libcw/README.md

# To Do

- Any socket function which takes a IP/port address should have a version which also takes a sockaddr_in*.
- Fix the time functions to make them more convenient and C++ish.
- implement floating point UI numbers
- UI needs a special UUID (not kInvalidId) to specify the 'root' UI element. See note in cwUi._createFromObj()
- Look at 'BUG' warnings in cwNumericConvert.h.
- cwObject must be able to parse without dynamic memory allocation into a fixed buffer
- cwObject must be able to be composed without dynamic memory allocation or from a fixed buffer.

- cwWebsock is allocating memory on send().
- cwWebsock: if the size of the recv and xmt buffer, as passed form the protocolArray[], is too small send() will fail without an error message.
This is easy to reproduce by simply decreasing the size of the buffers in the protocol array.

- Clean up the cwObject namespace - add an 'object' namespace inside 'cw'

- Add underscore to the member variables of object_t.


- logDefaultFormatter() in cwLog.cpp uses stack allocated memory in a way that could easily be exploited.

- lexIntMatcher() in cwLex.cpp doesn't handle 'e' notation correctly. See note in code.

- numeric_convert() in cwNumericConvert.h could be made more efficient using type_traits.

- numeric_convert() d_min is NOT zero, it's smallest positive number, this fails when src == 0.
  min value is now set to zero.

- The UI app id map should be validated after the UI is created.
In otherwords the parent/child pairs shoud actually exists.

- Add an ui::appIdToUuId() that returns the first matching appId, and then
optionally looks for duplicates as an error checking scheme. 

- thread needs setters and getters for internal variables

- change cwMpScNbQueue so that it does not require 'new'.

- cwAudioBuf.cpp - the ch->fn in update() does not have the correct memory fence.

- change file names to match object names

- (DONE) change all NULL's to nullptr

- (DONE) implement kTcpFl in cwTcpSocket.cpp

# UI Control Creation Protocol

The UI elements have four identifiers:

uuId  - An integer which is unique among all identifiers for a given cwUi object.
appId - A constant (enumerated) id assigned by the application. Unique among siblings.
jsId  - A string id used by Javascript to identify a control. Unique among siblings.
jsUuId - An integer which is unique among all identifers for the browser representation of a given cwUi object.

The 'jsId' is selected by the application when the object is created.
The 'jsUuId' is generated by the JS client when the UI element is created.
The 'uuId' is generated by the UI server when the JS client registers the control.
The 'appId' is assigned by the UI server when the JS client regsiters the control.

Client sends 'init' message.        
Server sends 'create' messages.      
Client sends 'register' messages.   
Server send' 'id_assign' messages.

# sockaddr_in reference


    #include <netinet/in.h>

    struct sockaddr_in {
        short            sin_family;   // e.g. AF_INET
        unsigned short   sin_port;     // e.g. htons(3490)
        struct in_addr   sin_addr;     // see struct in_addr, below
        char             sin_zero[8];  // zero this if you want to
    };

struct in_addr {
    unsigned long s_addr;  // load with inet_aton()
};



# Development Setup

1) Install libwebsockets.

```
    sudo dnf install g++ openssl-devel cmake
    cd sdk
    git clone https://libwebsockets.org/repo/libwebsockets
    cd libwebsockets
    mkdir build
    cd build
    cmake -DCMAKE_INSTALL_PREFIX:PATH=/home/kevin/sdk/libwebsockets/build/out ..
```

2) Environment setup:

    export LD_LIBRARY_PATH=~/sdk/libwebsockets/build/out/lib

# Raspberry Pi Build Notes:

    cd sdk
    mkdir libwebsockets
    cmake -DCMAKE_INSTALL_PREFIX:PATH=/home/pi/sdk/libwebsockets/build/out -DLWS_WITH_SSL=OFF ..
    make
    sudo make install

    apt install libasound2-dev