fix for a compile bug & added TF_DeInit()

* done with changes but now segfaulting

* fixed the bug

* fix some bad indents

* some cleanings

* updated readme

.gitignore

@@ -27,7 +27,14 @@
 *.i*86
 *.x86_64
 *.hex
+*.bin
 
 # Debug files
 *.dSYM/
 *.su
+
+cmake-build-debug/
+tf.bin
+
+.idea/
+

CMakeLists.txt

@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 3.7)
+project(tf)
+
+set(CMAKE_CXX_STANDARD GNU89)
+
+set(SOURCE_FILES
+        demo/simple/test.c
+        demo/simple/TF_Config.h
+        demo/socket_demo/master.c
+        demo/socket_demo/slave.c
+        demo/socket_demo/TF_Config.h
+        demo/multipart_tx/test.c
+        demo/multipart_tx/TF_Config.h
+        demo/demo.c
+        demo/demo.h
+        TinyFrame.c
+        TinyFrame.h
+        TF_Config.example.h
+        demo/utils.c
+        demo/utils.h
+        )
+
+include_directories(demo/simple)
+
+add_executable(tf ${SOURCE_FILES})

README.md

@@ -1,56 +1,94 @@
 # 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.
+to build with `--std=gnu89` and later.
 
-Frames are protected by a checksum and contain a "unique" ID,
+TinyFrame is suitable for a wide range of applications, including inter-microcontroller 
-which can be used for chaining messages. Each peer uses a different
+communication, as a protocol for FTDI-based PC applications or for messaging through
-value for the first bit of all IDs it generates (the "master flag"
+UDP packets. If you find a good use for it, please let me know so I can add it here!
-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
+Frames can be protected by a checksum (~XOR, CRC16 or CRC32) and contain 
-particular ID. This allows for easy implementation of async communication.
+a unique ID field which can be used for chaining related messages. The highest bit 
+of the generated IDs is different in each peer to avoid collisions.
+Peers are functionally equivalent and can send messages to each other 
+(the names "master" and "slave" are used only for convenience and have special meaning 
+in the demos).
+
+The library lets you register listeners (callback functions) to wait for (1) any frame, (2)
+a particular frame Type, or (3) a specific message ID. This  high-level API lets you 
+easily implement various async communication patterns.
+
+TinyFrame is re-entrant and supports creating multiple instances with the limitation
+that their structure (field sizes and checksum type) must be the same. There is a support
+for adding multi-threaded access to a shared instance using a mutex (via a callback stub).
 
