Files
opensim/OpenSim/Addons/os-webrtc-janus/Janus/BHasher.cs
2026-02-22 20:15:34 +00:00

429 lines
16 KiB
C#

/*
* Copyright (c) Contributors, http://opensimulator.org/
* See CONTRIBUTORS.TXT for a full list of copyright holders.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the OpenSimulator Project nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
namespace osWebRtcVoice
{
// There are several different hashing systems ranging from int's to SHA versions.
// The model here is to create a hasher of the desired type, do Add's of things to
// hash, and complete with a Finish() to return a BHash that contains the hash value.
// Since some hash functions are incremental (doing Add's) while some are buffer
// oriented (create a hash of a byte buffer), the interface is built to cover both.
// Some optimizations are implemented internally (like not copying the buffer
// for buffer based hashers if Finish(bytes) is used).
//
// var hasher = new BHashSHA256();
// BHash bHash = hasher.Finish(buffer);
// byte[] theHash = bHash.ToByte();
//
// Note that BHash has IEquatable and IComparible so it can be used in Dictionaries
// and sorted Lists.
//
// The C# GetHashCode() method returns an int that is usually based on location.
// Signatures should really be at least 64 bits so these routines generate
// ulong's for hashes and fold them to make the int for GetHashCode().
// Create a BHasher, do a bunch of 'Add's, then Finish().
public interface IBHasher {
// Create a new object implementing BHasher, then Add values to be hashed
void Add(byte c);
void Add(ushort c);
void Add(uint c);
void Add(ulong c);
void Add(float c);
void Add(byte[] c, int offset, int len);
void Add(string c);
void Add(BHash c);
BHash Finish();
// Finish and add byte array.
// If no Add's before, can do the hashing without copying the byte array
BHash Finish(byte[] c);
BHash Finish(byte[] c, int offset, int len);
// Get the hash code after doing a Finish()
BHash Hash();
}
// ======================================================================
// BHasher computes a BHash which holds the hash value after Finish() is called.
public abstract class BHash : IEquatable<BHash>, IComparable<BHash> {
public abstract override string ToString();
public abstract byte[] ToBytes();
public abstract ulong ToULong(); // returns the hash of the hash if not int based hash
public abstract bool Equals(BHash other);
public abstract int CompareTo(BHash obj);
// public abstract int Compare(BHash x, BHash y); // TODO: do we need this function?
public abstract override int GetHashCode(); // to match the C# standard hash function
}
// A hash that is an UInt64
public class BHashULong : BHash {
protected ulong _hash;
public BHashULong() {
_hash = 5131;
}
public BHashULong(ulong initialHash) {
_hash = initialHash;
}
// the .NET GetHashCode uses an int. Make conversion easy.
public BHashULong(int initialHash) {
_hash = (ulong)initialHash;
}
public override string ToString() {
return _hash.ToString();
}
public override byte[] ToBytes() {
return BitConverter.GetBytes(_hash);
}
public override ulong ToULong() {
return _hash;
}
public override bool Equals(BHash other) {
bool ret = false;
if (other != null) {
BHash bh = other as BHashULong;
if (bh != null) {
ret = _hash.Equals(bh.ToULong());
}
}
return ret;
}
public override int CompareTo(BHash other) {
int ret = 1;
if (other != null) {
if (other is BHashULong bh) {
ret = _hash.CompareTo(bh.ToULong());
}
}
return ret;
}
public override int GetHashCode() {
ulong upper = (_hash >> 32) & 0xffffffff;
ulong lower = _hash & 0xffffffff;
return (int)(upper ^ lower);
}
}
// A hash that is an array of bytes
