511 lines
13 KiB
JavaScript
511 lines
13 KiB
JavaScript
"use strict";
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/** @const */
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var ASYNC_SAFE = false;
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(function()
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{
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if(typeof XMLHttpRequest === "undefined")
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{
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v86util.load_file = load_file_nodejs;
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}
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else
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{
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v86util.load_file = load_file;
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}
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v86util.AsyncXHRBuffer = AsyncXHRBuffer;
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v86util.AsyncFileBuffer = AsyncFileBuffer;
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v86util.SyncFileBuffer = SyncFileBuffer;
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/**
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* @param {string} filename
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* @param {Object} options
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*/
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function load_file(filename, options)
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{
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var http = new XMLHttpRequest();
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http.open(options.method || "get", filename, true);
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if(!options.as_text)
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{
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http.responseType = "arraybuffer";
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}
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if(options.headers)
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{
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var header_names = Object.keys(options.headers);
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for(var i = 0; i < header_names.length; i++)
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{
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var name = header_names[i];
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http.setRequestHeader(name, options.headers[name]);
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}
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}
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http.onload = function(e)
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{
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if(http.readyState === 4)
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{
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if(http.status !== 200 && http.status !== 206)
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{
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console.error("Loading the image `" + filename + "` failed (status %d)", http.status);
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}
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else if(http.response)
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{
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options.done && options.done(http.response, http);
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}
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}
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};
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if(options.progress)
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{
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http.onprogress = function(e)
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{
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options.progress(e);
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};
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}
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http.send(null);
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}
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function load_file_nodejs(filename, options)
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{
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var o = {
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encoding: options.as_text ? "utf-8" : null,
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};
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require("fs")["readFile"](filename, o, function(err, data)
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{
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if(err)
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{
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console.log("Could not read file:", filename);
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}
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else
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{
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var result = data;
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if(!options.as_text)
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{
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result = new Uint8Array(result).buffer;
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}
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options.done(result);
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}
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});
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}
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/**
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* Asynchronous access to ArrayBuffer, loading blocks lazily as needed,
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* using the `Range: bytes=...` header
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*
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* @constructor
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* @param {string} filename Name of the file to download
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* @param {number|undefined} size
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*/
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function AsyncXHRBuffer(filename, size)
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{
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this.filename = filename;
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/** @const */
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this.block_size = 256;
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this.byteLength = size;
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this.loaded_blocks = {};
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this.onload = undefined;
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this.onprogress = undefined;
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}
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AsyncXHRBuffer.prototype.load = function()
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{
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if(this.byteLength !== undefined)
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{
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this.onload && this.onload({});
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return;
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}
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// Determine the size using a request
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load_file(this.filename, {
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done: function done(buffer, http)
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{
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var header = http.getResponseHeader("Content-Range") || "";
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var match = header.match(/\/(\d+)\s*$/);
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if(match)
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{
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this.byteLength = +match[1]
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this.onload && this.onload({});
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}
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else
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{
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console.assert(false,
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"Cannot use: " + this.filename + ". " +
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"`Range: bytes=...` header not supported (Got `" + header + "`)");
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}
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}.bind(this),
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headers: {
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Range: "bytes=0-0",
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//"Accept-Encoding": "",
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// Added by Chromium, but can cause the whole file to be sent
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// Settings this to empty also causes problems and Chromium
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// doesn't seem to create this header any more
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//"If-Range": "",
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}
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});
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}
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/**
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* @param {number} offset
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* @param {number} len
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* @param {function(!Uint8Array)} fn
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*/
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AsyncXHRBuffer.prototype.get_from_cache = function(offset, len, fn)
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{
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var number_of_blocks = len / this.block_size;
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var block_index = offset / this.block_size;
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for(var i = 0; i < number_of_blocks; i++)
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{
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var block = this.loaded_blocks[block_index + i];