 ## Frame structure
 
-The frame makeup is inspired by that of SBMP (my other, more complicated
+All fields in the message frame have a configurable size (see the top of the header file).
-and advanced UART protocol library).
+By just changing a definition in the header, such as `TF_LEN_BYTES` (1, 2 or 4), the library
+seamlessly switches between `uint8_t`, `uint16_t` and `uint32_t`. Choose field lengths that
+best suit your application needs. 
+
+For example, you don't need 4 bytes (`uint32_t`) for the 
+length field if your payloads are 20 bytes long, using a 1-byte field (`uint8_t`) will save
+3 bytes. This may be significant if you high throughput.
 
 ```
-<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.
 
+- All TinyFrame functions, typedefs and macros start with the `TF_` prefix.
+- Both peers must include the library with the same parameters (configured at the top of the header file)
+- Start by calling `TF_Init()` with `TF_MASTER` or `TF_SLAVE` as the argument. This creates a handle.
+  Use `TF_InitStatic()` to avoid the use of malloc(). If multiple instances are used, you can tag them 
+  using the `tf.userdata` / `tf.usertag` field.
+- Implement `TF_WriteImpl()` - declared at the bottom of the header file as `extern`.
+  This function is used by `TF_Send()` and others to write bytes to your UART (or other physical layer).
+  A frame can be sent in it's entirety, or in multiple parts, depending on its size.
+- If you wish to use timeouts, periodically call `TF_Tick()`. The calling 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) and can also time-out ID listeners.
+- Bind Type or Generic listeners using `TF_AddTypeListener()` or `TF_AddGenericListener()`.
+- Send a message using `TF_Send()`, `TF_Query()`, `TF_SendSimple()`, `TF_QuerySimple()`.
+  Query functions take a listener callback (function pointer)that 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 msg boject you received, replacing the `data` pointer (and `len`) with response.
+- Manually reset the parser using `TF_ResetParser()`
 
-## Usage hints
+### Message 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.
+Listeners return an enum constant based on what should be done next - remove the listener, 
-- 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.
+keep it, renew it's timeout, or let some other listener handle the message.
 
-- 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.
+### Examples
 
-- The function `TF_Accept()` is used to handle received chars. Call this in your UART Rx interrupt handler or a similar place.
+You'll find various examples in the `demo/` folder. Each example has it's own Makefile,
+read it to see what options are available.
+
+The demos are written for Linux, some using sockets and `clone()` for background processing.
+They try to simulate real TinyFrame behavior in an embedded system with asynchronous 
+Rx and Tx. If you can't run the demos, the source files are still good as examples.

TF_Config.example.h

@@ -0,0 +1,74 @@
+//
+// TinyFrame configuration file.
+//
+// Rename to TF_Config.h
+//
+
+#ifndef TF_CONFIG_H
+#define TF_CONFIG_H
+
+#include <stdint.h>
+//#include <esp8266.h> // when using with esphttpd
+
+//----------------------------- 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 PEERS 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
+
+// Checksum type
+//#define TF_CKSUM_TYPE TF_CKSUM_NONE
+//#define TF_CKSUM_TYPE TF_CKSUM_XOR
+#define TF_CKSUM_TYPE TF_CKSUM_CRC16
+//#define TF_CKSUM_TYPE TF_CKSUM_CRC32
+
+// 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
+
+//----------------------- PLATFORM COMPATIBILITY ----------------------------
+
+// used for timeout tick counters - should be large enough for all used timeouts
+typedef uint16_t TF_TICKS;
+
+// used in loops iterating over listeners
+typedef uint8_t TF_COUNT;
+
+//----------------------------- PARAMETERS ----------------------------------
+
+// Maximum received payload size (static buffer)
+// Larger payloads will be rejected.
+#define TF_MAX_PAYLOAD_RX 1024
+// Size of the sending buffer. Larger payloads will be split to pieces and sent
+// in multiple calls to the write function. This can be lowered to reduce RAM usage.
+#define TF_SENDBUF_LEN 128
+
+// --- Listener counts - determine sizes of the static slot tables ---
+
+// Frame ID listeners (wait for response / multi-part message)
+#define TF_MAX_ID_LST   10
+// Frame Type listeners (wait for frame with a specific first payload byte)
+#define TF_MAX_TYPE_LST 10
+// Generic listeners (fallback if no other listener catches it)
+#define TF_MAX_GEN_LST  5
+
+// Timeout for receiving & parsing a frame
+// ticks = number of calls to TF_Tick()
+#define TF_PARSER_TIMEOUT_TICKS 10
+
+//------------------------- End of user config ------------------------------
+
+#endif //TF_CONFIG_H

TF_Integration.example.c

@@ -0,0 +1,28 @@
+#include "TinyFrame.h"
+
+/**
+ * This is an example of integrating TinyFrame into the application.
+ * 
+ * TF_WriteImpl() is required, the mutex functions are weak and can
+ * be removed if not used. They are called from all TF_Send/Respond functions.
+ * 
+ * Also remember to periodically call TF_Tick() if you wish to use the 
+ * listener timeout feature.
+ */
+
+void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, size_t len)
+{
+    // send to UART
+}
+
+/** Claim the TX interface before composing and sending a frame */
+void TF_ClaimTx(TinyFrame *tf)
+{
+    // take mutex
+}
+
+/** Free the TX interface after composing and sending a frame */
+void TF_ReleaseTx(TinyFrame *tf)
+{
+    // release mutex
+}

TinyFrame.h

@@ -1,167 +1,384 @@
 #ifndef TinyFrameH
 #define TinyFrameH
-//---------------------------------------------------------------------------
-#include <stdint.h>
-#include <stdbool.h>
-//---------------------------------------------------------------------------
-
-// Frame ID listeners (wait for response / multi-part message)
-#ifndef TF_MAX_ID_LST
-# 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 16
-#endif
-
-// Generic listeners (fallback if no other listener catches it)
-#ifndef TF_MAX_GEN_LST
-# define TF_MAX_GEN_LST  4
-#endif
-
-#define TF_NEXT_ID -1
-#define TF_ERROR -1
 
 /**
- * TinyFrame receive callback type.
+ * TinyFrame protocol library
- * @param frame_id - ID of the received frame
+ * 
- * @param buff - byte buffer with the payload
+ * (c) Ondřej Hruška 2017, MIT License 
- * @param len - number of bytes in the buffer
+ * no liability/warranty, free for any use, must retain this notice & license
- * @return true if the frame was consumed
+ * 
+ * Upstream URL: https://github.com/MightyPork/TinyFrame
  */
-typedef bool (*TinyFrameListener)(unsigned int frame_id,
+
-                                  const unsigned char *buff,
+#define TF_VERSION "2.0.1"
-                                  unsigned int len);
+
+//---------------------------------------------------------------------------
+#include <stdint.h>  // for uint8_t etc
+#include <stdbool.h> // for bool
+#include <stddef.h>  // for NULL
+#include <string.h>  // for memset()
+//---------------------------------------------------------------------------
+
+// Select checksum type (0 = none, 8 = ~XOR, 16 = CRC16 0x8005, 32 = CRC32)
+#define TF_CKSUM_NONE  0
+#define TF_CKSUM_XOR   8
+#define TF_CKSUM_CRC16 16
+#define TF_CKSUM_CRC32 32
+
+#include "TF_Config.h"
+
+//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
+
+
+#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 == TF_CKSUM_XOR || TF_CKSUM_TYPE == TF_CKSUM_NONE
+// ~XOR (if 0, still use 1 byte - it won't be used)
+typedef uint8_t TF_CKSUM;
+#elif TF_CKSUM_TYPE == TF_CKSUM_CRC16
+// CRC16
+typedef uint16_t TF_CKSUM;
+#elif TF_CKSUM_TYPE == TF_CKSUM_CRC32
+// CRC32
+typedef uint32_t TF_CKSUM;
+#else
+#error Bad value for TF_CKSUM_TYPE, must be 8, 16 or 32
+#endif
+
+//endregion
+
+//---------------------------------------------------------------------------
+
+// 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;
+
+/** Response from listeners */
+typedef enum {
+    TF_NEXT = 0,   //!< Not handled, let other listeners handle it
