ndn-js
Version:
A JavaScript client library for Named Data Networking
105 lines (94 loc) • 3.77 kB
JavaScript
/**
* Copyright (C) 2013-2019 Regents of the University of California.
* @author: Jeff Thompson <jefft0@remap.ucla.edu>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
* A copy of the GNU Lesser General Public License is in the file COPYING.
*/
/** @ignore */
var Blob = require('./blob.js').Blob;
/**
* A SignedBlob extends Blob to keep the offsets of a signed portion (e.g., the
* bytes of Data packet). This inherits from Blob, including Blob.size and Blob.buf.
* @param {Blob|Buffer|Array<number>} value (optional) If value is a Blob, take
* another pointer to the Buffer without copying. If value is a Buffer or byte
* array, copy to create a new Buffer. If omitted, buf() will return null.
* @param {number} signedPortionBeginOffset (optional) The offset in the
* encoding of the beginning of the signed portion. If omitted, set to 0.
* @param {number} signedPortionEndOffset (optional) The offset in the encoding
* of the end of the signed portion. If omitted, set to 0.
* @constructor
*/
var SignedBlob = function SignedBlob(value, signedPortionBeginOffset, signedPortionEndOffset)
{
// Call the base constructor.
Blob.call(this, value);
if (this.buffer == null) {
this.signedPortionBeginOffset = 0;
this.signedPortionEndOffset = 0;
}
else if (typeof value === 'object' && value instanceof SignedBlob) {
// Copy the SignedBlob, allowing override for offsets.
this.signedPortionBeginOffset = signedPortionBeginOffset == null ?
value.signedPortionBeginOffset : signedPortionBeginOffset;
this.signedPortionEndOffset = signedPortionEndOffset == null ?
value.signedPortionEndOffset : signedPortionEndOffset;
}
else {
this.signedPortionBeginOffset = signedPortionBeginOffset || 0;
this.signedPortionEndOffset = signedPortionEndOffset || 0;
}
if (this.buffer == null)
this.signedBuffer = null;
else
this.signedBuffer = this.buffer.slice
(this.signedPortionBeginOffset, this.signedPortionEndOffset);
};
SignedBlob.prototype = new Blob();
SignedBlob.prototype.name = "SignedBlob";
exports.SignedBlob = SignedBlob;
/**
* Return the length of the signed portion of the immutable byte array.
* @return {number} The length of the signed portion. If signedBuf() is null,
* return 0.
*/
SignedBlob.prototype.signedSize = function()
{
if (this.signedBuffer != null)
return this.signedBuffer.length;
else
return 0;
};
/**
* Return a the signed portion of the immutable byte array.
* @return {Buffer} A slice into the Buffer which is the signed portion.
* If the pointer to the array is null, return null.
*/
SignedBlob.prototype.signedBuf = function() { return this.signedBuffer; };
/**
* Return the offset in the array of the beginning of the signed portion.
* @return {number} The offset in the array.
*/
SignedBlob.prototype.getSignedPortionBeginOffset = function()
{
return this.signedPortionBeginOffset;
};
/**
* Return the offset in the array of the end of the signed portion.
* @return {number} The offset in the array.
*/
SignedBlob.prototype.getSignedPortionEndOffset = function()
{
return this.signedPortionEndOffset;
};