src/mapgen_v6.cpp

/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program 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 2.1 of the License, or
(at your option) any later version.

This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "mapblock.h"

#include <sstream>
#include "map.h"
#include "light.h"
#include "nodedef.h"
#include "nodemetadata.h"
#include "gamedef.h"
#include "log.h"
#include "nameidmapping.h"
#include "content_mapnode.h" // For legacy name-id mapping
#include "content_nodemeta.h" // For legacy deserialization
#include "serialization.h"
#ifndef SERVER
#include "mapblock_mesh.h"
#endif
#include "util/string.h"
#include "util/serialize.h"

#define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"

static const char *modified_reason_strings[] = {
	"initial",
	"reallocate",
	"setIsUnderground",
	"setLightingExpired",
	"setGenerated",
	"setNode",
	"setNodeNoCheck",
	"setTimestamp",
	"NodeMetaRef::reportMetadataChange",
	"clearAllObjects",
	"Timestamp expired (step)",
	"addActiveObjectRaw",
	"removeRemovedObjects/remove",
	"removeRemovedObjects/deactivate",
	"Stored list cleared in activateObjects due to overflow",
	"deactivateFarObjects: Static data moved in",
	"deactivateFarObjects: Static data moved out",
	"deactivateFarObjects: Static data changed considerably",
	"finishBlockMake: expireDayNightDiff",
	"unknown",
};


/*
	MapBlock
*/

MapBlock::MapBlock(Map *parent, v3s16 pos, IGameDef *gamedef, bool dummy):
		m_parent(parent),
		m_pos(pos),
		m_gamedef(gamedef),
		m_modified(MOD_STATE_WRITE_NEEDED),
		m_modified_reason(MOD_REASON_INITIAL),
		is_underground(false),
		m_lighting_expired(true),
		m_day_night_differs(false),
		m_day_night_differs_expired(true),
		m_generated(false),
		m_timestamp(BLOCK_TIMESTAMP_UNDEFINED),
		m_disk_timestamp(BLOCK_TIMESTAMP_UNDEFINED),
		m_usage_timer(0),
		m_refcount(0)
{
	data = NULL;
	if(dummy == false)
		reallocate();

#ifndef SERVER
	mesh = NULL;
#endif
}

MapBlock::~MapBlock()
{
#ifndef SERVER
	{
		//JMutexAutoLock lock(mesh_mutex);

		if(mesh)
		{
			delete mesh;
			mesh = NULL;
		}
	}
#endif

	if(data)
		delete[] data;
}

bool MapBlock::isValidPositionParent(v3s16 p)
{
	if(isValidPosition(p))
	{
		return true;
	}
	else{
		return m_parent->isValidPosition(getPosRelative() + p);
	}
}

MapNode MapBlock::getNodeParent(v3s16 p, bool *is_valid_position)
{
	if (isValidPosition(p) == false)
		return m_parent->getNodeNoEx(getPosRelative() + p, is_valid_position);

	if (data == NULL) {
		if (is_valid_position)
			*is_valid_position = false;
		return MapNode(CONTENT_IGNORE);
	}
	if (is_valid_position)
		*is_valid_position = true;
	return data[p.Z * zstride + p.Y * ystride + p.X];
}

std::string MapBlock::getModifiedReasonString()
{
	std::string reason;

	const u32 ubound = MYMIN(sizeof(m_modified_reason) * CHAR_BIT,
		ARRLEN(modified_reason_strings));

	for (u32 i = 0; i != ubound; i++) {
		if ((m_modified_reason & (1 << i)) == 0)
			continue;

		reason += modified_reason_strings[i];
		reason += ", ";
	}

	if (reason.length() > 2)
		reason.resize(reason.length() - 2);

	return reason;
}

/*
	Propagates sunlight down through the block.
	Doesn't modify nodes that are not affected by sunlight.

	Returns false if sunlight at bottom block is invalid.
	Returns true if sunlight at bottom block is valid.
	Returns true if bottom block doesn't exist.

	If there is a block above, continues from it.
	If there is no block above, assumes there is sunlight, unless
	is_underground is set or highest node is water.

