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'use strict'
const length = (a, b) => {
if (a.byteLength === b.byteLength) return a.byteLength
else if (a.byteLength > b.byteLength) return a.byteLength
return b.byteLength
}
const bytes = (_from, encoding) => bytes.from(_from, encoding)
bytes.sorter = (a, b) => {
a = bytes(a)
b = bytes(b)
const len = length(a, b)
let i = 0
while (i < (len - 1)) {
if (i >= a.byteLength) return 1
else if (i >= b.byteLength) return -1
if (a.getUint8(i) < b.getUint8(i)) return -1
else if (a.getUint8(i) > b.getUint8(i)) return 1
i++
}
return 0
}
bytes.compare = (a, b) => !bytes.sorter(a, b)
bytes.memcopy = (_from, encoding) => {
const b = bytes(_from, encoding)
return b.buffer.slice(b.byteOffset, b.byteOffset + b.byteLength)
}
bytes.arrayBuffer = (_from, encoding) => {
_from = bytes(_from, encoding)
if (_from.buffer.byteLength === _from.byteLength) return _from.buffer
return _from.buffer.slice(_from.byteOffset, _from.byteOffset + _from.byteLength)
}
const sliceOptions = (_from, start = 0, end = null) => {
_from = bytes(_from)
end = (end === null ? _from.byteLength : end) - start
return [_from.buffer, _from.byteOffset + start, end]
}
bytes.slice = (_from, start, end) => new DataView(...sliceOptions(_from, start, end))
bytes.memcopySlice = (_from, start, end) => {
const [buffer, offset, length] = sliceOptions(_from, start, end)
return buffer.slice(offset, length + offset)
}
bytes.typedArray = (_from, _Class = Uint8Array) => {
_from = bytes(_from)
return new _Class(_from.buffer, _from.byteOffset, _from.byteLength / _Class.BYTES_PER_ELEMENT)
}
bytes.concat = (_from) => {
_from = Array.from(_from)
_from = _from.map(b => bytes(b))
const length = _from.reduce((x, y) => x + y.byteLength, 0)
const ret = new Uint8Array(length)
let i = 0
for (const part of _from) {
const view = bytes.typedArray(part)
ret.set(view, i)
i += view.byteLength
}
return ret.buffer
}
const maxEntropy = 65536
bytes.random = length => {
const ab = new ArrayBuffer(length)
if (length > maxEntropy) {
let i = 0
while (i < ab.byteLength) {
let len
if (i + maxEntropy > ab.byteLength) len = ab.byteLength - i
else len = maxEntropy
const view = new Uint8Array(ab, i, len)
i += maxEntropy
bytes._randomFill(view)
}
} else {
const view = new Uint8Array(ab)
bytes._randomFill(view)
}
return ab
}
module.exports = bytes
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