September 1990/XMODEM, XMODEM-1K, And XMODEM/CRC/Listing 1
/*--------------------------------------------
XMODEM.H
Author Date Description
-------------------------------------
Jon Ward 22 Apr 90 Initial Revision.
--------------------------------------------*/
#ifndef XMODEM_H
#define XMODEM_H
/*--------------------------------------------
Xmodem Transfer Errors
--------------------------------------------*/
enum xmodem_errors
{
XERR_OK, /* No errors */
XERR_XMIT_FUNC, /* NULL Transmit function pointer */
XERR_RCVR_FUNC, /* NULL Receive function pointer */
XERR_RCVR_CANCEL, /* Receiver cancelled the transfer */
XERR_SEND_CANCEL, /* Sender cancelled the transfer */
XERR_USER CANCEL, /* User cancelled the transfer */
XERR_FILE_READ, /* Error reading the file */
XERR_FILE_WRITE, /* Error writing the file */
XERR_ACK_TIMEOUT, /* Timed out waiting for data pack ACK */
XERR_NAK_TIMEOUT, /* Timed out waiting for initial NAK */
XERR_SOH_TIMEOUT, /* Timed out waiting for SOH */
XERR_DATA_TIMEOUT, /* Timed out waiting for data */
XERR_LAST_ACK_TIMEOUT,/* Timed out waiting for final ACK */
XERR_INVALID_SOH, /* Invalid char waiting for SOH */
XERR_INVALID_BLOCK_NUM,/* Block mismatch in packet header */
XERR_INVALID_CRC, /* CRC is incorrect */
XERR_INVALID_CHECKSUM,/* Checksum is incorrect */
XERR_BLOCK_SEQUENCE, /* Block out of sequence */
XERR_CHAR_ERROR, /* Received character error */
XERR_OFFLINE, /* Modem not online */
XERR_BLOCK_NAK, /* NAK received */
};
#ifdef XMODEM_LIB
/*------------------------------------------------
Number of attempts and timeout for each attempt
to transferr using CRC.
------------------------------------------------*/
#define CRC_RETRY_COUNT 4
#define CRC_TIMEOUT (3L * MS_PER_SEC)
/*------------------------------------------------
Number of attempts and timeout for each attempt
to Negative Acknowledge a bad packet. This also
includes the initial NAK to get the thing started.
------------------------------------------------*/
#define NAK_RETRY_COUNT 10
#define NAK_TIMEOUT (10L * MS_PER_SEC)
/*------------------------------------------------
Number of attempts and timeout for each attempt
to Acknowledge a good packet.
------------------------------------------------*/
#define ACK_RETRY_COUNT 10
#define ACK_TIMEOUT (10L * MS_PER_SEC)
/*------------------------------------------------
Number of consecutive CANs and the timeout between
them.
------------------------------------------------*/
#define CAN_COUNT_ABORT 2
#define CAN_TIMEOUT (2L * MS_PER_SEC)
/*------------------------------------------------
Timeout between packet data bytes.
------------------------------------------------*/
#define DATA_TIMEOUT (1L * MS_PER_SEC)
/*------------------------------------------------
Number of false start characters that the sender
can receive before aborting the transmission.
------------------------------------------------*/
#define START_XMIT_RETRY_COUNT 10
#define START_XMIT_TIMEOUT (60L * MS_PER_SEC)
/*------------------------------------------------
Maximum number of attempts to send a single block.
------------------------------------------------*/
#define BLOCK_RETRY_COUNT 10
/*------------------------------------------------
Timeout for block responses.
------------------------------------------------*/
#define BLOCK_RESP_TIMEOUT (10L * MS_PER_SEC)
/*------------------------------------------------
Macro to purge all characters from the receive
buffer. This waits until there are no characters
received for a 1 second period.
------------------------------------------------*/
#define PURGE_RECEIVER(c) \
while ((*(c)) (MS_PER_SEC, NULL) != RECV_TIMEOUT)
#endif /* XMODEM_LIB */
/*------------------------------------------------
Number of milliseconds in a second. I know this
is silly, but it makes the meaning a little more
obvious.
