array-buffer-transfer.js 2.1 KB

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  1. 'use strict';
  2. var global = require('../internals/global');
  3. var uncurryThis = require('../internals/function-uncurry-this');
  4. var uncurryThisAccessor = require('../internals/function-uncurry-this-accessor');
  5. var toIndex = require('../internals/to-index');
  6. var isDetached = require('../internals/array-buffer-is-detached');
  7. var arrayBufferByteLength = require('../internals/array-buffer-byte-length');
  8. var PROPER_TRANSFER = require('../internals/structured-clone-proper-transfer');
  9. var TypeError = global.TypeError;
  10. var structuredClone = global.structuredClone;
  11. var ArrayBuffer = global.ArrayBuffer;
  12. var DataView = global.DataView;
  13. var min = Math.min;
  14. var ArrayBufferPrototype = ArrayBuffer.prototype;
  15. var DataViewPrototype = DataView.prototype;
  16. var slice = uncurryThis(ArrayBufferPrototype.slice);
  17. var isResizable = uncurryThisAccessor(ArrayBufferPrototype, 'resizable', 'get');
  18. var maxByteLength = uncurryThisAccessor(ArrayBufferPrototype, 'maxByteLength', 'get');
  19. var getInt8 = uncurryThis(DataViewPrototype.getInt8);
  20. var setInt8 = uncurryThis(DataViewPrototype.setInt8);
  21. module.exports = PROPER_TRANSFER && function (arrayBuffer, newLength, preserveResizability) {
  22. var byteLength = arrayBufferByteLength(arrayBuffer);
  23. var newByteLength = newLength === undefined ? byteLength : toIndex(newLength);
  24. var fixedLength = !isResizable || !isResizable(arrayBuffer);
  25. if (isDetached(arrayBuffer)) throw TypeError('ArrayBuffer is detached');
  26. var newBuffer = structuredClone(arrayBuffer, { transfer: [arrayBuffer] });
  27. if (byteLength === newByteLength && (preserveResizability || fixedLength)) return newBuffer;
  28. if (byteLength >= newByteLength && (!preserveResizability || fixedLength)) return slice(newBuffer, 0, newByteLength);
  29. var options = (preserveResizability && !fixedLength) && maxByteLength ? { maxByteLength: maxByteLength(newBuffer) } : undefined;
  30. var newNewBuffer = new ArrayBuffer(newByteLength, options);
  31. var a = new DataView(newBuffer);
  32. var b = new DataView(newNewBuffer);
  33. var copyLength = min(newByteLength, byteLength);
  34. for (var i = 0; i < copyLength; i++) setInt8(b, i, getInt8(a, i));
  35. return newNewBuffer;
  36. };