planning

node_modules/geotiff/dist-module/dataview64.js

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