public class BHashBytes : BHash {
private readonly byte[] _hash;
public BHashBytes() {
_hash = new byte[0];
}
public BHashBytes(byte[] initialHash) {
_hash = initialHash;
}
public override string ToString() {
// BitConverter puts a hyphen between each byte. Remove them
return BitConverter.ToString(_hash).Replace("-", String.Empty);
}
public override byte[] ToBytes() {
return _hash;
}
public override ulong ToULong() {
return this.MakeHashCode();
}
public override bool Equals(BHash other) {
bool ret = false;
if (other != null) {
BHash bh = other as BHashBytes;
if (bh != null) {
ret = _hash.Equals(bh.ToBytes());
}
}
return ret;
}
public override int CompareTo(BHash other) {
int ret = 1;
if (other != null) {
BHash bh = other as BHashBytes;
if (bh != null) {
byte[] otherb = bh.ToBytes();
if (_hash.Length != otherb.Length) {
ret = _hash.Length.CompareTo(otherb.Length);
}
else {
ret = 0; // start off assuming they are equal
for (int ii = 0; ii < _hash.Length; ii++) {
ret = _hash[ii].CompareTo(otherb[ii]);
if (ret != 0) break;
}
}
}
}
return ret;
}
public override int GetHashCode()
{
ulong hashhash = this.MakeHashCode();
ulong upper = (hashhash >> 32 )& 0xffffffff;
ulong lower = hashhash & 0xffffffff;
return (int)(upper ^ lower);
}
public ulong MakeHashCode() {
ulong h = 5381;
for (int ii = 0; ii < _hash.Length; ii++) {
h = ((h << 5) + h) + (ulong)(_hash[ii]);
}
return h;
}
}
// ======================================================================
// ======================================================================
public abstract class BHasher : IBHasher
{
public BHasher() {
}
public abstract void Add(byte c);
public abstract void Add(ushort c);
public abstract void Add(uint c);
public abstract void Add(ulong c);
public abstract void Add(float c);
public abstract void Add(byte[] c, int offset, int len);
public abstract void Add(string c);
public abstract void Add(BHash c);
public abstract BHash Finish();
public abstract BHash Finish(byte[] c);
public abstract BHash Finish(byte[] c, int offset, int len);
public abstract BHash Hash();
}
// A hasher that builds up a buffer of bytes ('building') and then hashes over same
public abstract class BHasherBytes : BHasher {
protected byte[] building;
protected int buildingLoc;
protected int allocStep = 1024;
public BHasherBytes() : base() {
building = new byte[allocStep];
buildingLoc = 0;
}
private byte[] oneByte = new byte[1];
public override void Add(byte c) {
oneByte[0] = c;
AddBytes(oneByte, 0, 1);
}
public override void Add(ushort c) {
byte[] bytes = BitConverter.GetBytes(c);
AddBytes(bytes, 0, bytes.Length);
}
public override void Add(uint c) {
byte[] bytes = BitConverter.GetBytes(c);
AddBytes(bytes, 0, bytes.Length);
}
public override void Add(ulong c) {
byte[] bytes = BitConverter.GetBytes(c);
AddBytes(bytes, 0, bytes.Length);
}
public override void Add(float c) {
byte[] bytes = BitConverter.GetBytes(c);
AddBytes(bytes, 0, bytes.Length);
}
public override void Add(byte[] c, int offset, int len) {
AddBytes(c, offset, len);
}
public override void Add(string c)
{
byte[] bytes = Encoding.UTF8.GetBytes(c);
AddBytes(bytes, 0, bytes.Length);
}
public override void Add(BHash c) {
byte[] bytes = c.ToBytes();
AddBytes(bytes, 0, bytes.Length);
}
// Implemented by derived class
// public abstract BHash Finish();
// Helper function for simple byte array
public override BHash Finish(byte[] c) {
return this.Finish(c, 0, c.Length);
}
// Implemented by derived class
// public abstract BHash Finish(byte[] c, int offset, int len);
// Implemented by derived class
// public abstract BHash Hash();
// Add the given number of bytes to the byte array being built
