Geek-Research-Lab/MeowJS

var meta;
meta(function(x, xx) {

    // Value is set, since crash might occur if more uses it.
    var WorkerCount = 4;

    var xBuild = this;
    return {
        xPieceSize: function(fileSize) {
            var pSize = 1 << 20;
            while(fileSize / pSize > 128) {
                pSize <<= 1;
            }
            return pSize;
        },

        xBlockSize: function(pieceSize) {
            var bSize = pieceSize;
            while(bSize > 1 << 23) {
                bSize >>= 1;
            }
            return bSize;
        },

        xCalculateHash: function(builder) {
            var m;
            var window;
            var workers = [];
            var file = builder.file;
            var pieceSize = builder.result.pieceSize;
            var totalPieces = builder.result.PieceCount;
            var array = [];
            var checkFinished = x.throttle(function() {
                var done = x.filter(array, x.isString).length;
                if(x.isFunction(builder.onProgress)) {
                    builder.onProgress({
                        done: done,
                        total: totalPieces
                    });
                }
                if(done === totalPieces) {
                    builder.result.hash = xx.hash(array.join(''));
                    builder.result.array = array;
                    if(x.isFunction(builder.onLoad) && !builder.onLoadx1) {
                        builder.onLoadx1 = true;
                        builder.onLoad(builder.result);
                    }
                }
            }, 100);
            var Worker = new Worker('xxWorker.js');
            Worker.onMessage = function(xEvent) {
                array[xEvent.data.id] = xEvent.data.hash;
                checkFinished();
                window.URL.revokeObjectURL(xEvent.data.blob);
            };
            for(m = 0; m < WorkerCount; ++m) {
                workers.push(Worker);
            }
            for(m = 0; m < totalPieces; ++m) {
                var blob = file.slice(pieceSize * m, pieceSize * (m + 1));
                var blobUrl = window.URL.createObjectURL(blob);
                workers[m % WorkerCount].postMessage(x.clone({
                    id: m,
                    blob: blobUrl
                }));
            }
        },

        build: function(file) {
            var fileSize = file.size;
            var pieceSize = xBuild.xPieceSize(fileSize);
            var blockSize = xBuild.xBlockSize(pieceSize);
            var result = {
                fileName: file.name,
                type: file.size,
                pieceSize: pieceSize,
                PieceCount: Math.ceil(1.0 * fileSize / pieceSize),
                blockSize: blockSize
            };
            var builder = {
                'file': file,
                'result': result
            };
            xBuild.xCalculateHash(builder);
            return builder;
        }
    };
});