Release 1.0  Copyright ã 1994 Eric Norum.  All rights reserved.

MiscXmodem 

Inherits From:	Object

Declared In:	<misckit/MiscXmodem.h>

Class Description

The MiscXmodem class implements the XMODEM, XMODEM-CRC and XMODEM-1k-CRC serial-line file transfer prtocols.  A complete description of these protocols can be found in, XMODEM/YMODEM PROTOCOL REFERENCE -- A compendium of documents describing the XMODEM and YMODEM File Transfer Protocols, Chuck Forsberg, Omen Technology Incorporated, Portland, Oregon, 1988.

Objects of this class do not modify the serial line settings in any way.  Before invoking the data transfer methods (sendSerialPort:toStream:, sendStream:toSerialPort:) the serial line must be configured to provide an 8-bit-clean path at the appropriate speed. 

MiscXmodem objects are multithreaded but the sub-thread makes no Objective-C calls, so applications using these objects do not have to call objc_setMultithreaded().  Applications should however use cthread_errno() rather than errno, at least while data transfer is in progress.

Instance Variables

BOOL isActive;
BOOL isText;
BOOL use1kPackets;
BOOL isDynamicCheck;
BOOL useCRC;
MiscSerialPort *serialPort;
BOOL serialPortWasSuspended;
int fd;
fd_set checkFdSet;
NXStream *stream;
cthread_t xmodemThread;
port_t messagePort;
port_t replyPort;
id delegate;
unsigned char packetBuffer[1024+5];
unsigned char smallPacketData[1024];
int smallPacketIndex;
int smallPacketCount;
BOOLnewlineFlag;
BOOL isDynamicCheckPacket;
int lastPacketNumber;
int goodPacketCount;
float kbytes;

isActive 	YES if a data transfer operation in in progress.

isText 	YES if data will be treated as ASCII text.

use1kPackets 	YES if data transmission will use large packets.

isDynamicCheck 	YES if error checking method will be determined dynamically.

useCRC 	YES if 16-bit CRC error checking method is in use.

MiscSerialPort	Serial port object to be used for data transfer.

serialPortWasSuspended	Remember whether or not to continue serial port object when data transfer is complete.

fd	Serial line file descriptor.

checkFdSet	Select(2) file descriptor bitmap.

stream	The stream to be used for data transfer.

xmodemThread	Data transfer thread.

messagePort	Mach port for messages from data transfer thread to main thread.

replyPort	Mach port for messages from main thread to data transfer thread.

delegate 	The object that responds to notification messages.

packetBuffer 	Current incoming or outgoing packet.

smallPacketData 	Storage for small packet transmission.

smallPacketIndex 	Index of next small packet data item to transmit.

smallPacketCount 	Number of data bytes in smallPacketData.

newlineFlag 	YES if a newline character needs to be transmitted (text mode data transfers).

isDynamicCheckPacket 	YES if the next packet will be used to determine the error-checking method.

lastPacketNumber 	Packet number (0-255) of most recent successfully-received packet.

goodPacketCount 	Number of packets successfully transferred.

kbytes 	Number of kbytes of data successfully transferred.

Method Types

Initializing and freeing instances	- init
	- free
	
Data transfer options	- setFileTypeText:
	- xmodemSet1kPackets:
	- xmodemSetCheckTypeDynamic:
	- xmodemSetCheckTypeCRC:
	- isFileTypeText
	- xmodemIs1kPackets
	- xmodemIsCheckTypeDynamic
	- xmodemIsCheckTypeCRC

Data transfer operations	- sendToSerialPort:fromStream:
	- sendToStream:fromSerialPort:
	- isActive

Delegate	- setDelegate:
	- delegate
	- didTransferPacket:kbytes:
	- didRetryNumber:
	- didFinish:

Instance Methods

delegate
-delegate

Returns the object's delegate.

free
-free

Cancels the data transfer operation, if any, and frees the object.

init
-init

Initializes a new MiscXmodem instance.  The default settings are text files, 1k packets, and dynamic selection of error checking method.

setDelegate:
-setDelegate:id 

Sets the object's delegate.  Delegate objects are sent messages describing the progress of data transfer operations.

