MTA:Eir/FileSystem/file/readDouble
From Multi Theft Auto: Wiki
This function attempts to read a double (native type) from a file and return it. The amount of bytes read should be eight.
Syntax
double file.readDouble ()
Returns
Returns a double if it was successfully read from the file, false otherwise.
Example
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ServerThis snippet demonstrates a basic binary object map format. It can be extended to support more parameters.
-- Grab some objects to store into our map. local storeObjects = getElementsByType( "object" ); -- Function to store data about objects. local function saveObjects( theFile, objects ) -- Write the amount of entries into the stream. theFile.writeShort( #objects ); -- Now add every object into it. for m,n in ipairs( objects ) do local posX, posY, posZ = getElementPosition( n ); local rotX, rotY, rotZ = getElementRotation( n ); local model = getElementModel( n ); local dimension, interior = getElementDimension( n ), getElementInterior( n ); -- Write the parameters of the object into the stream. theFile.writeDouble( posX ); theFile.writeDouble( posY ); theFile.writeDouble( posZ ); theFile.writeDouble( rotX ); theFile.writeDouble( rotY ); theFile.writeDouble( rotZ ); theFile.writeShort( model ); theFile.writeShort( dimension ); theFile.writeShort( interior ); end end -- Function to load back data from a file stream. local function loadObjects( theFile ) -- Get the amount of entries. local objectCount = theFile.readShort(); -- Create the objects. local n = 1; while ( n <= objectCount ) do local posX, posY, posZ = theFile.readDouble(), theFile.readDouble(), theFile.readDouble(); local rotX, rotY, rotZ = theFile.readDouble(), theFile.readDouble(), theFile.readDouble(); local model = theFile.readShort(); local dimension, interior = theFile.readShort(), theFile.readShort(); -- Create this particular object, if all values are properly read. -- We can optimize this condition by checking the last value that was read. if ( interior ) then local object = createObject( model, posX, posY, posZ, rotX, rotY, rotZ ); if ( object ) then -- Continue applying advanced properties of creation of object succeeded. setElementDimension( object, dimension ); setElementInterior( object, interior ); end end end end -- Save our current objects into a file. local saveFile = fileCreate( "world_objects.dat" ); saveObjects( saveFile, storeObjects ); -- todo: maybe load the objects.