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if(!block)
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{
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return;
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}
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}
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if(number_of_blocks === 1)
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{
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return this.loaded_blocks[block_index];
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}
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else
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{
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var result = new Uint8Array(len);
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for(var i = 0; i < number_of_blocks; i++)
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{
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result.set(this.loaded_blocks[block_index + i], i * this.block_size);
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}
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return result;
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}
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};
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/**
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* @param {number} offset
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* @param {number} len
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* @param {function(!Uint8Array)} fn
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*/
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AsyncXHRBuffer.prototype.get = function(offset, len, fn)
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{
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console.assert(offset + len <= this.byteLength);
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console.assert(offset % this.block_size === 0);
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console.assert(len % this.block_size === 0);
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console.assert(len);
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var block = this.get_from_cache(offset, len, fn);
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if(block)
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{
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if(ASYNC_SAFE)
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{
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setTimeout(fn.bind(this, block), 0);
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}
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else
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{
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fn(block);
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}
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return;
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}
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var range_start = offset;
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var range_end = offset + len - 1;
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load_file(this.filename, {
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done: function done(buffer)
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{
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var block = new Uint8Array(buffer);
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this.handle_read(offset, len, block);
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fn(block);
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}.bind(this),
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headers: {
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Range: "bytes=" + range_start + "-" + range_end,
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}
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});
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}
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/**
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* Relies on this.byteLength, this.loaded_blocks and this.block_size
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*
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* @this {AsyncFileBuffer|AsyncXHRBuffer}
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*
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* @param {number} start
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* @param {!Uint8Array} data
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* @param {function()} fn
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*/
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AsyncXHRBuffer.prototype.set = function(start, data, fn)
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{
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console.assert(start + data.byteLength <= this.byteLength);
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var len = data.length;
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console.assert(start % this.block_size === 0);
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console.assert(len % this.block_size === 0);
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console.assert(len);
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var start_block = start / this.block_size;
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var block_count = len / this.block_size;
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for(var i = 0; i < block_count; i++)
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{
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var block = this.loaded_blocks[start_block + i];
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if(block === undefined)
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{
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block = this.loaded_blocks[start_block + i] = new Uint8Array(this.block_size);
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}
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var data_slice = data.subarray(i * this.block_size, (i + 1) * this.block_size);
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block.set(data_slice);
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console.assert(block.byteLength === data_slice.length);
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}
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fn();
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}
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/**
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* @this {AsyncFileBuffer|AsyncXHRBuffer}
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* @param {number} offset
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* @param {number} len
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* @param {!Uint8Array} block
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*/
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AsyncXHRBuffer.prototype.handle_read = function(offset, len, block)
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{
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// Used by AsyncXHRBuffer and AsyncFileBuffer
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// Overwrites blocks from the original source that have been written since
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var start_block = offset / this.block_size;
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var block_count = len / this.block_size;
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for(var i = 0; i < block_count; i++)
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{
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var written_block = this.loaded_blocks[start_block + i];
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if(written_block)
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{
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block.set(written_block, i * this.block_size);
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}
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//else
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//{
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// var cached = this.loaded_blocks[start_block + i] = new Uint8Array(this.block_size);
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// cached.set(block.subarray(i * this.block_size, (i + 1) * this.block_size));
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//}
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}
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};
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AsyncXHRBuffer.prototype.get_buffer = function(fn)
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{
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// We must download all parts, unlikely a good idea for big files
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fn();
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};
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/**
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* Synchronous access to File, loading blocks from the input type=file
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* The whole file is loaded into memory during initialisation
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*
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* @constructor
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*/
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function SyncFileBuffer(file)
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{
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this.file = file;
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this.byteLength = file.size;
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if(file.size > (1 << 30))
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{
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console.warn("SyncFileBuffer: Allocating buffer of " + (file.size >> 20) + " MB ...");
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}
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this.buffer = new ArrayBuffer(file.size);
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this.onload = undefined;
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this.onprogress = undefined;
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}
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SyncFileBuffer.prototype.load = function()
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{
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this.load_next(0);
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}
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/**
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* @param {number} start