	All sunlighted nodes are added to light_sources.

	if remove_light==true, sets non-sunlighted nodes black.

	if black_air_left!=NULL, it is set to true if non-sunlighted
	air is left in block.
*/
bool MapBlock::propagateSunlight(std::set<v3s16> & light_sources,
		bool remove_light, bool *black_air_left)
{
	INodeDefManager *nodemgr = m_gamedef->ndef();

	// Whether the sunlight at the top of the bottom block is valid
	bool block_below_is_valid = true;

	v3s16 pos_relative = getPosRelative();

	for(s16 x=0; x<MAP_BLOCKSIZE; x++)
	{
		for(s16 z=0; z<MAP_BLOCKSIZE; z++)
		{
#if 1
			bool no_sunlight = false;
			//bool no_top_block = false;

			// Check if node above block has sunlight

			bool is_valid_position;
			MapNode n = getNodeParent(v3s16(x, MAP_BLOCKSIZE, z),
				&is_valid_position);
			if (is_valid_position)
			{
				if(n.getContent() == CONTENT_IGNORE)
				{
					// Trust heuristics
					no_sunlight = is_underground;
				}
				else if(n.getLight(LIGHTBANK_DAY, m_gamedef->ndef()) != LIGHT_SUN)
				{
					no_sunlight = true;
				}
			}
			else
			{
				//no_top_block = true;

				// NOTE: This makes over-ground roofed places sunlighted
				// Assume sunlight, unless is_underground==true
				if(is_underground)
				{
					no_sunlight = true;
				}
				else
				{
					MapNode n = getNodeNoEx(v3s16(x, MAP_BLOCKSIZE-1, z));
					if(m_gamedef->ndef()->get(n).sunlight_propagates == false)
					{
						no_sunlight = true;
					}
				}
				// NOTE: As of now, this just would make everything dark.
				// No sunlight here
				//no_sunlight = true;
			}
#endif
#if 0 // Doesn't work; nothing gets light.
			bool no_sunlight = true;
			bool no_top_block = false;
			// Check if node above block has sunlight
			try{
				MapNode n = getNodeParent(v3s16(x, MAP_BLOCKSIZE, z));
				if(n.getLight(LIGHTBANK_DAY) == LIGHT_SUN)
				{
					no_sunlight = false;
				}
			}
			catch(InvalidPositionException &e)
			{
				no_top_block = true;
			}
#endif

			/*std::cout<<"("<<x<<","<<z<<"): "
					<<"no_top_block="<<no_top_block
					<<", is_underground="<<is_underground
					<<", no_sunlight="<<no_sunlight
					<<std::endl;*/

			s16 y = MAP_BLOCKSIZE-1;

			// This makes difference to diminishing in water.
			bool stopped_to_solid_object = false;

			u8 current_light = no_sunlight ? 0 : LIGHT_SUN;

			for(; y >= 0; y--)
			{
				v3s16 pos(x, y, z);
				MapNode &n = getNodeRef(pos);

				if(current_light == 0)
				{
					// Do nothing
				}
				else if(current_light == LIGHT_SUN && nodemgr->get(n).sunlight_propagates)
				{
					// Do nothing: Sunlight is continued
				}
				else if(nodemgr->get(n).light_propagates == false)
				{
					// A solid object is on the way.
					stopped_to_solid_object = true;

					// Light stops.
					current_light = 0;
				}
				else
				{
					// Diminish light
					current_light = diminish_light(current_light);
				}

				u8 old_light = n.getLight(LIGHTBANK_DAY, nodemgr);

				if(current_light > old_light || remove_light)
				{
					n.setLight(LIGHTBANK_DAY, current_light, nodemgr);
				}

				if(diminish_light(current_light) != 0)
				{
					light_sources.insert(pos_relative + pos);
				}

				if(current_light == 0 && stopped_to_solid_object)
				{
					if(black_air_left)
					{
						*black_air_left = true;
					}
				}
			}

			// Whether or not the block below should see LIGHT_SUN
			bool sunlight_should_go_down = (current_light == LIGHT_SUN);

			/*
				If the block below hasn't already been marked invalid:

				Check if the node below the block has proper sunlight at top.
				If not, the block below is invalid.

