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//
// MiscXmodem.m -- XMODEM/YMODEM file transfer over serial line
// Written by W. Eric Norum Copyright (c) 1997 by W. Eric Norum.
// $Revision: 2.1 $ $Date: 1997/04/02 15:32:59 $
// All rights reserved.
// This notice may not be removed from this source code.
//
// This object is included in the MiscKit by permission from the author
// and its use is governed by the MiscKit license, found in the file
// "LICENSE.rtf" in the MiscKit distribution. Please refer to that file
// for a list of all applicable permissions and restrictions.
//
/*
* Xmodem file transfer
*
* Based on ``XMODEM/YMODEM PROTOCOL REFERENCE -- A compendium of documents
* describing the XMODEM and YMODEM File Transfer Protocols'', Chuck Forsberg,
* Omen Technology Incorporated, Portland, Oregon, 1988.
*/
#import <Foundation/NSDictionary.h>
#import "MiscXmodem.h"
/*
* All timeouts are in seconds
*/
#define RECEIVE_INITIAL_TIMEOUT 2
#define RECEIVE_PACKET_TIMEOUT 4
#define RECEIVE_CRC_ADAPT_TIMEOUT 3
#define RECEIVE_PACKET_RETRY_LIMIT 20
#define RECEIVE_CRC_ADAPT_RETRY_LIMIT 8
#define TRANSMIT_TIMEOUT 60
#define TRANSMIT_STARTUP_BAD_NAK_LIMIT 100
#define SOH '\001'
#define STX '\002'
#define EOT '\004'
#define ACK '\006'
#define NAK '\025'
#define CTRLZ '\032'
#define CRC_NAK 'C'
/*
* Define notification names and dictionary keys
*/
NSString *MiscXmodemPacketNotification = @"MiscXmodemPacketNotification";
NSString *MiscXmodemRetryNotification = @"MiscXmodemRetryNotification";
NSString *MiscXmodemCompletionNotification = @"MiscXmodemCompletionNotification";
NSString *MiscXmodemCompletionNotificationDataItem = @"MiscXmodemCompletionNotificationDataItem";
NSString *MiscXmodemCompletionNotificationFailureReason = @"MiscXmodemCompletionNotificationFailureReason";
@implementation MiscXmodem
/*
* Report completion (successful or unsuccessful) of a transfer.
*/
- (void)finishTransferWithErrorString:(NSString *)message
{
NSMutableDictionary *completionDictionary;
completionDictionary = [NSMutableDictionary dictionaryWithCapacity:2];
if (message) {
[completionDictionary setObject:message
forKey:MiscXmodemCompletionNotificationFailureReason];
}
else {
if (isReceiving)
[completionDictionary setObject:data
forKey:MiscXmodemCompletionNotificationDataItem];
}
[[NSNotificationCenter defaultCenter]
postNotificationName:MiscXmodemCompletionNotification
object:self
userInfo:completionDictionary];
[data release];
data = nil;
[timer invalidate];
timer = nil;
transferInProgress = NO;
}
/*
* Send a character
*/
- (void)sendChar:(unsigned char)c
{
if (![self _writeRawBuffer:&c length:1])
[self finishTransferWithErrorString:[self errorString]];
}
/*
* Compute packet checksum
*/
- (void)computeChecksum:(unsigned char *)result
{
unsigned char *cp = &pkBuffer[3];
int length = (pkBuffer[0] == SOH) ? 128 : 1024;
int checksum = 0;
while (length--)
checksum += *cp++;
*result = checksum;
}
/*
* Compute packet CRC
*/
- (void)computeCRC:(unsigned char *)hi lo:(unsigned char *)lo
{
unsigned char *cp = &pkBuffer[3];
int length = (pkBuffer[0] == SOH) ? (128+2) : (1024+2);
int crc = 0;
/*
* The table is the CRC resulting from all possible eight bit
* values shifted out of the top of the register.
