%% Integrate External C Functions with Instance-Specific Persistent Memory
% Integrate legacy C functions that use instance-specific persistent memory
% by using the Legacy Code Tool.
%
% With the Legacy Code Tool, you can:
%
% * Provide the legacy function specification.
% * Generate a C-MEX S-function that calls the legacy code during
% simulation.
% * Compile and build the generated S-function for simulation.
% * Generate a TLC block file and optional rtwmakecfg.m file that specifies
% how the generated code for a model calls the legacy code.


%   Copyright 1990-2015 The MathWorks, Inc.

%% Provide the Legacy Function Specification
% Legacy Code Tool functions take a specific data structure or array of
% structures as the argument. You can initialize the data structure by
% calling the function legacy_code() using 'initialize' as the first input.
% After initializing the structure, assign its properties to values
% corresponding to the legacy code being integrated. For detailed help on
% the properties, call <matlab:legacy_code('help') legacy_code('help')>.
% The prototypes of the legacy functions being called in this example are:
%
% void memory_bus_init(COUNTERBUS *mem, int32_T upper_sat, int32_T lower_sat);
%
% void memory_bus_step(COUNTERBUS *input, COUNTERBUS *mem, COUNTERBUS *output);
%
% mem is an instance-specific persistent memory for applying a one
% integration step delay.
% COUNTERBUS is a struct typedef defined in
% <matlab:rtwdemo_lct_util('edit','rtwdemo_lct_src/counterbus.h') counterbus.h>
% and implemented with a Simulink.Bus object in the base workspace. The 
% legacy source code is in the files
% <matlab:rtwdemo_lct_util('edit','rtwdemo_lct_src/memory_bus.h') memory_bus.h>, and
% <matlab:rtwdemo_lct_util('edit','rtwdemo_lct_src/memory_bus.c') memory_bus.c>.

evalin('base','load rtwdemo_lct_data.mat')

% rtwdemo_sfun_work
def = legacy_code('initialize');
def.SFunctionName = 'rtwdemo_sfun_work';
def.InitializeConditionsFcnSpec = ...
    'void memory_bus_init(COUNTERBUS work1[1], int32 p1, int32 p2)';
def.OutputFcnSpec = ...
    'void memory_bus_step(COUNTERBUS u1[1], COUNTERBUS work1[1], COUNTERBUS y1[1])';
def.HeaderFiles   = {'memory_bus.h'};
def.SourceFiles   = {'memory_bus.c'};
def.IncPaths      = {'rtwdemo_lct_src'}; 
def.SrcPaths      = {'rtwdemo_lct_src'}; 

%%  Generate an S-Function for Simulation
% To generate a C-MEX S-function according to the description provided by
% the input argument 'def', call the function legacy_code() again with the
% first input set to 'sfcn_cmex_generate'. The S-function calls the legacy
% functions during simulation.
% The source code for the S-function is in the file
% <matlab:rtwdemo_lct_util('edit','rtwdemo_sfun_work.c') rtwdemo_sfun_work.c>.

legacy_code('sfcn_cmex_generate', def);

%% Compile the Generated S-Function for Simulation
% After you generate the C-MEX S-function source file, to compile the S-function 
% for simulation with Simulink(R), call the function 
% legacy_code() again with the first input set to 'compile'. 

legacy_code('compile', def);

%% Generate a TLC Block File for Code Generation
% After you compile the S-function and use it in simulation, you can call
% the function legacy_code() again with the first input set to
% 'sfcn_tlc_generate' to generate a TLC block file. The block file
% specifies how the generated code for a model calls the legacy code. If
% you do not generate a TLC block file and you try to generate code for a
% model that includes the S-function, code generation fails. The TLC block
% file for the S-function is:
% <matlab:rtwdemo_lct_util('edit','rtwdemo_sfun_work.tlc') rtwdemo_sfun_work.tlc>.

legacy_code('sfcn_tlc_generate', def);

%% Generate an rtwmakecfg.m File for Code Generation
% After you create the TLC block file, you can call the function
% legacy_code() again with the first input set to 'rtwmakecfg_generate' 
% to generate an rtwmakecfg.m file to support code generation.
% If the required source and header files for the S-function are not 
% in the same folder as the S-function, and you want to add these 
% dependencies in the makefile produced during code generation, generate the rtwmakecfg.m 
% file.

legacy_code('rtwmakecfg_generate', def);

%% Generate a Masked S-Function Block for Calling the Generated S-Function
% After you compile the C-MEX S-function source, you can call the function
% legacy_code() again with the first input set to 'slblock_generate' to
% generate a masked S-function block that calls that S-function.  The
% software places the block in a new model. From there you can copy it to
% an existing model.

legacy_code('slblock_generate', def);

%% Show the Integration of the Model with Legacy Code
% The model <matlab:rtwdemo_lct_work rtwdemo_lct_work> 
% shows integration of the model with the legacy
% code.  The subsystem memory_bus serves as a harness for the call to the
% legacy C function.

open_system('rtwdemo_lct_work')
open_system('rtwdemo_lct_work/memory_bus')
sim('rtwdemo_lct_work')