				Ignore non-transparent nodes as they always have no light
			*/

			if(block_below_is_valid)
			{
				MapNode n = getNodeParent(v3s16(x, -1, z), &is_valid_position);
				if (is_valid_position) {
					if(nodemgr->get(n).light_propagates)
					{
						if(n.getLight(LIGHTBANK_DAY, nodemgr) == LIGHT_SUN
								&& sunlight_should_go_down == false)
							block_below_is_valid = false;
						else if(n.getLight(LIGHTBANK_DAY, nodemgr) != LIGHT_SUN
								&& sunlight_should_go_down == true)
							block_below_is_valid = false;
					}
				}
				else
				{
					/*std::cout<<"InvalidBlockException for bottom block node"
							<<std::endl;*/
					// Just no block below, no need to panic.
				}
			}
		}
	}

	return block_below_is_valid;
}


void MapBlock::copyTo(VoxelManipulator &dst)
{
	v3s16 data_size(MAP_BLOCKSIZE, MAP_BLOCKSIZE, MAP_BLOCKSIZE);
	VoxelArea data_area(v3s16(0,0,0), data_size - v3s16(1,1,1));

	// Copy from data to VoxelManipulator
	dst.copyFrom(data, data_area, v3s16(0,0,0),
			getPosRelative(), data_size);
}

void MapBlock::copyFrom(VoxelManipulator &dst)
{
	v3s16 data_size(MAP_BLOCKSIZE, MAP_BLOCKSIZE, MAP_BLOCKSIZE);
	VoxelArea data_area(v3s16(0,0,0), data_size - v3s16(1,1,1));

	// Copy from VoxelManipulator to data
	dst.copyTo(data, data_area, v3s16(0,0,0),
			getPosRelative(), data_size);
}

void MapBlock::actuallyUpdateDayNightDiff()
{
	INodeDefManager *nodemgr = m_gamedef->ndef();

	// Running this function un-expires m_day_night_differs
	m_day_night_differs_expired = false;

	if (data == NULL) {
		m_day_night_differs = false;
		return;
	}

	bool differs;

	/*
		Check if any lighting value differs
	*/
	for (u32 i = 0; i < nodecount; i++) {
		MapNode &n = data[i];

		differs = !n.isLightDayNightEq(nodemgr);
		if (differs)
			break;
	}

	/*
		If some lighting values differ, check if the whole thing is
		just air. If it is just air, differs = false
	*/
	if (differs) {
		bool only_air = true;
		for (u32 i = 0; i < nodecount; i++) {
			MapNode &n = data[i];
			if (n.getContent() != CONTENT_AIR) {
				only_air = false;
				break;
			}
		}
		if (only_air)
			differs = false;
	}

	// Set member variable
	m_day_night_differs = differs;
}

void MapBlock::expireDayNightDiff()
{
	//INodeDefManager *nodemgr = m_gamedef->ndef();

	if(data == NULL){
		m_day_night_differs = false;
		m_day_night_differs_expired = false;
		return;
	}

	m_day_night_differs_expired = true;
}

s16 MapBlock::getGroundLevel(v2s16 p2d)
{
	if(isDummy())
		return -3;
	try
	{
		s16 y = MAP_BLOCKSIZE-1;
		for(; y>=0; y--)
		{
			MapNode n = getNodeRef(p2d.X, y, p2d.Y);
			if(m_gamedef->ndef()->get(n).walkable)
			{
				if(y == MAP_BLOCKSIZE-1)
					return -2;
				else
					return y;
			}
		}
		return -1;
	}
	catch(InvalidPositionException &e)
	{
		return -3;
	}
}

/*
	Serialization
*/
// List relevant id-name pairs for ids in the block using nodedef
// Renumbers the content IDs (starting at 0 and incrementing
// use static memory requires about 65535 * sizeof(int) ram in order to be
// sure we can handle all content ids. But it's absolutely worth it as it's
// a speedup of 4 for one of the major time consuming functions on storing
// mapblocks.
static content_t getBlockNodeIdMapping_mapping[USHRT_MAX + 1];
static void getBlockNodeIdMapping(NameIdMapping *nimap, MapNode *nodes,
		INodeDefManager *nodedef)
{
	memset(getBlockNodeIdMapping_mapping, 0xFF, (USHRT_MAX + 1) * sizeof(content_t));

	std::set<content_t> unknown_contents;
	content_t id_counter = 0;
	for (u32 i = 0; i < MapBlock::nodecount; i++) {
		content_t global_id = nodes[i].getContent();
		content_t id = CONTENT_IGNORE;

