syntax fixes for bad compilers

.gitignore

@@ -31,3 +31,9 @@
 # Debug files
 *.dSYM/
 *.su
+
+cmake-build-debug/
+tf.bin
+
+.idea/
+

CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.7)
+project(tf)
+
+set(CMAKE_CXX_STANDARD GNU89)
+
+set(SOURCE_FILES
+        test.c
+        TinyFrame.c
+        TinyFrame.h)
+
+add_executable(tf ${SOURCE_FILES})

Makefile

@@ -0,0 +1,10 @@
+build: tf.bin
+
+run: tf.bin
+	./tf.bin
+
+debug: tf.bin
+	gdb -q -ex run ./tf.bin
+
+tf.bin: test.c TinyFrame.c TinyFrame.h
+	gcc -Os --std=gnu89 -Wall -Wno-main -Wno-unused -Wextra test.c TinyFrame.c -I. -o tf.bin

README.md

@@ -1,56 +1,117 @@
 # TinyFrame
 
-TinyFrame is a simple library for building and parsing frames
+TinyFrame is a simple library for building and parsing frames to be sent 
-(packets) to be sent over a serial interface (like UART). It's implemented
+over a serial interface (e.g. UART, telnet etc.). The code is written 
-to be compatible with C89 and platform agnostic.
+in `--std=gnu89`.
 
-Frames are protected by a checksum and contain a "unique" ID,
+Frames are protected by a checksum (~XOR, CRC16 or CRC32) and contain 
-which can be used for chaining messages. Each peer uses a different
+a unique ID field, which can be used for chaining messages. The highest value 
-value for the first bit of all IDs it generates (the "master flag"
+of the ID is different for each peer (TF_MASTER or TF_SLAVE) to avoid collisions.
-or "peer_bit") to ensure there are no clashes. Typically the master
-(PC, main microcontroller) will use "1" and the surrogate (WiFi module,
-USB-serial connected gadget, display driver...) uses "0".
 
-The library lets you bind listeners waiting for any frame, or a
+All fields in the frame have configurable size (see the top of the header file).
-particular ID. This allows for easy implementation of async communication.
+By just changing a value, like `TF_LEN_BYTES`, the library seamlessly switches 
+from `uint8_t` to `uint16_t` or `uint32_t` to support longer payloads.
+
+The library lets you bind listeners waiting for any frame, a particular frame Type,
+or a specific message ID. This lets you easily implement asynchronous
+communication.
 
 ## Frame structure
 
-The frame makeup is inspired by that of SBMP (my other, more complicated
-and advanced UART protocol library).
-
 ```
-<SOF><ID><NOB><PAYLOAD><CKSUM>
+,-----+----+-----+------+------------+- - - -+------------,                
+| SOF | ID | LEN | TYPE | HEAD_CKSUM | DATA  | PLD_CKSUM  |                
+| 1   | ?  | ?   | ?    | ?          | ...   | ?          | <- size (bytes)
+'-----+----+-----+------+------------+- - - -+------------'                
 
-SOF ... start of frame, 0x01
+SOF ......... start of frame, 0x01
-ID  ... (master_flag | 7-bit counter) - the frame ID
+ID  ......... the frame ID (MSb is the peer bit)
-NOB ... nr of payload bytes in the frame (1..256)
+LEN ......... nr of data bytes in the frame
-PAYLOAD ... NOB bytes of data, can contain any byte values 1..256
+TYPE ........ message type (used to run Type Listeners, pick any values you like)
-CKSUM ... checksum, implemented as XOR of all preceding bytes in the message
+HEAD_CKSUM .. header checksum
+DATA ........ LEN bytes of data
+DATA_CKSUM .. checksum, implemented as XOR of all preceding bytes in the message
 ```
 
-The frame ID (in SBMP called "session ID") can be used to chain multiple related
+## Usage Hints
-messages and maintain the context this way. For example, a response may copy
-the frame ID of the request frame, which then triggers a callback bound by the
-requesting peer. Such behavior is application specific and is thus left to the
-upper layers of the protocol.
 
+- Both peers must include the library with the same parameters (config in the header file)
+- Start by calling `TF_Init()` with MASTER or SLAVE as the argument
+- Implement `TF_WriteImpl()` - declared at the bottom of the header file as `extern`.
+  This function is used by `TF_Send()` to write bytes to your UART (or other physical layer).
+  Presently, always a full frame is sent to this function.
+- If you wish to use `TF_PARSER_TIMEOUT_TICKS`, periodically call `TF_Tick()`. The period 
+  determines the length of 1 tick. This is used to time-out the parser in case it gets stuck 
+  in a bad state (such as receiving a partial frame).
+- Bind Type or Generic listeners using `TF_AddTypeListener()` or `TF_AddGenericListener()`.
+- Send a message using `TF_Send()` or the other Send functions.
+  If you provide a listener callback (function pointer) to the function,
+  the listener will be added as an ID listener and wait for a response.
+- To reply to a message (when your listener gets called), use `TF_Respond()`
+  with the same frame_id as in the received message.
+- Remove the ID listener using `TF_RemoveIdListener()` when it's no longer
+  needed. (Same for other listener types.) The slot count is limited.
+- If the listener function returns `false`, some other listener will get
+  a chance to handle it
+- Manually reset the parser using `TF_ResetParser()`
 
-## Usage hints
+### The concept of listeners
 
-- Both sides of the protocol (slave and master) should include the same TinyFrame
+Listeners are callback functions that are called by TinyFrame when a message which 
-code.
+they can handle is received.
-- Master inits the lib with `TF_Init(1);`, while slave uses `TF_Init(0);`. This is to avoid a message ID conflict.
-- Both sides can add Generic and Type listeners (callbacks) using `TF_AddGenericListener(func)` and `TF_AddTypeListener(type, func)`. The listener is a function as showin in the example file test.c or declared in TinyFrame.h
 
-  `bool myListener(unsigned int frame_id, const unsigned char *buff, unsigned int len) { ... }`
+There are 3 listener types:
  
-  The listener returns `true` if the message was consumed. If it returns `false`, it can be handled by some other listener (possibly a Generic Listener, if you added one)
+- ID listeners
-- A message is sent using `TF_Send()`, and to use it, the `TF_WriteImpl()` stub must be implemented in the application code. See `test.c` for an example.
+- Type listeners
+- Generic listeners
 
-  There are also helper functions `TF_Send1()` and `TF_Send2()` which send one or two bytes.
+They handle the message in this order, and if they decide not to handle it, they can return `false`
-- To reply, use `TF_Respond()` with ID same as in the received message (the listener gets this as it's argument). A listener provided as the last parameter to `TF_Send()` will be called after receiving the response.
+and let it be handled by some other listener, or discarded.
 