*/
static const unsigned short crctab[256] = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};
while (length--) {
unsigned char c = *cp++;
crc = crctab[(((crc)>>8) & 0xFF)] ^ (((crc)<<8) | (c));
}
*hi = crc >> 8;
*lo = crc;
}
/*
* Verify that received packet is correct
*/
- (BOOL)verifyPacket
{
if ((pkBuffer[1] - ~pkBuffer[2]) & 0xFF)
return NO;
if (rxCRC) {
unsigned char lo, hi;
[self computeCRC:&hi lo:&lo];
if (hi || lo)
return NO;
}
else {
int length = (pkBuffer[0] == SOH) ? 128 : 1024;
unsigned char checksum;
[self computeChecksum:&checksum];
if ((pkBuffer[3 + length] - checksum) & 0xFF)
return NO;
}
return YES;
}
/*
* Start the packet reception timer
*/
- (void)startPacketReceptionTimer:(NSTimeInterval)seconds
{
timer = [NSTimer scheduledTimerWithTimeInterval:seconds
target:self
selector:@selector(receiveTimeout:)
userInfo:nil
repeats:NO];
}
/*
* Start the transmit timer
*/
- (void)startTransmitTimer
{
timer = [NSTimer scheduledTimerWithTimeInterval:TRANSMIT_TIMEOUT
target:self
selector:@selector(transmitTimeout:)
userInfo:nil
repeats:NO];
}
/*
* Cancel the timer
*/
- (void)cancelTimer
{
[timer invalidate];
timer = nil;
}
/*
* Create a transmit packet
*/
- (void)makePacket
{
int pkLimit = tx1kPackets ? 1024+3 : 128+3;
unsigned int dataCount = [data length];
char c;
const char *dp = [data bytes];
unsigned int txIndex = txCount;
/*
* All data sent?
*/
if ((txIndex == dataCount) && !txNewline) {
pkBuffer[0] = EOT;
pkIndex = 1;
return;
}
/*
* Fill the data portion of the packet
*/
pkIndex = 3;
for (;;) {
if (txNewline) {
pkBuffer[pkIndex++] = '\n';
txNewline = NO;
if (pkIndex == pkLimit)
break;
}
if (txIndex < dataCount) {
c = dp[txIndex++];
if (isText) {
if (c == '\n') {
c = '\r';
txNewline = YES;
}
}
}
else {
if (tx1kPackets) {
if (pkIndex < (1024 + 3 - 128)) {
/*
* Switch to small packets
*/
tx1kPackets = NO;
if (pkIndex > (128 + 3))
/*
* Send remainder as more than one small packet
*/
[self makePacket];
return;
}
}
c = CTRLZ;
}
pkBuffer[pkIndex++] = c;
if (pkIndex == pkLimit)
break;
}
txCount = txIndex;
/*
* Fill in the packet header
*/
if (tx1kPackets)
pkBuffer[0] = STX;
else
pkBuffer[0] = SOH;
pkBuffer[1] = ++lastPacketNumber;
pkBuffer[2] = ~lastPacketNumber;
/*
* Fill in the packet check
*/
if (txCRC) {
pkBuffer[pkIndex] = 0;
pkBuffer[pkIndex+1] = 0;
[self computeCRC:pkBuffer+pkIndex lo:pkBuffer+pkIndex+1];
pkIndex += 2;
}
else {
[self computeChecksum:pkBuffer+pkIndex];
}
}
/*
* Handle incoming characters by overriding MiscSerialPort observer.
*/
- (void)_serialDataArrived:(NSNotification *)notification
{
NSData *newData;
int newCount;
/*
* Just pass the notification along if it does not apply to us
*/
if (!transferInProgress) {
[super _serialDataArrived:notification];
return;
}
/*
* Continue reading
*/
[fileHandle readInBackgroundAndNotify];
/*
* Get the data
*/
newData = [[notification userInfo] objectForKey:NSFileHandleNotificationDataItem];
newCount = [newData length];
if (newCount == 0)
return;
/*
* Handle the incoming data
*/
if (isReceiving) {
/*
* Ignore data till we are expecting a packet
*/
if (!rxExpectPacket)
return;
/*
* Don't overrun the packet buffer
*/
if (newCount > (sizeof pkBuffer - pkIndex))
newCount = sizeof pkBuffer - pkIndex;
[newData getBytes:pkBuffer + pkIndex length:newCount];
/*
* Are we at the beginning of a packet?
