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buffer_utils.ts
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buffer_utils.ts
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import type { DigestFunction } from '../runtime/interfaces.d.ts'
export const encoder = new TextEncoder()
export const decoder = new TextDecoder()
const MAX_INT32 = 2 ** 32
export function concat(...buffers: Uint8Array[]): Uint8Array {
const size = buffers.reduce((acc, { length }) => acc + length, 0)
const buf = new Uint8Array(size)
let i = 0
buffers.forEach((buffer) => {
buf.set(buffer, i)
i += buffer.length
})
return buf
}
export function p2s(alg: string, p2sInput: Uint8Array) {
return concat(encoder.encode(alg), new Uint8Array([0]), p2sInput)
}
function writeUInt32BE(buf: Uint8Array, value: number, offset?: number) {
if (value < 0 || value >= MAX_INT32) {
throw new RangeError(`value must be >= 0 and <= ${MAX_INT32 - 1}. Received ${value}`)
}
buf.set([value >>> 24, value >>> 16, value >>> 8, value & 0xff], offset)
}
export function uint64be(value: number) {
const high = Math.floor(value / MAX_INT32)
const low = value % MAX_INT32
const buf = new Uint8Array(8)
writeUInt32BE(buf, high, 0)
writeUInt32BE(buf, low, 4)
return buf
}
export function uint32be(value: number) {
const buf = new Uint8Array(4)
writeUInt32BE(buf, value)
return buf
}
export function lengthAndInput(input: Uint8Array) {
return concat(uint32be(input.length), input)
}
export async function concatKdf(
digest: DigestFunction,
secret: Uint8Array,
bits: number,
value: Uint8Array,
) {
const iterations = Math.ceil((bits >> 3) / 32)
let res!: Uint8Array
for (let iter = 1; iter <= iterations; iter++) {
const buf = new Uint8Array(4 + secret.length + value.length)
buf.set(uint32be(iter))
buf.set(secret, 4)
buf.set(value, 4 + secret.length)
if (!res) {
res = await digest('sha256', buf)
} else {
res = concat(res, await digest('sha256', buf))
}
}
res = res.slice(0, bits >> 3)
return res
}