如何将一个NodeJS二进制缓冲区转换为JavaScript数组缓冲区?
当前回答
我尝试了上面的Float64Array,它只是没有工作。
我最终意识到,真正的数据需要读入正确的块视图。这意味着一次从源Buffer读取8个字节。
总之,这是我最后得到的……
var buff = new Buffer("40100000000000004014000000000000", "hex");
var ab = new ArrayBuffer(buff.length);
var view = new Float64Array(ab);
var viewIndex = 0;
for (var bufferIndex=0;bufferIndex<buff.length;bufferIndex=bufferIndex+8) {
view[viewIndex] = buff.readDoubleLE(bufferIndex);
viewIndex++;
}
其他回答
令人惊讶的是,在我的情况下(电子:发送缓冲区渲染器ArrayBuffer),这只是工作
function bufferToArrayBuffer(buffer: Buffer): ArrayBuffer {
return buffer.buffer as ArrayBuffer;
}
快了100倍
function bufferToArrayBuffer(buf) {
const ab = new ArrayBuffer(buf.length);
const view = new Uint8Array(ab);
for (let i = 0; i < buf.length; ++i) {
view[i] = buf[i];
}
return ab;
}
Buffer的实例也是node.js 4中Uint8Array的实例。X和更高。因此,最有效的解决方案是直接访问缓冲区自己的.buffer属性,如https://stackoverflow.com/a/31394257/1375574。Buffer构造函数也接受一个ArrayBufferView参数,如果你需要走另一个方向。
注意,这不会创建一个副本,这意味着对任何ArrayBufferView的写入都将写入原始的Buffer实例。
In older versions, node.js has both ArrayBuffer as part of v8, but the Buffer class provides a more flexible API. In order to read or write to an ArrayBuffer, you only need to create a view and copy across.
从Buffer到ArrayBuffer:
function toArrayBuffer(buffer) {
const arrayBuffer = new ArrayBuffer(buffer.length);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
view[i] = buffer[i];
}
return arrayBuffer;
}
从ArrayBuffer到Buffer:
function toBuffer(arrayBuffer) {
const buffer = Buffer.alloc(arrayBuffer.byteLength);
const view = new Uint8Array(arrayBuffer);
for (let i = 0; i < buffer.length; ++i) {
buffer[i] = view[i];
}
return buffer;
}
现在有一个非常有用的npm包:buffer https://github.com/feross/buffer
它试图提供一个API,是100%相同的节点的缓冲区API,并允许:
将类型化数组转换为缓冲区:https://github.com/feross/buffer#convert-typed-array-to-buffer 将缓冲区转换为类型化数组:https://github.com/feross/buffer#convert-buffer-to-typed-array
还有更多。
Buffer是ArrayBuffer的视图。你可以使用buffer属性访问内部包装的ArrayBuffer。
这是共享内存,不需要复制。
const arrayBuffer = theBuffer.buffer
如果你想要数据的副本,从原始的Buffer(不是从包装的ArrayBuffer)创建另一个Buffer,然后引用它的包装的ArrayBuffer。
const newArrayBuffer = Buffer.from(theBuffer).buffer
作为参考,从另一个方向,从ArrayBuffer到Buffer
const arrayBuffer = getArrayBuffer()
const sharedBuffer = Buffer.from(arrayBuffer)
const copiedBuffer = Buffer.from(sharedBuffer)
const copiedArrayBuffer = copiedBuffer.buffer
一种更快的写法
var arrayBuffer = new Uint8Array(nodeBuffer).buffer;
然而,在包含1024个元素的缓冲区上,这似乎比建议的toArrayBuffer函数慢了大约4倍。