dynamic library load - for squirrel

/* <aromaembed.h> */

#include <string.h>

#define TYPE_BOOL     'b'
#define TYPE_INT      'i'
#define TYPE_STRING   's'
#define TYPE_FLOAT    'f'
#define TYPE_DOUBLE   'd'
#define TYPE_POINTER  'p'

#define RET_BOOL_TRUE  1
#define RET_BOOL_FALSE 0

/* dynamic variable structure */
typedef struct{
  void * data;  /* data pointer */
  char   type;  /* data type */
  size_t sz;    /* data size */
} APP_VAR;

/* function argument structure */
typedef struct{
  APP_VAR * argv;     /* function arguments */
  int       argn;     /* number of arguments */
  APP_VAR   retval;   /* return value */
} APP_ARG;

/* function */
typedef int (*APP_FN)(APP_ARG *);

/* register function */
typedef struct{
  APP_FN fn;          /* callback */
  const char *  name; /* function name */
} APP_FN_REG;

inline int app_return_string(APP_ARG * v, char * str){
  if (v&&str){
    int len = strlen(str);
    char * out = (char *) malloc(len+1);
    snprintf(out,len+1,"%s",str);
    v->retval.data = (void *) out;
    v->retval.type = TYPE_STRING;
    v->retval.sz   = len;
    return 1;
  }
  return 0;
}

inline int app_return_int(APP_ARG * v, int value){
  if (v){
    int * out = (int *) malloc(sizeof(int));
    out[0]=value;
    v->retval.data = (void *) out;
    v->retval.type = TYPE_INT;
    v->retval.sz   = sizeof(int);
    return 1;
  }
  return 0;
}

inline int app_return_bool(APP_ARG * v, char value){
  if (v){
    char * out = (char *) malloc(sizeof(char));
    out[0]=value?1:0;
    v->retval.data = (void *) out;
    v->retval.type = TYPE_BOOL;
    v->retval.sz   = sizeof(char);
    return 1;
  }
  return 0;
}

inline int app_return_float(APP_ARG * v, float value){
  if (v){
    float * out = (float *) malloc(sizeof(float));
    out[0]=value;
    v->retval.data = (void *) out;
    v->retval.type = TYPE_DOUBLE;
    v->retval.sz   = sizeof(float);
    return 1;
  }
  return 0;
}

inline int app_return_double(APP_ARG * v, double value){
  if (v){
    double * out = (double *) malloc(sizeof(double));
    out[0]=value;
    v->retval.data = (void *) out;
    v->retval.type = TYPE_FLOAT;
    v->retval.sz   = sizeof(double);
    return 1;
  }
  return 0;
}

-------------------------------------------------------------------------------------------
/* EXAMPLE OF LIBRARY SOURCE */
<aromaembed.h>

int print_something(APP_ARG * v){
  if (v->argn==1){
    if (v->argv[0].type==TYPE_STRING){
      /* string */
      char * text = (char *) v->argv[0].data;
      printf("print_something with argument: %s",text);
    }
  }
  return 0; /* no return */
}

int get_ok(APP_ARG * v){
  return app_return_string(v, "OK");
}


int app_start(){
  return 1; /* have register */
}

static APP_FN_REG _app_func[]={
  { print_something, "print" },
  { get_ok, "get_ok" },
  { 0, 0 } /* end of app regs */
};

APP_FN_REG * app_reg(){
  return _app_func;
}

-------------------------------------------------------------------------------------------
/* nut/squirrel test */
if (Application.LoadLibrary("main.so","MainClass")){
  MainClass::print("Hello World");
  local retget = MainClass::get_ok();
  MainClass::print(retget);
}