Diff: Parser.cpp

Revision:

0:c8dd8b2c6942

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Parser.cpp	Thu Nov 12 19:17:47 2015 +0000
@@ -0,0 +1,94 @@
+#include "./Parser.h"
+#include <string.h>
+#include <stdio.h>
+
+ char *commandTokens[20];
+ char invalidMessage[]     = "INVALID NEMA SENTENCE";
+ char endOfTokensMessage[] =  "END OF TOKENS";
+ 
+char validateCommandSentence(char *pSentence)
+{
+    char chkSumToken[3];
+    unsigned char calculatedChecksum = 0;
+    char errorCode = NOERROR;
+    printf("\n\r\n\r>>>>>>>>>>>> %s <<<<\n\n\n\r", pSentence);
+    if(*pSentence != '$')
+        {
+        printf("error no $\n\r");
+        return ERROR;
+        }
+    pSentence++;
+    
+    while (*pSentence != '\0' && *pSentence != '*') {
+        calculatedChecksum ^= *pSentence;
+        pSentence++;
+    }
+    
+    if(*pSentence == '*'){
+        sprintf(chkSumToken, "%02x", calculatedChecksum);
+        printf("Calc chksum %s<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n\r", chkSumToken);
+        pSentence++;
+        if(strcmp(pSentence, chkSumToken) != 0)
+            {
+            printf("checksum error>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
+            errorCode = ERROR;
+            }
+        }
+    else {
+        printf("error:***** %s\n\r",pSentence);
+        errorCode = ERROR;
+        }
+   
+    printf("<<<<< errorcode %d\n\r", errorCode);
+    return errorCode;
+}
+
+// parseCommandSentence() requires that the trailing <cr><lf> characters
+// be removed prior to calling this function. Failing to do so will cause
+// validateNemaSentence() to report an ERROR
+
+void parseCommandSentence( char *pBuffer)
+{
+    if (validateCommandSentence(pBuffer) == ERROR) {
+        commandTokens[0]= invalidMessage;
+        commandTokens[1]= endOfTokensMessage;
+        }
+    else{
+        //so valid sentence ...................................
+        int tokenCounter = 0;
+        
+        commandTokens[tokenCounter]=pBuffer;
+        pBuffer++;
+        tokenCounter++;
+        
+        while( *pBuffer != '\0'){
+            //until the end of sentence is found,
+            //search for comma deliminators
+            if(*pBuffer == ','){
+                //found end of token
+                *pBuffer = '\0';    //replace deliminator with a null character
+                
+                pBuffer++;          // save address of next token
+                commandTokens[tokenCounter]=pBuffer;               
+                tokenCounter++;
+                }
+            else pBuffer++;
+            }//eo while not end of string
+        commandTokens[tokenCounter] = endOfTokensMessage;
+      
+        }//eo Valid sentence:::::::::::::::::::::::::::::::::::::
+    
+}//eo parseNemaSentence( char *pBuffer) ========================================
+
+
+//calculate a XOR checksum for a string
+char calcChecksum(char *pSentence)
+{
+    unsigned char calculatedChecksum = 0;
+    
+    while (*pSentence != '\0' ) {
+        calculatedChecksum ^= *pSentence;
+        pSentence++;
+    }
+    return calculatedChecksum;
+}