introduced AltColorHeader

README.md

@@ -66,14 +66,12 @@ The DmdStreamHeader is defined as a struct:
 ```
   struct DMDUtil::DMD::StreamHeader
   {
-    char protocol[10] = "DMDStream"; // \0 terminated string 
+    char header[10] = "DMDStream"; // \0 terminated string
     uint8_t version = 1;
-    Mode mode = Mode::Data;          // int
+    Mode mode = Mode::Data;        // int
     uint16_t width = 0;
     uint16_t height = 0;
     uint32_t length = 0;
-    char name[16] = {0};             // \0 terminated string, ROM name 
-    char path[256] = {0};            // \0 terminated string, altcolor path
   };
 
 ```
@@ -97,9 +95,11 @@ Each pixel consist of one uint16_t having its color encoded in 16bit according t
 `Mode::Data` is a serialized stream of the `DMDUtil::DMD::Update` struct.
 It will be sent from a client which uses libdmdutil itself (for example VPX Standalone or PPUC).
 In case of `Mode::Data`, `StreamHeader.width`, `StreamHeader.height` and `StreamHeader.length` should be set to zero.
-`StreamHeader.name` and `StreamHeader.path` have to be set to the ROM name and the altcolor path if Serum colorization should be used.
-The data itself contains that information and a lot of additional data like instructions to map alphanummeric displays to DMDs or
-colorizations of grayscale content.
+There will be an additional `AltColorHeader` header sent before the data to the transmit the ROM name and the altcolor path
+in case Serum colorization should be used.
+The data itself contains a lot of additional data like instructions to map alphanummeric displays to DMDs or colorizations of
+grayscale content.
+
 So if you want to write a general purpose client to display images or text, you're adviced to use `Mode::RGB24` or `Mode::RGB216`!
 
 ### Notes
@@ -108,9 +108,6 @@ At the moment, `StreamHeader.length` is a redundant information as it could be c
 `StreamHeader.height` in combination with `StreamHeader.mode`.
 But if data compression will be supported in future versions, it will become important.
 
-In case of `Mode::RGB24` and `Mode::RGB216` it seems strange to append 16 + 256 zeros to the end of the header.
-But for effency and maintainability we decided to work with a fixed header size for all modes.
-
 ### Examples
 
 To send a RGB24 image of 4x2 pixels, you have to sent these two packages:
@@ -122,8 +119,6 @@ To send a RGB24 image of 4x2 pixels, you have to sent these two packages:
 0x04 0x00                                          // width 4 (if your system is big endian, the byte order needs to be swapped)
 0x02 0x00                                          // height 2 (if your system is big endian, the byte order needs to be swapped)
 0x18 0x00 0x00 0x00                                // length 24 (if your system is big endian, the byte order needs to be swapped)
-0x00 ...                                           // 16 bytes of zeros
-0x00 ...                                           // 256 bytes of zeros
 ```
 
 ```

include/DMDUtil/DMD.h

@@ -97,12 +97,17 @@ class DMDUTILAPI DMD
 
   struct StreamHeader
   {
-    char protocol[10] = "DMDStream";
+    char header[10] = "DMDStream";
     uint8_t version = 1;
     Mode mode = Mode::Data;  // int
     uint16_t width = 0;
     uint16_t height = 0;
     uint32_t length = 0;
+  };
+
+  struct AltColorHeader
+  {
+    char header[9] = "AltColor";
     char name[DMDUTIL_MAX_NAME_SIZE] = {0};
     char path[DMDUTIL_MAX_ALTCOLORPATH_SIZE] = {0};
   };

src/DMD.cpp

@@ -297,10 +297,12 @@ void DMD::QueueUpdate(Update dmdUpdate)
 
         if (m_pDMDServerConnector)
         {
-          StreamHeader header;
-          strcpy(header.name, m_romName);
-          strcpy(header.path, m_altColorPath);
-          m_pDMDServerConnector->write_n(&header, sizeof(StreamHeader));
+          StreamHeader streamHeader;
+          m_pDMDServerConnector->write_n(&streamHeader, sizeof(StreamHeader));
+          AltColorHeader altColorHeader;
+          strcpy(altColorHeader.name, m_romName);
+          strcpy(altColorHeader.path, m_altColorPath);
+          m_pDMDServerConnector->write_n(&altColorHeader, sizeof(AltColorHeader));
           m_pDMDServerConnector->write_n(&dmdUpdate, sizeof(Update));
         }
       })

src/dmdServer.cpp

@@ -47,7 +47,7 @@ void DMDUTILCALLBACK LogCallback(const char* format, va_list args)
 void run(sockpp::tcp_socket sock, uint32_t threadId)
 {
   uint8_t buffer[sizeof(DMDUtil::DMD::Update)];
-  DMDUtil::DMD::StreamHeader* pHeader = (DMDUtil::DMD::StreamHeader*)malloc(sizeof(DMDUtil::DMD::StreamHeader));
+  DMDUtil::DMD::StreamHeader* pStreamHeader = (DMDUtil::DMD::StreamHeader*)malloc(sizeof(DMDUtil::DMD::StreamHeader));
   ssize_t n;
 