-- To remove a listener, use `TF_RemoveListener()`. *Always remove your ID listeners after handling the response!* There's a limit to the number of listeners.
+### Implementing "synchronous query"
 
-- The function `TF_Accept()` is used to handle received chars. Call this in your UART Rx interrupt handler or a similar place.
+Sometimes it's necessary to send a message and wait for a response to arrive.
+
+One (not too pretty) way to do this is using a global variable - pseudocode:
+
+```c
+#define MSG_PING 42
+
+static volatile bool got_response = false;
+
+/** ID listener */
+static bool onResponse(TF_ID frame_id, TF_TYPE type, const uint8_t *data, TF_LEN len)
+{
+    // ... Do something ... 
+    // (eg. copy data to a global variable)
+    
+    got_response = true;
+    return true;
+}
+
+bool syncQuery(void) 
+{
+    TF_ID id;
+    // Send our request, and bind an ID listener
+    got_response = false;
+    TF_Send0(MSG_PING, onResponse, &id); // Send0 sends zero bytes of data, just TYPE
+    
+    // the ID is now in `id` so we can remove the listener after a timeout
+    
+    // Wait for the response
+    bool suc = true;
+    while (!got_response) {
+        //delay()
+        if (/*timeout*/) {
+            TF_RemoveIdListener(id); // free the listener slot
+            return false;
+        }
+    }
+    
+    // ... Do something with the received data? ...
+    // (can be passed from the listener using a global variable)
+    
+    return true;
+}
+```

TinyFrame.c

@@ -3,31 +3,35 @@
 #include <string.h>
 //---------------------------------------------------------------------------
 
-/* Note: payload length determines the Rx buffer size. Max 256 */
+// Compatibility with ESP8266 SDK
-#define TF_MAX_PAYLOAD 256
+#ifdef ICACHE_FLASH_ATTR
-#define TF_SOF_BYTE 0x01
+	#define _TF_FN ICACHE_FLASH_ATTR
-
+#else
+	#define _TF_FN
+#endif
 
 enum TFState {
 	TFState_SOF = 0,      //!< Wait for SOF
+	TFState_LEN,          //!< Wait for Number Of Bytes
+	TFState_HEAD_CKSUM,   //!< Wait for header Checksum
 	TFState_ID,           //!< Wait for ID
-    TFState_NOB,      //!< Wait for Number Of Bytes
+	TFState_TYPE,         //!< Wait for message type
-    TFState_PAYLOAD,  //!< Receive payload
+	TFState_DATA,         //!< Receive payload
-    TFState_CKSUM     //!< Wait for Checksum
+	TFState_DATA_CKSUM    //!< Wait for Checksum
 };
 
 typedef struct _IdListener_struct {
-    unsigned int id;
+	TF_ID id;
-    TinyFrameListener fn;
+	TF_LISTENER fn;
 } IdListener;
 
 typedef struct _TypeListener_struct_ {
-    unsigned char type;
+	TF_TYPE type;
-    TinyFrameListener fn;
+	TF_LISTENER fn;
 } TypeListener;
 
 typedef struct _GenericListener_struct_ {
-    TinyFrameListener fn;
+	TF_LISTENER fn;
 } GenericListener;
 
 /**
@@ -35,16 +39,20 @@ typedef struct _GenericListener_struct_ {
  */
 static struct TinyFrameStruct {
 	/* Own state */
-    bool peer_bit;          //!< Own peer bit (unqiue to avoid msg ID clash)
+	TF_PEER peer_bit;       //!< Own peer bit (unqiue to avoid msg ID clash)
-    unsigned int next_id;   //!< Next frame / frame chain ID
+	TF_ID next_id;          //!< Next frame / frame chain ID
 
 	/* Parser state */
 	enum TFState state;
-    unsigned int id;        //!< Incoming packet ID
+	int parser_timeout_ticks;
-    unsigned int nob;       //!< Payload length
+	TF_ID id;               //!< Incoming packet ID
-    unsigned char pldbuf[TF_MAX_PAYLOAD+1]; //!< Payload byte buffer
+	TF_LEN len;             //!< Payload length
-    unsigned int rxi;       //!< Receive counter (for payload or other fields)
+	uint8_t data[TF_MAX_PAYLOAD]; //!< Data byte buffer
-    unsigned int cksum;     //!< Continually updated checksum
+	size_t rxi;             //!< Byte counter
+	TF_CKSUM cksum;         //!< Checksum calculated of the data stream
+	TF_CKSUM ref_cksum;     //!< Reference checksum read from the message
+	TF_TYPE type;           //!< Collected message type number
+	bool discard_data;      //!< Set if (len > TF_MAX_PAYLOAD) to read the frame, but ignore the data.
 
 	/* --- Callbacks --- */
 
@@ -53,301 +61,596 @@ static struct TinyFrameStruct {
 	TypeListener type_listeners[TF_MAX_TYPE_LST];
 	GenericListener generic_listeners[TF_MAX_GEN_LST];
 
-    char sendbuf[TF_MAX_PAYLOAD+1];
+	size_t count_id_lst;
+	size_t count_type_lst;
+	size_t count_generic_lst;
+
+	// Buffer for building frames
+	uint8_t sendbuf[TF_MAX_PAYLOAD + TF_OVERHEAD_BYTES];
 } tf;
 
-void TF_Init(bool peer_bit)
+//region Checksums
+
+#if TF_CKSUM_TYPE == 0
+
+// NONE
+#define CKSUM_RESET(cksum)
+#define CKSUM_ADD(cksum, byte)
+#define CKSUM_FINALIZE(cksum)
+
+#elif TF_CKSUM_TYPE == 8
+
+// ~XOR
+#define CKSUM_RESET(cksum) do { cksum = 0; } while (0)
+#define CKSUM_ADD(cksum, byte) do { cksum ^= byte; } while(0)
+#define CKSUM_FINALIZE(cksum)  do { cksum = (TF_CKSUM)~cksum; } while(0)
+
+#elif TF_CKSUM_TYPE == 16
+
+/** CRC table for the CRC-16. The poly is 0x8005 (x^16 + x^15 + x^2 + 1) */
+static const uint16_t crc16_table[256] = {
+	0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
+	0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
+	0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
+	0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
+	0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
+	0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
+	0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
+	0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
+	0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
+	0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
+	0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
+	0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
+	0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
+	0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
+	0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
+	0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
+	0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
+	0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
+	0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
+	0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
+	0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
+	0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
+	0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
+	0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
+	0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
+	0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
+	0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
+	0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
+	0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
+	0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
+	0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
+	0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
+};
+
+static inline uint16_t crc16_byte(uint16_t cksum, const uint8_t byte)
 {
+	return (cksum >> 8) ^ crc16_table[(cksum ^ byte) & 0xff];
+}
+
+#define CKSUM_RESET(cksum) do { cksum = 0; } while (0)
+#define CKSUM_ADD(cksum, byte) do { cksum = crc16_byte(cksum, byte); } while(0)
+#define CKSUM_FINALIZE(cksum)
+
+#elif TF_CKSUM_TYPE == 32
+
+static const uint32_t crc32_table[] = { /* CRC polynomial 0xedb88320 */
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+	0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+	0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+	0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+	0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+static inline uint32_t crc32_byte(uint32_t cksum, const uint8_t byte)
+{
+	return (crc32_table[((cksum) ^ ((uint8_t)byte)) & 0xff] ^ ((cksum) >> 8));
+}
+
+#define CKSUM_RESET(cksum) do { cksum = (TF_CKSUM)0xFFFFFFFF; } while (0)
+#define CKSUM_ADD(cksum, byte) do { cksum = crc32_byte(cksum, byte); } while(0)
+#define CKSUM_FINALIZE(cksum)  do { cksum = (TF_CKSUM)~cksum; } while(0)
+
+#endif
+
+//endregion
+
+
+void _TF_FN TF_Init(TF_PEER peer_bit)
+{
+	// Zero it out
 	memset(&tf, 0, sizeof(struct TinyFrameStruct));
 
