%PDF-
%PDF-
Mini Shell
Mini Shell
// Copyright 2011 Mark Cavage <mcavage@gmail.com> All rights reserved.
var assert = require('assert');
var Buffer = require('safer-buffer').Buffer;
var ASN1 = require('./types');
var errors = require('./errors');
// --- Globals
var newInvalidAsn1Error = errors.newInvalidAsn1Error;
var DEFAULT_OPTS = {
size: 1024,
growthFactor: 8
};
// --- Helpers
function merge(from, to) {
assert.ok(from);
assert.equal(typeof (from), 'object');
assert.ok(to);
assert.equal(typeof (to), 'object');
var keys = Object.getOwnPropertyNames(from);
keys.forEach(function (key) {
if (to[key])
return;
var value = Object.getOwnPropertyDescriptor(from, key);
Object.defineProperty(to, key, value);
});
return to;
}
// --- API
function Writer(options) {
options = merge(DEFAULT_OPTS, options || {});
this._buf = Buffer.alloc(options.size || 1024);
this._size = this._buf.length;
this._offset = 0;
this._options = options;
// A list of offsets in the buffer where we need to insert
// sequence tag/len pairs.
this._seq = [];
}
Object.defineProperty(Writer.prototype, 'buffer', {
get: function () {
if (this._seq.length)
throw newInvalidAsn1Error(this._seq.length + ' unended sequence(s)');
return (this._buf.slice(0, this._offset));
}
});
Writer.prototype.writeByte = function (b) {
if (typeof (b) !== 'number')
throw new TypeError('argument must be a Number');
this._ensure(1);
this._buf[this._offset++] = b;
};
Writer.prototype.writeInt = function (i, tag) {
if (typeof (i) !== 'number')
throw new TypeError('argument must be a Number');
if (typeof (tag) !== 'number')
tag = ASN1.Integer;
var sz = 4;
while ((((i & 0xff800000) === 0) || ((i & 0xff800000) === 0xff800000 >> 0)) &&
(sz > 1)) {
sz--;
i <<= 8;
}
if (sz > 4)
throw newInvalidAsn1Error('BER ints cannot be > 0xffffffff');
this._ensure(2 + sz);
this._buf[this._offset++] = tag;
this._buf[this._offset++] = sz;
while (sz-- > 0) {
this._buf[this._offset++] = ((i & 0xff000000) >>> 24);
i <<= 8;
}
};
Writer.prototype.writeNull = function () {
this.writeByte(ASN1.Null);
this.writeByte(0x00);
};
Writer.prototype.writeEnumeration = function (i, tag) {
if (typeof (i) !== 'number')
throw new TypeError('argument must be a Number');
if (typeof (tag) !== 'number')
tag = ASN1.Enumeration;
return this.writeInt(i, tag);
};
Writer.prototype.writeBoolean = function (b, tag) {
if (typeof (b) !== 'boolean')
throw new TypeError('argument must be a Boolean');
if (typeof (tag) !== 'number')
tag = ASN1.Boolean;
this._ensure(3);
this._buf[this._offset++] = tag;
this._buf[this._offset++] = 0x01;
this._buf[this._offset++] = b ? 0xff : 0x00;
};
Writer.prototype.writeString = function (s, tag) {
if (typeof (s) !== 'string')
throw new TypeError('argument must be a string (was: ' + typeof (s) + ')');
if (typeof (tag) !== 'number')
tag = ASN1.OctetString;
var len = Buffer.byteLength(s);
this.writeByte(tag);
this.writeLength(len);
if (len) {
this._ensure(len);
this._buf.write(s, this._offset);
this._offset += len;
}
};
Writer.prototype.writeBuffer = function (buf, tag) {
if (typeof (tag) !== 'number')
throw new TypeError('tag must be a number');
if (!Buffer.isBuffer(buf))
throw new TypeError('argument must be a buffer');
this.writeByte(tag);
this.writeLength(buf.length);
this._ensure(buf.length);
buf.copy(this._buf, this._offset, 0, buf.length);
this._offset += buf.length;
};
Writer.prototype.writeStringArray = function (strings) {
if ((!strings instanceof Array))
throw new TypeError('argument must be an Array[String]');
var self = this;
