asarfuckery/electronasar/development/common/buffer-utils.js

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2019-01-17 18:22:05 +00:00
'use strict'
// Note: Don't use destructuring assignment for `Buffer`, or we'll hit a
// browserify bug that makes the statement invalid, throwing an error in
// sandboxed renderer.
const Buffer = require('buffer').Buffer
const typedArrays = {
Buffer,
ArrayBuffer,
Int8Array,
Uint8Array,
Uint8ClampedArray,
Int16Array,
Uint16Array,
Int32Array,
Uint32Array,
Float32Array,
Float64Array
}
function getType (value) {
for (const type of Object.keys(typedArrays)) {
if (value instanceof typedArrays[type]) {
return type
}
}
return null
}
function getBuffer (value) {
if (value instanceof Buffer) {
return value
} else if (value instanceof ArrayBuffer) {
return Buffer.from(value)
} else {
return Buffer.from(value.buffer, value.byteOffset, value.byteLength)
}
}
exports.isBuffer = function (value) {
return ArrayBuffer.isView(value) || value instanceof ArrayBuffer
}
exports.bufferToMeta = function (value) {
return {
type: getType(value),
data: getBuffer(value),
length: value.length
}
}
exports.metaToBuffer = function (value) {
const constructor = typedArrays[value.type]
const data = getBuffer(value.data)
if (constructor === Buffer) {
return data
} else if (constructor === ArrayBuffer) {
return data.buffer
} else if (constructor) {
return new constructor(data.buffer, data.byteOffset, value.length)
} else {
return data
}
}