protected void AddBytes(byte[] addition, int offset, int len) {
// byte[] tempBytes = new byte[len]; // DEBUG DEBUG
// Array.Copy(addition, offset, tempBytes, 0, len); // DEBUG DEBUG
// System.Console.WriteLine(String.Format("AddBytes: offset={0}, len={1}, bytes={2}", // DEBUG DEBUG
// offset, len, BitConverter.ToString(tempBytes).Replace("-", String.Empty))); // DEBUG DEBUG
if (len < 0 || offset < 0 || addition == null) {
throw new ArgumentException(String.Format("BHasherBytes.AddBytes: Bad parameters. offset={0}, len={1}",
offset, len));
}
if (offset + len > addition.Length) {
throw new ArgumentException(String.Format("BHasherBytes.AddBytes: addition parameters off end of array. addition.len={0}, offset={1}, len={2}",
addition.Length, offset, len));
}
if (len > 0) {
if (buildingLoc + len > building.Length) {
// New data requires expanding the data buffer
byte[] newBuilding = new byte[buildingLoc + len + allocStep];
Buffer.BlockCopy(building, 0, newBuilding, 0, buildingLoc);
building = newBuilding;
}
Buffer.BlockCopy(addition, offset, building, buildingLoc, len);
buildingLoc += len;
}
}
}
// ======================================================================
// ULong hash code taken from Meshmerizer
public class BHasherMdjb2 : BHasherBytes, IBHasher {
BHashULong hash = new BHashULong();
public BHasherMdjb2() : base() {
}
public override BHash Finish() {
hash = new BHashULong(ComputeMdjb2Hash(building, 0, buildingLoc));
return hash;
}
public override BHash Finish(byte[] c, int offset, int len) {
if (building.Length > 0) {
AddBytes(c, offset, len);
hash = new BHashULong(ComputeMdjb2Hash(building, 0, buildingLoc));
}
else {
// if no 'Add's were done, don't copy the input data
hash = new BHashULong(ComputeMdjb2Hash(c, offset, len));
}
return hash;
}
private ulong ComputeMdjb2Hash(byte[] c, int offset, int len) {
ulong h = 5381;
for (int ii = offset; ii < offset+len; ii++) {
h = ((h << 5) + h) + (ulong)(c[ii]);
}
return h;
}
public override BHash Hash() {
return hash;
}
}
// ======================================================================
public class BHasherMD5 : BHasherBytes, IBHasher {
BHashBytes hash = new BHashBytes();
public BHasherMD5() : base() {
}
public override BHash Finish() {
MD5 md5 = MD5.Create();
hash = new BHashBytes(md5.ComputeHash(building, 0, buildingLoc));
return hash;
}
public override BHash Finish(byte[] c) {
return this.Finish(c, 0, c.Length);
}
public override BHash Finish(byte[] c, int offset, int len) {
MD5 md5 = MD5.Create();
if (building.Length > 0) {
AddBytes(c, offset, len);
hash = new BHashBytes(md5.ComputeHash(building, 0, buildingLoc));
}
else {
// if no 'Add's were done, don't copy the input data
hash = new BHashBytes(md5.ComputeHash(c, offset, len));
}
return hash;
}
public override BHash Hash() {
return hash;
}
}
// ======================================================================
public class BHasherSHA256 : BHasherBytes, IBHasher {
BHashBytes hash = new BHashBytes();
public BHasherSHA256() : base() {
}
public override BHash Finish() {
using (SHA256 SHA256 = SHA256.Create()) {
hash = new BHashBytes(SHA256.ComputeHash(building, 0, buildingLoc));
}
return hash;
}
public override BHash Finish(byte[] c) {
return this.Finish(c, 0, c.Length);
}
public override BHash Finish(byte[] c, int offset, int len) {
using (SHA256 SHA256 = SHA256.Create()) {
if (buildingLoc > 0) {
AddBytes(c, offset, len);
hash = new BHashBytes(SHA256.ComputeHash(building, 0, buildingLoc));
}
else {
// if no 'Add's were done, don't copy the input data
hash = new BHashBytes(SHA256.ComputeHash(c, offset, len));
}
}
return hash;
}
public override BHash Hash() {
return hash;
}
}
}