mirror of
https://github.com/permissionlesstech/bitchat.git
synced 2026-07-25 13:45:20 +00:00
Convert JSON protocol to efficient binary format
- Implemented compact binary encoding for packets and messages - Reduced packet size significantly (13-byte fixed header + variable payload) - Optimized for BLE's limited MTU with smaller message sizes - Added BinaryProtocol.swift with encode/decode functions - Updated all message types to use binary serialization - Maintains all existing functionality with better performance
This commit is contained in:
jack
@@ -0,0 +1,320 @@
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import Foundation
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// Binary Protocol Format:
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// Header (Fixed 13 bytes):
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// - Version: 1 byte
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// - Type: 1 byte
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// - TTL: 1 byte
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// - Timestamp: 8 bytes (UInt64)
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// - Flags: 1 byte (bit 0: hasRecipient, bit 1: hasSignature)
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// - PayloadLength: 2 bytes (UInt16)
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//
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// Variable sections:
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// - SenderID: 8 bytes (fixed)
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// - RecipientID: 8 bytes (if hasRecipient flag set)
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// - Payload: Variable length
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// - Signature: 64 bytes (if hasSignature flag set)
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struct BinaryProtocol {
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static let headerSize = 13
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static let senderIDSize = 8
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static let recipientIDSize = 8
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static let signatureSize = 64
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struct Flags {
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static let hasRecipient: UInt8 = 0x01
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static let hasSignature: UInt8 = 0x02
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}
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// Encode BitchatPacket to binary format
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static func encode(_ packet: BitchatPacket) -> Data? {
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var data = Data()
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// Header
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data.append(packet.version)
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data.append(packet.type)
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data.append(packet.ttl)
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// Timestamp (8 bytes, big-endian)
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withUnsafeBytes(of: packet.timestamp.bigEndian) { bytes in
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data.append(contentsOf: bytes)
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}
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// Flags
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var flags: UInt8 = 0
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if packet.recipientID != nil {
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flags |= Flags.hasRecipient
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}
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if packet.signature != nil {
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flags |= Flags.hasSignature
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}
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data.append(flags)
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// Payload length (2 bytes, big-endian)
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let payloadLength = UInt16(packet.payload.count)
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withUnsafeBytes(of: payloadLength.bigEndian) { bytes in
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data.append(contentsOf: bytes)
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}
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// SenderID (exactly 8 bytes)
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let senderBytes = packet.senderID.prefix(senderIDSize)
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data.append(senderBytes)
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if senderBytes.count < senderIDSize {
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data.append(Data(repeating: 0, count: senderIDSize - senderBytes.count))
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}
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// RecipientID (if present)
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if let recipientID = packet.recipientID {
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let recipientBytes = recipientID.prefix(recipientIDSize)
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data.append(recipientBytes)
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if recipientBytes.count < recipientIDSize {
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data.append(Data(repeating: 0, count: recipientIDSize - recipientBytes.count))
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}
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}
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// Payload
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data.append(packet.payload)
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// Signature (if present)
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if let signature = packet.signature {
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data.append(signature.prefix(signatureSize))
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}
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return data
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}
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// Decode binary data to BitchatPacket
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static func decode(_ data: Data) -> BitchatPacket? {
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guard data.count >= headerSize + senderIDSize else { return nil }
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var offset = 0
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// Header
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_ = data[offset]; offset += 1 // version
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let type = data[offset]; offset += 1
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let ttl = data[offset]; offset += 1
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// Timestamp
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let timestamp = data[offset..<offset+8].withUnsafeBytes { bytes in
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bytes.load(as: UInt64.self).bigEndian
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}
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offset += 8
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// Flags
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let flags = data[offset]; offset += 1
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let hasRecipient = (flags & Flags.hasRecipient) != 0
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let hasSignature = (flags & Flags.hasSignature) != 0
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// Payload length
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let payloadLength = data[offset..<offset+2].withUnsafeBytes { bytes in
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bytes.load(as: UInt16.self).bigEndian
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}
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offset += 2
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// Calculate expected total size
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var expectedSize = headerSize + senderIDSize + Int(payloadLength)
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if hasRecipient {
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expectedSize += recipientIDSize
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}
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if hasSignature {
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expectedSize += signatureSize
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}
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guard data.count >= expectedSize else { return nil }
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// SenderID
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let senderID = data[offset..<offset+senderIDSize]
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offset += senderIDSize
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// RecipientID
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var recipientID: Data?
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if hasRecipient {
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recipientID = data[offset..<offset+recipientIDSize]
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offset += recipientIDSize
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}
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// Payload
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let payload = data[offset..<offset+Int(payloadLength)]
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offset += Int(payloadLength)
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// Signature
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var signature: Data?