+    TF_STAY = 1,   //!< Handled, stay
+    TF_RENEW = 2,  //!< Handled, stay, renew - useful only with listener timeout
+    TF_CLOSE = 3,  //!< Handled, remove self
+} TF_Result;
+
+/** Data structure for sending / receiving messages */
+typedef struct _TF_MSG_STRUCT_ {
+    TF_ID frame_id;       //!< message ID
+    bool is_response;     //!< internal flag, set when using the Respond function. frame_id is then kept unchanged.
+    TF_TYPE type;         //!< received or sent message type
+    const uint8_t *data;  //!< buffer of received data or data to send. NULL = listener timed out, free userdata!
+    TF_LEN len;           //!< length of the buffer
+    void *userdata;       //!< here's a place for custom data; this data will be stored with the listener
+    void *userdata2;
+} TF_Msg;
+
+/**
+ * Clear message struct
+ */
+static inline void TF_ClearMsg(TF_Msg *msg)
+{
+    memset(msg, 0, sizeof(TF_Msg));
+}
+
+typedef struct TinyFrame_ TinyFrame;
+
+/**
+ * TinyFrame Type Listener callback
+ *
+ * @param frame_id - ID of the received frame
+ * @param type - type field from the message
+ * @param data - byte buffer with the application data
+ * @param len - number of bytes in the buffer
+ * @return listener result
+ */
+typedef TF_Result (*TF_Listener)(TinyFrame *tf, TF_Msg *msg);
+
+// -------------------------------------------------------------------
+
+// region Internal
+
+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_TYPE,         //!< Wait for message type
+    TFState_DATA,         //!< Receive payload
+    TFState_DATA_CKSUM    //!< Wait for Checksum
+};
+
+struct TF_IdListener_ {
+    TF_ID id;
+    TF_Listener fn;
+    TF_TICKS timeout;     // nr of ticks remaining to disable this listener
+    TF_TICKS timeout_max; // the original timeout is stored here
+    void *userdata;
+    void *userdata2;
+};
+
+struct TF_TypeListener_ {
+    TF_TYPE type;
+    TF_Listener fn;
+};
+
+struct TF_GenericListener_ {
+    TF_Listener fn;
+};
+
+/**
+ * Frame parser internal state.
+ */
+struct TinyFrame_ {
+    /* Public user data */
+    void *userdata;
+    uint32_t usertag;
+
+    // --- the rest of the struct is internal, do not access directly ---
+
+    /* Own state */
+    TF_Peer peer_bit;       //!< Own peer bit (unqiue to avoid msg ID clash)
+    TF_ID next_id;          //!< Next frame / frame chain ID
+
+    /* Parser state */
+    enum TFState_ state;
+    TF_TICKS parser_timeout_ticks;
+    TF_ID id;               //!< Incoming packet ID
+    TF_LEN len;             //!< Payload length
+    uint8_t data[TF_MAX_PAYLOAD_RX]; //!< Data byte buffer
+    TF_LEN rxi;             //!< Field size 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 --- */
+
+    /* Transaction callbacks */
+    struct TF_IdListener_ id_listeners[TF_MAX_ID_LST];
+    struct TF_TypeListener_ type_listeners[TF_MAX_TYPE_LST];
+    struct TF_GenericListener_ generic_listeners[TF_MAX_GEN_LST];
+
+    // Those counters are used to optimize look-up times.
+    // They point to the highest used slot number,
+    // or close to it, depending on the removal order.
+    TF_COUNT count_id_lst;
+    TF_COUNT count_type_lst;
+    TF_COUNT count_generic_lst;
+
+    // Buffer for building frames
+    uint8_t sendbuf[TF_SENDBUF_LEN];
+};
+
+// endregion
+
+// -------------------------------------------------------------------
 
 /**
  * Initialize the TinyFrame engine.
- * This can also be used to completely reset it (removing all listeners etc)
+ * This can also be used to completely reset it (removing all listeners etc).
+ *
+ * The field .userdata (or .usertag) can be used to identify different instances
+ * in the TF_WriteImpl() function etc. Set this field after the init.
+ *
+ * This function is a wrapper around TF_InitStatic that calls malloc() to obtain
+ * the instance.
+ *
  * @param peer_bit - peer bit to use for self
  */
-void TF_Init(bool peer_bit);
+TinyFrame *TF_Init(TF_Peer peer_bit);
+
+
+/**
+ * Initialize the TinyFrame engine using a statically allocated instance struct.
+ *
+ * The .userdata / .usertag field is preserved when TF_InitStatic is called.
+ *
+ * @param peer_bit - peer bit to use for self
+ */
+void TF_InitStatic(TinyFrame *tf, TF_Peer peer_bit);
+
+/**
+ * De-init the dynamically allocated TF instance
+ *
+ * @param tf
+ */
+void TF_DeInit(TinyFrame *tf);
 
 /**
  * Reset the frame parser state machine.
+ * This does not affect registered listeners.
  */
-void TF_ResetParser(void);
+void TF_ResetParser(TinyFrame *tf);
-
-/**
- * Accept incoming bytes & parse frames
- * @param buffer - byte buffer to process
- * @param count - nr of bytes in the buffer
- */
-void TF_Accept(const unsigned char *buffer, unsigned int count);
-
-/**
- * Accept a single incoming byte
- * @param c - a received char
- */
-void TF_AcceptChar(unsigned char c);
 
 /**
  * Register a frame type listener.
- * @param frame_type - frame ID to listen for
+ *
+ * @param msg - message (contains frame_id and userdata)
  * @param cb - callback
+ * @param timeout - timeout in ticks to auto-remove the listener (0 = keep forever)
  * @return slot index (for removing), or TF_ERROR (-1)
  */
-int TF_AddIdListener(unsigned int frame_id, TinyFrameListener cb);
+bool TF_AddIdListener(TinyFrame *tf, TF_Msg *msg, TF_Listener cb, TF_TICKS timeout);
+
+/**
+ * Remove a listener by the message ID it's registered for
+ *
+ * @param frame_id - the frame we're listening for
+ */
+bool TF_RemoveIdListener(TinyFrame *tf, TF_ID frame_id);
 
 /**
  * Register a frame type listener.
+ *
  * @param frame_type - frame type to listen for
  * @param cb - callback
  * @return slot index (for removing), or TF_ERROR (-1)
  */
-int TF_AddTypeListener(unsigned char frame_type, TinyFrameListener cb);
+bool TF_AddTypeListener(TinyFrame *tf, TF_TYPE frame_type, TF_Listener cb);
-
-/**
- * Register a generic listener.
- * @param cb - callback
- * @return slot index (for removing), or TF_ERROR (-1)
- */
-int TF_AddGenericListener(TinyFrameListener cb);
-
-/**
- * Remove any listener by the index received when registering it
- * @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);
+bool TF_RemoveTypeListener(TinyFrame *tf, TF_TYPE type);
 
 /**
- * Remove a callback by the function pointer
+ * Register a generic listener.
+ *
+ * @param cb - callback
+ * @return slot index (for removing), or TF_ERROR (-1)
+ */
+bool TF_AddGenericListener(TinyFrame *tf, TF_Listener cb);
+
+/**
+ * Remove a generic listener by function pointer
+ *
  * @param cb - callback function to remove
  */
-void TF_RemoveListenerFn(TinyFrameListener cb); // search all listener types
+bool TF_RemoveGenericListener(TinyFrame *tf, TF_Listener cb);
 
 /**
- * Compose a frame
+ * Send a frame, no listener
  *
- * @param outbuff - buffer to store the result in
+ * @param msg - message struct. ID is stored in the frame_id field
- * @param msgid - message ID is stored here, if not NULL
+ * @return success
- * @param payload - data buffer
- * @param len - payload size in bytes, 0 to use strlen
- * @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,
+bool TF_Send(TinyFrame *tf, TF_Msg *msg);
-               const unsigned char *payload, unsigned int payload_len,
-               int explicit_id);
 
 /**
- * Send a frame, and optionally attach an ID listener for response.
+ * Like TF_Send, but without the struct
+ */
+bool TF_SendSimple(TinyFrame *tf, TF_TYPE type, const uint8_t *data, TF_LEN len);
+
+/**
+ * Send a frame, and optionally attach an ID listener.
  *
- * @param payload - data to send
+ * @param msg - message struct. ID is stored in the frame_id field
- * @param payload_len - nr of bytes to send
+ * @param listener - listener waiting for the response (can be NULL)
- * @param id_ptr - store the ID here, NULL to don't store.
+ * @param timeout - listener expiry time in ticks
- *                 The ID may be used to unbind the listener after a timeout.
+ * @return success
- * @return listener ID if listener was attached, else -1 (FT_ERROR).
- *         If the listener arg was NULL, returned -1 does not indicate an error.
