use async web server

lib/queue/GwBuffer.cpp

@@ -0,0 +1,145 @@
+#include "GwBuffer.h"
+
+void GwBuffer::lp(const char *fkt, int p)
+{
+    LOG_DEBUG(GwLog::DEBUG + 1, "Buffer[%s]: buf=%p,wp=%d,rp=%d,used=%d,free=%d, p=%d",
+              fkt, buffer, offset(writePointer), offset(readPointer), usedSpace(), freeSpace(), p);
+}
+
+GwBuffer::GwBuffer(GwLog *logger)
+{
+    this->logger = logger;
+}
+void GwBuffer::reset()
+{
+    writePointer = buffer;
+    readPointer = buffer;
+    lp("reset");
+}
+size_t GwBuffer::freeSpace()
+{
+    if (readPointer < writePointer)
+    {
+        size_t rt = BUFFER_SIZE - offset(writePointer) - 1 + offset(readPointer);
+        return rt;
+    }
+    if (readPointer == writePointer)
+        return BUFFER_SIZE - 1;
+    return readPointer - writePointer - 1;
+}
+size_t GwBuffer::usedSpace()
+{
+    if (readPointer == writePointer)
+        return 0;
+    if (readPointer < writePointer)
+        return writePointer - readPointer;
+    return BUFFER_SIZE - offset(readPointer) - 1 + offset(writePointer);
+}
+size_t GwBuffer::addData(const uint8_t *data, size_t len)
+{
+    lp("addDataE", len);
+    if (len == 0)
+        return 0;
+    if (freeSpace() < len)
+        return 0;
+    size_t written = 0;
+    if (writePointer >= readPointer)
+    {
+        written = BUFFER_SIZE - offset(writePointer) - 1;
+        if (written > len)
+            written = len;
+        if (written)
+        {
+            memcpy(writePointer, data, written);
+            len -= written;
+            data += written;
+            writePointer += written;
+            if (offset(writePointer) >= (BUFFER_SIZE - 1))
+                writePointer = buffer;
+        }
+        lp("addData1", written);
+        if (len <= 0)
+        {
+            return written;
+        }
+    }
+    //now we have the write pointer before the read pointer
+    //and we did the length check before - so we can safely copy
+    memcpy(writePointer, data, len);
+    writePointer += len;
+    lp("addData2", len);
+    return len + written;
+}
+/**
+         * write some data to the buffer writer
+         * return an error if the buffer writer returned < 0
+         */
+GwBuffer::WriteStatus GwBuffer::fetchData(GwBufferWriter *writer, bool errorIf0 )
+{
+    lp("fetchDataE");
+    size_t len = usedSpace();
+    if (len == 0)
+        return OK;
+    size_t written = 0;
+    size_t plen = len;
+    if (writePointer < readPointer)
+    {
+        //we need to write from readPointer till end and then till writePointer-1
+        plen = BUFFER_SIZE - offset(readPointer) - 1;
+        int rt = writer->write(readPointer, plen);
+        lp("fetchData1", rt);
+        if (rt < 0)
+        {
+            LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write returns error %d", rt);
+            return ERROR;
+        }
+        if (rt > plen)
+        {
+            LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write too many bytes(1) %d", rt);
+            return ERROR;
+        }
+        if (rt == 0)
+        {
+            LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write returns 0 (1)");
+            return (errorIf0 ? ERROR : AGAIN);
+        }
+        readPointer += rt;
+        if (offset(readPointer) >= (BUFFER_SIZE - 1))
+            readPointer = buffer;
+        if (rt < plen)
+            return AGAIN;
+        if (plen >= len)
+            return OK;
+        len -= rt;
+        written += rt;
+        //next part - readPointer should be at buffer now
+    }
+    plen = writePointer - readPointer;
+    if (plen == 0)
+        return OK;
+    int rt = writer->write(readPointer, plen);
+    lp("fetchData2", rt);
+    if (rt < 0)
+    {
+        LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write returns error %d", rt);
+        return ERROR;
+    }
+    if (rt == 0)
+    {
+        LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write returns 0 (1)");
+        return (errorIf0 ? ERROR : AGAIN);
+    }
+    if (rt > plen)
+    {
+        LOG_DEBUG(GwLog::DEBUG + 1, "buffer: write too many bytes(2)");
+        return ERROR;
+    }
+    readPointer += rt;
+    if (offset(readPointer) >= (BUFFER_SIZE - 1))
+        readPointer = buffer;
+    lp("fetchData3");
+    written += rt;
+    if (written < len)
+        return AGAIN;
+    return OK;
+}