Add support for streaming archive writing and unknown filesizes in zip files

openVulkanoCpp/IO/Archive/ArchiveStreamBufferWriter.hpp

@@ -0,0 +1,53 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include "ArchiveWriter.hpp"
+#include <archive.h>
+#include <ostream>
+
+namespace OpenVulkano
+{
+	class ArchiveStreamBufferWriter final : public std::streambuf
+	{
+		ArchiveWriter* m_archive;
+		size_t m_maxSize, m_written;
+
+	public:
+		ArchiveStreamBufferWriter(ArchiveWriter* archive, size_t size)
+				: m_archive(archive), m_maxSize(size), m_written(0)
+		{}
+
+		std::streamsize xsputn(const char* s, std::streamsize n) override
+		{
+			if (!m_archive) return 0;
+			if (m_maxSize < m_written + n) n = m_maxSize - m_written;
+			if (n == 0) return 0;
+			m_archive->ChkErr(archive_write_data(m_archive->m_archive, s, n));
+			m_written += n;
+			if (m_written == m_maxSize) Close();
+			return n;
+		}
+
+		void Close()
+		{
+			if (!m_archive) return;
+			if (m_maxSize > m_written && m_maxSize != FileDescription::UNKNOWN_SIZE)
+			{ //Zero fill till eof
+				std::vector<char> data(m_maxSize - m_written, 0);
+				archive_write_data(m_archive->m_archive, data.data(), data.size());
+			}
+			m_archive->ChkErr(archive_write_finish_entry(m_archive->m_archive));
+			m_archive = nullptr;
+		}
+
+		~ArchiveStreamBufferWriter() override
+		{
+			if (m_archive) Close();
+		}
+	};
+}