  */
-int TF_Send(const unsigned char *payload,
+bool TF_Query(TinyFrame *tf, TF_Msg *msg, TF_Listener listener, TF_TICKS timeout);
-             unsigned int payload_len,
-             TinyFrameListener listener, unsigned int *id_ptr);
 
 /**
- * A shorthand for TF_Send() with just one byte as the payload
+ * Like TF_Query, but without the struct
  */
-int TF_Send1(const unsigned char b0,
+bool TF_QuerySimple(TinyFrame *tf, TF_TYPE type, const uint8_t *data, TF_LEN len,
-             TinyFrameListener listener, unsigned int *id_ptr);
+                    TF_Listener listener, TF_TICKS timeout);
-
-/**
- * A shorthand for TF_Send() with just 2 bytes as the payload
- */
-int TF_Send2(const unsigned char b0,
-             const unsigned char b1,
-             TinyFrameListener listener, unsigned int *id_ptr);
 
 /**
  * Send a response to a received message.
  *
- * @param payload - data to send
+ * @param msg - message struct. ID is read from frame_id. set ->renew to reset listener timeout
- * @param payload_len - nr of bytes to send
+ * @return success
- * @param frame_id - ID of the original frame
  */
-void TF_Respond(const unsigned char *payload,
+bool TF_Respond(TinyFrame *tf, TF_Msg *msg);
-               unsigned int payload_len,
-               unsigned int frame_id);
 
 /**
- * Write implementation for TF, to be provided by user code.
+ * Renew an ID listener timeout externally (as opposed to by returning TF_RENEW from the ID listener)
- * This sends frames composed by TinyFrame to UART
+ *
+ * @param id - listener ID to renew
+ * @return true if listener was found and renewed
  */
-extern void TF_WriteImpl(const unsigned char *buff, unsigned int len);
+bool TF_RenewIdListener(TinyFrame *tf, TF_ID id);
+
+/**
+ * Accept incoming bytes & parse frames
+ *
+ * @param buffer - byte buffer to process
+ * @param count - nr of bytes in the buffer
+ */
+void TF_Accept(TinyFrame *tf, const uint8_t *buffer, size_t count);
+
+/**
+ * Accept a single incoming byte
+ *
+ * @param c - a received char
+ */
+void TF_AcceptChar(TinyFrame *tf, uint8_t c);
+
+/**
+ * This function should 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(TinyFrame *tf);
+
+// --- TO BE IMPLEMENTED BY USER ---
+
+/**
+ * 'Write bytes' function that sends data to UART
+ *
+ * ! Implement this in your application code !
+ */
+extern void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, size_t len);
+
+/** Claim the TX interface before composing and sending a frame */
+extern void TF_ClaimTx(TinyFrame *tf);
+
+/** Free the TX interface after composing and sending a frame */
+extern void TF_ReleaseTx(TinyFrame *tf);
 
 #endif

demo/demo.c

@@ -0,0 +1,226 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#include "demo.h"
+
+// those magic defines are needed so we can use clone()
+#define _GNU_SOURCE
+#define __USE_GNU
+
+#include <sched.h>
+
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <signal.h>
+#include <malloc.h>
+#include <stdlib.h>
+
+volatile int sockfd = -1;
+volatile bool conn_disband = false;
+
+TinyFrame *demo_tf;
+
+/**
+ * Close socket
+ */
+void demo_disconn(void)
+{
+    conn_disband = true;
+    if (sockfd >= 0) close(sockfd);
+}
+
+/**
+ * Demo WriteImpl - send stuff to our peer
+ *
+ * @param buff
+ * @param len
+ */
+void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, size_t len)
+{
+    printf("\033[32mTF_WriteImpl - sending frame:\033[0m\n");
+    dumpFrame(buff, len);
+    usleep(1000);
+
+    if (sockfd != -1) {
+        write(sockfd, buff, len);
+    }
+    else {
+        printf("\nNo peer!\n");
+    }
+}
+
+
+/**
+ * Client bg thread
+ *
+ * @param unused
+ * @return unused
+ */
+static int demo_client(void *unused)
+{
+    (void) unused;
+
+    ssize_t n = 0;
+    uint8_t recvBuff[1024];
+    struct sockaddr_in serv_addr;
+
+    printf("\n--- STARTING CLIENT! ---\n");
+
+    memset(recvBuff, '0', sizeof(recvBuff));
+    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+        printf("\n Error : Could not create socket \n");
+        return false;
+    }
+
+    memset(&serv_addr, '0', sizeof(serv_addr));
+
+    serv_addr.sin_family = AF_INET;
+    serv_addr.sin_port = htons(PORT);
+
+    if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
+        printf("\n inet_pton error occured\n");
+        return false;
+    }
+
+    if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
+        printf("\n Error : Connect Failed \n");
+        perror("PERROR ");
+        return false;
+    }
+
+    printf("\n Child Process \n");
+
+    while ((n = read(sockfd, recvBuff, sizeof(recvBuff) - 1)) > 0) {
+        printf("\033[36m--- RX %ld bytes ---\033[0m\n", n);
+        dumpFrame(recvBuff, (size_t) n);
+        TF_Accept(demo_tf, recvBuff, (size_t) n);
+    }
+    return 0;
+}
+
+/**
+ * Server bg thread
+ *
+ * @param unused
+ * @return unused
+ */
+static int demo_server(void *unused)
+{
+    (void) unused;
+    ssize_t n;
+    int listenfd = 0;
+    uint8_t recvBuff[1024];
+    struct sockaddr_in serv_addr;
+    int option;
+
+    printf("\n--- STARTING SERVER! ---\n");
+
+    listenfd = socket(AF_INET, SOCK_STREAM, 0);
+    memset(&serv_addr, '0', sizeof(serv_addr));
+
+    option = 1;
+    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (char *) &option, sizeof(option));
+
+    serv_addr.sin_family = AF_INET;
+    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+    serv_addr.sin_port = htons(PORT);
+
+    if (bind(listenfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
+        perror("Failed to bind");
+        return 1;
+    }
+
+    if (listen(listenfd, 10) < 0) {
+        perror("Failed to listen");
+        return 1;
+    }
+
+    while (1) {
+        printf("\nWaiting for client...\n");
+        sockfd = accept(listenfd, (struct sockaddr *) NULL, NULL);
+        setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *) &option, sizeof(option));
+        printf("\nClient connected\n");
+        conn_disband = false;
+
+        while ((n = read(sockfd, recvBuff, sizeof(recvBuff) - 1)) > 0 && !conn_disband) {
+            printf("\033[36m--- RX %ld bytes ---\033[0m\n", n);
+            dumpFrame(recvBuff, n);
+            TF_Accept(demo_tf, recvBuff, (size_t) n);
+        }
+
+        if (n < 0) {
+            printf("\n Read error \n");
+        }
+
+        printf("Closing socket\n");
+        close(sockfd);
+        sockfd = -1;
+    }
+    return 0;
+}
+
+/**
+ * Trap - clean up
+ *
+ * @param sig - signal that caused this
+ */
+static void signal_handler(int sig)
+{
+    (void) sig;
+    printf("Shutting down...");
+    demo_disconn();
+
+    exit(sig); // pass the signal through - this is nonstandard behavior but useful for debugging
+}
+
+/**
+ * Sleaping Beauty's fave function
+ */
+void demo_sleep(void)
+{
+    while (1) usleep(10);
+}
+
+/**
+ * Start the background thread
+ *
+ * Slave is started first and doesn't normally init transactions - but it could
+ *
+ * @param peer what peer we are
+ */
+void demo_init(TF_Peer peer)
+{
+    signal(SIGTERM, signal_handler);
+    signal(SIGINT, signal_handler);
+
+    int retc;
+    void *stack = malloc(8192);
+    if (stack == NULL) {
+        perror("Oh fuck");
+        signal_handler(9);
+        return;
+    }
+
+    printf("Starting %s...\n", peer == TF_MASTER ? "MASTER" : "SLAVE");
+
+    // CLONE_VM    --- share heap
+    // CLONE_FILES --- share stdout and stderr
+    if (peer == TF_MASTER) {
+        retc = clone(&demo_client, (char *) stack + 8192, CLONE_VM | CLONE_FILES, 0);
+    }
+    else {
+        retc = clone(&demo_server, (char *) stack + 8192, CLONE_VM | CLONE_FILES, 0);
+    }
+
+    if (retc == 0) {
+        perror("Clone fail");
+        signal_handler(9);
+        return;
+    }
+
+    printf("Thread started\n");
+}

demo/demo.h

@@ -0,0 +1,25 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#ifndef TF_DEMO_H
+#define TF_DEMO_H
+
+#include <stdbool.h>
+#include "../TinyFrame.h"
+#include "utils.h"
+
+#define PORT 9798
+
+extern TinyFrame *demo_tf;
+
+/** Sleep and wait for ^C */
+void demo_sleep(void);
+
+/** Init server - DOES NOT init TinyFrame! */
