Sdl RWCreate

SDL.RWCreate

• SDL.RWCreate
  • Function
    • SYNOPSIS
    • ARGUMENTS
    • RETURNS
  • Table description
    • Size
      • Returns
    • Seek
      • Arguments
      • Returns
    • Read
      • Arguments
      • Returns
    • Write
      • Arguments
      • Returns
    • Close
  • EXAMPLE

Create a custom RWops object.

Function

SYNOPSIS

rw, err = function SDL.RWCreate(funcs)

ARGUMENTS

• funcs, the table with the functions (see Table description).

RETURNS

• rw, the RWops object or nil
• err, the error message

Table description

Size

function size()

Returns

The size of the stream

Seek

function seek(offset, whence)

Arguments

• offset, the offset count
• whence, type of seek

Returns

The seek

Read

function read(n, size)

Arguments

• n, the number to read
• size, each block to read

Returns

1. The string read
2. The number of bytes read

Write

function write(data, n, size)

Arguments

• data, the data string
• n, the number to write
• size, each block to write

Returns

1. The number of bytes written

Close

function close()

EXAMPLE

local SDL       = require "SDL" 

-- The table for RW ops
local reader    = { }

function reader.size()
return -1
end

function reader.read(n, size)
local r = reader.file:read(n * size)    

if not r then
return nil, 0
end

return r, #r
end

function reader.write(data, n, size)
local r = reader.file:write(data)

if not r then
return 0
end

return n * size
end

function reader.seek(offset, whence)
local v = nil

if whence == SDL.rwopsSeek.Set then
                v = "set" 
elseif whence == SDL.rwopsSeek.Current then
                v = "cur" 
elseif whence == SDL.rwopsSeek.End then
                v = "end" 
end

if not v then
error("unknown whence")
end

local r = reader.file:seek(v, offset)

if not r then
return 0
end

return r
end

function reader.close()
        reader.file:close()
end

reader.file = io.open("mario.png", "r")
if not reader.file then
-- Handle your error here
error("Failed to load")
end

local rw = SDL.RWCreate(reader)