** Loads `MappyMap` instances from '.FMP' data streams.
** See `MapViewer` for details on rendering a `MappyMap` to the screen.
@Js
class MapLoader {
private static const Log log := MapLoader#.pod.log
@NoDoc
protected Str:Type chunkLoaders := [:]
@NoDoc
protected Int mapSize
// ---- Constructors ------------------------------------------------------
internal new make() {
// by having instances of MapLoaders they become self initialising and
// the ChunkLoader instances (below) get automatically garbage collected
registerChunkLoaders
}
// ---- Public Methods ----------------------------------------------------
** Create a `MappyMap` from the given input stream of '.FMP' data.
**
** Note this method closes the input stream.
static MappyMap loadMap(InStream fmpStream) {
return MapLoader().doLoadMap(fmpStream)
}
// ---- Protected Methods -------------------------------------------------
** Performs the actual FMP map loading.
private MappyMap doLoadMap(InStream fmpStream) {
log.debug("loadMap() - Starting...")
log.info("Loading Map from InputStream")
try {
map := MappyMap()
// load the map header
chkMapHeader := createChunkLoader(fmpStream, Endian.big)
if (chkMapHeader.chunkName != "FORM")
throw FantomMappyErr("Map does not start with chunk [FORM] :: ChunkIf = [$chkMapHeader.chunkName]")
// find out how many bytes are contained in the map data
chkMapHeader.loadChunk(map)
bytesToRead := mapSize - 4
// read chunks while there's still chunks to read
while (bytesToRead > 0) {
// find and create the next chunk loader
chunkLoader := createChunkLoader(fmpStream, map.mapHeader.endian)
// load the chunk
chunkLoader.loadChunk(map)
// check that all the data was loaded
if (chunkLoader.bytesRemaining > 0) {
log.warn("Chunk [$chunkLoader.chunkName] still has [$chunkLoader.bytesRemaining] bytes remaining, skipping...");
}
// the countdown continues
bytesToRead -= 8 // for the chunk header
bytesToRead -= chunkLoader.chunkSize
}
log.debug("loadMap() - Done.")
return map
} finally {
fmpStream.close
}
}
// ---- Internal Methods -------------------------------------------------
** Factory method for producing instances of ChunkLoaders.
** Note: This method does not close the given input stream.
internal ChunkLoader createChunkLoader(InStream fmpStream, Endian endian) {
log.debug("createChunkLoader() - Starting...")
ChunkLoader? chunkLoader := null
Str? errorMessage := null
try {
errorMessage = "Could not read chunkId"
chunkId := fmpStream.readChars(4)
errorMessage = "Could not read chunk length for ChunkId [$chunkId]"
chunkSize := fmpStream.readU4 // ignore the LSB / MSB thing for chunk lengths
if (chunkId == "FORM") // a little fudge
mapSize = chunkSize
errorMessage = "Could not read raw chunk data for ChunkId [$chunkId]"
buf := fmpStream.readBufFully(null, chunkId == "FORM" ? 4 : chunkSize)
// set a default return value
errorMessage = "Problem creating DefaultChunkLoader"
chunkLoader = DefaultChunkLoader(chunkId, buf, endian)
// find actual ChunkLoader
errorMessage = "Could not find ChunkLoader for ChunkId [$chunkId]"
chunkLoaderType := chunkLoaders.getOrThrow(chunkId)
errorMessage = "Problem initialising ChunkLoader for ChunkId [$chunkId]"
chunkLoader = chunkLoaderType.make([chunkId, buf, endian])
} catch (Err e) {
// always return a default chunk loader if we can, so we may
// continue reading the rest of the map. Not finding a particular
// ChunkLoader is going to be a common problem.
if (chunkLoader != null) {
log.warn(errorMessage)
} else {
throw ChunkLoadErr(errorMessage, e)
}
}
log.info(chunkLoader.toStr)
log.debug("createChunkLoader() - Done.")
return chunkLoader
}
** This is where we hard code chunk loader class references to chunk names.
** We do this so that (J2ME) obfuscaters can rename classes. It also allows
** us to delete empty chunk loader classes like ChunkLoaderLRYx.
internal Void registerChunkLoaders() {
chunkLoaders["ANDT"] = ChunkLoaderANDT#
chunkLoaders["ATHR"] = ChunkLoaderATHR#
// chunkLoaders["BGFX"] = ChunkLoaderBGFX#
chunkLoaders["BKDT"] = ChunkLoaderBKDT#
// chunkLoaders["CMAP"] = ChunkLoaderCMAP#
chunkLoaders["FORM"] = ChunkLoaderFORM#
chunkLoaders["MPHD"] = ChunkLoaderMPHD#
// chunkLoaders["OBDT"] = ChunkLoaderOBDT#
// chunkLoaders["OBFN"] = ChunkLoaderOBFN#
// chunkLoaders["TSTR"] = ChunkLoaderTSTR#
chunkLoaders["BODY"] = ChunkLoaderBODY#
chunkLoaders["LYR1"] = ChunkLoaderBODY#
chunkLoaders["LYR2"] = ChunkLoaderBODY#
chunkLoaders["LYR3"] = ChunkLoaderBODY#
chunkLoaders["LYR4"] = ChunkLoaderBODY#
chunkLoaders["LYR5"] = ChunkLoaderBODY#
chunkLoaders["LYR6"] = ChunkLoaderBODY#
chunkLoaders["LYR7"] = ChunkLoaderBODY#
}
}
@Js
internal class DefaultChunkLoader : ChunkLoader {
new make(Str chunkName, Buf chunkData, Endian endian) : super(chunkName, chunkData, endian) {}
override Void loadChunk(MappyMap map) {
// prevent the warning log
super.skip(super.bytesRemaining)
}
}
