Author Topic: Netcruzer Library: cbufFindByte  (Read 2160 times)


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Netcruzer Library: cbufFindByte
« on: February 07, 2014, 04:29:51 AM »
I've been seeing errors with our application, and have narrowed it down to cbufFindByte() returning false matches.
It happens when a new character arrives (from interrupt routine) while executing cbufFindByte().
(The routine falsely assumes that there's more data starting from the beginning of the buffer.)
The following fix works for me:

WORD cbufFindByte(CIRBUF* pBuf, WORD offset, BYTE value) {
-    WORD i;
+    WORD i, n;
     WORD sizeCtgs;          //Size of block of contiguous data we can search
     BYTE* pCtgs;            //Pointer to block of contiguous data we can search
     BOOL firstLoop = TRUE;
     WORD rdArrSize=0;
+    n = cbufGetCount(pBuf); //This might change, so read it now - idb
     //Get pointer and size of first continuous block of data
     pCtgs = cbufGetRdArr(pBuf);
     sizeCtgs = cbufGetRdArrSize(pBuf);
@@ -260,10 +261,10 @@
         //Byte not found yet:
         // - Check if there is a second contiguous block of data. If so, search it too
         // - If no second contigous block, return "Not Found"
-        if (firstLoop && (cbufGetCount(pBuf) > sizeCtgs)){
+        if (firstLoop && (n > sizeCtgs)){
             firstLoop = FALSE;
             rdArrSize = sizeCtgs;    //Remember size of first contiguous block.
-            sizeCtgs = cbufGetCount(pBuf) - sizeCtgs;
+            sizeCtgs = n - sizeCtgs;
             pCtgs = pBuf->buf;   //Second contiguous block is from beginning of buffer