		// Try to find an existing mapping
		if (getBlockNodeIdMapping_mapping[global_id] != 0xFFFF) {
			id = getBlockNodeIdMapping_mapping[global_id];
		}
		else
		{
			// We have to assign a new mapping
			id = id_counter++;
			getBlockNodeIdMapping_mapping[global_id] = id;

			const ContentFeatures &f = nodedef->get(global_id);
			const std::string &name = f.name;
			if(name == "")
				unknown_contents.insert(global_id);
			else
				nimap->set(id, name);
		}

		// Update the MapNode
		nodes[i].setContent(id);
	}
	for(std::set<content_t>::const_iterator
			i = unknown_contents.begin();
			i != unknown_contents.end(); i++){
		errorstream<<"getBlockNodeIdMapping(): IGNORING ERROR: "
				<<"Name for node id "<<(*i)<<" not known"<<std::endl;
	}
}
// Correct ids in the block to match nodedef based on names.
// Unknown ones are added to nodedef.
// Will not update itself to match id-name pairs in nodedef.
static void correctBlockNodeIds(const NameIdMapping *nimap, MapNode *nodes,
		IGameDef *gamedef)
{
	INodeDefManager *nodedef = gamedef->ndef();
	// This means the block contains incorrect ids, and we contain
	// the information to convert those to names.
	// nodedef contains information to convert our names to globally
	// correct ids.
	std::set<content_t> unnamed_contents;
	std::set<std::string> unallocatable_contents;
	for (u32 i = 0; i < MapBlock::nodecount; i++) {
		content_t local_id = nodes[i].getContent();
		std::string name;
		bool found = nimap->getName(local_id, name);
		if(!found){
			unnamed_contents.insert(local_id);
			continue;
		}
		content_t global_id;
		found = nodedef->getId(name, global_id);
		if(!found){
			global_id = gamedef->allocateUnknownNodeId(name);
			if(global_id == CONTENT_IGNORE){
				unallocatable_contents.insert(name);
				continue;
			}
		}
		nodes[i].setContent(global_id);
	}
	for(std::set<content_t>::const_iterator
			i = unnamed_contents.begin();
			i != unnamed_contents.end(); i++){
		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
				<<"Block contains id "<<(*i)
				<<" with no name mapping"<<std::endl;
	}
	for(std::set<std::string>::const_iterator
			i = unallocatable_contents.begin();
			i != unallocatable_contents.end(); i++){
		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
				<<"Could not allocate global id for node name \""
				<<(*i)<<"\""<<std::endl;
	}
}

void MapBlock::serialize(std::ostream &os, u8 version, bool disk)
{
	if(!ser_ver_supported(version))
		throw VersionMismatchException("ERROR: MapBlock format not supported");

	if(data == NULL)
	{
		throw SerializationError("ERROR: Not writing dummy block.");
	}

	FATAL_ERROR_IF(version < SER_FMT_CLIENT_VER_LOWEST, "Serialize version error");

	// First byte
	u8 flags = 0;
	if(is_underground)
		flags |= 0x01;
	if(getDayNightDiff())
		flags |= 0x02;
	if(m_lighting_expired)
		flags |= 0x04;
	if(m_generated == false)
		flags |= 0x08;
	writeU8(os, flags);

	/*
		Bulk node data
	*/
	NameIdMapping nimap;
	if(disk)
	{
		MapNode *tmp_nodes = new MapNode[nodecount];
		for(u32 i=0; i<nodecount; i++)
			tmp_nodes[i] = data[i];
		getBlockNodeIdMapping(&nimap, tmp_nodes, m_gamedef->ndef());

		u8 content_width = 2;
		u8 params_width = 2;
		writeU8(os, content_width);
		writeU8(os, params_width);
		MapNode::serializeBulk(os, version, tmp_nodes, nodecount,
				content_width, params_width, true);
		delete[] tmp_nodes;
	}
	else
	{
		u8 content_width = 2;
		u8 params_width = 2;
		writeU8(os, content_width);
		writeU8(os, params_width);
		MapNode::serializeBulk(os, version, data, nodecount,
				content_width, params_width, true);
	}

	/*
		Node metadata
	*/
	std::ostringstream oss(std::ios_base::binary);
	m_node_metadata.serialize(oss);
	compressZlib(oss.str(), os);

	/*
		Data that goes to disk, but not the network
	*/
	if(disk)
	{
		if(version <= 24){
			// Node timers
			m_node_timers.serialize(os, version);
		}

