder.

Author: NathanJPhillips

jbmc/src/java_bytecode/mz_zip_archive.cpp

@@ -103,3 +103,16 @@ std::string mz_zip_archivet::extract(const size_t index)
   }
   throw std::runtime_error("Could not extract the file");
 }
+
+void mz_zip_archivet::extract_to_file(
+  const size_t index,
+  const std::string &path)
+{
+  const auto id = static_cast<mz_uint>(index);
+  if(
+    mz_zip_reader_extract_to_file(m_state.get(), id, path.c_str(), 0) !=
+    MZ_TRUE)
+  {
+    throw std::runtime_error("Could not extract the file");
+  }
+}

jbmc/src/java_bytecode/mz_zip_archive.h

@@ -51,6 +51,12 @@ class mz_zip_archivet final
   /// \throw Throws std::runtime_error if file cannot be extracted
   /// \return Contents of the file in the archive
   std::string extract(size_t index);
+  /// Write contents of nth file in the archive to a file
+  /// \param index: id of the file in the archive
+  /// \param path:  path to which to write the contents of the file
+  /// \throw Throws std::runtime_error if file cannot be written
+  void extract_to_file(size_t index, const std::string &path);
+
 private:
   std::unique_ptr<mz_zip_archive_statet> m_state;
 };