 	tf.peer_bit = peer_bit;
 }
 
-void TF_ResetParser(void)
+//region Listeners
-{
-    tf.state = TFState_SOF;
-    tf.cksum = 0;
-}
 
-int TF_AddIdListener(unsigned int frame_id, TinyFrameListener cb)
+bool _TF_FN TF_AddIdListener(TF_ID frame_id, TF_LISTENER cb)
 {
-    int i;
+	size_t i;
-
 	for (i = 0; i < TF_MAX_ID_LST; i++) {
 		if (tf.id_listeners[i].fn == NULL) {
 			tf.id_listeners[i].fn = cb;
 			tf.id_listeners[i].id = frame_id;
-            return i;
+			if (i >= tf.count_id_lst) {
+				tf.count_id_lst = i + 1;
 			}
+			return true;
+		}
+	}
+	return false;
 }
 
-    return TF_ERROR;
+bool _TF_FN TF_AddTypeListener(TF_TYPE frame_type, TF_LISTENER cb)
-}
-
-int TF_AddTypeListener(unsigned char frame_type, TinyFrameListener cb)
 {
-    int i;
+	size_t i;
-
 	for (i = 0; i < TF_MAX_TYPE_LST; i++) {
 		if (tf.type_listeners[i].fn == NULL) {
 			tf.type_listeners[i].fn = cb;
 			tf.type_listeners[i].type = frame_type;
-            return TF_MAX_ID_LST + i;
+			if (i >= tf.count_type_lst) {
+				tf.count_type_lst = i + 1;
 			}
+			return true;
+		}
+	}
+	return false;
 }
 
-    return TF_ERROR;
+bool _TF_FN TF_AddGenericListener(TF_LISTENER cb)
-}
-
-int TF_AddGenericListener(TinyFrameListener cb)
 {
-    int i;
+	size_t i;
-
 	for (i = 0; i < TF_MAX_GEN_LST; i++) {
 		if (tf.generic_listeners[i].fn == NULL) {
 			tf.generic_listeners[i].fn = cb;
-            return TF_MAX_ID_LST + TF_MAX_TYPE_LST + i;
+			if (i >= tf.count_generic_lst) {
+				tf.count_generic_lst = i + 1;
 			}
+			return true;
+		}
+	}
+	return false;
 }
 
-    return TF_ERROR;
+bool _TF_FN TF_RemoveIdListener(TF_ID frame_id)
-}
-
-void TF_RemoveListener(unsigned int index)
 {
-    // all listener arrays share common "address space"
+	size_t i;
-    if (index < TF_MAX_ID_LST) {
+	for (i = 0; i < tf.count_id_lst; i++) {
-        tf.id_listeners[index].fn = NULL;
+		if (tf.id_listeners[i].fn != NULL
-    }
+			&& tf.id_listeners[i].id == frame_id) {
-    else if (index < TF_MAX_ID_LST + TF_MAX_TYPE_LST) {
-        tf.type_listeners[index - TF_MAX_ID_LST].fn = NULL;
-    }
-    else if (index < TF_MAX_ID_LST + TF_MAX_TYPE_LST + TF_MAX_GEN_LST) {
-        tf.generic_listeners[index - TF_MAX_ID_LST - TF_MAX_TYPE_LST].fn = NULL;
-    }
-}
-
-void TF_RemoveIdListener(unsigned int frame_id)
-{
-    int i;
-    for (i = 0; i < TF_MAX_ID_LST; i++) {
-        if (tf.id_listeners[i].fn != NULL && tf.id_listeners[i].id == frame_id) {
 			tf.id_listeners[i].fn = NULL;
+			if (i == tf.count_id_lst - 1) {
+				tf.count_id_lst--;
+			}
+			return true;
 		}
 	}
+	return false;
 }
 
-void TF_RemoveTypeListener(unsigned char type)
+bool _TF_FN TF_RemoveTypeListener(TF_TYPE type)
 {
-    int i;
+	size_t i;
-    for (i = 0; i < TF_MAX_TYPE_LST; i++) {
+	for (i = 0; i < tf.count_type_lst; i++) {
-        if (tf.type_listeners[i].fn != NULL && tf.type_listeners[i].type == type) {
+		if (tf.type_listeners[i].fn != NULL
+			&& tf.type_listeners[i].type == type) {
 			tf.type_listeners[i].fn = NULL;
+			if (i == tf.count_type_lst - 1) {
+				tf.count_type_lst--;
+			}
+			return true;
 		}
 	}
+	return false;
 }
 
-void TF_RemoveListenerFn(TinyFrameListener cb)
+bool _TF_FN TF_RemoveGenericListener(TF_LISTENER cb)
 {
-    int i;
+	size_t i;
-
+	for (i = 0; i < tf.count_generic_lst; i++) {
-    for (i = 0; i < TF_MAX_ID_LST; i++) {
-        if (tf.id_listeners[i].fn == cb) {
-            tf.id_listeners[i].fn = NULL;
-        }
-    }
-
-    for (i = 0; i < TF_MAX_TYPE_LST; i++) {
-        if (tf.type_listeners[i].fn == cb) {
-            tf.type_listeners[i].fn = NULL;
-        }
-    }
-
-    for (i = 0; i < TF_MAX_GEN_LST; i++) {
 		if (tf.generic_listeners[i].fn == cb) {
 			tf.generic_listeners[i].fn = NULL;
+			if (i == tf.count_generic_lst - 1) {
+				tf.count_generic_lst--;
+			}
+			return true;
 		}
 	}
+	return false;
 }
 
-void TF_Accept(const unsigned char *buffer, unsigned int count)
+/** Handle a message that was just collected & verified by the parser */
+static void _TF_FN TF_HandleReceivedMessage(TF_ID frame_id, TF_TYPE type, uint8_t *data, TF_LEN data_len)
 {
-    unsigned int i;
+	size_t i;
 