		// Static objects
		m_static_objects.serialize(os);

		// Timestamp
		writeU32(os, getTimestamp());

		// Write block-specific node definition id mapping
		nimap.serialize(os);

		if(version >= 25){
			// Node timers
			m_node_timers.serialize(os, version);
		}
	}
}

void MapBlock::serializeNetworkSpecific(std::ostream &os, u16 net_proto_version)
{
	if(data == NULL)
	{
		throw SerializationError("ERROR: Not writing dummy block.");
	}

	if(net_proto_version >= 21){
		int version = 1;
		writeU8(os, version);
		writeF1000(os, 0); // deprecated heat
		writeF1000(os, 0); // deprecated humidity
	}
}

void MapBlock::deSerialize(std::istream &is, u8 version, bool disk)
{
	if(!ser_ver_supported(version))
		throw VersionMismatchException("ERROR: MapBlock format not supported");

	TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())<<std::endl);

	m_day_night_differs_expired = false;

	if(version <= 21)
	{
		deSerialize_pre22(is, version, disk);
		return;
	}

	u8 flags = readU8(is);
	is_underground = (flags & 0x01) ? true : false;
	m_day_night_differs = (flags & 0x02) ? true : false;
	m_lighting_expired = (flags & 0x04) ? true : false;
	m_generated = (flags & 0x08) ? false : true;

	/*
		Bulk node data
	*/
	TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
			<<": Bulk node data"<<std::endl);
	u8 content_width = readU8(is);
	u8 params_width = readU8(is);
	if(content_width != 1 && content_width != 2)
		throw SerializationError("MapBlock::deSerialize(): invalid content_width");
	if(params_width != 2)
		throw SerializationError("MapBlock::deSerialize(): invalid params_width");
	MapNode::deSerializeBulk(is, version, data, nodecount,
			content_width, params_width, true);

	/*
		NodeMetadata
	*/
	TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
			<<": Node metadata"<<std::endl);
	// Ignore errors
	try{
		std::ostringstream oss(std::ios_base::binary);
		decompressZlib(is, oss);
		std::istringstream iss(oss.str(), std::ios_base::binary);
		if(version >= 23)
			m_node_metadata.deSerialize(iss, m_gamedef);
		else
			content_nodemeta_deserialize_legacy(iss,
					&m_node_metadata, &m_node_timers,
					m_gamedef);
	}
	catch(SerializationError &e)
	{
		errorstream<<"WARNING: MapBlock::deSerialize(): Ignoring an error"
				<<" while deserializing node metadata at ("
				<<PP(getPos())<<": "<<e.what()<<std::endl;
	}

	/*
		Data that is only on disk
	*/
	if(disk)
	{
		// Node timers
		if(version == 23){
			// Read unused zero
			readU8(is);
		}
		if(version == 24){
			TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
					<<": Node timers (ver==24)"<<std::endl);
			m_node_timers.deSerialize(is, version);
		}

		// Static objects
		TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
				<<": Static objects"<<std::endl);
		m_static_objects.deSerialize(is);

		// Timestamp
		TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
				<<": Timestamp"<<std::endl);
		setTimestamp(readU32(is));
		m_disk_timestamp = m_timestamp;

		// Dynamically re-set ids based on node names
		TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
				<<": NameIdMapping"<<std::endl);
		NameIdMapping nimap;
		nimap.deSerialize(is);
		correctBlockNodeIds(&nimap, data, m_gamedef);

		if(version >= 25){
			TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
					<<": Node timers (ver>=25)"<<std::endl);
			m_node_timers.deSerialize(is, version);
		}
	}

	TRACESTREAM(<<"MapBlock::deSerialize "<<PP(getPos())
			<<": Done."<<std::endl);
}

void MapBlock::deSerializeNetworkSpecific(std::istream &is)
{
	try {
		int version = readU8(is);
		//if(version != 1)
		//	throw SerializationError("unsupported MapBlock version");
		if(version >= 1) {
			readF1000(is); // deprecated heat
			readF1000(is); // deprecated humidity
		}
	}
	catch(SerializationError &e)
	{
		errorstream<<"WARNING: MapBlock::deSerializeNetworkSpecific(): Ignoring an error"
				<<": "<<e.what()<<std::endl;
	}
}

