Added block size adjustment during sends (and configurable "max_block_size").

Simplified progress callback even more with zm.start_transfer_pos member.
Added consecutive error counter.
Increased default send/recv timeouts from 10 to 15 seconds.

src/sbbs3/zmodem.c

@@ -1323,6 +1323,7 @@ int zmodem_get_zfin(zmodem_t* zm)
 	return 0;
 }
 
+
 /*
  * send from the current position in the file
  * all the way to end of file or until something goes wrong.
@@ -1352,8 +1353,6 @@ int zmodem_send_from(zmodem_t* zm, FILE* fp, ulong pos, ulong* sent)
 		/*
 		 * read a block from the file
 		 */
-		if(zm->block_size < 128 || zm->block_size > sizeof(zm->tx_data_subpacket))
-			zm->block_size = 1024;	/* sanity check block size here */
 
 		n = fread(zm->tx_data_subpacket,sizeof(BYTE),zm->block_size,fp);
 
@@ -1367,7 +1366,7 @@ int zmodem_send_from(zmodem_t* zm, FILE* fp, ulong pos, ulong* sent)
 		}
 #endif
 		if(zm->progress!=NULL)
-			zm->progress(zm->cbdata, pos, ftell(fp));
+			zm->progress(zm->cbdata, ftell(fp));
 
 		type = ZCRCG;
 
@@ -1389,11 +1388,6 @@ int zmodem_send_from(zmodem_t* zm, FILE* fp, ulong pos, ulong* sent)
 		if(zmodem_send_data(zm, type, zm->tx_data_subpacket, n)!=0)
 			return(TIMEOUT);
 
-		if(sent!=NULL)
-			*sent+=n;
-		
-		buf_sent+=n;
-
 		if(type == ZCRCW || type == ZCRCE) {	
 			int ack;
 			lprintf(zm,LOG_DEBUG,"Sent end-of-frame (%s sub-packet)", chr(type));
@@ -1420,7 +1414,6 @@ int zmodem_send_from(zmodem_t* zm, FILE* fp, ulong pos, ulong* sent)
 				lprintf(zm,LOG_DEBUG,"zmodem_send_from: read error at offset %lu", ftell(fp) );
 				return ZACK;
 			}
-
 		}
 
 		/* 
@@ -1445,6 +1438,19 @@ int zmodem_send_from(zmodem_t* zm, FILE* fp, ulong pos, ulong* sent)
 		if(zm->cancelled)
 			return(-1);
 
+		if(sent!=NULL)
+			*sent+=n;
+		
+		buf_sent+=n;
+
+		zm->consecutive_errors = 0;
+
+		if(zm->block_size < zm->max_block_size) {
+			zm->block_size*=2;
+			if(zm->block_size > zm->max_block_size)
+				zm->block_size = zm->max_block_size;
+		}
+
 		if(type == ZCRCW)	/* end-of-frame */
 			zmodem_send_pos_header(zm, ZDATA, ftell(fp), /* Hex? */ FALSE);
 	}
@@ -1477,6 +1483,21 @@ BOOL zmodem_send_file(zmodem_t* zm, char* fname, FILE* fp, BOOL request_init, ti
 	int		i;
 	unsigned errors;
 
+	if(zm->block_size == 0)
+		zm->block_size = ZBLOCKLEN;	
+
+	if(zm->block_size < 128)
+		zm->block_size = 128;	
+
+	if(zm->block_size > sizeof(zm->tx_data_subpacket))
+		zm->block_size = sizeof(zm->tx_data_subpacket);
+
+	if(zm->max_block_size < zm->block_size)
+		zm->max_block_size = zm->block_size;
+
+	if(zm->max_block_size > sizeof(zm->rx_data_subpacket))
+		zm->max_block_size = sizeof(zm->rx_data_subpacket);
+
 	if(sent!=NULL)	
 		*sent=0;
 
@@ -1624,27 +1645,19 @@ BOOL zmodem_send_file(zmodem_t* zm, char* fname, FILE* fp, BOOL request_init, ti
 
 	} while(type != ZRPOS);
 