*/
if (pkIndex == 0) {
switch (pkBuffer[0]) {
case SOH:
pkCount = 3 + 128 + (rxCRC ? 2 : 1);
break;
case STX:
pkCount = 3 + 1024 + (rxCRC ? 2 : 1);
break;
case EOT:
[self sendChar:ACK];
[self finishTransferWithErrorString:nil];
return;
}
}
pkIndex += newCount;
if (pkIndex >= pkCount) {
/*
* Reset packet index
* This throws away any extra characters received after the
* end of the packet. Given the interlocked handshaking of
* these protocols there shouldn't be any characters after
* the packet, so tossing any that are there is acceptable.
*/
[self cancelTimer];
pkIndex = 0;
if ([self verifyPacket]) {
/*
* Received the same packet as last time?
* Our ACK must have been lost. Reacknowledge and ignore
* the duplicate packet.
*/
int packetNumber, expectedPacketNumber;
rxSendDynamicCheck = NO;
packetNumber = pkBuffer[1];
if (packetNumber == lastPacketNumber) {
[self sendChar:ACK];
[self startPacketReceptionTimer:RECEIVE_PACKET_TIMEOUT];
return;
}
/*
* Received the correct packet?
* Acknowledge packet and store data
*/
expectedPacketNumber = (lastPacketNumber + 1) & 0xFF;
if (packetNumber == expectedPacketNumber) {
int pkSize = ((pkBuffer[0] == SOH) ? 128 : 1024);
nakCount = 0;
[self sendChar:ACK];
[self startPacketReceptionTimer:RECEIVE_PACKET_TIMEOUT];
lastPacketNumber = packetNumber;
transferByteCount += pkSize;
transferPacketCount++;
if (isText) {
char cbuf[1024], *cp = cbuf;
unsigned char *rp = pkBuffer+3;
while (pkSize--) {
if (*rp == CTRLZ)
break;
if (*rp != '\r')
*cp++ = *rp;
rp++;
}
if (cp != cbuf)
[data appendBytes:cbuf length:cp-cbuf];
}
else {
[data appendBytes:pkBuffer+3 length:pkSize];
}
[[NSNotificationCenter defaultCenter]
postNotificationName:MiscXmodemPacketNotification
object:self];
return;
}
}
/*
* Something is wrong with the packet.
* Wait for the timeout to send a NAK.
* This gives time to flush any other bad incoming characters.
*/
transferRetryCount++;
if (nakCount++ == RECEIVE_PACKET_RETRY_LIMIT) {
[self finishTransferWithErrorString:@"Too many bad packets"];
}
else {
rxExpectPacket = NO;
[self startPacketReceptionTimer:RECEIVE_PACKET_TIMEOUT];
}
}
}
else {
char replyChar = *(const char *)[newData bytes];
[self cancelTimer];
if (lastPacketNumber == 0) {
const char *cp = [newData bytes];
for (;;) {
replyChar = *cp++;
switch (replyChar) {
case '\r':
case '\n':
break;
case NAK:
txCRC = NO;
replyChar = ACK;
break;
case CRC_NAK:
txCRC = YES;
replyChar = ACK;
break;
default:
if (++nakCount == TRANSMIT_STARTUP_BAD_NAK_LIMIT) {
[self finishTransferWithErrorString:
@"Receiver did not send inital NAK"];
return;
}
replyChar = NAK;
break;
}
if (replyChar == ACK) {
pkBuffer[0] = 0;
break;
}
if (--newCount == 0) {
[self startTransmitTimer];
return;
}
}
}
switch (replyChar) {
default:
[self startTransmitTimer];
return;
case ACK:
if (pkBuffer[0] == EOT) {
[self finishTransferWithErrorString:nil];
if (newCount > 1) {
/*
* Pass leftover data to the intended recipient
*/
NSRange leftOver;
leftOver.location = 1;
leftOver.length = newCount - 1;
[[NSNotificationCenter defaultCenter]
postNotificationName:
MiscSerialPortReadCompletionNotification
object:self
userInfo:[NSDictionary dictionaryWithObject:
[newData subdataWithRange:leftOver]
forKey:MiscSerialPortNotificationDataItem]];