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if hasSignature {
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signature = data[offset..<offset+signatureSize]
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}
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return BitchatPacket(
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type: type,
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senderID: senderID,
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recipientID: recipientID,
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timestamp: timestamp,
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payload: payload,
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signature: signature,
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ttl: ttl
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)
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}
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}
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// Binary encoding for BitchatMessage
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extension BitchatMessage {
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func toBinaryPayload() -> Data? {
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var data = Data()
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// Message format:
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// - Flags: 1 byte (bit 0: isRelay, bit 1: isPrivate, bit 2: hasOriginalSender, bit 3: hasRecipientNickname, bit 4: hasSenderPeerID)
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// - Timestamp: 8 bytes (seconds since epoch)
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// - ID length: 1 byte
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// - ID: variable
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// - Sender length: 1 byte
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// - Sender: variable
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// - Content length: 2 bytes
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// - Content: variable
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// Optional fields based on flags:
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// - Original sender length + data
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// - Recipient nickname length + data
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// - Sender peer ID length + data
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var flags: UInt8 = 0
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if isRelay { flags |= 0x01 }
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if isPrivate { flags |= 0x02 }
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if originalSender != nil { flags |= 0x04 }
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if recipientNickname != nil { flags |= 0x08 }
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if senderPeerID != nil { flags |= 0x10 }
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data.append(flags)
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// Timestamp
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let timestampSeconds = UInt64(timestamp.timeIntervalSince1970)
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withUnsafeBytes(of: timestampSeconds.bigEndian) { bytes in
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data.append(contentsOf: bytes)
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}
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// ID
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if let idData = id.data(using: .utf8) {
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data.append(UInt8(min(idData.count, 255)))
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data.append(idData.prefix(255))
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} else {
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data.append(0)
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}
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// Sender
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if let senderData = sender.data(using: .utf8) {
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data.append(UInt8(min(senderData.count, 255)))
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data.append(senderData.prefix(255))
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} else {
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data.append(0)
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}
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// Content
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if let contentData = content.data(using: .utf8) {
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let length = UInt16(min(contentData.count, 65535))
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withUnsafeBytes(of: length.bigEndian) { bytes in
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data.append(contentsOf: bytes)
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}
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data.append(contentData.prefix(Int(length)))
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} else {
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data.append(contentsOf: [0, 0])
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}
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// Optional fields
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if let originalSender = originalSender, let origData = originalSender.data(using: .utf8) {
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data.append(UInt8(min(origData.count, 255)))
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data.append(origData.prefix(255))
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}
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if let recipientNickname = recipientNickname, let recipData = recipientNickname.data(using: .utf8) {
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data.append(UInt8(min(recipData.count, 255)))
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data.append(recipData.prefix(255))
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}
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if let senderPeerID = senderPeerID, let peerData = senderPeerID.data(using: .utf8) {
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data.append(UInt8(min(peerData.count, 255)))
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data.append(peerData.prefix(255))
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}
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return data
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}
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static func fromBinaryPayload(_ data: Data) -> BitchatMessage? {
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guard data.count >= 13 else { return nil } // Minimum size
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var offset = 0
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// Flags
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let flags = data[offset]; offset += 1
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let isRelay = (flags & 0x01) != 0
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let isPrivate = (flags & 0x02) != 0
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let hasOriginalSender = (flags & 0x04) != 0
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let hasRecipientNickname = (flags & 0x08) != 0
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let hasSenderPeerID = (flags & 0x10) != 0
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// Timestamp
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let timestampSeconds = data[offset..<offset+8].withUnsafeBytes { bytes in
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bytes.load(as: UInt64.self).bigEndian
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}
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offset += 8
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let timestamp = Date(timeIntervalSince1970: TimeInterval(timestampSeconds))
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// ID
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let idLength = Int(data[offset]); offset += 1
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guard offset + idLength <= data.count else { return nil }
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_ = String(data: data[offset..<offset+idLength], encoding: .utf8) ?? UUID().uuidString
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offset += idLength
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// Sender
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guard offset < data.count else { return nil }
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let senderLength = Int(data[offset]); offset += 1
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guard offset + senderLength <= data.count else { return nil }
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let sender = String(data: data[offset..<offset+senderLength], encoding: .utf8) ?? "unknown"
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offset += senderLength
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// Content
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guard offset + 2 <= data.count else { return nil }
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let contentLength = data[offset..<offset+2].withUnsafeBytes { bytes in
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Int(bytes.load(as: UInt16.self).bigEndian)
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}
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offset += 2
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guard offset + contentLength <= data.count else { return nil }
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let content = String(data: data[offset..<offset+contentLength], encoding: .utf8) ?? ""
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offset += contentLength
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// Optional fields
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var originalSender: String?
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if hasOriginalSender && offset < data.count {
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let length = Int(data[offset]); offset += 1
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if offset + length <= data.count {
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originalSender = String(data: data[offset..<offset+length], encoding: .utf8)
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offset += length
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}
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}
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var recipientNickname: String?
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if hasRecipientNickname && offset < data.count {
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let length = Int(data[offset]); offset += 1
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if offset + length <= data.count {
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recipientNickname = String(data: data[offset..<offset+length], encoding: .utf8)
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offset += length
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}
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}
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var senderPeerID: String?
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if hasSenderPeerID && offset < data.count {
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let length = Int(data[offset]); offset += 1
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if offset + length <= data.count {
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senderPeerID = String(data: data[offset..<offset+length], encoding: .utf8)
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offset += length
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}
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}
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return BitchatMessage(
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sender: sender,
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content: content,
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timestamp: timestamp,
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isRelay: isRelay,
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originalSender: originalSender,
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isPrivate: isPrivate,
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recipientNickname: recipientNickname,
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senderPeerID: senderPeerID
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)
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}
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}
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@@ -34,11 +34,11 @@ struct BitchatPacket: Codable {
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}
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var data: Data? {
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try? JSONEncoder().encode(self)
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BinaryProtocol.encode(self)
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}
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static func from(_ data: Data) -> BitchatPacket? {
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try? JSONDecoder().decode(BitchatPacket.self, from: data)
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BinaryProtocol.decode(data)
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}
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}
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