107 lines
2.4 KiB
JavaScript
107 lines
2.4 KiB
JavaScript
import {Base} from './Base.js';
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import {Number as NumberT} from './Number.js';
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import * as utils from './utils.js';
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class ArrayT extends Base {
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constructor(type, length, lengthType = 'count') {
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super();
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this.type = type;
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this.length = length;
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this.lengthType = lengthType;
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}
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decode(stream, parent) {
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let length;
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const { pos } = stream;
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const res = [];
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let ctx = parent;
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if (this.length != null) {
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length = utils.resolveLength(this.length, stream, parent);
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}
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if (this.length instanceof NumberT) {
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// define hidden properties
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Object.defineProperties(res, {
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parent: { value: parent },
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_startOffset: { value: pos },
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_currentOffset: { value: 0, writable: true },
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_length: { value: length }
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});
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ctx = res;
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}
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if ((length == null) || (this.lengthType === 'bytes')) {
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const target = (length != null) ?
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stream.pos + length
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: (parent != null ? parent._length : undefined) ?
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parent._startOffset + parent._length
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:
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stream.length;
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while (stream.pos < target) {
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res.push(this.type.decode(stream, ctx));
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}
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} else {
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for (let i = 0, end = length; i < end; i++) {
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res.push(this.type.decode(stream, ctx));
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}
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}
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return res;
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}
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size(array, ctx, includePointers = true) {
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if (!array) {
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return this.type.size(null, ctx) * utils.resolveLength(this.length, null, ctx);
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}
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let size = 0;
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if (this.length instanceof NumberT) {
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size += this.length.size();
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ctx = {parent: ctx, pointerSize: 0};
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}
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for (let item of array) {
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size += this.type.size(item, ctx);
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}
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if (ctx && includePointers && this.length instanceof NumberT) {
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size += ctx.pointerSize;
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}
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return size;
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}
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encode(stream, array, parent) {
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let ctx = parent;
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if (this.length instanceof NumberT) {
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ctx = {
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pointers: [],
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startOffset: stream.pos,
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parent
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};
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ctx.pointerOffset = stream.pos + this.size(array, ctx, false);
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this.length.encode(stream, array.length);
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}
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for (let item of array) {
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this.type.encode(stream, item, ctx);
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}
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if (this.length instanceof NumberT) {
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let i = 0;
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while (i < ctx.pointers.length) {
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const ptr = ctx.pointers[i++];
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ptr.type.encode(stream, ptr.val, ptr.parent);
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}
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}
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}
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}
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export {ArrayT as Array};
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