See also: - didFinish:, - didTransferPacket:kbytes:,  - didRetryNumber:

didFinish:
-didFinish:(const char *)failureCode 

Sent to the delegate when data transfer operation completes.  If the transfer completed successfully, the failureCode string will be empty (""), otherwise the string will describe the condition that caused the transfer to fail.

didRetryNumber:
-didRetryNumber:(int)anInt 

Sent to the delegate when the data transfer operation retries a packet transfer.  The argument is the number of times that the current packet has been retried.

didTransferPacket:kbytes:
-didTransferPacket:(int)anInt kbytes:(float)aFloat 

Sent to the delegate when the a packet is successfully transferred.  The arguments are the number of packets and the amount of data (in kbytes) that have been transferred so far.

xmodemIs1kPackets
-(BOOL)xmodemIs1kPackets

Returns YES if data transmission will use 1k packets, NO if it will use only 128-byte packets.  The default value is YES.

See also: - xmodemSet1kPackets:

isActive
-(BOOL)isActive

Returns YES if the MiscXmodem object is in the process of transferring data between the seria port and the stream, NO if it is not.

See also: - sendFromSerialPort:toStream:, - sendFromStream:toSerialPort:, - xmodemIsDone:

xmodemIsCheckTypeCRC
-(BOOL)xmodemIsCheckTypeCRC

Returns YES if data reception will use CRC error checking, NO if it will use a checksum.  The default value is YES.

See also: - xmodemSet1kPackets:, - xmodemSetDynamicCheck:

xmodemIsCheckTypeDynamic
-(BOOL)xmodemIsCheckTypeDynamic

Returns YES if data reception will first attempt to use CRC error checking and automatically revert to use a checksum if the sender does not support CRC error checking.  Returns NO if data reception will not dynamically  adapt to the sender's preference.  The default value is YES.

See also: - xmodemSetDynamicCheck, - xmodemSet1kPackets

isFileTypeText
-(BOOL)isFileTypeText

Returns YES if data transfer will convert files to/from DOS text format.  Returns NO if data will be transferred unmodified.

See also: - setFileTypeText

sendToStream:fromSerialPort:
-sendToStream:(NXStream *)aStream fromSerialPort:(int)ttyFd 

Spawns a subthread to perform a data reception operation and returns self if a transfer is not already in progress. Does nothing, and returns nil, if a transfer is already in progress.  The application must not use the stream or the tty until the transfer is complete.

See also: - isActive, - didFinish:, - didTransferPacket:kbytes:,  - didRetryNumber:

sendToSerialPort:fromStream:
-sendToSerialPort:(int)ttyFd fromStream:(NXStream *)aStream 

Spawns a subthread to perform a data transmission operation and returns self if a transfer is not already in progress. Does nothing, and returns nil, if a transfer is already in progress.  The application must not use the stream or the tty until the transfer is complete.

See also: - isActive, - didFinish:, - didTransferPacket:kbytes:,  - didRetryNumber:

xmodemSet1kPackets:
-xmodemSet1kPackets:(BOOL)flag 

Control the use of 1k packets when transmitting.  If flag is YES, 1-kbyte packets will be transmitted until there are fewer than 1024 bytes left to send at which point 128-byte packets will be used.  If flag is NO, only 128-byte packets will be used. Both 128-byte and 1-kbyte packets are always accepted when receiving.    

See also: - xmodemIs1kPackets

xmodemSetCheckTypeCRC:
-xmodemSetCheckTypeCRC:(BOOL)flag 

Select the error checking method to be used.  If flag is YES, a 16-bit CRC error checking code will be used.  If flag is NO, a simple 8-bit checksum will be used.  This option is used only when receiving a file, since data transmission operations always adapts to the check method chosen by the receiver.

See also: - xmodemIsCheckTypeCRC, -xmodemSetCheckTypeDynamic

xmodemSetCheckTypeDynamic:
-xmodemSetCheckTypeDynamic:(BOOL)flag 

If flag is YES, data reception operations will first try to use a 16-bit CRC error checking code.  If the sender does not support CRC, the receiver will automatically revert to an 8-bit checksum.  If flag is YES, data reception operations will use the check method specified by xmodemSetCheckTypeCRC:.

See also: - xmodemIsCheckTypeDynamic, -xmodemSetCheckTypeCRC:

setFileTypeText:
-setFileTypeText:(BOOL)flag 

Controls the interpretation of transferred data.  If flag is NO, data will be transferred unmodified.  Data will be padded to a 128-byte boundary so the contents of a data transfer operation can grow by up to 127 bytes.  If flag is YES, data will be transferred in DOS text format.  On transmission, <newline> characters will be converted to <carriage return><newline> pairs and a control-Z character (ASCII 032) will be used to mark the end of the data.  On reception,
<carriage return> characters will be removed and a control-Z and subsequent characters will not be added to the stream.

See also: - isFileTypeText