// SPDX-FileCopyrightText: 2013, 2015 ljfa-ag <ljfa-ag@web.de>
//
// SPDX-License-Identifier: LGPL-3.0-or-later

/*
 * libnbt++ - A library for the Minecraft Named Binary Tag format.
 * Copyright (C) 2013, 2015  ljfa-ag
 *
 * This file is part of libnbt++.
 *
 * libnbt++ is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libnbt++ is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libnbt++.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "io/izlibstream.h"
#include "io/zlib_streambuf.h"

namespace zlib
{

	inflate_streambuf::inflate_streambuf(std::istream& input, size_t bufsize,
										 int window_bits)
		: zlib_streambuf(bufsize), is(input), stream_end(false)
	{
		zstr.next_in = Z_NULL;
		zstr.avail_in = 0;
		int ret = zng_inflateInit2(&zstr, window_bits);
		if (ret != Z_OK)
			throw zlib_error(zstr.msg, ret);

		char* end = out.data() + out.size();
		setg(end, end, end);
	}

	inflate_streambuf::~inflate_streambuf() noexcept
	{
		zng_inflateEnd(&zstr);
	}

	inflate_streambuf::int_type inflate_streambuf::underflow()
	{
		if (gptr() < egptr())
			return traits_type::to_int_type(*gptr());

		size_t have;
		do {
			// Read if input buffer is empty
			if (zstr.avail_in <= 0) {
				is.read(in.data(), in.size());
				if (is.bad())
					throw std::ios_base::failure("Input stream is bad");
				size_t count = is.gcount();
				if (count == 0 && !stream_end)
					throw zlib_error("Unexpected end of stream", Z_DATA_ERROR);

				zstr.next_in = reinterpret_cast<uint8_t*>(in.data());
				zstr.avail_in = count;
			}

			zstr.next_out = reinterpret_cast<uint8_t*>(out.data());
			zstr.avail_out = out.size();

			int ret = zng_inflate(&zstr, Z_NO_FLUSH);
			have = out.size() - zstr.avail_out;
			switch (ret) {
				case Z_NEED_DICT:
				case Z_DATA_ERROR:
					throw zlib_error(zstr.msg, ret);

				case Z_MEM_ERROR:
					throw std::bad_alloc();

				case Z_STREAM_END:
					if (!stream_end) {
						stream_end = true;
						// In case we consumed too much, we have to rewind the
						// input stream
						is.clear();
						is.seekg(-static_cast<std::streamoff>(zstr.avail_in),
								 std::ios_base::cur);
					}
					if (have == 0)
						return traits_type::eof();
					break;
			}
		} while (have == 0);

		setg(out.data(), out.data(), out.data() + have);
		return traits_type::to_int_type(*gptr());
	}

} // namespace zlib
