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'use strict';
const fs = require('fs');
const pify = require('pify');
const withOpenFile = require('with-open-file');
const fsReadP = pify(fs.read, {multiArgs: true});
const readChunk = (filePath, startPosition, length) => {
const buffer = Buffer.alloc(length);
return withOpenFile(filePath, 'r', fileDescriptor =>
fsReadP(fileDescriptor, buffer, 0, length, startPosition)
)
.then(([bytesRead, buffer]) => {
if (bytesRead < length) {
buffer = buffer.slice(0, bytesRead);
}
return buffer;
});
};
module.exports = readChunk;
// TODO: Remove this for the next major release
module.exports.default = readChunk;
module.exports.sync = (filePath, startPosition, length) => {
let buffer = Buffer.alloc(length);
const bytesRead = withOpenFile.sync(filePath, 'r', fileDescriptor =>
fs.readSync(fileDescriptor, buffer, 0, length, startPosition)
);
if (bytesRead < length) {
buffer = buffer.slice(0, bytesRead);
}
return buffer;
};