+	// Any listener can consume the message (return true),
+	// or let someone else handle it.
+
+	// The loop upper bounds are the highest currently used slot index
+	// (or close to it, depending on the order of listener removals)
+
+	// ID listeners first
+	for (i = 0; i < tf.count_id_lst; i++) {
+		if (tf.id_listeners[i].fn && (tf.id_listeners[i].id == frame_id)) {
+			if (tf.id_listeners[i].fn(frame_id, type, data, data_len)) {
+				return;
+			}
+		}
+	}
+
+	// Type listeners
+	for (i = 0; i < tf.count_type_lst; i++) {
+		if (tf.type_listeners[i].fn && (tf.type_listeners[i].type == type)) {
+			if (tf.type_listeners[i].fn(frame_id, type, data, data_len)) {
+				return;
+			}
+		}
+	}
+
+	// Generic listeners
+	for (i = 0; i < tf.count_generic_lst; i++) {
+		if (tf.generic_listeners[i].fn) {
+			if (tf.generic_listeners[i].fn(frame_id, type, data, data_len)) {
+				return;
+			}
+		}
+	}
+}
+
+//endregion Listeners
+
+void _TF_FN TF_Accept(const uint8_t *buffer, size_t count)
+{
+	size_t i;
 	for (i = 0; i < count; i++) {
 		TF_AcceptChar(buffer[i]);
 	}
 }
 
-void TF_AcceptChar(unsigned char c)
+void _TF_FN TF_ResetParser(void)
 {
-    int i;
+	tf.state = TFState_SOF;
-    bool rv, brk;
+}
 
-    switch (tf.state)
+/** SOF was received */
+static void _TF_FN TF_ParsBeginFrame(void) {
+	// Reset state vars
+	CKSUM_RESET(tf.cksum);
+	#if TF_USE_SOF_BYTE
+		CKSUM_ADD(tf.cksum, TF_SOF_BYTE);
+	#endif
+
+	tf.discard_data = false;
+
+	// Enter ID state
+	tf.state = TFState_ID;
+	tf.rxi = 0;
+}
+
+void _TF_FN TF_AcceptChar(unsigned char c)
 {
+	// Timeout - clear
+	if (tf.parser_timeout_ticks >= TF_PARSER_TIMEOUT_TICKS) {
+		TF_ResetParser();
+	}
+	tf.parser_timeout_ticks = 0;
+
+// DRY snippet - collect multi-byte number from the input stream
+#define COLLECT_NUMBER(dest, type) dest = (type)(((dest) << 8) | c); \
+								   if (++tf.rxi == sizeof(type))
+
+	#if !TF_USE_SOF_BYTE
+		if (tf.state == TFState_SOF) {
+			TF_ParsBeginFrame();
+		}
+	#endif
+
+	switch (tf.state) {
 		case TFState_SOF:
 			if (c == TF_SOF_BYTE) {
-            tf.cksum = 0;
+				TF_ParsBeginFrame();
-            tf.state = TFState_ID;
 			}
 			break;
 
 		case TFState_ID:
-        tf.id = c;
+			CKSUM_ADD(tf.cksum, c);
-        tf.state = TFState_NOB;
+			COLLECT_NUMBER(tf.id, TF_ID) {
-        break;
+				// Enter LEN state
-
+				tf.state = TFState_LEN;
-    case TFState_NOB:
-        tf.nob = c + 1; // using 0..255 as 1..256
-        tf.state = TFState_PAYLOAD;
 				tf.rxi = 0;
-        break;
-
-    case TFState_PAYLOAD:
-        tf.pldbuf[tf.rxi++] = c;
-        if (tf.rxi == tf.nob) {
-            tf.state = TFState_CKSUM;
 			}
 			break;
 
-    case TFState_CKSUM:
+		case TFState_LEN:
-        tf.state = TFState_SOF;
+			CKSUM_ADD(tf.cksum, c);
+			COLLECT_NUMBER(tf.len, TF_LEN) {
+				// Enter TYPE state
+				tf.state = TFState_TYPE;
+				tf.rxi = 0;
+			}
+			break;
 
-        if (tf.cksum == (unsigned int)c) {
+		case TFState_TYPE:
-            // Add 0 at the end of the data in the buffer (useful if it was a string)
+			CKSUM_ADD(tf.cksum, c);
-            tf.pldbuf[tf.rxi] = '\0';
+			COLLECT_NUMBER(tf.type, TF_TYPE) {
-            brk = false;
+				#if TF_CKSUM_TYPE == 0
+					tf.state = TFState_DATA;
+					tf.rxi = 0;
+				#else
+					// enter HEAD_CKSUM state
+					tf.state = TFState_HEAD_CKSUM;
+					tf.rxi = 0;
+					tf.ref_cksum = 0;
+				#endif
+			}
+			break;
 
-            // Fire listeners
+		case TFState_HEAD_CKSUM:
-            for (i = 0; i < TF_MAX_ID_LST; i++) {
+			COLLECT_NUMBER(tf.ref_cksum, TF_CKSUM) {
-                if (tf.id_listeners[i].fn && tf.id_listeners[i].id == tf.id) {
+				// Check the header checksum against the computed value
-                    rv = tf.id_listeners[i].fn(tf.id, tf.pldbuf, tf.nob);
+				CKSUM_FINALIZE(tf.cksum);
-                    if (rv) {
+
-                        brk = true;
+				if (tf.cksum != tf.ref_cksum) {
+					TF_ResetParser();
 					break;
 				}
-                }
-            }
 
-            if (!brk) {
+				if (tf.len == 0) {
-                for (i = 0; i < TF_MAX_TYPE_LST; i++) {
+					TF_HandleReceivedMessage(tf.id, tf.type, NULL, 0);
-                    if (tf.type_listeners[i].fn &&
+					TF_ResetParser();
-                        tf.type_listeners[i].type == tf.pldbuf[0]) {
-                        rv = tf.type_listeners[i].fn(tf.id, tf.pldbuf, tf.nob);
-                        if (rv) {
-                            brk = true;
 					break;
 				}
-                    }
-                }
-            }
 
-            if (!brk) {
+				// Enter DATA state
-                for (i = 0; i < TF_MAX_GEN_LST; i++) {
+				tf.state = TFState_DATA;
-                    if (tf.generic_listeners[i].fn) {
+				tf.rxi = 0;
-                        rv = tf.generic_listeners[i].fn(tf.id, tf.pldbuf, tf.nob);
+
-                        if (rv) {
+				CKSUM_RESET(tf.cksum); // Start collecting the payload
+
+				if (tf.len >= TF_MAX_PAYLOAD) {
+					// ERROR - frame too long. Consume, but do not store.
+					tf.discard_data = true;
+				}
+			}
 			break;
-                        }
+
-                    }
+		case TFState_DATA:
-                }
+			if (tf.discard_data) {
-            }
+				tf.rxi++;
 			} else {
-            // Fail, return to base state
+				CKSUM_ADD(tf.cksum, c);
-            tf.state = TFState_SOF;
+				tf.data[tf.rxi++] = c;
+			}
+
+			if (tf.rxi == tf.len) {
+				#if TF_CKSUM_TYPE == 0
+					// All done
+					TF_HandleReceivedMessage(tf.id, tf.type, tf.data, tf.len);
+					TF_ResetParser();
+				#else
+					// Enter DATA_CKSUM state
+					tf.state = TFState_DATA_CKSUM;
+					tf.rxi = 0;
+					tf.ref_cksum = 0;
+				#endif
+			}
+			break;
+
+		case TFState_DATA_CKSUM:
+			COLLECT_NUMBER(tf.ref_cksum, TF_CKSUM) {
+				// Check the header checksum against the computed value
+				CKSUM_FINALIZE(tf.cksum);
+				if (!tf.discard_data && tf.cksum == tf.ref_cksum) {
+					TF_HandleReceivedMessage(tf.id, tf.type, tf.data, tf.len);
+				}
+
+				TF_ResetParser();
 			}
 			break;
 	}
-
-    // Update the checksum
-    tf.cksum ^= c;
 }
 
