51 lines
1.2 KiB
JavaScript
51 lines
1.2 KiB
JavaScript
const { Transform } = require('readable-stream')
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class Block extends Transform {
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constructor (size, opts = {}) {
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super(opts)
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if (typeof size === 'object') {
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opts = size
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size = opts.size
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}
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this.size = size || 512
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const { nopad, zeroPadding = true } = opts
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if (nopad) this._zeroPadding = false
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else this._zeroPadding = !!zeroPadding
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this._buffered = []
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this._bufferedBytes = 0
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}
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_transform (buf, enc, next) {
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this._bufferedBytes += buf.length
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this._buffered.push(buf)
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while (this._bufferedBytes >= this.size) {
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const b = Buffer.concat(this._buffered)
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this._bufferedBytes -= this.size
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this.push(b.slice(0, this.size))
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this._buffered = [ b.slice(this.size, b.length) ]
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}
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next()
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}
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_flush () {
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if (this._bufferedBytes && this._zeroPadding) {
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const zeroes = Buffer.alloc(this.size - this._bufferedBytes)
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this._buffered.push(zeroes)
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this.push(Buffer.concat(this._buffered))
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this._buffered = null
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} else if (this._bufferedBytes) {
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this.push(Buffer.concat(this._buffered))
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this._buffered = null
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}
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this.push(null)
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}
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}
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module.exports = Block
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