intermediate: restructure buffer handling

lib/queue/GwBuffer.cpp

@@ -18,8 +18,9 @@ GwBuffer::GwBuffer(GwLog *logger,size_t bufferSize)
 GwBuffer::~GwBuffer(){
     delete buffer;
 }
-void GwBuffer::reset()
+void GwBuffer::reset(String reason)
 {
+    LOG_DEBUG(GwLog::LOG,"reseting buffer %p, reason %s",this,reason.c_str());
     writePointer = buffer;
     readPointer = buffer;
     lp("reset");
@@ -131,6 +132,45 @@ GwBuffer::WriteStatus GwBuffer::fetchData(GwBufferWriter *writer, int maxLen,boo
     }
     return (written == len)?OK:AGAIN;
 }
+size_t GwBuffer::fetchData(int maxLen, GwBufferHandleFunction handler, void *param){
+    if (usedSpace() < 1) return 0;
+    size_t len=0;
+    if (writePointer > readPointer){
+        len=writePointer-readPointer;
+    }
+    else{
+        len=bufferSize-offset(readPointer)-1;
+    }
+    if (maxLen >= 0 && maxLen < len) len=maxLen;
+    size_t handled=handler(readPointer,len,param);
+    if (handled > len) handled=len;
+    readPointer+=handled;
+    if (offset(readPointer) >= bufferSize ) readPointer-=bufferSize;
+    return handled;
+}
+size_t GwBuffer::fillData(int maxLen, GwBufferHandleFunction handler, void *param)
+{
+    if (freeSpace() < 1)
+        return 0;
+    size_t len = 0;
+    if (writePointer > readPointer)
+    {
+        len = bufferSize - offset(writePointer) - 1;
+    }
+    else
+    {
+        len = readPointer - writePointer - 1;
+    }
+    if (maxLen >= 0 && maxLen < len)
+        len = maxLen;
+    size_t handled = handler(writePointer, len,param);
+    if (handled > len)
+        handled = len;
+    writePointer += handled;
+    if (offset(writePointer) >= bufferSize)
+        writePointer -= bufferSize;
+    return handled;
+}
 
 int GwBuffer::findChar(char x){
     lp("findChar",x);
@@ -159,4 +199,34 @@ GwBuffer::WriteStatus GwBuffer::fetchMessage(GwBufferWriter *writer,char delimit
         return AGAIN;
     }
     return fetchData(writer,pos+1,true);
+}
+
+size_t GwMessageFetcher::fetchMessageToBuffer(GwBuffer *gwbuffer,uint8_t *buffer, size_t bufferLen,char delimiter){
+    int offset=gwbuffer->findChar(delimiter);
+    if (offset <0) {
+        if (! gwbuffer->freeSpace()){
+            gwbuffer->reset(F("Message to long for input buffer"));
+        }
+        return 0;
+    }
+    offset+=1; //we include the delimiter
+    if (offset >= bufferLen){
+        gwbuffer->reset(F("Message to long for message buffer"));
+        return 0;
+    }
+    size_t fetched=0;
+    while (fetched < offset){
+        size_t max=offset-fetched;
+        size_t rd=gwbuffer->fetchData(max,[](uint8_t *buffer, size_t len, void *p)->size_t{
+            memcpy(p,buffer,len);
+            return len;
+        },buffer+fetched);
+        if (rd == 0){
+            //some internal error
+            gwbuffer->reset(F("Internal fetch error"));
+            return 0;
+        }
+        fetched+=rd;
+    }
+    return fetched;
 }

lib/queue/GwBuffer.h

@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include "GwLog.h"
 
+class GwBuffer;
 class GwBufferWriter{
     public:
         int id=0; //can be set be users
@@ -12,11 +13,19 @@ class GwBufferWriter{
         virtual ~GwBufferWriter(){};
 };
 
+class GwMessageFetcher{
+    public:
+        int id=0;
+        virtual bool handleBuffer(GwBuffer *buffer)=0;
+        virtual size_t fetchMessageToBuffer(GwBuffer *gwbuffer,uint8_t *buffer, size_t bufferLen,char delimiter);  
+};
+
 /**
  * an implementation of a
  * buffer to safely inserte data if it fits
  * and to write out data if possible
  */
+typedef size_t (*GwBufferHandleFunction)(uint8_t *buffer, size_t len, void *param);
 class GwBuffer{
     public:
         static const size_t TX_BUFFER_SIZE=1620; // app. 20 NMEA messages
@@ -36,25 +45,26 @@ class GwBuffer{
         }
         GwLog *logger;
         void lp(const char *fkt,int p=0);
-        /**
-         * find the first occurance of x in the buffer, -1 if not found
-         */
-        int findChar(char x);
     public:
         GwBuffer(GwLog *logger,size_t bufferSize);
         ~GwBuffer();
-        void reset();
+        void reset(String reason="");
         size_t freeSpace();
         size_t usedSpace();
         size_t addData(const uint8_t *data,size_t len,bool addPartial=false);
+        size_t fillData(int maxLen,GwBufferHandleFunction handler, void *param);
         int read();
         int peek();
+        size_t fetchData(int maxLen,GwBufferHandleFunction handler, void *param);
         /**
          * write some data to the buffer writer
          * return an error if the buffer writer returned < 0
          */
         WriteStatus fetchData(GwBufferWriter *writer, int maxLen=-1,bool errorIf0 = true);
-
+        /**
+         * find the first occurance of x in the buffer, -1 if not found
+         */
+        int findChar(char x);
         WriteStatus fetchMessage(GwBufferWriter *writer,char delimiter,bool emptyIfFull=true);
 };