Can receive a packet

Author: FozzTexx

lib/bus/rs232/FujiBusPacket.cpp

@@ -1,12 +1,5 @@
 #include "FujiBusPacket.h"
 
-enum {
-    SLIP_END     = 0xC0,
-    SLIP_ESCAPE  = 0xDB,
-    SLIP_ESC_END = 0xDC,
-    SLIP_ESC_ESC = 0xDD,
-};
-
 typedef struct {
     uint8_t device;   /* Destination Device */
     uint8_t command;  /* Command */
@@ -47,7 +40,7 @@ std::string FujiBusPacket::decodeSLIP(const std::string &input)
             break;
     }
 
-    for (idx = 0; idx < input.size(); idx++)
+    for (idx++; idx < input.size(); idx++)
     {
         val = ptr[idx];
         if (val == SLIP_END)
@@ -96,11 +89,12 @@ std::string FujiBusPacket::encodeSLIP(const std::string &input)
     return output;
 }
 
-uint8_t FujiBusPacket::calcChecksum(const std::string &buf)
+uint8_t FujiBusPacket::calcChecksum(const std::string &input)
 {
     uint16_t idx, chk;
+    uint8_t *buf = (uint8_t *) input.data();
 
-    for (idx = chk = 0; idx < buf.size(); idx++)
+    for (idx = chk = 0; idx < input.size(); idx++)
         chk = ((chk + buf[idx]) >> 8) + ((chk + buf[idx]) & 0xFF);
     return (uint8_t) chk;
 }
@@ -121,6 +115,8 @@ bool FujiBusPacket::parse(const std::string &input)
         return false;
 
     decoded = decodeSLIP(input);
+    if (decoded.size() < sizeof(fujibus_header))
+        return false;
     hdr = (fujibus_header *) &decoded[0];
     if (hdr->length != decoded.size())
         return false;

lib/bus/rs232/FujiBusPacket.h

@@ -9,6 +9,13 @@
 #include <string>
 #include <memory>
 
+enum {
+    SLIP_END     = 0xC0,
+    SLIP_ESCAPE  = 0xDB,
+    SLIP_ESC_END = 0xDC,
+    SLIP_ESC_ESC = 0xDD,
+};
+
 class FujiBusPacket
 {
 private:
@@ -22,7 +29,7 @@ class FujiBusPacket
     FujiCommandID command;
     unsigned int fieldSize;
     std::vector<unsigned int> fields;
-    std::optional<std::string> data = nullptr;
+    std::optional<std::string> data = std::nullopt;
 
     FujiBusPacket(const std::string &input);
     std::string serialize();

lib/bus/rs232/rs232.cpp

@@ -177,9 +177,16 @@ void systemBus::_rs232_process_cmd()
 
     // Read CMD frame
     std::string packet;
-    int val;
-    while ((val = _port.read()) > -1)
+    int val, count;
+    for (count = 0; count < 2; )
+    {
+        val = _port.read();
+        if (val < 0)
+            break;
         packet.push_back(val);
+        if (val == SLIP_END)
+            count++;
+    }
 
     auto tempFrame = FujiBusPacket::fromSerialized(packet);
     if (!tempFrame)
@@ -253,12 +260,14 @@ void systemBus::service()
     {
         _modemDev->rs232_handle_modem();
     }
+#ifdef OBSOLETE
     else
     // Neither CMD nor active modem, so throw out any stray input data
     {
         //Debug_println("RS232 Srvc Flush");
         _port.discardInput();
     }
+#endif /* OBSOLETE */
 
     // Handle interrupts from network protocols
     for (int i = 0; i < 8; i++)

lib/hardware/IOChannel.cpp

@@ -70,7 +70,7 @@ int IOChannel::read(void)
     int result = read(buf, 1);
 
     if (result < 1)
-        return result;
+        return -1;
     return buf[0];
 }