-int TF_Compose(unsigned char *outbuff, unsigned int *msgid,
+/**
-               const unsigned char *payload, unsigned int payload_len,
+ * Compose a frame (used internally by TF_Send and TF_Respond).
-               int explicit_id
+ * The frame can be sent using TF_WriteImpl(), or received by TF_Accept()
-) {
+ *
-    unsigned int i;
+ * @param outbuff - buffer to store the result in
-    unsigned int id;
+ * @param msgid - message ID is stored here, if not NULL
-    int xor;
+ * @param type - message type
+ * @param data - data buffer
+ * @param len - payload size in bytes
+ * @param explicit_id - ID to use in the frame (8-bit)
+ * @param use_expl_id - whether to use the previous param
+ * @return nr of bytes in outbuff used by the frame, TF_ERROR (-1) on failure
+ */
+static int _TF_FN TF_Compose(uint8_t *outbuff, TF_ID *id_ptr,
+			      TF_TYPE type,
+				  const uint8_t *data, TF_LEN data_len,
+				  TF_ID explicit_id, bool use_expl_id)
+{
+	int i;
+	uint8_t b;
+	TF_ID id;
+	TF_CKSUM cksum;
+	int pos = 0;
+
+	CKSUM_RESET(cksum);
 
 	// sanitize len
-    if (payload_len > TF_MAX_PAYLOAD) return TF_ERROR;
+	if (data_len > TF_MAX_PAYLOAD) {
-    if (payload_len == 0) payload_len = strlen(payload);
+		return TF_ERROR;
+	}
 
 	// Gen ID
-    if (explicit_id == TF_NEXT_ID) {
+	if (use_expl_id) {
-        id = tf.next_id++;
-        if (tf.peer_bit) {
-            id |= 0x80;
-        }
-
-        if (tf.next_id > 0x7F) {
-            tf.next_id = 0;
-        }
-    } else {
 		id = explicit_id;
 	}
-
+	else {
-    outbuff[0] = TF_SOF_BYTE;
+		id = (TF_ID) (tf.next_id++ & TF_ID_MASK);
-    outbuff[1] = id & 0xFF;
+		if (tf.peer_bit) {
-    outbuff[2] = (payload_len - 1) & 0xFF; // use 0..255 as 1..256
+			id |= TF_ID_PEERBIT;
-    memcpy(outbuff+3, payload, payload_len);
+		}
-
-    xor = 0;
-    for (i = 0; i < payload_len + 3; i++) {
-        xor ^= outbuff[i];
 	}
 
-    outbuff[payload_len + 3] = xor;
+	if (id_ptr != NULL)
+		*id_ptr = id;
 
-    if (msgid != NULL) *msgid = id;
+	// DRY helper for writing a multi-byte variable to the buffer
-
+#define WRITENUM_BASE(type, num, xtra) \
-    return payload_len + 4;
+	for (i = sizeof(type)-1; i>=0; i--) { \
+		b = (uint8_t)(num >> (i*8) & 0xFF); \
+		outbuff[pos++] = b; \
+		xtra; \
 	}
 	
-int TF_Send(const unsigned char *payload,
+#define _NOOP()
-             unsigned int payload_len,
+#define WRITENUM(type, num)       WRITENUM_BASE(type, num, _NOOP())
-             TinyFrameListener listener,
+#define WRITENUM_CKSUM(type, num) WRITENUM_BASE(type, num, CKSUM_ADD(cksum, b))
-             unsigned int *id_ptr)
+
+	// --- Start ---
+	CKSUM_RESET(cksum);
+
+	#if TF_USE_SOF_BYTE
+		outbuff[pos++] = TF_SOF_BYTE;
+		CKSUM_ADD(cksum, TF_SOF_BYTE);
+	#endif
+
+	WRITENUM_CKSUM(TF_ID, id);
+	WRITENUM_CKSUM(TF_LEN, data_len);
+	WRITENUM_CKSUM(TF_TYPE, type);
+
+	#if TF_CKSUM_TYPE != 0
+		CKSUM_FINALIZE(cksum);
+		WRITENUM(TF_CKSUM, cksum);
+	#endif
+
+	// --- payload begin ---
+	if (data_len > 0) {
+		CKSUM_RESET(cksum);
+
+		// DATA
+		for (i = 0; i < data_len; i++) {
+			b = data[i];
+			outbuff[pos++] = b;
+			CKSUM_ADD(cksum, b);
+		}
+
+		#if TF_CKSUM_TYPE != 0
+			CKSUM_FINALIZE(cksum);
+			WRITENUM(TF_CKSUM, cksum);
+		#endif
+	}
+
+	return pos;
+}
+
+bool _TF_FN TF_Send(TF_TYPE type,
+			 const uint8_t *payload, TF_LEN payload_len,
+			 TF_LISTENER listener,
+			 TF_ID *id_ptr)
 {
-    unsigned int msgid;
+	TF_ID msgid = 0;
 	int len;
-    int lstid = TF_ERROR;
+	len = TF_Compose(tf.sendbuf, &msgid, type, payload, payload_len, 0, false);
-    len = TF_Compose(tf.sendbuf, &msgid, payload, payload_len, TF_NEXT_ID);
+	if (len == TF_ERROR) return false;
-    if (listener) lstid = TF_AddIdListener(msgid, listener);
-    TF_WriteImpl(tf.sendbuf, len);
 
+	if (listener) TF_AddIdListener(msgid, listener);
 	if (id_ptr) *id_ptr = msgid;
 
-    return lstid;
+	TF_WriteImpl((const uint8_t *) tf.sendbuf, (TF_LEN)len);
+	return true;
 }
 
