Add an "expand_cr" to telnet_expand(), taken from syncterm/telnet_io.c.

Now, it assumes the CR is bare (not followed by LF or NUL), so that should
probably be fixed. But for now, just copied pretty much as is from telnet_io.c
so I can eliminate another version of this function.

src/sbbs3/main.cpp

@@ -2183,7 +2183,7 @@ void passthru_thread(void* arg)
 			BYTE*	bp = (BYTE*)inbuf;
 
 			if(!(sbbs->telnet_mode&TELNET_MODE_OFF))
-				rd = telnet_expand((BYTE*)inbuf, rd, telnet_buf, sizeof(telnet_buf), &bp);
+				rd = telnet_expand((BYTE*)inbuf, rd, telnet_buf, sizeof(telnet_buf), /* expand_cr */false, &bp);
 
     		if(!RingBufWrite(&sbbs->outbuf, bp, rd)) {
 				lprintf(LOG_ERR,"Cannot pass from passthru socket to outbuf");

src/sbbs3/telnet.c

@@ -154,17 +154,25 @@ uchar telnet_opt_nak(uchar cmd)
 // 'result' may point to either inbuf (if there were no IACs) or outbuf
 // Returns the final byte count of the result
 /*****************************************************************************/
-size_t telnet_expand(const uchar* inbuf, size_t inlen, uchar* outbuf, size_t outlen, uchar** result)
+size_t telnet_expand(const uchar* inbuf, size_t inlen, uchar* outbuf, size_t outlen, bool expand_cr, uchar** result)
 {
     BYTE* first_iac = (BYTE*)memchr(inbuf, TELNET_IAC, inlen);
+	BYTE*   first_cr=NULL;
+	if(expand_cr)
+	    first_cr = (BYTE*)memchr(inbuf, '\r', inlen);
 
-	if(first_iac == NULL) {	/* Nothing to expand */
+	if(first_iac == NULL && first_cr==NULL) {	/* Nothing to expand */
 		if(result != NULL)
 			*result = (uchar*)inbuf;
 		return inlen;
 	}
 
-	size_t o = first_iac - inbuf;
+	size_t o;
+
+	if(first_iac != NULL && (first_cr == NULL || first_iac < first_cr))
+		o = first_iac - inbuf;
+	else
+		o = first_cr - inbuf;
 	memcpy(outbuf, inbuf, o);
 
 	for(size_t i = o; i < inlen && o < outlen; i++) {
@@ -173,6 +181,8 @@ size_t telnet_expand(const uchar* inbuf, size_t inlen, uchar* outbuf, size_t out
 		if(o >= outlen)
 			break;
 		outbuf[o++] = inbuf[i];
+		if(expand_cr && inbuf[i] == '\r' && o < outlen)
+			outbuf[o++] = '\n'; // See RFC5198
 	}
 	if(result != NULL)
 		*result = outbuf;

src/sbbs3/telnet.h

@@ -38,6 +38,7 @@
 #ifndef _TELNET_H
 #define _TELNET_H
 
+#include <stdbool.h>
 #include "gen_defs.h"	/* uchar */
 
 /* commands */
@@ -165,7 +166,8 @@ DLLEXPORT const char* telnet_cmd_desc(uchar cmd);
 DLLEXPORT const char* telnet_opt_desc(uchar opt);
 DLLEXPORT		uchar telnet_opt_ack(uchar cmd);
 DLLEXPORT		uchar telnet_opt_nak(uchar cmd);
-DLLEXPORT size_t telnet_expand(const uchar* inbuf, size_t inlen, uchar* outbuf, size_t outlen, uchar** result);
+DLLEXPORT size_t telnet_expand(const uchar* inbuf, size_t inlen, uchar* outbuf, size_t outlen
+								,bool expand_cr, uchar** result);
 
 #ifdef __cplusplus
 }

src/sbbs3/xtrn.cpp

@@ -901,7 +901,7 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 					} else if(telnet_mode&TELNET_MODE_OFF) {
 						bp=buf;
 					} else {
-                		rd = telnet_expand(buf, rd, telnet_buf, sizeof(telnet_buf), &bp);
+                		rd = telnet_expand(buf, rd, telnet_buf, sizeof(telnet_buf), /* expand_cr: */false, &bp);
 					}
 					if(rd>RingBufFree(&outbuf)) {
 						lprintf(LOG_ERR,"output buffer overflow");
@@ -969,7 +969,7 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 					} else if(telnet_mode&TELNET_MODE_OFF) {
 						bp=buf;
 					} else {
-                		rd = telnet_expand(buf, rd, telnet_buf, sizeof(telnet_buf), &bp);
+                		rd = telnet_expand(buf, rd, telnet_buf, sizeof(telnet_buf), /* expand_cr: */false, &bp);
 					}
 					if(rd>RingBufFree(&outbuf)) {
 						lprintf(LOG_ERR,"output buffer overflow");
@@ -1919,7 +1919,7 @@ int sbbs_t::external(const char* cmdline, long mode, const char* startup_dir)
 					output_len=rd;
 				}
 				else
-   	       			output_len = telnet_expand(buf, rd, output_buf, sizeof(output_buf), &bp);
+   	       			output_len = telnet_expand(buf, rd, output_buf, sizeof(output_buf), /* expand_cr: */false, &bp);
 			} else {
 				if ((mode & EX_STDIO) != EX_STDIO) {
 					/* LF to CRLF expansion */