/*
	Legacy serialization
*/

void MapBlock::deSerialize_pre22(std::istream &is, u8 version, bool disk)
{
	// Initialize default flags
	is_underground = false;
	m_day_night_differs = false;
	m_lighting_expired = false;
	m_generated = true;

	// Make a temporary buffer
	u32 ser_length = MapNode::serializedLength(version);
	SharedBuffer<u8> databuf_nodelist(nodecount * ser_length);

	// These have no compression
	if(version <= 3 || version == 5 || version == 6)
	{
		char tmp;
		is.read(&tmp, 1);
		if(is.gcount() != 1)
			throw SerializationError
					("MapBlock::deSerialize: no enough input data");
		is_underground = tmp;
		is.read((char*)*databuf_nodelist, nodecount * ser_length);
		if((u32)is.gcount() != nodecount * ser_length)
			throw SerializationError
					("MapBlock::deSerialize: no enough input data");
	}
	else if(version <= 10)
	{
		u8 t8;
		is.read((char*)&t8, 1);
		is_underground = t8;

		{
			// Uncompress and set material data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				databuf_nodelist[i*ser_length] = s[i];
			}
		}
		{
			// Uncompress and set param data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				databuf_nodelist[i*ser_length + 1] = s[i];
			}
		}

		if(version >= 10)
		{
			// Uncompress and set param2 data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				databuf_nodelist[i*ser_length + 2] = s[i];
			}
		}
	}
	// All other versions (newest)
	else
	{
		u8 flags;
		is.read((char*)&flags, 1);
		is_underground = (flags & 0x01) ? true : false;
		m_day_night_differs = (flags & 0x02) ? true : false;
		m_lighting_expired = (flags & 0x04) ? true : false;
		if(version >= 18)
			m_generated = (flags & 0x08) ? false : true;

		// Uncompress data
		std::ostringstream os(std::ios_base::binary);
		decompress(is, os, version);
		std::string s = os.str();
		if(s.size() != nodecount*3)
			throw SerializationError
					("MapBlock::deSerialize: decompress resulted in size"
					" other than nodecount*3");

		// deserialize nodes from buffer
		for(u32 i=0; i<nodecount; i++)
		{
			databuf_nodelist[i*ser_length] = s[i];
			databuf_nodelist[i*ser_length + 1] = s[i+nodecount];
			databuf_nodelist[i*ser_length + 2] = s[i+nodecount*2];
		}

		/*
			NodeMetadata
		*/
		if(version >= 14)
		{
			// Ignore errors
			try{
				if(version <= 15)
				{
					std::string data = deSerializeString(is);
					std::istringstream iss(data, std::ios_base::binary);
					content_nodemeta_deserialize_legacy(iss,
							&m_node_metadata, &m_node_timers,
							m_gamedef);
				}
				else
				{
					//std::string data = deSerializeLongString(is);
					std::ostringstream oss(std::ios_base::binary);
					decompressZlib(is, oss);
					std::istringstream iss(oss.str(), std::ios_base::binary);
					content_nodemeta_deserialize_legacy(iss,
							&m_node_metadata, &m_node_timers,
							m_gamedef);
				}
			}
			catch(SerializationError &e)
			{
				errorstream<<"WARNING: MapBlock::deSerialize(): Ignoring an error"
						<<" while deserializing node metadata"<<std::endl;
			}
		}
	}

	// Deserialize node data
	for(u32 i=0; i<nodecount; i++)
	{
		data[i].deSerialize(&databuf_nodelist[i*ser_length], version);
	}

	if(disk)
	{
		/*
			Versions up from 9 have block objects. (DEPRECATED)
		*/
		if(version >= 9){
			u16 count = readU16(is);
			// Not supported and length not known if count is not 0
			if(count != 0){
				errorstream<<"WARNING: MapBlock::deSerialize_pre22(): "
						<<"Ignoring stuff coming at and after MBOs"<<std::endl;
				return;
			}
		}

		/*
			Versions up from 15 have static objects.
		*/
		if(version >= 15)
			m_static_objects.deSerialize(is);

		// Timestamp
		if(version >= 17){
			setTimestamp(readU32(is));
			m_disk_timestamp = m_timestamp;
		} else {
			setTimestamp(BLOCK_TIMESTAMP_UNDEFINED);
		}

