106 lines
2.4 KiB
JavaScript
106 lines
2.4 KiB
JavaScript
'use strict';
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var TYPED_OK = (typeof Uint8Array !== 'undefined') &&
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(typeof Uint16Array !== 'undefined') &&
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(typeof Int32Array !== 'undefined');
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function _has(obj, key) {
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return Object.prototype.hasOwnProperty.call(obj, key);
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}
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exports.assign = function (obj /*from1, from2, from3, ...*/) {
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var sources = Array.prototype.slice.call(arguments, 1);
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while (sources.length) {
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var source = sources.shift();
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if (!source) { continue; }
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if (typeof source !== 'object') {
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throw new TypeError(source + 'must be non-object');
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}
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for (var p in source) {
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if (_has(source, p)) {
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obj[p] = source[p];
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}
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}
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}
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return obj;
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};
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// reduce buffer size, avoiding mem copy
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exports.shrinkBuf = function (buf, size) {
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if (buf.length === size) { return buf; }
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if (buf.subarray) { return buf.subarray(0, size); }
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buf.length = size;
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return buf;
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};
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var fnTyped = {
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arraySet: function (dest, src, src_offs, len, dest_offs) {
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if (src.subarray && dest.subarray) {
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dest.set(src.subarray(src_offs, src_offs + len), dest_offs);
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return;
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}
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// Fallback to ordinary array
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for (var i = 0; i < len; i++) {
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dest[dest_offs + i] = src[src_offs + i];
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}
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},
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// Join array of chunks to single array.
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flattenChunks: function (chunks) {
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var i, l, len, pos, chunk, result;
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// calculate data length
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len = 0;
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for (i = 0, l = chunks.length; i < l; i++) {
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len += chunks[i].length;
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}
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// join chunks
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result = new Uint8Array(len);
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pos = 0;
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for (i = 0, l = chunks.length; i < l; i++) {
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chunk = chunks[i];
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result.set(chunk, pos);
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pos += chunk.length;
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}
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return result;
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}
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};
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var fnUntyped = {
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arraySet: function (dest, src, src_offs, len, dest_offs) {
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for (var i = 0; i < len; i++) {
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dest[dest_offs + i] = src[src_offs + i];
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}
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},
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// Join array of chunks to single array.
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flattenChunks: function (chunks) {
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return [].concat.apply([], chunks);
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}
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};
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// Enable/Disable typed arrays use, for testing
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//
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exports.setTyped = function (on) {
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if (on) {
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exports.Buf8 = Uint8Array;
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exports.Buf16 = Uint16Array;
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exports.Buf32 = Int32Array;
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exports.assign(exports, fnTyped);
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} else {
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exports.Buf8 = Array;
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exports.Buf16 = Array;
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exports.Buf32 = Array;
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exports.assign(exports, fnUntyped);
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}
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};
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exports.setTyped(TYPED_OK);
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