+void demo_init(TF_Peer peer);
+
+/** Disconnect client from the server - can be called by a server-side callback */
+void demo_disconn(void);
+
+#endif //TF_DEMO_H

demo/multipart_tx/Makefile

@@ -0,0 +1,12 @@
+CFILES=../utils.c ../../TinyFrame.c
+INCLDIRS=-I. -I.. -I../..
+CFLAGS=-O0 -ggdb --std=gnu99 -Wno-main -Wall -Wno-unused -Wextra $(CFILES) $(INCLDIRS)
+
+
+build: test.bin
+
+run: test.bin
+	./test.bin
+
+test.bin: test.c $(CFILES)
+	gcc test.c $(CFLAGS) -o test.bin

demo/multipart_tx/TF_Config.h

@@ -0,0 +1,25 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#ifndef TF_CONFIG_H
+#define TF_CONFIG_H
+
+#include <stdint.h>
+
+#define TF_ID_BYTES     1
+#define TF_LEN_BYTES    2
+#define TF_TYPE_BYTES   1
+#define TF_CKSUM_TYPE TF_CKSUM_CRC16
+#define TF_USE_SOF_BYTE 1
+#define TF_SOF_BYTE     0x01
+typedef uint16_t TF_TICKS;
+typedef uint8_t TF_COUNT;
+#define TF_MAX_PAYLOAD_RX 10240
+#define TF_SENDBUF_LEN 64
+#define TF_MAX_ID_LST   10
+#define TF_MAX_TYPE_LST 10
+#define TF_MAX_GEN_LST  5
+#define TF_PARSER_TIMEOUT_TICKS 10
+
+#endif //TF_CONFIG_H

demo/multipart_tx/test.c

@@ -0,0 +1,300 @@
+#include <stdio.h>
+#include <string.h>
+#include "../../TinyFrame.h"
+#include "../utils.h"
+
+TinyFrame *demo_tf;
+
+extern const char *romeo;
+
+/**
+ * This function should be defined in the application code.
+ * It implements the lowest layer - sending bytes to UART (or other)
+ */
+void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, size_t len)
+{
+    printf("--------------------\n");
+    printf("\033[32mTF_WriteImpl - sending frame:\033[0m\n");
+    dumpFrame(buff, len);
+
+    // Send it back as if we received it
+    TF_Accept(tf, buff, len);
+}
+
+/** An example listener function */
+TF_Result myListener(TinyFrame *tf, TF_Msg *msg)
+{
+    dumpFrameInfo(msg);
+    if (strcmp((const char *) msg->data, romeo) == 0) {
+        printf("FILE TRANSFERRED OK!\r\n");
+    }
+    else {
+        printf("FAIL!!!!\r\n");
+    }
+    return TF_STAY;
+}
+
+void main(void)
+{
+    TF_Msg msg;
+
+    // Set up the TinyFrame library
+    demo_tf = TF_Init(TF_MASTER); // 1 = master, 0 = slave
+    TF_AddGenericListener(demo_tf, myListener);
+
+    printf("------ Simulate sending a LOOONG message --------\n");
+
+    TF_ClearMsg(&msg);
+    msg.type = 0x22;
+    msg.data = (pu8) romeo;
+    msg.len = (TF_LEN) strlen(romeo);
+    TF_Send(demo_tf, &msg);
+}
+
+const char *romeo = "THE TRAGEDY OF ROMEO AND JULIET\n"
+    "\n"
+    "by William Shakespeare\n"
+    "\n"
+    "\n"
+    "\n"
+    "Dramatis Personae\n"
+    "\n"
+    "  Chorus.\n"
+    "\n"
+    "\n"
+    "  Escalus, Prince of Verona.\n"
+    "\n"
+    "  Paris, a young Count, kinsman to the Prince.\n"
+    "\n"
+    "  Montague, heads of two houses at variance with each other.\n"
+    "\n"
+    "  Capulet, heads of two houses at variance with each other.\n"
+    "\n"
+    "  An old Man, of the Capulet family.\n"
+    "\n"
+    "  Romeo, son to Montague.\n"
+    "\n"
+    "  Tybalt, nephew to Lady Capulet.\n"
+    "\n"
+    "  Mercutio, kinsman to the Prince and friend to Romeo.\n"
+    "\n"
+    "  Benvolio, nephew to Montague, and friend to Romeo\n"
+    "\n"
+    "  Tybalt, nephew to Lady Capulet.\n"
+    "\n"
+    "  Friar Laurence, Franciscan.\n"
+    "\n"
+    "  Friar John, Franciscan.\n"
+    "\n"
+    "  Balthasar, servant to Romeo.\n"
+    "\n"
+    "  Abram, servant to Montague.\n"
+    "\n"
+    "  Sampson, servant to Capulet.\n"
+    "\n"
+    "  Gregory, servant to Capulet.\n"
+    "\n"
+    "  Peter, servant to Juliet's nurse.\n"
+    "\n"
+    "  An Apothecary.\n"
+    "\n"
+    "  Three Musicians.\n"
+    "\n"
+    "  An Officer.\n"
+    "\n"
+    "\n"
+    "  Lady Montague, wife to Montague.\n"
+    "\n"
+    "  Lady Capulet, wife to Capulet.\n"
+    "\n"
+    "  Juliet, daughter to Capulet.\n"
+    "\n"
+    "  Nurse to Juliet.\n"
+    "\n"
+    "\n"
+    "  Citizens of Verona; Gentlemen and Gentlewomen of both houses;\n"
+    "    Maskers, Torchbearers, Pages, Guards, Watchmen, Servants, and\n"
+    "    Attendants.\n"
+    "\n"
+    "                            SCENE.--Verona; Mantua.\n"
+    "\n"
+    "\n"
+    "\n"
+    "                        THE PROLOGUE\n"
+    "\n"
+    "                        Enter Chorus.\n"
+    "\n"
+    "\n"
+    "  Chor. Two households, both alike in dignity,\n"
+    "    In fair Verona, where we lay our scene,\n"
+    "    From ancient grudge break to new mutiny,\n"
+    "    Where civil blood makes civil hands unclean.\n"
+    "    From forth the fatal loins of these two foes\n"
+    "    A pair of star-cross'd lovers take their life;\n"
+    "    Whose misadventur'd piteous overthrows\n"
+    "    Doth with their death bury their parents' strife.\n"
+    "    The fearful passage of their death-mark'd love,\n"
+    "    And the continuance of their parents' rage,\n"
+    "    Which, but their children's end, naught could remove,\n"
+    "    Is now the two hours' traffic of our stage;\n"
+    "    The which if you with patient ears attend,\n"
+    "    What here shall miss, our toil shall strive to mend.\n"
+    "                                                         [Exit.]\n"
+    "\n"
+    "\n"
+    "\n"
+    "\n"
+    "ACT I. Scene I.\n"
+    "Verona. A public place.\n"
+    "\n"
+    "Enter Sampson and Gregory (with swords and bucklers) of the house\n"
+    "of Capulet.\n"
+    "\n"
+    "\n"
+    "  Samp. Gregory, on my word, we'll not carry coals.\n"
+    "\n"
+    "  Greg. No, for then we should be colliers.\n"
+    "\n"
+    "  Samp. I mean, an we be in choler, we'll draw.\n"
+    "\n"
+    "  Greg. Ay, while you live, draw your neck out of collar.\n"
+    "\n"
+    "  Samp. I strike quickly, being moved.\n"
+    "\n"
+    "  Greg. But thou art not quickly moved to strike.\n"
+    "\n"
+    "  Samp. A dog of the house of Montague moves me.\n"
+    "\n"
+    "  Greg. To move is to stir, and to be valiant is to stand.\n"
+    "    Therefore, if thou art moved, thou runn'st away.\n"
+    "\n"
+    "  Samp. A dog of that house shall move me to stand. I will take\n"
+    "    the wall of any man or maid of Montague's.\n"
+    "\n"
+    "  Greg. That shows thee a weak slave; for the weakest goes to the\n"
+    "    wall.\n"
+    "\n"
+    "  Samp. 'Tis true; and therefore women, being the weaker vessels,\n"
+    "    are ever thrust to the wall. Therefore I will push Montague's men\n"
+    "    from the wall and thrust his maids to the wall.\n"
+    "\n"
+    "  Greg. The quarrel is between our masters and us their men.\n"
+    "\n"
+    "  Samp. 'Tis all one. I will show myself a tyrant. When I have\n"
+    "    fought with the men, I will be cruel with the maids- I will cut off\n"
+    "    their heads.\n"
+    "\n"
+    "  Greg. The heads of the maids?\n"
+    "\n"
+    "  Samp. Ay, the heads of the maids, or their maidenheads.\n"
+    "    Take it in what sense thou wilt.\n"
+    "\n"
+    "  Greg. They must take it in sense that feel it.\n"
+    "\n"
+    "  Samp. Me they shall feel while I am able to stand; and 'tis known I\n"
+    "    am a pretty piece of flesh.\n"
+    "\n"
+    "  Greg. 'Tis well thou art not fish; if thou hadst, thou hadst\n"
+    "    been poor-John. Draw thy tool! Here comes two of the house of\n"
+    "    Montagues.\n"
+    "\n"
+    "           Enter two other Servingmen [Abram and Balthasar].\n"
+    "\n"
+    "\n"
+    "  Samp. My naked weapon is out. Quarrel! I will back thee.\n"
+    "\n"
+    "  Greg. How? turn thy back and run?\n"
+    "\n"
+    "  Samp. Fear me not.\n"
+    "\n"
+    "  Greg. No, marry. I fear thee!\n"
+    "\n"
+    "  Samp. Let us take the law of our sides; let them begin.\n"
+    "\n"
+    "  Greg. I will frown as I pass by, and let them take it as they list.\n"
+    "\n"
+    "  Samp. Nay, as they dare. I will bite my thumb at them; which is\n"
+    "    disgrace to them, if they bear it.\n"
+    "\n"
+    "  Abr. Do you bite your thumb at us, sir?\n"
+    "\n"
+    "  Samp. I do bite my thumb, sir.\n"
+    "\n"
+    "  Abr. Do you bite your thumb at us, sir?\n"
+    "\n"