-void TF_Respond(const unsigned char *payload,
+// Like TF_Send, but with explicit frame ID
-               unsigned int payload_len,
+bool _TF_FN TF_Respond(TF_TYPE type,
-               unsigned int frame_id)
+				const uint8_t *data, TF_LEN data_len,
+				TF_ID frame_id)
 {
 	int len;
-    len = TF_Compose(tf.sendbuf, NULL, payload, payload_len, frame_id);
+	len = TF_Compose(tf.sendbuf, NULL, type, data, data_len, frame_id, true);
-    TF_WriteImpl(tf.sendbuf, len);
+	if (len == TF_ERROR) return false;
+
+	TF_WriteImpl(tf.sendbuf, (TF_LEN)len);
+	return true;
 }
 
-
+/**
-int TF_Send1(const unsigned char b0,
+ * Like TF_Send(), but with no data
-             TinyFrameListener listener,
+ */
-             unsigned int *id_ptr)
+bool _TF_FN TF_Send0(TF_TYPE type,
+			  TF_LISTENER listener,
+			  TF_ID *id_ptr)
 {
-    unsigned char b[] = {b0};
+	return TF_Send(type, NULL, 0, listener, id_ptr);
-    return TF_Send(b, 1, listener, id_ptr);
 }
 
-
+/**
-int TF_Send2(const unsigned char b0,
+ * Like TF_Send(), but with just 1 data byte
-             const unsigned char b1,
+ */
-             TinyFrameListener listener,
+bool _TF_FN TF_Send1(TF_TYPE type, uint8_t b1,
-             unsigned int *id_ptr)
+			  TF_LISTENER listener,
+			  TF_ID *id_ptr)
 {
-    unsigned char b[] = {b0, b1};
+	unsigned char b[] = {b1};
-    return TF_Send(b, 2, listener, id_ptr);
+	return TF_Send(type, b, 1, listener, id_ptr);
 }
+
+/**
+ * Like TF_Send(), but with just 2 data bytes
+ */
+bool _TF_FN TF_Send2(TF_TYPE type, uint8_t b1, uint8_t b2,
+			  TF_LISTENER listener,
+			  TF_ID *id_ptr)
+{
+	unsigned char b[] = {b1, b2};
+	return TF_Send(type, b, 2, listener, id_ptr);
+}
+
+/** Timebase hook - for timeouts */
+void _TF_FN TF_Tick(void)
+{
+	if (tf.parser_timeout_ticks < TF_PARSER_TIMEOUT_TICKS) {
+		tf.parser_timeout_ticks++;
+	}
+}
+

TinyFrame.h

@@ -1,45 +1,154 @@
 #ifndef TinyFrameH
 #define TinyFrameH
+
 //---------------------------------------------------------------------------
-#include <stdint.h>
+#include <stdint.h>  // for uint8_t etc
-#include <stdbool.h>
+#include <stdbool.h> // for bool
+#include <stdlib.h>  // for NULL
+//#include "messages.h" // for your message IDs (enum or defines)
+//#include <esp8266.h> // when using with esphttpd
 //---------------------------------------------------------------------------
 
+
+//----------------------------- PARAMETERS ----------------------------------
+
+// Maximum send / receive payload size (static buffers size)
+// Larger payloads will be rejected.
+#define TF_MAX_PAYLOAD 1024
+
+// --- Listener counts - determine sizes of the static slot tables ---
+
 // Frame ID listeners (wait for response / multi-part message)
-#ifndef TF_MAX_ID_LST
+#define TF_MAX_ID_LST   20
-# define TF_MAX_ID_LST   64
-#endif
-
 // Frame Type listeners (wait for frame with a specific first payload byte)
-#ifndef TF_MAX_TYPE_LST
+#define TF_MAX_TYPE_LST 20
-# define TF_MAX_TYPE_LST 16
-#endif
-
 // Generic listeners (fallback if no other listener catches it)
-#ifndef TF_MAX_GEN_LST
 #define TF_MAX_GEN_LST  4
+
+// Timeout for receiving & parsing a frame
+// ticks = number of calls to TF_Tick()
+#define TF_PARSER_TIMEOUT_TICKS 10
+
+//----------------------------- FRAME FORMAT ---------------------------------
+// The format can be adjusted to fit your particular application needs
+
+// If the connection is reliable, you can disable the SOF byte and checksums.
+// That can save up to 9 bytes of overhead.
+
+// ,-----+----+-----+------+------------+- - - -+------------,
+// | SOF | ID | LEN | TYPE | HEAD_CKSUM | DATA  | PLD_CKSUM  |
+// | 1   | ?  | ?   | ?    | ?          | ...   | ?          | <- size (bytes)
+// '-----+----+-----+------+------------+- - - -+------------'
+
+// !!! BOTH SIDES MUST USE THE SAME SETTINGS !!!
+
+// Adjust sizes as desired (1,2,4)
+#define TF_ID_BYTES     1
+#define TF_LEN_BYTES    2
+#define TF_TYPE_BYTES   1
+
+// Select checksum type (0 = none, 8 = ~XOR, 16 = CRC16 0x8005, 32 = CRC32)
+#define TF_CKSUM_TYPE   16
+
+// Use a SOF byte to mark the start of a frame
+#define TF_USE_SOF_BYTE 1
+// Value of the SOF byte (if TF_USE_SOF_BYTE == 1)
+#define TF_SOF_BYTE     0x01
+
+//------------------------- End of user config ------------------------------
+
+
+//----------------------------- USAGE HINTS ---------------------------------
+
+//---------------------------------------------------------------------------
+
+//region Resolve data types
+
+#if TF_LEN_BYTES == 1
+	typedef uint8_t TF_LEN;
+#elif TF_LEN_BYTES == 2
+	typedef uint16_t TF_LEN;
+#elif TF_LEN_BYTES == 4
+	typedef uint32_t TF_LEN;
+#else
+	#error Bad value of TF_LEN_BYTES, must be 1, 2 or 4
 #endif
 
-#define TF_NEXT_ID -1
+
+#if TF_TYPE_BYTES == 1
+	typedef uint8_t TF_TYPE;
+#elif TF_TYPE_BYTES == 2
+	typedef uint16_t TF_TYPE;
+#elif TF_TYPE_BYTES == 4
+	typedef uint32_t TF_TYPE;
+#else
+	#error Bad value of TF_TYPE_BYTES, must be 1, 2 or 4
+#endif
+
+
+#if TF_ID_BYTES == 1
+	typedef uint8_t TF_ID;
+#elif TF_ID_BYTES == 2
+	typedef uint16_t TF_ID;
+#elif TF_ID_BYTES == 4
+	typedef uint32_t TF_ID;
+#else
+	#error Bad value of TF_ID_BYTES, must be 1, 2 or 4
+#endif
+
+
+#if TF_CKSUM_TYPE == 8 || TF_CKSUM_TYPE == 0
+	// ~XOR (if 0, still use 1 byte - it won't be used)
+	typedef uint8_t TF_CKSUM;
+#elif TF_CKSUM_TYPE == 16
+	// CRC16
+	typedef uint16_t TF_CKSUM;
+#elif TF_CKSUM_TYPE == 32
+	// CRC32
+	typedef uint32_t TF_CKSUM;
+#else
+	#error Bad value for TF_CKSUM_TYPE, must be 8, 16 or 32
+#endif
+
+
+// Bytes added to TF_MAX_PAYLOAD for the send buffer size.
+#define TF_OVERHEAD_BYTES (1+sizeof(TF_ID)+sizeof(TF_LEN)+sizeof(TF_CKSUM)+sizeof(TF_TYPE)+sizeof(TF_CKSUM))
+
+//endregion
+
+//---------------------------------------------------------------------------
+
 #define TF_ERROR -1
 