		// Dynamically re-set ids based on node names
		NameIdMapping nimap;
		// If supported, read node definition id mapping
		if(version >= 21){
			nimap.deSerialize(is);
		// Else set the legacy mapping
		} else {
			content_mapnode_get_name_id_mapping(&nimap);
		}
		correctBlockNodeIds(&nimap, data, m_gamedef);
	}


	// Legacy data changes
	// This code has to convert from pre-22 to post-22 format.
	INodeDefManager *nodedef = m_gamedef->ndef();
	for(u32 i=0; i<nodecount; i++)
	{
		const ContentFeatures &f = nodedef->get(data[i].getContent());
		// Mineral
		if(nodedef->getId("default:stone") == data[i].getContent()
				&& data[i].getParam1() == 1)
		{
			data[i].setContent(nodedef->getId("default:stone_with_coal"));
			data[i].setParam1(0);
		}
		else if(nodedef->getId("default:stone") == data[i].getContent()
				&& data[i].getParam1() == 2)
		{
			data[i].setContent(nodedef->getId("default:stone_with_iron"));
			data[i].setParam1(0);
		}
		// facedir_simple
		if(f.legacy_facedir_simple)
		{
			data[i].setParam2(data[i].getParam1());
			data[i].setParam1(0);
		}
		// wall_mounted
		if(f.legacy_wallmounted)
		{
			u8 wallmounted_new_to_old[8] = {0x04, 0x08, 0x01, 0x02, 0x10, 0x20, 0, 0};
			u8 dir_old_format = data[i].getParam2();
			u8 dir_new_format = 0;
			for(u8 j=0; j<8; j++)
			{
				if((dir_old_format & wallmounted_new_to_old[j]) != 0)
				{
					dir_new_format = j;
					break;
				}
			}
			data[i].setParam2(dir_new_format);
		}
	}

}

/*
	Get a quick string to describe what a block actually contains
*/
std::string analyze_block(MapBlock *block)
{
	if(block == NULL)
		return "NULL";

	std::ostringstream desc;

	v3s16 p = block->getPos();
	char spos[20];
	snprintf(spos, 20, "(%2d,%2d,%2d), ", p.X, p.Y, p.Z);
	desc<<spos;

	switch(block->getModified())
	{
	case MOD_STATE_CLEAN:
		desc<<"CLEAN,           ";
		break;
	case MOD_STATE_WRITE_AT_UNLOAD:
		desc<<"WRITE_AT_UNLOAD, ";
		break;
	case MOD_STATE_WRITE_NEEDED:
		desc<<"WRITE_NEEDED,    ";
		break;
	default:
		desc<<"unknown getModified()="+itos(block->getModified())+", ";
	}

	if(block->isGenerated())
		desc<<"is_gen [X], ";
	else
		desc<<"is_gen [ ], ";

	if(block->getIsUnderground())
		desc<<"is_ug [X], ";
	else
		desc<<"is_ug [ ], ";

	if(block->getLightingExpired())
		desc<<"lighting_exp [X], ";
	else
		desc<<"lighting_exp [ ], ";

	if(block->isDummy())
	{
		desc<<"Dummy, ";
	}
	else
	{
		bool full_ignore = true;
		bool some_ignore = false;
		bool full_air = true;
		bool some_air = false;
		for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
		for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
		for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
		{
			v3s16 p(x0,y0,z0);
			MapNode n = block->getNodeNoEx(p);
			content_t c = n.getContent();
			if(c == CONTENT_IGNORE)
				some_ignore = true;
			else
				full_ignore = false;
			if(c == CONTENT_AIR)
				some_air = true;
			else
				full_air = false;
		}

		desc<<"content {";

		std::ostringstream ss;

		if(full_ignore)
			ss<<"IGNORE (full), ";
		else if(some_ignore)
			ss<<"IGNORE, ";

		if(full_air)
			ss<<"AIR (full), ";
		else if(some_air)
			ss<<"AIR, ";

		if(ss.str().size()>=2)
			desc<<ss.str().substr(0, ss.str().size()-2);