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*/
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SyncFileBuffer.prototype.load_next = function(start)
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{
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/** @const */
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var PART_SIZE = 4 << 20;
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var filereader = new FileReader();
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filereader.onload = function(e)
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{
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var buffer = new Uint8Array(e.target.result);
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new Uint8Array(this.buffer, start).set(buffer);
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this.load_next(start + PART_SIZE);
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}.bind(this);
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if(this.onprogress)
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{
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this.onprogress({
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loaded: start,
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total: this.byteLength,
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lengthComputable: true,
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});
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}
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if(start < this.byteLength)
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{
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var end = Math.min(start + PART_SIZE, this.byteLength);
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var slice = this.file.slice(start, end);
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filereader.readAsArrayBuffer(slice);
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}
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else
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{
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this.file = undefined;
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this.onload && this.onload({ buffer: this.buffer });
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}
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}
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/**
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* @param {number} start
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* @param {number} len
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* @param {function(!Uint8Array)} fn
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*/
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SyncFileBuffer.prototype.get = function(start, len, fn)
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{
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console.assert(start + len <= this.byteLength);
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fn(new Uint8Array(this.buffer, start, len));
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};
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/**
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* @param {number} offset
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* @param {!Uint8Array} slice
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* @param {function()} fn
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*/
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SyncFileBuffer.prototype.set = function(offset, slice, fn)
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{
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console.assert(offset + slice.byteLength <= this.byteLength);
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new Uint8Array(this.buffer, offset, slice.byteLength).set(slice);
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fn();
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};
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SyncFileBuffer.prototype.get_buffer = function(fn)
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{
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fn(this.buffer);
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};
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/**
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* Asynchronous access to File, loading blocks from the input type=file
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*
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* @constructor
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*/
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function AsyncFileBuffer(file)
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{
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this.file = file;
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this.byteLength = file.size;
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/** @const */
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this.block_size = 256
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this.loaded_blocks = {};
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this.onload = undefined;
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this.onprogress = undefined;
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}
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AsyncFileBuffer.prototype.load = function()
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{
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this.onload && this.onload({});
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};
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/**
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* @param {number} offset
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* @param {number} len
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* @param {function(!Uint8Array)} fn
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*/
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AsyncFileBuffer.prototype.get = function(offset, len, fn)
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{
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console.assert(offset % this.block_size === 0);
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console.assert(len % this.block_size === 0);
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console.assert(len);
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var block = this.get_from_cache(offset, len, fn);
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if(block)
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{
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fn(block);
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return;
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}
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var fr = new FileReader();
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fr.onload = function(e)
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{
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var buffer = e.target.result;
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var block = new Uint8Array(buffer);
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this.handle_read(offset, len, block);
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fn(block);
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}.bind(this);
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fr.readAsArrayBuffer(this.file.slice(offset, offset + len));
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}
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AsyncFileBuffer.prototype.get_from_cache = AsyncXHRBuffer.prototype.get_from_cache;
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AsyncFileBuffer.prototype.set = AsyncXHRBuffer.prototype.set;
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AsyncFileBuffer.prototype.handle_read = AsyncXHRBuffer.prototype.handle_read;
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AsyncFileBuffer.prototype.get_buffer = function(fn)
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{
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// We must load all parts, unlikely a good idea for big files
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fn();
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};
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AsyncFileBuffer.prototype.get_as_file = function(name)
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{
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var parts = [];
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var existing_blocks = Object.keys(this.loaded_blocks)
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.map(Number)
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.sort(function(x, y) { return x - y; });
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var current_offset = 0;
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for(var i = 0; i < existing_blocks.length; i++)
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{
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var block_index = existing_blocks[i];
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var block = this.loaded_blocks[block_index];
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var start = block_index * this.block_size;
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console.assert(start >= current_offset);
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if(start !== current_offset)
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{
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parts.push(this.file.slice(current_offset, start));
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current_offset = start;
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}
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parts.push(block);
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current_offset += block.length;
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}
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if(current_offset !== this.file.size)
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{
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parts.push(this.file.slice(current_offset));
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}
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var file = new File(parts, name);
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console.assert(file.size === this.file.size);
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return file;
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};
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})();
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