+// Type-dependent masks for bit manipulation in the ID field
+#define TF_ID_MASK (TF_ID)(((TF_ID)1 << (sizeof(TF_ID)*8 - 1)) - 1)
+#define TF_ID_PEERBIT (TF_ID)((TF_ID)1 << ((sizeof(TF_ID)*8) - 1))
+
+//---------------------------------------------------------------------------
+
+/** Peer bit enum (used for init) */
+typedef enum {
+	TF_SLAVE = 0,
+	TF_MASTER = 1
+} TF_PEER;
+
 /**
- * TinyFrame receive callback type.
+ * TinyFrame Type Listener callback
  * @param frame_id - ID of the received frame
- * @param buff - byte buffer with the payload
+ * @param data - byte buffer with the application data
  * @param len - number of bytes in the buffer
  * @return true if the frame was consumed
  */
-typedef bool (*TinyFrameListener)(unsigned int frame_id,
+typedef bool (*TF_LISTENER)(TF_ID frame_id,
-                                  const unsigned char *buff,
+							TF_TYPE type,
-                                  unsigned int len);
+							const uint8_t *data, TF_LEN len);
 
 /**
  * Initialize the TinyFrame engine.
  * This can also be used to completely reset it (removing all listeners etc)
  * @param peer_bit - peer bit to use for self
  */
-void TF_Init(bool peer_bit);
+void TF_Init(TF_PEER peer_bit);
 
 /**
  * Reset the frame parser state machine.
@@ -51,13 +160,13 @@ void TF_ResetParser(void);
  * @param buffer - byte buffer to process
  * @param count - nr of bytes in the buffer
  */
-void TF_Accept(const unsigned char *buffer, unsigned int count);
+void TF_Accept(const uint8_t *buffer, size_t count);
 
 /**
  * Accept a single incoming byte
  * @param c - a received char
  */
-void TF_AcceptChar(unsigned char c);
+void TF_AcceptChar(uint8_t c);
 
 /**
  * Register a frame type listener.
@@ -65,7 +174,13 @@ void TF_AcceptChar(unsigned char c);
  * @param cb - callback
  * @return slot index (for removing), or TF_ERROR (-1)
  */
-int TF_AddIdListener(unsigned int frame_id, TinyFrameListener cb);
+bool TF_AddIdListener(TF_ID frame_id, TF_LISTENER cb);
+
+/**
+ * Remove a listener by the message ID it's registered for
+ * @param frame_id - the frame we're listening for
+ */
+bool TF_RemoveIdListener(TF_ID frame_id);
 
 /**
  * Register a frame type listener.
@@ -73,95 +188,90 @@ int TF_AddIdListener(unsigned int frame_id, TinyFrameListener cb);
  * @param cb - callback
  * @return slot index (for removing), or TF_ERROR (-1)
  */
-int TF_AddTypeListener(unsigned char frame_type, TinyFrameListener cb);
+bool TF_AddTypeListener(TF_TYPE frame_type, TF_LISTENER cb);
+
+/**
+ * Remove a listener by type.
+ * @param type - the type it's registered for
+ */
+bool TF_RemoveTypeListener(TF_TYPE type);
 
 /**
  * Register a generic listener.
  * @param cb - callback
  * @return slot index (for removing), or TF_ERROR (-1)
  */
-int TF_AddGenericListener(TinyFrameListener cb);
+bool TF_AddGenericListener(TF_LISTENER cb);
 
 /**
- * Remove any listener by the index received when registering it
+ * Remove a generic listener by function pointer
- * @param index - index in the callbacks table
- */
-void TF_RemoveListener(unsigned int index);
-
-/**
- * Remove a listener by the message ID it's registered for
- * @param frame_id - the frame we're listening for
- */
-void TF_RemoveIdListener(unsigned int frame_id);
-
-/**
- * Remove a listener by type.
- * @param type - the type it's registered for
- */
-void TF_RemoveTypeListener(unsigned char type);
-
-/**
- * Remove a callback by the function pointer
  * @param cb - callback function to remove
  */
-void TF_RemoveListenerFn(TinyFrameListener cb); // search all listener types
+bool TF_RemoveGenericListener(TF_LISTENER cb);
 
 /**
- * Compose a frame
+ * Send a frame, and optionally attach an ID listener.
  *
- * @param outbuff - buffer to store the result in
+ * @param type - message type
- * @param msgid - message ID is stored here, if not NULL
+ * @param data - data to send (can be NULL if 'data_len' is 0)
- * @param payload - data buffer
+ * @param data_len - nr of bytes to send
- * @param len - payload size in bytes, 0 to use strlen
+ * @param listener - listener waiting for the response
- * @param explicit_id - ID to use, TF_NEXT_ID (-1) to chose next free
- * @return nr of bytes in outbuff used by the frame, TF_ERROR (-1) on failure
- */
-int TF_Compose(unsigned char *outbuff, unsigned int *msgid,
-               const unsigned char *payload, unsigned int payload_len,
-               int explicit_id);
-
-/**
- * Send a frame, and optionally attach an ID listener for response.
- *
- * @param payload - data to send
- * @param payload_len - nr of bytes to send
  * @param id_ptr - store the ID here, NULL to don't store.
  *                 The ID may be used to unbind the listener after a timeout.
- * @return listener ID if listener was attached, else -1 (FT_ERROR).
+ * @return success
- *         If the listener arg was NULL, returned -1 does not indicate an error.
  */
-int TF_Send(const unsigned char *payload,
+bool TF_Send(TF_TYPE type, const uint8_t *data, TF_LEN data_len,
-             unsigned int payload_len,
+			 TF_LISTENER listener,
-             TinyFrameListener listener, unsigned int *id_ptr);
+			 TF_ID *id_ptr);
 
 /**
- * A shorthand for TF_Send() with just one byte as the payload
+ * Like TF_Send(), but no data, just the type
  */
-int TF_Send1(const unsigned char b0,
+bool TF_Send0(TF_TYPE type, TF_LISTENER listener, TF_ID *id_ptr);
-             TinyFrameListener listener, unsigned int *id_ptr);
 
 /**
- * A shorthand for TF_Send() with just 2 bytes as the payload
+ * Like TF_Send(), but with just 1 data byte
  */
-int TF_Send2(const unsigned char b0,
+bool TF_Send1(TF_TYPE type, uint8_t b1,
-             const unsigned char b1,
+			  TF_LISTENER listener,
-             TinyFrameListener listener, unsigned int *id_ptr);
+			  TF_ID *id_ptr);
+/**
+ * Like TF_Send(), but with just 2 data bytes
+ */
+bool TF_Send2(TF_TYPE type, uint8_t b1, uint8_t b2,
+			  TF_LISTENER listener,
+			  TF_ID *id_ptr);
 