-	zm->transfer_start = time(NULL);
+	zm->transfer_start_time = time(NULL);
+	zm->transfer_start_pos = 0;
+	if(zm->rxd_header_pos && zm->rxd_header_pos <= zm->current_file_size) {
+		pos = zm->transfer_start_pos = zm->rxd_header_pos;
+		lprintf(zm,LOG_INFO,"Starting transfer at offset: %lu (resume)", pos);
+	}
 
 	if(start!=NULL)		
-		*start=zm->transfer_start;
+		*start=zm->transfer_start_time;
 
 	rewind(fp);
+	zm->consecutive_errors = 0;
 	do {
-		/*
-		 * fetch pos from the ZRPOS header
-		 */
-
-		if(type == ZRPOS) {
-			if(zm->rxd_header_pos <= zm->current_file_size) {
-				if(pos != zm->rxd_header_pos) {
-					pos = zm->rxd_header_pos;
-					lprintf(zm,LOG_INFO,"Resuming transfer from offset: %lu", pos);
-				}
-			} else
-				lprintf(zm,LOG_WARNING,"Invalid ZRPOS offset: %lu", zm->rxd_header_pos);
-		}
-
 		/*
 		 * and start sending
 		 */
@@ -1654,13 +1667,39 @@ BOOL zmodem_send_file(zmodem_t* zm, char* fname, FILE* fp, BOOL request_init, ti
 		if(!is_connected(zm))
 			return(FALSE);
 
+		if(type == ZFERR || type == ZABORT || zm->cancelled)
+			return(FALSE);
+
 		if(sent!=NULL)
 			*sent+=sent_bytes;
 
-		if(type == ZFERR || type == ZABORT || type == TIMEOUT || zm->cancelled)
+		if(type == ZACK)	/* success */
+			break;
+
+		if(zm->block_size == zm->max_block_size && zm->max_block_size > ZBLOCKLEN)
+			zm->max_block_size /= 2;
+
+		if(zm->block_size > 128)
+			zm->block_size /= 2; 
+
+		if(++zm->consecutive_errors > zm->max_errors)
 			return(FALSE);
 
-	} while(type == ZRPOS || type == ZNAK);
+		/*
+		 * fetch pos from the ZRPOS header
+		 */
+
+		if(type == ZRPOS) {
+			if(zm->rxd_header_pos <= zm->current_file_size) {
+				if(pos != zm->rxd_header_pos) {
+					pos = zm->rxd_header_pos;
+					lprintf(zm,LOG_INFO,"Resuming transfer from offset: %lu", pos);
+				}
+			} else
+				lprintf(zm,LOG_WARNING,"Invalid ZRPOS offset: %lu", zm->rxd_header_pos);
+		}
+
+	} while(type == ZRPOS || type == ZNAK || type==TIMEOUT);
 
 
 	lprintf(zm,LOG_INFO,"Finishing transfer on rx of header type: %s", chr((uchar)type));
@@ -1775,7 +1814,7 @@ int zmodem_recv_files(zmodem_t* zm, const char* download_dir, ulong* bytes_recei
 					lprintf(zm,LOG_WARNING,"Incomplete download (%ld bytes received, expected %lu)"
 						,l,bytes);
 				} else {
-					if((t=time(NULL)-zm->transfer_start)<=0)
+					if((t=time(NULL)-zm->transfer_start_time)<=0)
 						t=1;
 					b=l-start_bytes;
 					if((cps=b/t)==0)
@@ -1898,7 +1937,8 @@ unsigned zmodem_recv_file_data(zmodem_t* zm, FILE* fp, ulong offset)
 	int			i=0;
 	unsigned	errors=0;
 
-	zm->transfer_start=time(NULL);
+	zm->transfer_start_pos=offset;
+	zm->transfer_start_time=time(NULL);
 
 	fseek(fp,offset,SEEK_SET);
 	offset=ftell(fp);
@@ -1909,7 +1949,7 @@ unsigned zmodem_recv_file_data(zmodem_t* zm, FILE* fp, ulong offset)
 		if(i!=ENDOFFRAME)
 			zmodem_send_pos_header(zm, ZRPOS, ftell(fp), /* Hex? */ TRUE);
 
-		if((i = zmodem_recv_file_frame(zm,fp,offset)) == ZEOF)
+		if((i = zmodem_recv_file_frame(zm,fp)) == ZEOF)
 			break;
 		if(i!=ENDOFFRAME) {
 			if(i>0)
@@ -1921,7 +1961,7 @@ unsigned zmodem_recv_file_data(zmodem_t* zm, FILE* fp, ulong offset)
 }
 
