97 lines
2.6 KiB
JavaScript
97 lines
2.6 KiB
JavaScript
import { getFloat16 } from '@petamoriken/float16';
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export default class DataView64 {
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constructor(arrayBuffer) {
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this._dataView = new DataView(arrayBuffer);
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}
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get buffer() {
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return this._dataView.buffer;
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}
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getUint64(offset, littleEndian) {
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const left = this.getUint32(offset, littleEndian);
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const right = this.getUint32(offset + 4, littleEndian);
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let combined;
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if (littleEndian) {
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combined = left + ((2 ** 32) * right);
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if (!Number.isSafeInteger(combined)) {
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throw new Error(
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`${combined} exceeds MAX_SAFE_INTEGER. `
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+ 'Precision may be lost. Please report if you get this message to https://github.com/geotiffjs/geotiff.js/issues',
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);
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}
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return combined;
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}
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combined = ((2 ** 32) * left) + right;
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if (!Number.isSafeInteger(combined)) {
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throw new Error(
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`${combined} exceeds MAX_SAFE_INTEGER. `
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+ 'Precision may be lost. Please report if you get this message to https://github.com/geotiffjs/geotiff.js/issues',
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);
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}
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return combined;
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}
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// adapted from https://stackoverflow.com/a/55338384/8060591
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getInt64(offset, littleEndian) {
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let value = 0;
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const isNegative = (this._dataView.getUint8(offset + (littleEndian ? 7 : 0)) & 0x80) > 0;
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let carrying = true;
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for (let i = 0; i < 8; i++) {
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let byte = this._dataView.getUint8(offset + (littleEndian ? i : 7 - i));
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if (isNegative) {
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if (carrying) {
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if (byte !== 0x00) {
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byte = ~(byte - 1) & 0xff;
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carrying = false;
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}
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} else {
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byte = ~byte & 0xff;
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}
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}
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value += byte * (256 ** i);
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}
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if (isNegative) {
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value = -value;
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}
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return value;
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}
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getUint8(offset, littleEndian) {
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return this._dataView.getUint8(offset, littleEndian);
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}
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getInt8(offset, littleEndian) {
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return this._dataView.getInt8(offset, littleEndian);
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}
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getUint16(offset, littleEndian) {
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return this._dataView.getUint16(offset, littleEndian);
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}
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getInt16(offset, littleEndian) {
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return this._dataView.getInt16(offset, littleEndian);
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}
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getUint32(offset, littleEndian) {
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return this._dataView.getUint32(offset, littleEndian);
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}
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getInt32(offset, littleEndian) {
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return this._dataView.getInt32(offset, littleEndian);
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}
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getFloat16(offset, littleEndian) {
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return getFloat16(this._dataView, offset, littleEndian);
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}
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getFloat32(offset, littleEndian) {
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return this._dataView.getFloat32(offset, littleEndian);
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}
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getFloat64(offset, littleEndian) {
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return this._dataView.getFloat64(offset, littleEndian);
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}
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}
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