+    "  Samp. [aside to Gregory] Is the law of our side if I say ay?\n"
+    "\n"
+    "  Greg. [aside to Sampson] No.\n"
+    "\n"
+    "  Samp. No, sir, I do not bite my thumb at you, sir; but I bite my\n"
+    "    thumb, sir.\n"
+    "\n"
+    "  Greg. Do you quarrel, sir?\n"
+    "\n"
+    "  Abr. Quarrel, sir? No, sir.\n"
+    "\n"
+    "  Samp. But if you do, sir, am for you. I serve as good a man as\n"
+    "    you.\n"
+    "\n"
+    "  Abr. No better.\n"
+    "\n"
+    "  Samp. Well, sir.\n"
+    "\n"
+    "                        Enter Benvolio.\n"
+    "\n"
+    "\n"
+    "  Greg. [aside to Sampson] Say 'better.' Here comes one of my\n"
+    "    master's kinsmen.\n"
+    "\n"
+    "  Samp. Yes, better, sir.\n"
+    "\n"
+    "  Abr. You lie.\n"
+    "\n"
+    "  Samp. Draw, if you be men. Gregory, remember thy swashing blow.\n"
+    "                                                     They fight.\n"
+    "\n"
+    "  Ben. Part, fools! [Beats down their swords.]\n"
+    "    Put up your swords. You know not what you do.\n"
+    "\n"
+    "                          Enter Tybalt.\n"
+    "\n"
+    "\n"
+    "  Tyb. What, art thou drawn among these heartless hinds?\n"
+    "    Turn thee Benvolio! look upon thy death.\n"
+    "\n"
+    "  Ben. I do but keep the peace. Put up thy sword,\n"
+    "    Or manage it to part these men with me.\n"
+    "\n"
+    "  Tyb. What, drawn, and talk of peace? I hate the word\n"
+    "    As I hate hell, all Montagues, and thee.\n"
+    "    Have at thee, coward!                            They fight.\n"
+    "\n"
+    "     Enter an officer, and three or four Citizens with clubs or\n"
+    "                          partisans.\n"
+    "\n"
+    "\n"
+    "  Officer. Clubs, bills, and partisans! Strike! beat them down!\n"
+    "\n"
+    "  Citizens. Down with the Capulets! Down with the Montagues!\n"
+    "\n"
+    "           Enter Old Capulet in his gown, and his Wife.\n"
+    "\n"
+    "\n"
+    "  Cap. What noise is this? Give me my long sword, ho!\n"
+    "\n"
+    "  Wife. A crutch, a crutch! Why call you for a sword?\n"
+    "\n"
+    "  Cap. My sword, I say! Old Montague is come\n"
+    "    And flourishes his blade in spite of me.\n"
+    "\n"
+    "                 Enter Old Montague and his Wife.\n"
+    "\n"
+    "\n"
+    "  Mon. Thou villain Capulet!- Hold me not, let me go.\n"
+    "\n"
+    "  M. Wife. Thou shalt not stir one foot to seek a foe.\n"
+    "\n"
+    "                Enter Prince Escalus, with his Train.\n"
+    "\n"
+    "\n"
+    "END OF FILE\n";

demo/simple/Makefile

@@ -0,0 +1,11 @@
+CFILES=../utils.c ../../TinyFrame.c
+INCLDIRS=-I. -I.. -I../..
+CFLAGS=-O0 -ggdb --std=gnu99 -Wno-main -Wno-unused -Wall -Wextra $(CFILES) $(INCLDIRS)
+
+run: test.bin
+	./test.bin
+
+build: test.bin
+
+test.bin: test.c $(CFILES)
+	gcc test.c $(CFLAGS) -o test.bin

demo/simple/TF_Config.h

@@ -0,0 +1,25 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#ifndef TF_CONFIG_H
+#define TF_CONFIG_H
+
+#include <stdint.h>
+
+#define TF_ID_BYTES     1
+#define TF_LEN_BYTES    2
+#define TF_TYPE_BYTES   1
+#define TF_CKSUM_TYPE TF_CKSUM_CRC16
+#define TF_USE_SOF_BYTE 1
+#define TF_SOF_BYTE     0x01
+typedef uint16_t TF_TICKS;
+typedef uint8_t TF_COUNT;
+#define TF_MAX_PAYLOAD_RX 1024
+#define TF_SENDBUF_LEN 1024
+#define TF_MAX_ID_LST   10
+#define TF_MAX_TYPE_LST 10
+#define TF_MAX_GEN_LST  5
+#define TF_PARSER_TIMEOUT_TICKS 10
+
+#endif //TF_CONFIG_H

demo/simple/test.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <string.h>
+#include "../../TinyFrame.h"
+#include "../utils.h"
+
+TinyFrame *demo_tf;
+
+/**
+ * This function should be defined in the application code.
+ * It implements the lowest layer - sending bytes to UART (or other)
+ */
+void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, size_t len)
+{
+    printf("--------------------\n");
+    printf("\033[32mTF_WriteImpl - sending frame:\033[0m\n");
+    dumpFrame(buff, len);
+
+    // Send it back as if we received it
+    TF_Accept(tf, buff, len);
+}
+
+/** An example listener function */
+TF_Result myListener(TinyFrame *tf, TF_Msg *msg)
+{
+    dumpFrameInfo(msg);
+    return TF_STAY;
+}
+
+TF_Result testIdListener(TinyFrame *tf, TF_Msg *msg)
+{
+    printf("OK - ID Listener triggered for msg!\n");
+    dumpFrameInfo(msg);
+    return TF_CLOSE;
+}
+
+void main(void)
+{
+    TF_Msg msg;
+    const char *longstr = "Lorem ipsum dolor sit amet.";
+
+    // Set up the TinyFrame library
+    demo_tf = TF_Init(TF_MASTER); // 1 = master, 0 = slave
+    TF_AddGenericListener(demo_tf, myListener);
+
+    printf("------ Simulate sending a message --------\n");
+
+    TF_ClearMsg(&msg);
+    msg.type = 0x22;
+    msg.data = (pu8) "Hello TinyFrame";
+    msg.len = 16;
+    TF_Send(demo_tf, &msg);
+
+    msg.type = 0x33;
+    msg.data = (pu8) longstr;
+    msg.len = (TF_LEN) (strlen(longstr) + 1); // add the null byte
+    TF_Send(demo_tf, &msg);
+
+    msg.type = 0x44;
+    msg.data = (pu8) "Hello2";
+    msg.len = 7;
+    TF_Send(demo_tf, &msg);
+
+    msg.len = 0;
+    msg.type = 0x77;
+    TF_Query(demo_tf, &msg, testIdListener, 0);
+}

demo/socket_demo/Makefile

@@ -0,0 +1,17 @@
+CFILES=../demo.c ../utils.c ../../TinyFrame.c
+INCLDIRS=-I. -I.. -I../..
+CFLAGS=-O0 -ggdb --std=gnu99 -Wno-main -Wall -Wno-unused -Wextra $(CFILES) $(INCLDIRS)
+
+build: master.bin slave.bin
+
+master: master.bin
+	./master.bin
+
+slave: slave.bin
+	./slave.bin
+
+master.bin: master.c $(CFILES)
+	gcc master.c $(CFLAGS) -o master.bin
+
+slave.bin: slave.c $(CFILES)
+	gcc slave.c $(CFLAGS) -o slave.bin

demo/socket_demo/TF_Config.h

@@ -0,0 +1,25 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#ifndef TF_CONFIG_H
+#define TF_CONFIG_H
+
+#include <stdint.h>
+
+#define TF_ID_BYTES     1
+#define TF_LEN_BYTES    2
+#define TF_TYPE_BYTES   1
+#define TF_CKSUM_TYPE TF_CKSUM_CRC16
+#define TF_USE_SOF_BYTE 1
+#define TF_SOF_BYTE     0x01
+typedef uint16_t TF_TICKS;
+typedef uint8_t TF_COUNT;
+#define TF_MAX_PAYLOAD_RX 1024
+#define TF_SENDBUF_LEN 1024
+#define TF_MAX_ID_LST   10
+#define TF_MAX_TYPE_LST 10
+#define TF_MAX_GEN_LST  5
+#define TF_PARSER_TIMEOUT_TICKS 10
+
+#endif //TF_CONFIG_H

demo/socket_demo/master.c

@@ -0,0 +1,35 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#include <stdio.h>
+#include "../demo.h"
+
+TF_Result testIdListener(TinyFrame *tf, TF_Msg *msg)
+{
+    printf("testIdListener()\n");
+    dumpFrameInfo(msg);
+    return TF_CLOSE;
+}
+
+TF_Result testGenericListener(TinyFrame *tf, TF_Msg *msg)
+{
+    printf("testGenericListener()\n");
+    dumpFrameInfo(msg);
+    return TF_STAY;
+}
+
+int main(void)
+{
+    demo_tf = TF_Init(TF_MASTER);
+    TF_AddGenericListener(demo_tf, testGenericListener);
+
+    demo_init(TF_MASTER);
+
+    TF_SendSimple(demo_tf, 1, (pu8) "Ahoj", 5);
+    TF_SendSimple(demo_tf, 1, (pu8) "Hello", 6);
+
+    TF_QuerySimple(demo_tf, 2, (pu8) "Query!", 6, testIdListener, 0);
+
+    demo_sleep();
+}

demo/socket_demo/slave.c

@@ -0,0 +1,41 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#include <stdio.h>
+#include "../demo.h"
+
+TF_Result helloListener(TinyFrame *tf, TF_Msg *msg)
+{
+    printf("helloListener()\n");
+    dumpFrameInfo(msg);
+    return TF_STAY;
+}
+
+TF_Result replyListener(TinyFrame *tf, TF_Msg *msg)
+{
+    printf("replyListener()\n");
+    dumpFrameInfo(msg);
+    msg->data = (const uint8_t *) "response to query";
+    msg->len = (TF_LEN) strlen((const char *) msg->data);
+    TF_Respond(tf, msg);
+
+    // unsolicited reply - will not be handled by the ID listener, which is already gone
+    msg->data = (const uint8_t *) "SPAM";
+    msg->len = 5;
+    TF_Respond(tf, msg);
+
+    // unrelated message
+    TF_SendSimple(tf, 77, (const uint8_t *) "NAZDAR", 7);
+    return TF_STAY;
+}
+
+int main(void)
+{
+    demo_tf = TF_Init(TF_SLAVE);
+    TF_AddTypeListener(demo_tf, 1, helloListener);
+    TF_AddTypeListener(demo_tf, 2, replyListener);
+
+    demo_init(TF_SLAVE);
+    demo_sleep();
+}

demo/utils.c

@@ -0,0 +1,33 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#include "utils.h"
