MTA:Eir/FileSystem/file/readByte - Revision history

Quiret at 23:33, 16 January 2022

2022-01-16T23:33:26Z

← Older revision		Revision as of 23:33, 16 January 2022
Line 4:		Line 4:
	==Syntax==		==Syntax==
	<syntaxhighlight lang="lua">		<syntaxhighlight lang="lua">
	signed_byte file.readByte ()		signed_byte file:readByte ()
	</syntaxhighlight>		</syntaxhighlight>

Line 76:		Line 76:
	-- Here our byte functions come into play.		-- Here our byte functions come into play.
	local function readSmallString( theFile )		local function readSmallString( theFile )
	theFile.read( theFile.readUByte() );		theFile:read( theFile:readUByte() );
	end		end

	local function writeSmallString( theFile, string )		local function writeSmallString( theFile, string )
	theFile.writeUByte( #string );		theFile:writeUByte( #string );
	theFile.write( string );		theFile:write( string );
	end		end

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	local storageFile = false;		local storageFile = false;

	if ( resRoot.exists( "player.dat" ) ) then		if ( resRoot:exists( "player.dat" ) ) then
	-- Load player information.		-- Load player information.
	storageFile = resRoot.open( "player.dat", "rb+" );		storageFile = resRoot:open( "player.dat", "rb+" );

	-- Make sure we could open the file correctly.		-- Make sure we could open the file correctly.
	if ( storageFile ) then		if ( storageFile ) then
	-- Read the header.		-- Read the header.
	local numPlayerEntries = storageFile.readInt();		local numPlayerEntries = storageFile:readInt();

	-- Process each player entry.		-- Process each player entry.
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	for m=1,12 do		for m=1,12 do
	local info = {		local info = {
	weaponType = theFile.readUByte(),		weaponType = theFile:readUByte(),
	currentAmmo = theFile.readUShort(),		currentAmmo = theFile:readUShort(),
	totalAmmo = theFile.readUShort()		totalAmmo = theFile:readUShort()
	};		};
	table.insert( weapons, info );		table.insert( weapons, info );
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	end		end
	else		else
	storageFile = resRoot.open( "player.dat", "wb" );		storageFile = resRoot:open( "player.dat", "wb" );
	end		end

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	if ( storageFile ) then		if ( storageFile ) then
	-- Write the number of playerData entries.		-- Write the number of playerData entries.
	storageFile.writeInt( #playerData );		storageFile:writeInt( #playerData );

	for m,n in ipairs( playerData ) do		for m,n in ipairs( playerData ) do
Line 188:		Line 188:
	-- Now write the player information.		-- Now write the player information.
	for m,n in ipairs( n.weapons ) do		for m,n in ipairs( n.weapons ) do
	theFile.writeUByte( n.weaponType );		theFile:writeUByte( n.weaponType );
	theFile.writeUShort( n.currentAmmo );		theFile:writeUShort( n.currentAmmo );
	theFile.writeUShort( n.maxAmmo );		theFile:writeUShort( n.maxAmmo );
	end		end
	end		end

	-- Clean up the file handle.		-- Clean up the file handle.
	storageFile.destroy();		storageFile:destroy();

	-- We are finished saving. Tell the server owner.		-- We are finished saving. Tell the server owner.

The GTA at 09:42, 31 January 2014

2014-01-31T09:42:08Z

← Older revision		Revision as of 09:42, 31 January 2014
Line 21:		Line 21:
	return false;		return false;
	end		end

			-- Get a file translator to this resource.
			local resRoot = fsys.createTranslator( "mods/deathmatch/resources/playerManager/" );

	-- Keep track of player information.		-- Keep track of player information.
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	local storageFile = false;		local storageFile = false;

	if ( ~~fileExists~~( "player.dat" ) ) then		if ( resRoot.exists( "player.dat" ) ) then
	-- Load player information.		-- Load player information.
	storageFile = ~~fileOpen~~( "player.dat" );		storageFile = resRoot.open( "player.dat", "rb+" );

	-- Make sure we could open the file correctly.		-- Make sure we could open the file correctly.
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	end		end
	else		else
	storageFile = ~~fileCreate~~( "player.dat" );		storageFile = resRoot.open( "player.dat", "wb" );
	end		end

Line 135:		Line 138:
	for m,n in ipairs(playerData) do		for m,n in ipairs(playerData) do
	if ( n.nickname == nickname ) then		if ( n.nickname == nickname ) then
	n.player ~~= player~~;		n.setPlayer( player );
	return n;		return n;
	end		end
Line 159:		Line 162:
	addEventHandler( "onPlayerQuit", root,		addEventHandler( "onPlayerQuit", root,
	function()		function()
	-- Make sure we do not have a player information anymore.		-- Make sure we do not have a player information attached to the quit player anymore.
	local info = getPlayerInfo( source, false );		local info = getPlayerInfo( source, false );

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	end		end
	end		end

			-- Clean up the file handle.
			storageFile.destroy();

	-- We are finished saving. Tell the server owner.		-- We are finished saving. Tell the server owner.

The GTA: Created page with "NOTOC This function attempts to read a signed byte (native type) from a file and returns it. The amount of bytes read should be one. ==Syntax== signed_byte fil..."