strings.forEach(function (s) {
self.writeString(s);
});
};
// This is really to solve DER cases, but whatever for now
Writer.prototype.writeOID = function (s, tag) {
if (typeof (s) !== 'string')
throw new TypeError('argument must be a string');
if (typeof (tag) !== 'number')
tag = ASN1.OID;
if (!/^([0-9]+\.){3,}[0-9]+$/.test(s))
throw new Error('argument is not a valid OID string');
function encodeOctet(bytes, octet) {
if (octet < 128) {
bytes.push(octet);
} else if (octet < 16384) {
bytes.push((octet >>> 7) | 0x80);
bytes.push(octet & 0x7F);
} else if (octet < 2097152) {
bytes.push((octet >>> 14) | 0x80);
bytes.push(((octet >>> 7) | 0x80) & 0xFF);
bytes.push(octet & 0x7F);
} else if (octet < 268435456) {
bytes.push((octet >>> 21) | 0x80);
bytes.push(((octet >>> 14) | 0x80) & 0xFF);
bytes.push(((octet >>> 7) | 0x80) & 0xFF);
bytes.push(octet & 0x7F);
} else {
bytes.push(((octet >>> 28) | 0x80) & 0xFF);
bytes.push(((octet >>> 21) | 0x80) & 0xFF);
bytes.push(((octet >>> 14) | 0x80) & 0xFF);
bytes.push(((octet >>> 7) | 0x80) & 0xFF);
bytes.push(octet & 0x7F);
}
}
var tmp = s.split('.');
var bytes = [];
bytes.push(parseInt(tmp[0], 10) * 40 + parseInt(tmp[1], 10));
tmp.slice(2).forEach(function (b) {
encodeOctet(bytes, parseInt(b, 10));
});
var self = this;
this._ensure(2 + bytes.length);
this.writeByte(tag);
this.writeLength(bytes.length);
bytes.forEach(function (b) {
self.writeByte(b);
});
};
Writer.prototype.writeLength = function (len) {
if (typeof (len) !== 'number')
throw new TypeError('argument must be a Number');
this._ensure(4);
if (len <= 0x7f) {
this._buf[this._offset++] = len;
} else if (len <= 0xff) {
this._buf[this._offset++] = 0x81;
this._buf[this._offset++] = len;
} else if (len <= 0xffff) {
this._buf[this._offset++] = 0x82;
this._buf[this._offset++] = len >> 8;
this._buf[this._offset++] = len;
} else if (len <= 0xffffff) {
this._buf[this._offset++] = 0x83;
this._buf[this._offset++] = len >> 16;
this._buf[this._offset++] = len >> 8;
this._buf[this._offset++] = len;
} else {
throw newInvalidAsn1Error('Length too long (> 4 bytes)');
}
};
Writer.prototype.startSequence = function (tag) {
if (typeof (tag) !== 'number')
tag = ASN1.Sequence | ASN1.Constructor;
this.writeByte(tag);
this._seq.push(this._offset);
this._ensure(3);
this._offset += 3;
};
Writer.prototype.endSequence = function () {
var seq = this._seq.pop();
var start = seq + 3;
var len = this._offset - start;
if (len <= 0x7f) {
this._shift(start, len, -2);
this._buf[seq] = len;
} else if (len <= 0xff) {
this._shift(start, len, -1);
this._buf[seq] = 0x81;
this._buf[seq + 1] = len;
} else if (len <= 0xffff) {
this._buf[seq] = 0x82;
this._buf[seq + 1] = len >> 8;
this._buf[seq + 2] = len;
} else if (len <= 0xffffff) {
this._shift(start, len, 1);
this._buf[seq] = 0x83;
this._buf[seq + 1] = len >> 16;
this._buf[seq + 2] = len >> 8;
this._buf[seq + 3] = len;
} else {
throw newInvalidAsn1Error('Sequence too long');
}
};
Writer.prototype._shift = function (start, len, shift) {
assert.ok(start !== undefined);
assert.ok(len !== undefined);
assert.ok(shift);
this._buf.copy(this._buf, start + shift, start, start + len);
this._offset += shift;
};
Writer.prototype._ensure = function (len) {
assert.ok(len);
if (this._size - this._offset < len) {
var sz = this._size * this._options.growthFactor;
if (sz - this._offset < len)
sz += len;
var buf = Buffer.alloc(sz);
this._buf.copy(buf, 0, 0, this._offset);
this._buf = buf;
this._size = sz;
}
};
// --- Exported API
module.exports = Writer;
Zerion Mini Shell 1.0