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// SDLSmartDeviceLinkV2ProtocolHeader.m
//
#import "SDLV2ProtocolHeader.h"
const int V2PROTOCOL_HEADERSIZE = 12;
@interface SDLV2ProtocolHeader ()
@end
@implementation SDLV2ProtocolHeader
- (instancetype)init {
// TODO: Should this be changed to whatever the current version is from SDLGlobals
return [self initWithVersion:2];
}
- (instancetype)initWithVersion:(UInt8)version {
if (self = [super init]) {
_version = version;
_size = V2PROTOCOL_HEADERSIZE;
}
return self;
}
- (NSData *)data {
// Assembles the properties in the binary header format
Byte headerBytes[V2PROTOCOL_HEADERSIZE] = {0};
Byte version = (self.version & 0xF) << 4; // first 4 bits
Byte encrypted = (self.encrypted ? 1 : 0) << 3; // next 1 bit
Byte frameType = (self.frameType & 0x7); // last 3 bits
headerBytes[0] = version | encrypted | frameType;
headerBytes[1] = self.serviceType;
headerBytes[2] = self.frameData;
headerBytes[3] = self.sessionID;
// Need to write these ints as big-endian.
UInt32 *p = (UInt32 *)&headerBytes[4];
*p = CFSwapInt32HostToBig(self.bytesInPayload);
p = (UInt32 *)&headerBytes[8];
*p = CFSwapInt32HostToBig(self.messageID);
// Now put it all in an NSData object.
NSData *dataOut = [NSData dataWithBytes:headerBytes length:V2PROTOCOL_HEADERSIZE];
return dataOut;
}
- (id)copyWithZone:(NSZone *)zone {
SDLV2ProtocolHeader *newHeader = [[SDLV2ProtocolHeader allocWithZone:zone] init];
newHeader->_version = self.version;
newHeader.encrypted = self.encrypted;
newHeader.frameType = self.frameType;
newHeader.serviceType = self.serviceType;
newHeader.frameData = self.frameData;
newHeader.bytesInPayload = self.bytesInPayload;
newHeader.sessionID = self.sessionID;
newHeader.messageID = self.messageID;
return newHeader;
}
- (void)parse:(NSData *)data {
NSParameterAssert(data != nil);
NSAssert(data.length >= _size, @"Error: insufficient data available to parse V2 header.");
Byte *bytePointer = (Byte *)data.bytes;
Byte firstByte = bytePointer[0];
self.encrypted = ((firstByte & 8) != 0);
self.frameType = (firstByte & 7);
self.serviceType = bytePointer[1];
self.frameData = bytePointer[2];
self.sessionID = bytePointer[3];
UInt32 *uintPointer = (UInt32 *)data.bytes;
self.bytesInPayload = CFSwapInt32BigToHost(uintPointer[1]); // Data is coming in in big-endian, so swap it.
self.messageID = CFSwapInt32BigToHost(uintPointer[2]); // Data is coming in in big-endian, so swap it.
}
- (NSString *)description {
NSString *frameTypeString = nil;
if (self.frameType >= 0 && self.frameType <= 3) {
NSArray<NSString *> *frameTypeNames = @[@"Control", @"Single", @"First", @"Consecutive"];
frameTypeString = frameTypeNames[self.frameType];
}
NSString *frameDataString = nil;
if (self.frameType == SDLFrameType_Control) {
if (self.frameData >= 0 && self.frameData <= 5) {
NSArray<NSString *> *controlFrameDataNames = @[@"Heartbeat", @"StartSession", @"StartSessionACK", @"StartSessionNACK", @"EndSession", @"EndSessionNACK"];
frameDataString = controlFrameDataNames[self.frameData];
} else {
frameDataString = @"Reserved";
}
} else if (self.frameType == SDLFrameType_Single || self.frameType == SDLFrameType_First) {
frameDataString = @"Reserved";
} else if (self.frameType == SDLFrameType_Consecutive) {
frameDataString = @"Frame#";
}
NSMutableString *description = [[NSMutableString alloc] init];
[description appendFormat:@"Version:%i, compressed:%i, frameType:%@(%i), serviceType:%i, frameData:%@(%i), sessionID:%i, dataSize:%i, messageID:%i ",
self.version,
self.encrypted,
frameTypeString,
self.frameType,
self.serviceType,
frameDataString,
self.frameData,
self.sessionID,
(unsigned int)self.bytesInPayload,
(unsigned int)self.messageID];
return description;
}
@end
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