70 lines
1.6 KiB
JavaScript
70 lines
1.6 KiB
JavaScript
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var toString = Object.prototype.toString
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var isModern = (
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typeof Buffer.alloc === 'function' &&
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typeof Buffer.allocUnsafe === 'function' &&
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typeof Buffer.from === 'function'
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)
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function isArrayBuffer (input) {
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return toString.call(input).slice(8, -1) === 'ArrayBuffer'
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}
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function fromArrayBuffer (obj, byteOffset, length) {
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byteOffset >>>= 0
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var maxLength = obj.byteLength - byteOffset
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if (maxLength < 0) {
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throw new RangeError("'offset' is out of bounds")
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}
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if (length === undefined) {
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length = maxLength
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} else {
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length >>>= 0
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if (length > maxLength) {
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throw new RangeError("'length' is out of bounds")
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}
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}
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return isModern
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? Buffer.from(obj.slice(byteOffset, byteOffset + length))
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: new Buffer(new Uint8Array(obj.slice(byteOffset, byteOffset + length)))
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}
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function fromString (string, encoding) {
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if (typeof encoding !== 'string' || encoding === '') {
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encoding = 'utf8'
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}
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if (!Buffer.isEncoding(encoding)) {
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throw new TypeError('"encoding" must be a valid string encoding')
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}
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return isModern
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? Buffer.from(string, encoding)
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: new Buffer(string, encoding)
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}
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function bufferFrom (value, encodingOrOffset, length) {
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if (typeof value === 'number') {
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throw new TypeError('"value" argument must not be a number')
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}
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if (isArrayBuffer(value)) {
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return fromArrayBuffer(value, encodingOrOffset, length)
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}
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if (typeof value === 'string') {
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return fromString(value, encodingOrOffset)
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}
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return isModern
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? Buffer.from(value)
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: new Buffer(value)
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}
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module.exports = bufferFrom
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