		desc<<"}, ";
	}

	return desc.str().substr(0, desc.str().size()-2);
}


//END
	Commit message (Collapse)	Author	Age
*	Make flag strings clear specified flag with 'no' prefix	kwolekr	2014-02-08
\| \| \| \| \|	Remove flagmask field from set_mapgen_params table Add small bits of needed documentation
*	Remove blank default values for emergequeue_limit_* settings	kwolekr	2014-02-05
\| \| \| \| \|	Add checks for invalid user input for important settings Rename Settings::tryGet* to Settings::get*NoEx for consistency
*	Revert "Fix settings to honor numeric conversion errors"	kwolekr	2014-02-05
\| \| \| \|	This reverts commit 3f376a092e1c16429fb52f24736e9da98aff4cd5.
*	Fix settings to honor numeric conversion errors	sapier	2014-02-04
\| \| \| \|	Rename try* non exceptioning functions to *NoEx
*	Huge overhaul of the entire MapgenParams system	kwolekr	2014-02-03
\| \| \| \| \| \|	MapgenParams is no longer a polymorphic class, eliminating the need for messy and bug-prone reallocations. Separation between the common and mapgen-specific parameters is now strongly defined. Mapgen parameters objects are now properly encapsulated within the proper subsystems.
*	Mapgen V6: Add flag to stop mud flow	kwolekr	2014-01-12
\|
*	Add map feature generation notify Lua API	kwolekr	2013-12-14
\|
*	Dungeongen: Create dungeon gen tuneables; add desert temples for Mapgen V6	kwolekr	2013-12-07
\|
*	Mapgen V6: Respect water_level setting	kwolekr	2013-11-21
\|
*	Add Lua on_mapgen_init callback, and minetest.set_mapgen_params API	kwolekr	2013-06-27
\|
*	Decoration: Place decorations in mgv6, check if air or cignore before placement	kwolekr	2013-06-17
\|
*	Add initial Decoration support, many misc. improvements & modifications	kwolekr	2013-06-17
\|
*	Fix nearly all warnings	kwolekr	2013-05-19
\|
*	Remove no virtual dtor warnings, make MapgenParams contain actual NoiseParams	kwolekr	2013-05-19
\|
*	Enhance caves for mgv7, add ravines	kwolekr	2013-04-27
\|
*	Class-ify caves & move to cavegen.cpp, fix cave regression, add caves to ↵	kwolekr	2013-04-21
\| \| \| \|	Mapgen V7
*	Add param2 field for ores, some minor fixes and misc. code cleanup	kwolekr	2013-04-07
\|
*	Fix black tree leaves, reduce above-ground cave shadows	kwolekr	2013-04-07
\|
*	Fix MapgenV6::generateCaves possible division by 0 and misc. cosmetic fixes	kwolekr	2013-03-30
\|
*	Add Ore infrastructure and l_register_ore()	kwolekr	2013-03-24
\|
*	Mapgen indev: float islands, larger far biomes	proller	2013-03-24
\|
*	Add jungle grass to jungles	kwolekr	2013-03-17
\|
*	Some minor cleanups from the last commit	kwolekr	2013-03-16
\|
*	initial mapgen indev version with farscale feature and huge caves	proller	2013-03-16
\|
*	Re-add jungles, apple trees	kwolekr	2013-03-16
\|
*	Clean up Mapgen	kwolekr	2013-03-11
\|
*	Migrate to STL containers/algorithms.	Ilya Zhuravlev	2013-03-11
\|
*	Re-add dungeons in new dungeongen.cpp	kwolekr	2013-03-10
\|
*	Misc. cleanup and minor fixes	kwolekr	2013-02-25
\|
*	Add emerge.cpp, initial EmergeThread changes	kwolekr	2013-02-25
\| \| \| \| \| \| \|	- Neatly placed all emerge related code into a new file, emerge.cpp - Greatly cleaned up the code in EmergeThread::Thread() - Reworked Emerge queue. Now an actual std::queue of v3s16 block positions - Removed the completely unnecessary map of peer ids requesting blocks
*	Update Copyright Years	Sfan5	2013-02-24
\|
*	Change Minetest-c55 to Minetest	PilzAdam	2013-02-24
\|
*	Add flag string settings, flat map option	kwolekr	2013-02-06
\|
*	Make mapgen factory setup more elegant, add mapgen_v6.h	kwolekr	2013-01-23
\|
*	Fix MapgenV6::getGroundLevelAtPoint()	kwolekr	2013-01-21
\|
*	Finish and clean up mapgen configuration	kwolekr	2013-01-21
\|
*	Clean up EmergeManager, do initial work on Mapgen configuration	kwolekr	2013-01-21
\|
*	Readded and optimized mapgen V6	kwolekr	2013-01-21