2014-01-31T09:37:24Z

Created page with "__NOTOC__ This function attempts to read a signed byte (native type) from a file and returns it. The amount of bytes read should be one. ==Syntax== <syntaxhighlight lang="lua"> signed_byte fil..."

New page

__NOTOC__
This function attempts to read a signed byte (native type) from a file and returns it. The amount of bytes read should be one.

==Syntax==
<syntaxhighlight lang="lua">
signed_byte file.readByte ()
</syntaxhighlight>

==Returns==
Returns the signed byte if it was successfully read from the file, '''false''' otherwise.

==Example==
<section name="Server" class="server" show="true">
This snippet writes a snapshot of server-side player information into a file. This is a system that keeps persistent player data on a server based on the nickname. It should be expanded to manage the lifetime of player information, so the database does not grow too big. This is theoretical code and should be used as basis.
<syntaxhighlight lang="lua">
-- Create the filesystem interface.
local fsys = createFilesystemInterface();

if not ( fsys ) then
outputDebugString( "could not acquire filesystem interface handle" );
return false;
end

-- Keep track of player information.
local playerData = {};

local function createPlayerInfo( nickname )
local info = {
nickname = nickname,
weapons = {},
player = false
};

function info.setPlayer( player )
if ( player ) then
local weapons = info.weapons;

for m=1,12 do
local weapInfo = weapons[m];

if ( weapInfo ) then
-- Update the players weapon information.
setPlayerWeapon( m, weapInfo.weaponType );
setPlayerAmmoInClip( m, weapInfo.currentAmmo );
setPlayerTotalAmmo( m, weapInfo.maxAmmo );
end
end
end

-- Save the player object.
info.player = player;
end

function info.saveState()
local weapons = info.weapons;
local player = info.player;

if ( player ) then return; end;

for m=1,12 do
weapons[m] = {
weaponType = getPlayerWeapon( player ),
currentAmmo = getPlayerAmmoInClip( player ),
maxAmmo = getPlayerTotalAmmo( player )
};
end
end

return info;
end

-- Utilities for writing and reading short strings.
-- Here our byte functions come into play.
local function readSmallString( theFile )
theFile.read( theFile.readUByte() );
end

local function writeSmallString( theFile, string )
theFile.writeUByte( #string );
theFile.write( string );
end

-- Create player information from persistent storage.
local storageFile = false;

if ( fileExists( "player.dat" ) ) then
-- Load player information.
storageFile = fileOpen( "player.dat" );

-- Make sure we could open the file correctly.
if ( storageFile ) then
-- Read the header.
local numPlayerEntries = storageFile.readInt();

-- Process each player entry.
local n = 1;

while ( n <= numPlayerEntries ) do
local nickname = readSmallString( storageFile );
local weapons = {};

for m=1,12 do
local info = {
weaponType = theFile.readUByte(),
currentAmmo = theFile.readUShort(),
totalAmmo = theFile.readUShort()
};
table.insert( weapons, info );
end

-- Create and store the player information.
local playerInfo = createPlayerInfo( nickname );
playerInfo.weapons = weapons;

table.insert( playerData, playerInfo );
end
end
else
storageFile = fileCreate( "player.dat" );
end

local function getPlayerInfo( player, createNew )
if ( createNew == nil ) then createNew = true; end

-- Attempt to get by player handle.
for m,n in ipairs(playerData) do
if ( n.player == player ) then
return n;
end
end

-- Attempt to get by player nick.
local nickname = getPlayerName( player );

for m,n in ipairs(playerData) do
if ( n.nickname == nickname ) then
n.player = player;
return n;
end
end

if ( createNew ) then
-- We found nothing, so lets create a new player info.
local newInfo = createPlayerInfo( nickname );
newInfo.setPlayer( player );
return newInfo;
end

return false;
end

addEventHandler( "onPlayerJoin", root,
function()
-- Cache the player information.
getPlayerInfo( source );
end
);

addEventHandler( "onPlayerQuit", root,
function()
-- Make sure we do not have a player information anymore.
local info = getPlayerInfo( source, false );

if not ( info ) then return; end;

info.saveStatus();
info.setPlayer( false );
end
);

addEventHandler( "onResourceStop", resourceRoot,
function()
-- Store the player information to disk.
if ( storageFile ) then
-- Write the number of playerData entries.
storageFile.writeInt( #playerData );

for m,n in ipairs( playerData ) do
-- Make sure the info is up to date.
n.saveState();

-- Write player header.
writeSmallString( storageFile, getPlayerName( n.nickname ) );

-- Now write the player information.
for m,n in ipairs( n.weapons ) do
theFile.writeUByte( n.weaponType );
theFile.writeUShort( n.currentAmmo );
theFile.writeUShort( n.maxAmmo );
end
end

-- We are finished saving. Tell the server owner.
outputDebugString( "wrote persistent player storage." );
end
end
);
</syntaxhighlight>
</section>
{{:MTA:Eir/FileSystem/file/functions}}

MTA:Eir/FileSystem/file/readByte - Revision history

Quiret at 23:33, 16 January 2022

The GTA at 09:42, 31 January 2014

The GTA: Created page with "__NOTOC__ This function attempts to read a signed byte (native type) from a file and returns it. The amount of bytes read should be one. ==Syntax== signed_byte fil..."

The GTA: Created page with "NOTOC This function attempts to read a signed byte (native type) from a file and returns it. The amount of bytes read should be one. ==Syntax== signed_byte fil..."