You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
65 lines
1.3 KiB
JavaScript
65 lines
1.3 KiB
JavaScript
"use strict";
|
|
|
|
const generateID = require("../../generate-id");
|
|
|
|
const BLOB_INTERNAL = Buffer.from([ 0 ]);
|
|
const BLOB_EXTERNAL = Buffer.from([ 1 ]);
|
|
|
|
module.exports = {
|
|
encode: function (value, _asIndexKey) {
|
|
if (value.length < 256) {
|
|
return {
|
|
value: [
|
|
BLOB_INTERNAL,
|
|
Buffer.from([ value.length ]),
|
|
value
|
|
],
|
|
auxiliaryBlob: undefined
|
|
};
|
|
} else {
|
|
let blobID = generateID();
|
|
|
|
return {
|
|
value: [
|
|
BLOB_EXTERNAL,
|
|
blobID
|
|
],
|
|
auxiliaryBlob: {
|
|
key: blobID,
|
|
value: value
|
|
}
|
|
};
|
|
}
|
|
},
|
|
decode: function (buffer, offset) {
|
|
let blobType = buffer.readUInt8(offset);
|
|
|
|
if (blobType === 0) {
|
|
// Internal blob
|
|
let blobLength = buffer.readUInt8(offset + 1);
|
|
let blobPosition = offset + 2;
|
|
let bytes = buffer.slice(blobPosition, blobPosition + blobLength);
|
|
|
|
return {
|
|
bytesRead: 2 + blobLength,
|
|
value: bytes,
|
|
auxiliaryBlob: undefined
|
|
};
|
|
} else if (blobType === 1) {
|
|
// External blob
|
|
let idPosition = offset + 1;
|
|
|
|
return {
|
|
bytesRead: 13, // a blob ID is always 12 bytes
|
|
value: undefined,
|
|
auxiliaryBlob: {
|
|
key: buffer.slice(idPosition, idPosition + 12),
|
|
transform: (blob) => blob
|
|
}
|
|
};
|
|
} else {
|
|
throw new Error(`Invalid blob type: ${blobType}`);
|
|
}
|
|
}
|
|
};
|