source: imaps-frontend/node_modules/es-abstract/2024/ArrayBufferCopyAndDetach.js@ d565449

'use strict';

var GetIntrinsic = require('get-intrinsic');

var min = GetIntrinsic('%Math.min%');
var $TypeError = require('es-errors/type');
var $ArrayBuffer = GetIntrinsic('%ArrayBuffer%', true);
var $Uint8Array = GetIntrinsic('%Uint8Array%', true);

var callBound = require('call-bind/callBound');

var byteLength = require('array-buffer-byte-length');
var $maxByteLength = callBound('%ArrayBuffer.prototype.maxByteLength%', true);
var copy = function copyAB(src, start, end) {
        var that = new $Uint8Array(src);
        if (typeof end === 'undefined') {
                end = that.length; // eslint-disable-line no-param-reassign
        }
        var result = new $ArrayBuffer(end - start);
        var resultArray = new $Uint8Array(result);
        for (var i = 0; i < resultArray.length; i++) {
                resultArray[i] = that[i + start];
        }
        return result;
};
var $abSlice = callBound('%ArrayBuffer.prototype.slice%', true)
        || function slice(ab, a, b) { // in node < 0.11, slice is an own nonconfigurable property
                return ab.slice ? ab.slice(a, b) : copy(ab, a, b); // node 0.8 lacks `slice`
        };

var DetachArrayBuffer = require('./DetachArrayBuffer');
var IsDetachedBuffer = require('./IsDetachedBuffer');
var IsFixedLengthArrayBuffer = require('./IsFixedLengthArrayBuffer');
var ToIndex = require('./ToIndex');

var isArrayBuffer = require('is-array-buffer');
var isSharedArrayBuffer = require('is-shared-array-buffer');

module.exports = function ArrayBufferCopyAndDetach(arrayBuffer, newLength, preserveResizability) {
        if (preserveResizability !== 'PRESERVE-RESIZABILITY' && preserveResizability !== 'FIXED-LENGTH') {
                throw new $TypeError('`preserveResizability` must be ~PRESERVE-RESIZABILITY~ or ~FIXED-LENGTH~');
        }

        if (!isArrayBuffer(arrayBuffer) || isSharedArrayBuffer(arrayBuffer)) {
                throw new $TypeError('`arrayBuffer` must be an ArrayBuffer'); // steps 1 - 2
        }

        var abByteLength;

        var newByteLength;
        if (typeof newLength === 'undefined') { // step 3
                newByteLength = byteLength(arrayBuffer); // step 3.a
                abByteLength = newByteLength;
        } else { // step 4
                newByteLength = ToIndex(newLength); // step 4.a
        }

        if (IsDetachedBuffer(arrayBuffer)) {
                throw new $TypeError('`arrayBuffer` must not be detached'); // step 5
        }

        var newMaxByteLength;
        if (preserveResizability === 'PRESERVE-RESIZABILITY' && !IsFixedLengthArrayBuffer(arrayBuffer)) { // step 6
                newMaxByteLength = $maxByteLength(arrayBuffer); // step 6.a
        } else { // step 7
                newMaxByteLength = 'EMPTY'; // step 7.a
        }

        // commented out since there's no way to set or access this key

        // 8. If arrayBuffer.[[ArrayBufferDetachKey]] is not undefined, throw a TypeError exception.

        // 9. Let newBuffer be ? AllocateArrayBuffer(%ArrayBuffer%, newByteLength, newMaxByteLength).
        var newBuffer = newMaxByteLength === 'EMPTY' ? new $ArrayBuffer(newByteLength) : new $ArrayBuffer(newByteLength, { maxByteLength: newMaxByteLength });

        if (typeof abByteLength !== 'number') {
                abByteLength = byteLength(arrayBuffer);
        }
        var copyLength = min(newByteLength, abByteLength); // step 10
        if (newByteLength > copyLength) {
                var taNew = new $Uint8Array(newBuffer);
                var taOld = new $Uint8Array(arrayBuffer);
                for (var i = 0; i < copyLength; i++) {
                        taNew[i] = taOld[i];
                }
        } else {
                newBuffer = $abSlice(arrayBuffer, 0, copyLength); // ? optimization for when the new buffer will not be larger than the old one
        }
        /*
        11. Let fromBlock be arrayBuffer.[[ArrayBufferData]].
        12. Let toBlock be newBuffer.[[ArrayBufferData]].
        13. Perform CopyDataBlockBytes(toBlock, 0, fromBlock, 0, copyLength).
        14. NOTE: Neither creation of the new Data Block nor copying from the old Data Block are observable. Implementations may implement this method as a zero-copy move or a realloc.
        */

        DetachArrayBuffer(arrayBuffer); // step 15

        return newBuffer; // step 16
};