javascript 如何使用javascript逐字节读取二进制文件？
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How to read binary file byte by byte using javascript?
提问by robertklep
I need to read the binary file byte by byte using javascript.I had got below code in this site,but its not working.I think i have to add some extra src file as a reference to it.Please help me to do it.here the code...
我需要使用 javascript 逐字节读取二进制文件。我在本站点中得到了以下代码，但它不起作用。我想我必须添加一些额外的 src 文件作为对它的引用。请帮我做。这里的代码...
var fs = require('fs');
var Buffer = require('buffer').Buffer;
var constants = require('constants');
fs.open("file.txt", 'r', function(status, fd) {
if (status) {
console.log(status.message);
return;
}
var buffer = new Buffer(100);
fs.read(fd, buffer, 0, 100, 0, function(err, num) {
console.log(buffer.toString('utf-8', 0, num));
});
});
回答by robertklep
You can read the file synchronously, byte by byte:
您可以逐字节同步读取文件：
fs.open('file.txt', 'r', function(err, fd) {
if (err)
throw err;
var buffer = new Buffer(1);
while (true)
{
var num = fs.readSync(fd, buffer, 0, 1, null);
if (num === 0)
break;
console.log('byte read', buffer[0]);
}
});
回答by Cigodien
You can use the following code:
您可以使用以下代码：
var blob = file.slice(startingByte, endindByte);
reader.readAsBinaryString(blob);
Here's how it works:
这是它的工作原理：
file.slicewill slice a file into bytes and save to a variable as binary. You can slice by giving the start byte and end byte.reader.readAsBinaryStringwill print that byte as binary file. It doesn't matter how big the file is.
file.slice将文件切成字节并保存为二进制变量。您可以通过提供开始字节和结束字节来切片。reader.readAsBinaryString将该字节打印为二进制文件。文件有多大并不重要。
For more info, see this link.
有关详细信息，请参阅此链接。