}
return;
}
nakCount = 0;
if (lastPacketNumber != 0) {
transferPacketCount++;
transferByteCount += (tx1kPackets ? 1024 : 128);
[[NSNotificationCenter defaultCenter]
postNotificationName:MiscXmodemPacketNotification
object:self];
}
[self makePacket];
break;
case NAK:
nakCount++;
[[NSNotificationCenter defaultCenter]
postNotificationName:MiscXmodemRetryNotification
object:self];
break;
}
if (![self _writeRawBuffer:pkBuffer length:pkIndex]) {
[self finishTransferWithErrorString:[self errorString]];
return;
}
[self startTransmitTimer];
}
}
/*
* Handle a timeout during data transmission
*/
- (void)transmitTimeout:(NSTimer *)t
{
timer = nil;
[self finishTransferWithErrorString:@"Timed out"];
}
/*
* Handle a timeout during data reception
*/
- (void)receiveTimeout:(NSTimer *)t
{
timer = nil;
if (rxSendDynamicCheck) {
if (++nakCount <= RECEIVE_CRC_ADAPT_RETRY_LIMIT) {
[self startPacketReceptionTimer:RECEIVE_CRC_ADAPT_TIMEOUT];
pkIndex = 0;
rxExpectPacket = YES;
[self sendChar:CRC_NAK];
return;
}
rxSendDynamicCheck = NO;
rxCRC = NO;
nakCount = 0;
}
if (++nakCount <= RECEIVE_PACKET_RETRY_LIMIT) {
if (rxExpectPacket) {
transferRetryCount++;
[[NSNotificationCenter defaultCenter]
postNotificationName:MiscXmodemRetryNotification
object:self];
}
[self startPacketReceptionTimer:RECEIVE_PACKET_TIMEOUT];
pkIndex = 0;
rxExpectPacket = YES;
[self sendChar:NAK];
return;
}
[self finishTransferWithErrorString:@"Too many retries"];
}
- (void)xmodemCancelTransfer
{
if (transferInProgress)
[self finishTransferWithErrorString:@"Transfer cancelled"];
}
- (void)dealloc
{
[data release];
[timer invalidate];
[super dealloc];
}
- (BOOL)xmodemStartReceiving
{
if (transferInProgress)
return NO;
pkIndex = 0;
lastPacketNumber = 0;
transferByteCount = 0;
transferPacketCount = 0;
transferRetryCount = 0;
nakCount = 0;
transferInProgress = YES;
isReceiving = YES;
data = [[NSMutableData alloc] initWithCapacity:5000];
if (useDynamicCheck) {
rxSendDynamicCheck = YES;
rxCRC = YES;
}
else {
rxSendDynamicCheck = NO;
rxCRC = useCRC;
}
rxExpectPacket = NO;
[self startPacketReceptionTimer:RECEIVE_INITIAL_TIMEOUT];
return YES;
}
- (BOOL)xmodemStartSending:(NSData *)dataSource
{
if (transferInProgress)
return NO;
data = [dataSource copy];
lastPacketNumber = 0;
transferByteCount = 0;
transferPacketCount = 0;
transferRetryCount = 0;
nakCount = 0;
transferInProgress = YES;
isReceiving = NO;
txCount = 0;
txNewline = NO;
tx1kPackets = use1kPackets;
[self startTransmitTimer];
return YES;
}
- (void)xmodemSetFileTypeText:(BOOL)flag { isText = flag; }
- (void)xmodemSet1kPackets:(BOOL)flag { use1kPackets = flag; }
- (void)xmodemSetCheckTypeDynamic:(BOOL)flag { useDynamicCheck = flag; }
- (void)xmodemSetCheckTypeCRC:(BOOL)flag { useCRC = flag; }
- (BOOL)xmodemIsFileTypeText { return isText; }
- (BOOL)xmodemIs1kPackets { return use1kPackets; }
- (BOOL)xmodemIsCheckTypeDynamic { return useDynamicCheck; }
- (BOOL)xmodemIsCheckTypeCRC { return useCRC; }
- (unsigned int)xmodemTransferPacketCount { return transferPacketCount; }
- (unsigned int)xmodemTransferByteCount { return transferByteCount; }
- (unsigned int)xmodemTransferRetryCount { return transferRetryCount; }
@end
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