   while ((n = sock.read_n(buffer, sizeof(DMDUtil::DMD::StreamHeader))) > 0)
@@ -56,44 +56,55 @@ void run(sockpp::tcp_socket sock, uint32_t threadId)
     {
       // At the moment the server only listens on localhost.
       // Therefore, we don't have to take care about litte vs. big endian and can use memcpy.
-      memcpy(pHeader, buffer, n);
-      if (strcmp(pHeader->protocol, "DMDStream") == 0 && pHeader->version == 1)
+      memcpy(pStreamHeader, buffer, n);
+      if (strcmp(pStreamHeader->header, "DMDStream") == 0 && pStreamHeader->version == 1)
       {
-        switch (pHeader->mode)
+        switch (pStreamHeader->mode)
         {
           case DMDUtil::DMD::Mode::Data:
-            if ((n = sock.read_n(buffer, sizeof(DMDUtil::DMD::Update))) == sizeof(DMDUtil::DMD::Update) &&
+            if ((n = sock.read_n(buffer, sizeof(DMDUtil::DMD::AltColorHeader))) ==
+                    sizeof(DMDUtil::DMD::AltColorHeader) &&
                 threadId == currentThreadId)
             {
-              DMDUtil::DMD::Update data;
-              memcpy(&data, buffer, n);
+              DMDUtil::DMD::AltColorHeader altColorHeader;
+              memcpy(&altColorHeader, buffer, n);
 
-              if (data.width <= DMDSERVER_MAX_WIDTH && data.height <= DMDSERVER_MAX_HEIGHT)
+              if (strcmp(altColorHeader.header, "AltColor") == 0 &&
+                  (n = sock.read_n(buffer, sizeof(DMDUtil::DMD::Update))) == sizeof(DMDUtil::DMD::Update) &&
+                  threadId == currentThreadId)
               {
-                pDmd->SetRomName(pHeader->name);
-                pDmd->SetAltColorPath(pHeader->path);
+                DMDUtil::DMD::Update data;
+                memcpy(&data, buffer, n);
 
-                pDmd->QueueUpdate(data);
+                if (data.width <= DMDSERVER_MAX_WIDTH && data.height <= DMDSERVER_MAX_HEIGHT)
+                {
+                  pDmd->SetRomName(altColorHeader.name);
+                  pDmd->SetAltColorPath(altColorHeader.path);
+
+                  pDmd->QueueUpdate(data);
+                }
               }
             }
             break;
 
           case DMDUtil::DMD::Mode::RGB16:
-            if ((n = sock.read_n(buffer, pHeader->length)) == pHeader->length && threadId == currentThreadId &&
-                pHeader->width <= DMDSERVER_MAX_WIDTH && pHeader->height <= DMDSERVER_MAX_HEIGHT)
+            if ((n = sock.read_n(buffer, pStreamHeader->length)) == pStreamHeader->length &&
+                threadId == currentThreadId && pStreamHeader->width <= DMDSERVER_MAX_WIDTH &&
+                pStreamHeader->height <= DMDSERVER_MAX_HEIGHT)
             {
               // At the moment the server only listens on localhost.
               // Therefore, we don't have to take care about litte vs. big endian and can use the buffer as uint16_t as
               // it is.
-              pDmd->UpdateRGB16Data((uint16_t*)buffer, pHeader->width, pHeader->height);
+              pDmd->UpdateRGB16Data((uint16_t*)buffer, pStreamHeader->width, pStreamHeader->height);
             }
             break;
 
           case DMDUtil::DMD::Mode::RGB24:
-            if ((n = sock.read_n(buffer, pHeader->length)) == pHeader->length && threadId == currentThreadId &&
-                pHeader->width <= DMDSERVER_MAX_WIDTH && pHeader->height <= DMDSERVER_MAX_HEIGHT)
+            if ((n = sock.read_n(buffer, pStreamHeader->length)) == pStreamHeader->length &&
+                threadId == currentThreadId && pStreamHeader->width <= DMDSERVER_MAX_WIDTH &&
+                pStreamHeader->height <= DMDSERVER_MAX_HEIGHT)
             {
-              pDmd->UpdateRGB24Data(buffer, pHeader->width, pHeader->height);
+              pDmd->UpdateRGB24Data(buffer, pStreamHeader->width, pStreamHeader->height);
             }
             break;
 
@@ -113,7 +124,7 @@ void run(sockpp::tcp_socket sock, uint32_t threadId)
   threads.erase(remove(threads.begin(), threads.end(), threadId), threads.end());
   currentThreadId = threads.back();
 
-  free(pHeader);
+  free(pStreamHeader);
 }
 
 int main(int argc, char* argv[])