Fix corrupted csv file by removing last bad line

1 files changed, 38 insertions, 0 deletions

diff --git a/mycan.c b/mycan.c
index 5229c7f..7320b87 100644
--- a/mycan.c
+++ b/mycan.c
@@ -36,6 +36,14 @@ cansend vcan0 680#00.FF.02.00.02.00.02.00
 
 #define CAN_VOLT_LEN 24
 #define CAN_TEMP_LEN 16
+// max wire unsigned number is 65535
+// max wire signed number maybe is -32768 to 32767
+// voltage max format 7 bytes ,6.5535
+// temp max format 4 bytes ,255
+// timestamp max 10 bytes 1745742182
+// 1 timestamp, 96 voltage, 48 temp, 1 \n
+// 10+96*7+96*4+1=1067 bytes
+#define ENTRY_SIZE 1067
 
 // https://github.com/howerj/dbcc MIT
 static uint64_t u64_from_can_msg(const uint8_t m[8]) {
@@ -78,6 +86,36 @@ int main(int argc, char **argv)
 	// vcan, for test
 	//printf("this is a can receive demo\r\n");
 
+	// check and fix corrupted .csv file
+	{
+		FILE * fp;
+		char ch;
+		uint32_t offset;
+		int remain;
+		if((fp=fopen(filename,"r"))==NULL)
+		{
+			fprintf(stderr,"Can't open file \"%s\".\n",filename);
+			exit(1);
+		}
+		fseek(fp,-1L,SEEK_END);
+		fscanf(fp,"%c",&ch);
+		fseek(fp,0L,SEEK_END);
+		offset=ftell(fp);
+		printf("csv file end offset: %d\n",offset);
+		fclose(fp);
+		remain=offset%ENTRY_SIZE;
+		if(remain)
+		{
+			printf(".csv file not a multiple of %d, remove last line\n",ENTRY_SIZE);
+			truncate(filename,offset-remain);
+		}
+		else if(ch != '\n')
+		{
+			printf(".csv file last char not newline, remove last line\n");
+			truncate(filename,offset-ENTRY_SIZE);
+		}
+	}
+
 	//1.Create socket
 	s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 	if (s < 0) {