 
-int zmodem_recv_file_frame(zmodem_t* zm, FILE* fp, ulong offset)
+int zmodem_recv_file_frame(zmodem_t* zm, FILE* fp)
 {
 	unsigned n;
 	int type;
@@ -1957,8 +1997,11 @@ int zmodem_recv_file_frame(zmodem_t* zm, FILE* fp, ulong offset)
 			fwrite(zm->rx_data_subpacket,1,n,fp);
 		}
 
+		if(type==FRAMEOK)
+			zm->block_size = n;
+
 		if(zm->progress!=NULL)
-			zm->progress(zm->cbdata,offset,ftell(fp));
+			zm->progress(zm->cbdata,ftell(fp));
 
 		if(zm->cancelled)
 			return(ZCAN);
@@ -1983,7 +2026,7 @@ char* zmodem_ver(char *buf)
 
 void zmodem_init(zmodem_t* zm, void* cbdata
 				,int	(*lputs)(void*, int level, const char* str)
-				,void	(*progress)(void* unused, ulong, ulong)
+				,void	(*progress)(void* unused, ulong)
 				,int	(*send_byte)(void*, uchar ch, unsigned timeout)
 				,int	(*recv_byte)(void*, unsigned timeout)
 				,BOOL	(*is_connected)(void*)
@@ -1992,13 +2035,14 @@ void zmodem_init(zmodem_t* zm, void* cbdata
 	memset(zm,0,sizeof(zmodem_t));
 
 	/* Use sane default values */
-	zm->send_timeout=10;		/* seconds */
-	zm->recv_timeout=10;		/* seconds */
+	zm->send_timeout=15;		/* seconds */
+	zm->recv_timeout=15;		/* seconds */
 #if 0
 	zm->byte_timeout=3;			/* seconds */
 	zm->ack_timeout=10;			/* seconds */
 #endif
-	zm->block_size=1024;
+	zm->block_size=ZBLOCKLEN;
+	zm->max_block_size=ZBLOCKLEN;
 	zm->max_errors=9;
 
 	zm->cbdata=cbdata;

src/sbbs3/zmodem.h

@@ -36,6 +36,8 @@
  * zmodem constants
  */
 
+#define ZBLOCKLEN	1024		/* "true" Zmodem max subpacket length */
+
 #define ZMAXHLEN    0x10		/* maximum header information length */
 #define ZMAXSPLEN	0x400		/* maximum subpacket length */
 
@@ -232,7 +234,8 @@ typedef struct {
 	ulong		total_bytes;
 	unsigned	files_remaining;
 	unsigned	bytes_remaining;
-	time_t		transfer_start;
+	ulong		transfer_start_pos;
+	time_t		transfer_start_time;
 
 	int receive_32bit_data;
 	int use_crc16;
@@ -259,13 +262,15 @@ typedef struct {
 	unsigned	recv_timeout;
 	unsigned	max_errors;
 	unsigned	block_size;
+	unsigned	max_block_size;
+	unsigned	consecutive_errors;
 
 	/* Callbacks */
 	void*		cbdata;
 	int			(*lputs)(void*, int level, const char* str);
 	int			(*send_byte)(void*, BYTE ch, unsigned timeout);
 	int			(*recv_byte)(void*, unsigned timeout);
-	void		(*progress)(void*, ulong start_pos, ulong current_pos);
+	void		(*progress)(void*, ulong current_pos);
 	BOOL		(*is_connected)(void*);
 	BOOL		(*data_waiting)(void*);
 
@@ -273,7 +278,7 @@ typedef struct {
 
 void		zmodem_init(zmodem_t*, void* cbdata
 						,int	(*lputs)(void*, int level, const char* str)
-						,void	(*progress)(void*, ulong, ulong)
+						,void	(*progress)(void*, ulong current_pos)
 						,int	(*send_byte)(void*, BYTE ch, unsigned timeout)
 						,int	(*recv_byte)(void*, unsigned timeout)
 						,BOOL	(*is_connected)(void*)
@@ -299,7 +304,7 @@ BOOL		zmodem_send_file(zmodem_t*, char* name, FILE* fp, BOOL request_init, time_
 int			zmodem_recv_files(zmodem_t* zm, const char* download_dir, ulong* bytes_received);
 int			zmodem_recv_init(zmodem_t* zm);
 unsigned	zmodem_recv_file_data(zmodem_t*, FILE*, ulong offset);
-int			zmodem_recv_file_frame(zmodem_t* zm, FILE* fp, ulong offset);
+int			zmodem_recv_file_frame(zmodem_t* zm, FILE* fp);
 int			zmodem_recv_header_and_check(zmodem_t* zm);
 #endif