From 18a589ec46c5c31ee406bd65dc45dcf2628f6284 Mon Sep 17 00:00:00 2001
From: Juri Glass <juri.glass@dai-labor.de>
Date: Sat, 25 Jun 2011 00:44:03 +0200
Subject: [PATCH] added sml_transport_write, comments for sml_transport
 functions

---
 sml/include/sml/sml_transport.h | 19 ++++++++++---
 sml/src/sml.c                   | 10 -------
 sml/src/sml_transport.c         | 48 +++++++++++++++++++++++++++++----
 3 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/sml/include/sml/sml_transport.h b/sml/include/sml/sml_transport.h
index 92b1bb2..1d331f4 100644
--- a/sml/include/sml/sml_transport.h
+++ b/sml/include/sml/sml_transport.h
@@ -20,15 +20,28 @@
 #define	_SML_TRANSPORT_H
 
 #include <stdlib.h>
+#include <sml/sml.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-
-//void (*sml_transport_receiver_fun)(unsigned char *buffer, size_t buffer_len) = 0;
-
+// sml_transport_listen reads continously bytes from fd and scans 
+// for the SML transport protocol escape sequences. If a SML file
+// is detected, the sml_transporter_receiver is called with the 
+// complete bytes, including the escape sequences.
+// The buffer is free'd after the sml_transport_receiver comes 
+// back.
 void sml_transport_listen(int fd, void (*sml_transport_receiver)(unsigned char *buffer, size_t buffer_len));
+
+// sml_transport_writes adds the SML transport protocol escape 
+// sequences and writes the given file to fd. The file must be 
+// in the parsed format.
+// The number of bytes written is returned, 0 if there was an
+// error.
+// The sml_file must be free'd elsewhere.
+int sml_transport_write(int fd, sml_file *file);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/sml/src/sml.c b/sml/src/sml.c
index 7221b15..0cf510c 100644
--- a/sml/src/sml.c
+++ b/sml/src/sml.c
@@ -78,7 +78,6 @@ void sml_file_add_message(sml_file *file, sml_message *message) {
 }
 
 void sml_file_write(sml_file *file) {
-   
     int i;
     if (file->messages && file->messages_len > 0) {
         for (i = 0; i < file->messages_len; i++) {
@@ -119,12 +118,3 @@ void sml_file_print(sml_file *file) {
 
 
 
-
-
-
-
-											 
-											 
-
-
-
diff --git a/sml/src/sml_transport.c b/sml/src/sml_transport.c
index fced91f..86f0cbf 100644
--- a/sml/src/sml_transport.c
+++ b/sml/src/sml_transport.c
@@ -24,10 +24,11 @@
 #include <sys/types.h>
 #include <string.h>
 #include <unistd.h>
+#include <sml/sml_shared.h>
+#include <sml/sml_crc16.h>
 
 #define MC_SML_BUFFER_LEN 8096
 
-// Invokes on every incoming SML message the given method. The buffer is freed afterwards.
 void sml_transport_listen(int fd, void (*sml_transport_receiver)(unsigned char *buffer, size_t buffer_len)) {
 
 	fd_set readfds;
@@ -80,8 +81,7 @@ void sml_transport_listen(int fd, void (*sml_transport_receiver)(unsigned char *
 						if (end == 5) {
 							char *sml_file = (char *) malloc(i);
 							memcpy(sml_file, &(buf[0]), i);
-							// without the SML transport stuff
-							sml_transport_receiver((unsigned char *)(sml_file ), i);
+							sml_transport_receiver((unsigned char *)(sml_file), i);
 							free(sml_file);
 							i = -1;
 							esc = 0;
@@ -114,6 +114,44 @@ void sml_transport_listen(int fd, void (*sml_transport_receiver)(unsigned char *
 	printf("error: no end sequence found, buffer full.");
 }
 
-
-
+int sml_transport_write(int fd, sml_file *file) {
+	
+	unsigned char start_seq[] = {0x1b, 0x1b, 0x1b, 0x1b, 0x01, 0x01, 0x01, 0x01};
+	unsigned char end_seq[] = {0x1b, 0x1b, 0x1b, 0x1b, 0x1a};
+	sml_buffer *buf = file->buf;
+	buf->cursor = 0;
+	
+	// add start sequence
+	memcpy(sml_buf_get_current_buf(buf), start_seq, 8);
+	buf->cursor += 8;
+	
+	// add file
+	sml_file_write(file);
+	
+	// add padding bytes
+	int padding = (buf->cursor % 4) ? (4 - buf->cursor % 4) : 0;
+	if (padding) {
+		// write zeroed bytes 
+		memset(sml_buf_get_current_buf(buf), 0, padding);
+		buf->cursor += padding;
+	}
+	
+	// begin end sequence
+	memcpy(sml_buf_get_current_buf(buf), end_seq, 5);
+	buf->cursor += 5;
+	
+	// add padding info
+	buf->buffer[buf->cursor++] = (unsigned char) padding;
+	
+	// add crc checksum
+	u16 crc = sml_crc16_calculate(buf->buffer, buf->cursor);
+	buf->buffer[buf->cursor++] = (unsigned char) ((crc & 0xFF00) >> 8);
+	buf->buffer[buf->cursor++] = (unsigned char) (crc & 0x00FF);
+	
+	size_t wr = write(fd, buf->buffer, buf->cursor);
+	if (wr == buf->cursor) {
+		return wr;
+	}
+	return 0;
+}