+#include <stdio.h>
+
+// helper func for testing
+void dumpFrame(const uint8_t *buff, size_t len)
+{
+    size_t i;
+    for (i = 0; i < len; i++) {
+        printf("%3u \033[94m%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\n");
+}
+
+void dumpFrameInfo(TF_Msg *msg)
+{
+    printf("\033[33mFrame info\n"
+               "  type: %02Xh\n"
+               "  data: \"%.*s\"\n"
+               "   len: %u\n"
+               "    id: %Xh\033[0m\n\n",
+           msg->type, msg->len, msg->data, msg->len, msg->frame_id);
+}

demo/utils.h

@@ -0,0 +1,26 @@
+//
+// Created by MightyPork on 2017/10/15.
+//
+
+#ifndef TF_UTILS_H
+#define TF_UTILS_H
+
+#include <stdio.h>
+#include "../TinyFrame.h"
+
+/** pointer to unsigned char */
+typedef unsigned char* pu8;
+
+/**
+ * Dump a binary frame as hex, dec and ASCII
+ */
+void dumpFrame(const uint8_t *buff, size_t len);
+
+/**
+ * Dump message metadata (not the content)
+ *
+ * @param msg
+ */
+void dumpFrameInfo(TF_Msg *msg);
+
+#endif //TF_UTILS_H

test.c

@@ -1,82 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include "TinyFrame.h"
-
-// helper func for testing
-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)
-{
-	printf("\033[32;1mTF_WriteImpl - sending frame:\033[0m\n");
-	dumpFrame(buff, len);
-}
-
-/** An example listener function */
-bool myListener(unsigned int frame_id, const unsigned char *buff, unsigned int len)
-{
-	printf("\033[33mrx frame %s, len %d, id %d\033[0m\n", buff, len, frame_id);
-
-	return false; // Do not unbind
-}
-
-void main()
-{
-	int i;
-	int msgid;
-	int len;
-	char buff[100];
-
-	// Set up the TinyFrame library
-	TF_Init(1); // 1 = master, 0 = slave
-
-	printf("------ Simulate sending a message --------\n");
-
-	// Send a message
-	//   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()
-
-
-	printf("------ Simulate receiving a message --------\n");
-
-	// Adding global listeners
-	//   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)
-	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");
-	dumpFrame(buff, len);
-
-	// Accept the frame
-	// You will normally call this method in the UART IRQ handler etc
-	TF_Accept(buff, len);
-}

utilities/payload_builder.c

@@ -0,0 +1,100 @@
+#include <string.h>
+#include "payload_builder.h"
+
+#define pb_check_capacity(pb, needed) \
+    if ((pb)->current + (needed) > (pb)->end) { \
+        if ((pb)->full_handler == NULL || !(pb)->full_handler(pb, needed)) (pb)->ok = 0; \
+    }
+
+/** Write from a buffer */
+bool pb_buf(PayloadBuilder *pb, const uint8_t *buf, uint32_t len)
+{
+    pb_check_capacity(pb, len);
+    if (!pb->ok) return false;
+
+    memcpy(pb->current, buf, len);
+    pb->current += len;
+    return true;
+}
+
+/** Write s zero terminated string */
+bool pb_string(PayloadBuilder *pb, const char *str)
+{
+    uint32_t len = (uint32_t) strlen(str);
+    pb_check_capacity(pb, len+1);
+    if (!pb->ok) return false;
+
+    memcpy(pb->current, str, len+1);
+    pb->current += len+1;
+    return true;
+}
+
+/** Write uint8_t to the buffer */
+bool pb_u8(PayloadBuilder *pb, uint8_t byte)
+{
+    pb_check_capacity(pb, 1);
+    if (!pb->ok) return false;
+
+    *pb->current++ = byte;
+    return true;
+}
+
+/** Write uint16_t to the buffer. */
+bool pb_u16(PayloadBuilder *pb, uint16_t word)
+{
+    pb_check_capacity(pb, 2);
+    if (!pb->ok) return false;
+
+    if (pb->bigendian) {
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) (word & 0xFF);
+    } else {
+        *pb->current++ = (uint8_t) (word & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+    }
+    return true;
+}
+
+/** Write uint32_t to the buffer. */
+bool pb_u32(PayloadBuilder *pb, uint32_t word)
+{
+    pb_check_capacity(pb, 4);
+    if (!pb->ok) return false;
+
+    if (pb->bigendian) {
+        *pb->current++ = (uint8_t) ((word >> 24) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 16) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) (word & 0xFF);
+    } else {
+        *pb->current++ = (uint8_t) (word & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 8) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 16) & 0xFF);
+        *pb->current++ = (uint8_t) ((word >> 24) & 0xFF);
+    }
+    return true;
+}
+
+/** Write int8_t to the buffer. */
+bool pb_i8(PayloadBuilder *pb, int8_t byte)
+{
+    return pb_u8(pb, ((union conv8){.i8 = byte}).u8);
+}
+
+/** Write int16_t to the buffer. */
+bool pb_i16(PayloadBuilder *pb, int16_t word)
+{
+    return pb_u16(pb, ((union conv16){.i16 = word}).u16);
+}
+
+/** Write int32_t to the buffer. */
+bool pb_i32(PayloadBuilder *pb, int32_t word)
+{
+    return pb_u32(pb, ((union conv32){.i32 = word}).u32);
+}
+
+/** Write 4-byte float to the buffer. */
+bool pb_float(PayloadBuilder *pb, float f)
+{
+    return pb_u32(pb, ((union conv32){.f32 = f}).u32);
+}

utilities/payload_builder.h

@@ -0,0 +1,110 @@
+#ifndef PAYLOAD_BUILDER_H
+#define PAYLOAD_BUILDER_H
+
+/**
+ * PayloadBuilder, part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2014-2017. MIT license.
+ * 
+ * The builder supports big and little endian which is selected when 
+ * initializing it or by accessing the bigendian struct field.
+ * 
+ * This module helps you with building payloads (not only for TinyFrame)
+ *
+ * The builder performs bounds checking and calls the provided handler when 
+ * the requested write wouldn't fit. Use the handler to realloc / flush the buffer
+ * or report an error.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include "type_coerce.h"
+
+typedef struct PayloadBuilder_ PayloadBuilder;
+
+/**
+ * Full buffer handler. 
+ * 
+ * 'needed' more bytes should be written but the end of the buffer was reached.
+ * 
+ * Return true if the problem was solved (e.g. buffer was flushed and the 
+ * 'current' pointer moved to the beginning).
+ * 
+ * If false is returned, the 'ok' flag on the struct is set to false
+ * and all following writes are discarded.
+ */
+typedef bool (*pb_full_handler)(PayloadBuilder *pb, uint32_t needed);
+
+struct PayloadBuilder_ {
+    uint8_t *start;   //!< Pointer to the beginning of the buffer
+    uint8_t *current; //!< Pointer to the next byte to be read
+    uint8_t *end;     //!< Pointer to the end of the buffer (start + length)
+    pb_full_handler full_handler; //!< Callback for buffer overrun
+    bool bigendian;   //!< Flag to use big-endian parsing
+    bool ok;          //!< Indicates that all reads were successful
+};
+
+// --- initializer helper macros ---
+
+/** Start the builder. */
+#define pb_start_e(buf, capacity, bigendian, full_handler) ((PayloadBuilder){buf, buf, (buf)+(capacity), full_handler, bigendian, 1})
+
+/** Start the builder in big-endian mode */
+#define pb_start_be(buf, capacity, full_handler) pb_start_e(buf, capacity, 1, full_handler)
+
+/** Start the builder in little-endian mode */
+#define pb_start_le(buf, capacity, full_handler) pb_start_e(buf, capacity, 0, full_handler)
+
+/** Start the parser in little-endian mode (default) */
+#define pb_start(buf, capacity, full_handler) pb_start_le(buf, capacity, full_handler)
+
+// --- utilities ---
+
+/** Get already used bytes count */
+#define pb_length(pb) ((pb)->current - (pb)->start)
+
+/** Reset the current pointer to start */
+#define pb_rewind(pb) do { pb->current = pb->start; } while (0)
+
+
+/** Write from a buffer */
+bool pb_buf(PayloadBuilder *pb, const uint8_t *buf, uint32_t len);
+
+/** Write a zero terminated string */
+bool pb_string(PayloadBuilder *pb, const char *str);
+
+/** Write uint8_t to the buffer */
+bool pb_u8(PayloadBuilder *pb, uint8_t byte);
+
+/** Write boolean to the buffer. */
+static inline bool pb_bool(PayloadBuilder *pb, bool b)
+{
+    return pb_u8(pb, (uint8_t) b);
+}
+
+/** Write uint16_t to the buffer. */
+bool pb_u16(PayloadBuilder *pb, uint16_t word);
+
+/** Write uint32_t to the buffer. */
+bool pb_u32(PayloadBuilder *pb, uint32_t word);
+
+/** Write int8_t to the buffer. */
+bool pb_i8(PayloadBuilder *pb, int8_t byte);
+
+/** Write char (int8_t) to the buffer. */
+static inline bool pb_char(PayloadBuilder *pb, char c)
+{
+    return pb_i8(pb, c);
+}
+
