SmartStr

typedef struct SmartStr_st
{
    char*   buff; //the actual string,
    int size; //the number of allocated bytes in our buffer,
    int len;  //the length of the data inside the buffer.
} SmartStr;

/*
    Just some simple constructors, the returned object has 'size'
    bytes allocated for the buffer and length = 0.
    (or strlen(text)+1 bytes allocated)
*/
SmartStr*   smart_str_empty_new(int size);
SmartStr*   smart_str_new(char* text);

/*
    our realloc function
    ps.: this is declared and defined in the implementation ('.c') file since
    it's a private function.

    This function will expand the buffer. The final size will be 'str->size' + 'space'.
*/
static void smart_str_expand(SmartStr* str, int space)
{
char* aux = (char*)malloc(sizeof(char)*(str->size + space));

    strcpy(aux, str->buffer);
    free(str->buffer);
    str->buffer = aux;
    str->size += space;
}

/*
    And finally, the append functions:
*/
SmartStr* smart_str_raw_append(SmartStr* a, char* b, int blength)
{
    if (a->size < (a->len + blength))
        smart_str_expand(a, a->length + blength);

    strcat(a->buffer, b);
    return a; //The return is just for compatibility with other string libraries.
}

SmartStr* smart_str_append(SmartStr* a, SmartStr* b)
{
    return smart_str_raw_append(a, b->buffer, b->len);
}