------------------------------------------------*/
#define MS_PER_SEC 1000L
/*------------------------------------------------
Block sizes for normal and for 1K XMODEM
transfers.
------------------------------------------------*/
#define XMODEM_BLOCK_SIZE 128
#define XMODEM_1K_BLOCK_SIZE 1024
/*------------------------------------------------
Values returned by the receive character serial
interface function.
------------------------------------------------*/
#define RECV_TIMEOUT -1 /* receiver timed-out */
/*------------------------------------------------
Error bits stored in the receiv character error
flag.
------------------------------------------------*/
#define RE_OVERRUN_ 0x01 /* receiver overrun error */
#define RE_PARITY_ 0x02 /* receiver parity error */
#define RE_FRAMING_ 0x04 /* receiver framing error */
/*------------------------------------------------
Values returned by the transmit character serial
interface function.
------------------------------------------------*/
#define XMIT_OK 0 /* character enqued for transmission */
#define XMIT_OFFLINE -1 /* modem offline */
/*-----------------------------------------------
ASCII values used by XMODEM
-----------------------------------------------*/
#define SOH 1
#define STX 2
#define EOT 4
#define ACK 6
#define BACKSPACE 8
#define NAK 21
#define CAN 24
#define CPMEOF 26
/*-----------------------------------------------
XMODEM block description structure. This is only
used internally by the send and receive routines
and should not be visible outside of these.
-----------------------------------------------*/
#ifdef XMODEM_LIB
struct xmodem_block_st
{
long total_block_count; /* total blocks transferred */
long total_byte_count; /* total bytes transferred */
unsigned char start_char; /* block starting character */
unsigned char block_num; /* transmission block number */
unsigned char not_block_num; /* one's complement block number */
char buffer [XMODEM_1K_BLOCK_SIZE + 1]; /* data buffer */
int buflen; /* buffer length (128 or 1024) */
unsigned char checksum; /* data checksum */
unsigned int crc; /* data CRC-16 */
unsigned int crc_used: 1; /* 0=Checksum 1=CRC-16 */
};
typedef struct xmodem_block_st xblock;
#endif /* XMODEM_LIB */
/*-----------------------------------------------
XMODEM function pointer structure.
-----------------------------------------------*/
#ifdef XMODEM_LIB
struct xmodem_func_st
{
int (*transmit) ( /* xmit function */
char);
int (*receive) ( /* recv function */
long,
unsigned int *);
void (*dispstat) ( /* display function */
long,
long,
const char *);
int (*check_abort) (void); /* manual abort function */
};
typedef struct xmodem_func_st xfunc;
#endif /* XMODEM_LIB */
/*-----------------------------------------------
XMODEMR.C
-----------------------------------------------*/
int xmodem_recv (
FILE *f, /* file to write to */
int (*transmit) (char), /* xmit function */
int (*receive) (long, unsigned int *), /* recv function */
void (*dispstat) (long, long, const char *), /* display function */
int (*check_abort) (void)); /* manual abort function */
#ifdef XMODEM_LIB
int xm_perror (
int error, /* error number */
xfunc *xmf); /* xmodem external functions */
void xm_no_disp_func (
long a,
long b,
const char *buf);
int xm_no_abort_func (void);
#endif /* XMODEM_LIB */
/*-----------------------------------------------
XMODEMS.C
-----------------------------------------------*/
int xmodem_send (
int block_size, /* maximum block size */
FILE *f, /* file to write to */
int (*transmit) (char), /* xmit function */
int (*receive) (long, unsigned int *), /* recv function */
void (*dispstat) (long, long, const char *), /* display function */
int (*check_abort) (void)); /* manual abort function */
#ifdef XMODEM_LIB
unsigned int xm_update_CRC (
unsigned int crc, /* current CRC */
unsigned int c); /* character to add to CRC */
void xm_send_cancel (
int (*transmit) (char)); /* transmit function */
#endif /* XMODEM_LIB */
#endif /* XMODEM_H */