+/** Write int16_t to the buffer. */
+bool pb_i16(PayloadBuilder *pb, int16_t word);
+
+/** Write int32_t to the buffer. */
+bool pb_i32(PayloadBuilder *pb, int32_t word);
+
+/** Write 4-byte float to the buffer. */
+bool pb_float(PayloadBuilder *pb, float f);
+
+#endif // PAYLOAD_BUILDER_H

utilities/payload_parser.c

@@ -0,0 +1,121 @@
+#include "payload_parser.h"
+
+#define pp_check_capacity(pp, needed) \
+    if ((pp)->current + (needed) > (pp)->end) { \
+        if ((pp)->empty_handler == NULL || !(pp)->empty_handler(pp, needed)) {(pp)->ok = 0;} ; \
+    }
+
+void pp_skip(PayloadParser *pp, uint32_t num)
+{
+    pp->current += num;
+}
+
+uint8_t pp_u8(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 1);
+    if (!pp->ok) return 0;
+
+    return *pp->current++;
+}
+
+uint16_t pp_u16(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 2);
+    if (!pp->ok) return 0;
+
+    uint16_t x = 0;
+
+    if (pp->bigendian) {
+        x |= *pp->current++ << 8;
+        x |= *pp->current++;
+    } else {
+        x |= *pp->current++;
+        x |= *pp->current++ << 8;
+    }
+    return x;
+}
+
+uint32_t pp_u32(PayloadParser *pp)
+{
+    pp_check_capacity(pp, 4);
+    if (!pp->ok) return 0;
+
+    uint32_t x = 0;
+
+    if (pp->bigendian) {
+        x |= (uint32_t) (*pp->current++ << 24);
+        x |= (uint32_t) (*pp->current++ << 16);
+        x |= (uint32_t) (*pp->current++ << 8);
+        x |= *pp->current++;
+    } else {
+        x |= *pp->current++;
+        x |= (uint32_t) (*pp->current++ << 8);
+        x |= (uint32_t) (*pp->current++ << 16);
+        x |= (uint32_t) (*pp->current++ << 24);
+    }
+    return x;
+}
+
+const uint8_t *pp_tail(PayloadParser *pp, uint32_t *length)
+{
+    int32_t len = (int) (pp->end - pp->current);
+    if (!pp->ok || len <= 0) {
+        if (length != NULL) *length = 0;
+        return NULL;
+    }
+
+    if (length != NULL) {
+        *length = (uint32_t) len;
+    }
+
+    return pp->current;
+}
+
+/** Read int8_t from the payload. */
+int8_t pp_i8(PayloadParser *pp)
+{
+    return ((union conv8) {.u8 = pp_u8(pp)}).i8;
+}
+
+/** Read int16_t from the payload. */
+int16_t pp_i16(PayloadParser *pp)
+{
+    return ((union conv16) {.u16 = pp_u16(pp)}).i16;
+}
+
+/** Read int32_t from the payload. */
+int32_t pp_i32(PayloadParser *pp)
+{
+    return ((union conv32) {.u32 = pp_u32(pp)}).i32;
+}
+
+/** Read 4-byte float from the payload. */
+float pp_float(PayloadParser *pp)
+{
+    return ((union conv32) {.u32 = pp_u32(pp)}).f32;
+}
+
+/** Read a zstring */
+uint32_t pp_string(PayloadParser *pp, char *buffer, uint32_t maxlen)
+{
+    pp_check_capacity(pp, 1);
+    uint32_t len = 0;
+    while (len < maxlen-1 && pp->current != pp->end) {
+        char c = *buffer++ = *pp->current++;
+        if (c == 0) break;
+        len++;
+    }
+    *buffer = 0;
+    return len;
+}
+
+/** Read a buffer */
+uint32_t pp_buf(PayloadParser *pp, uint8_t *buffer, uint32_t maxlen)
+{
+    uint32_t len = 0;
+    while (len < maxlen && pp->current != pp->end) {
+        *buffer++ = *pp->current++;
+        len++;
+    }
+    return len;
+}

utilities/payload_parser.h

@@ -0,0 +1,143 @@
+#ifndef PAYLOAD_PARSER_H
+#define PAYLOAD_PARSER_H
+
+/**
+ * PayloadParser, part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2016-2017. MIT license.
+ * 
+ * This module helps you with parsing payloads (not only from TinyFrame).
+ * 
+ * The parser supports big and little-endian which is selected when 
+ * initializing it or by accessing the bigendian struct field.
+ *
+ * The parser performs bounds checking and calls the provided handler when 
+ * the requested read doesn't have enough data. Use the callback to take
+ * appropriate action, e.g. report an error.
+ * 
+ * If the handler function is not defined, the pb->ok flag is set to false
+ * (use this to check for success), and further reads won't have any effect 
+ * and always result in 0 or empty array.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include "type_coerce.h"
+
+typedef struct PayloadParser_ PayloadParser;
+
+/**
+ * Empty buffer handler. 
+ * 
+ * 'needed' more bytes should be read but the end was reached.
+ * 
+ * Return true if the problem was solved (e.g. new data loaded into 
+ * the buffer and the 'current' pointer moved to the beginning).
+ *  
+ * If false is returned, the 'ok' flag on the struct is set to false
+ * and all following reads will fail / return 0.
+ */
+typedef bool (*pp_empty_handler)(PayloadParser *pp, uint32_t needed);
+
+struct PayloadParser_ {
+    uint8_t *start;   //!< Pointer to the beginning of the buffer
+    uint8_t *current; //!< Pointer to the next byte to be read
+    uint8_t *end;     //!< Pointer to the end of the buffer (start + length)
+    pp_empty_handler empty_handler; //!< Callback for buffer underrun
+    bool bigendian;   //!< Flag to use big-endian parsing
+    bool ok;          //!< Indicates that all reads were successful
+};
+
+// --- initializer helper macros ---
+
+/** Start the parser. */
+#define pp_start_e(buf, length, bigendian, empty_handler) ((PayloadParser){buf, buf, (buf)+(length), empty_handler, bigendian, 1})
+
+/** Start the parser in big-endian mode */
+#define pp_start_be(buf, length, empty_handler) pp_start_e(buf, length, 1, empty_handler)
+
+/** Start the parser in little-endian mode */
+#define pp_start_le(buf, length, empty_handler) pp_start_e(buf, length, 0, empty_handler)
+
+/** Start the parser in little-endian mode (default) */
+#define pp_start(buf, length, empty_handler) pp_start_le(buf, length, empty_handler)
+
+// --- utilities ---
+
+/** Get remaining length */
+#define pp_length(pp) ((pp)->end - (pp)->current)
+
+/** Reset the current pointer to start */
+#define pp_rewind(pp) do { pp->current = pp->start; } while (0)
+
+
+/**
+ * @brief Get the remainder of the buffer.
+ *
+ * Returns NULL and sets 'length' to 0 if there are no bytes left.
+ *
+ * @param pp
+ * @param length : here the buffer length will be stored. NULL to do not store.
+ * @return the remaining portion of the input buffer
+ */
+const uint8_t *pp_tail(PayloadParser *pp, uint32_t *length);
+
+/** Read uint8_t from the payload. */
+uint8_t pp_u8(PayloadParser *pp);
+
+/** Read bool from the payload. */
+static inline int8_t pp_bool(PayloadParser *pp)
+{
+    return pp_u8(pp) != 0;
+}
+
+/** Skip bytes */
+void pp_skip(PayloadParser *pp, uint32_t num);
+
+/** Read uint16_t from the payload. */
+uint16_t pp_u16(PayloadParser *pp);
+
+/** Read uint32_t from the payload. */
+uint32_t pp_u32(PayloadParser *pp);
+
+/** Read int8_t from the payload. */
+int8_t pp_i8(PayloadParser *pp);
+
+/** Read char (int8_t) from the payload. */
+static inline int8_t pp_char(PayloadParser *pp)
+{
+    return pp_i8(pp);
+}
+
+/** Read int16_t from the payload. */
+int16_t pp_i16(PayloadParser *pp);
+
+/** Read int32_t from the payload. */
+int32_t pp_i32(PayloadParser *pp);
+
+/** Read 4-byte float from the payload. */
+float pp_float(PayloadParser *pp);
+
+/**
+ * Parse a zero-terminated string
+ *
+ * @param pp - parser
+ * @param buffer - target buffer
+ * @param maxlen - buffer size
+ * @return actual number of bytes, excluding terminator
+ */
+uint32_t pp_string(PayloadParser *pp, char *buffer, uint32_t maxlen);
+
+/**
+ * Parse a buffer
+ *
+ * @param pp - parser
+ * @param buffer - target buffer
+ * @param maxlen - buffer size
+ * @return actual number of bytes, excluding terminator
+ */
+uint32_t pp_buf(PayloadParser *pp, uint8_t *buffer, uint32_t maxlen);
+
+
+#endif // PAYLOAD_PARSER_H

utilities/type_coerce.h

@@ -0,0 +1,32 @@
+#ifndef TYPE_COERCE_H
+#define TYPE_COERCE_H
+
+/**
+ * Structs for conversion between types,
+ * part of the TinyFrame utilities collection
+ * 
+ * (c) Ondřej Hruška, 2016-2017. MIT license.
+ * 
+ * This is a support header file for PayloadParser and PayloadBuilder.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+union conv8 {
+    uint8_t u8;
+    int8_t i8;
+};
+
+union conv16 {
+    uint16_t u16;
+    int16_t i16;
+};
+
+union conv32 {
+    uint32_t u32;
+    int32_t i32;
+    float f32;
+};
+
+#endif // TYPE_COERCE_H