 /**
  * Send a response to a received message.
  *
- * @param payload - data to send
+ * @param type - message type. If an ID listener is waiting for this response,
- * @param payload_len - nr of bytes to send
+ *               then 'type' can be used to pass additional information.
- * @param frame_id - ID of the original frame
+ *               Otherwise, 'type' can be used to handle the message using a TypeListener.
+ * @param data - data to send
+ * @param data_len - nr of bytes to send
+ * @param frame_id - ID of the response frame (re-use ID from the original message)
+ * @return success
  */
-void TF_Respond(const unsigned char *payload,
+bool TF_Respond(TF_TYPE type,
-               unsigned int payload_len,
+				const uint8_t *data, TF_LEN data_len,
-               unsigned int frame_id);
+				TF_ID frame_id);
 
 /**
- * Write implementation for TF, to be provided by user code.
+ * 'Write bytes' function that sends data to UART
- * This sends frames composed by TinyFrame to UART
+ *
+ * ! Implement this in your application code !
  */
-extern void TF_WriteImpl(const unsigned char *buff, unsigned int len);
+extern void TF_WriteImpl(const uint8_t *buff, TF_LEN len);
+
+/**
+ * This function must be called periodically.
+ *
+ * The time base is used to time-out partial frames in the parser and
+ * automatically reset it.
+ *
+ * (suggestion - call this in a SysTick handler)
+ */
+void TF_Tick(void);
 
 #endif

test.c

@@ -1,82 +1,77 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include "TinyFrame.h"
 
-// helper func for testing
+static void dumpFrame(const uint8_t *buff, TF_LEN len);
-static void dumpFrame(const unsigned char *buff, unsigned int len)
-{
-	int i;
-	for(i = 0; i < len; i++) {
-		printf("%3u %c\n", buff[i], buff[i]);
-	}
-	printf("--- end of frame ---\n");
-}
 
 /**
  * This function should be defined in the application code.
  * It implements the lowest layer - sending bytes to UART (or other)
  */
-void TF_WriteImpl(const unsigned char *buff, unsigned int len)
+void TF_WriteImpl(const uint8_t *buff, TF_LEN len)
 {
-	printf("\033[32;1mTF_WriteImpl - sending frame:\033[0m\n");
+	printf("--------------------\n");
+	printf("\033[32mTF_WriteImpl - sending frame:\033[0m\n");
 	dumpFrame(buff, len);
+
+	// Send it back as if we received it
+	TF_Accept(buff, len);
 }
 
 /** An example listener function */
-bool myListener(unsigned int frame_id, const unsigned char *buff, unsigned int len)
+bool myListener(TF_ID frame_id, TF_TYPE type, const uint8_t *buff, TF_LEN len)
 {
-	printf("\033[33mrx frame %s, len %d, id %d\033[0m\n", buff, len, frame_id);
+	printf("\033[33mRX frame\n"
-
+			   "  type: %02Xh\n"
-	return false; // Do not unbind
+			   "  data: \"%.*s\"\n"
+			   "   len: %u\n"
+			   "    id: %Xh\033[0m\n", type, len, buff, len, frame_id);
+	return true;
 }
 
-void main()
+bool testIdListener(TF_ID frame_id, TF_TYPE type, const uint8_t *buff, TF_LEN len)
 {
-	int i;
+	printf("OK - ID Listener triggered for msg (type %02X, id %Xh)!", type, frame_id);
-	int msgid;
+	return true;
-	int len;
+}
-	char buff[100];
 
+void main(void)
+{
 	// Set up the TinyFrame library
-	TF_Init(1); // 1 = master, 0 = slave
+	TF_Init(TF_MASTER); // 1 = master, 0 = slave
+	TF_AddGenericListener(myListener);
 
 	printf("------ Simulate sending a message --------\n");
 
-	// Send a message
+	TF_Send(0x22, (unsigned char*)"Hello TinyFrame", 16, NULL, NULL);
-	//   args - payload, length (0 = strlen), listener, id_ptr (for storing the frame ID)
-	//   (see the .h file for details)
-	TF_Send("Hello TinyFrame", 0, NULL, NULL);
-	// This builds the frame in an internal buffer and sends it to
-	//   TF_WriteImpl()
 
+	const char *longstr = "Lorem ipsum dolor sit amet.";
+	TF_Send(0x33, (unsigned char*)longstr, (TF_LEN)(strlen(longstr)+1), NULL, NULL);
 
-	printf("------ Simulate receiving a message --------\n");
+	TF_Send(0x44, (unsigned char*)"Hello2", 7, NULL, NULL);
 
-	// Adding global listeners
+	TF_Send0(0xF0, NULL, NULL);
-	//   Listeners can listen to any frame (fallback listeners),
-	//   or to a specific Frame Type (AddTypeListener). There are
-	//   also ID listeners that can be bound automatically in TF_Send().
-	//
-	//   Type listeners are matched by the first character of the payload,
-	//   ID listeners by the message ID (which is the same in the response as in the request)
-	TF_AddGenericListener(myListener);
-	//TF_AddTypeListener(0xF1, myTypeListener);
-	//TF_AddIdListener(msgID, myIdListener);
 
-	// This lets us compose a frame (it's also used internally by TF_Send and TF_Respond)
+	TF_Send1(0xF1, 'Q', NULL, NULL);
-	len = TF_Compose(buff,          // Buffer to write the frame to
-	                 &msgid,        // Int to store the message ID in
-	                 "ALPHA BETA",  // Payload bytes
-	                 5,             // Length - this will cut it at "ALPHA" (showing that it works)
-	                                //   For string, we can use "0" to use strlen() internally
-	                 TF_NEXT_ID);   // Message ID - we could specify a particular ID if we were
-	                                //   trying to build a response frame, which has the same ID
-	                                //   as the request it responds to.
 
-	printf("The frame we'll receive is:\n");
+	TF_Send2(0xF2, 'A', 'Z', NULL, NULL);
-	dumpFrame(buff, len);
 
-	// Accept the frame
+	TF_Send0(0x77, testIdListener, NULL);
-	// You will normally call this method in the UART IRQ handler etc
+}
-	TF_Accept(buff, len);
+
+// helper func for testing
+static void dumpFrame(const uint8_t *buff, TF_LEN len)
+{
+	int i;
+	for(i = 0; i < len; i++) {
+		printf("%3u \033[34m%02X\033[0m", buff[i], buff[i]);
+		if (buff[i] >= 0x20 && buff[i] < 127) {
+			printf(" %c", buff[i]);
+		} else {
+			printf(" \033[31m.\033[0m");
+		}
+		printf("\n");
+	}
+	printf("--- end of frame ---\n");
 }