vcp_main.c

Source code for an Numeric Cmputer

    widget = malloc(sizeof(vcp_widget_t));
    if ( widget == NULL ) {
	printf( "get_child_widget(): unable to allocate memory\n" );
	return NULL;
    }
printf ( "  allocated\n" );
    /* zero the entire widget structure */
    cp = (char *)widget;
    for ( n = 0 ; n < sizeof(vcp_widget_t) ; n++ ) {
	*cp++ = 0;
    }
    /* initialize non-zero widget structures fields */
    widget->type = wdef;
    widget->parent = parent;
    widget->linenum = tf->tokenline;
printf ( "  inited\n" );
    /* link the widget to its parent */
    if ( parent != NULL ) {
	/* check if parent allows children */
	if ( ( parent->type->w_class_mask & CH_ONE ) == 0 ) {
	    printf ( "line %d: '%s' may not have child widgets\n",
		tf->tokenline, parent->type->name );
	    free_widget(widget);
	    return NULL;
	}
	/* check if it is a legal child of parent */
	if ( ( wdef->w_class & parent->type->w_class_mask ) == 0 ) {
	    printf ( "line %d: '%s' not permitted as child of '%s'\n",
		tf->tokenline, wdef->name, parent->type->name );
	    free_widget(widget);
	    return NULL;
	}
	if ( parent->child == NULL ) {
	    /* no existing child, link it */
	    parent->child = widget;
	} else {
	    /* parent has one child, does it support more than one? */
	    if ( ( parent->type->w_class_mask & CH_MANY ) == 0 ) {
		printf ( "line %d: '%s' can only have one child\n",
		    tf->tokenline, parent->type->name );
		free_widget(widget);
		return NULL;
	    }
	    /* link it as sibling of existing child(ren) */
	    wp = parent->child;
	    while ( wp->sibling != NULL ) {
		wp = wp->sibling;
	    }
	    wp->sibling = widget;
	}
    }
printf ( "  linked\n" );
    /* allocate the widget's private data */
    widget->priv_data = malloc(wdef->priv_data_size);
    if ( widget->priv_data == NULL ) {
	printf( "get_child_widget(): unable to allocate memory\n" );
	free_widget(widget);
	return NULL;
    }
printf ( "  pd allocated\n" );
    /* clear private data */
    cp = widget->priv_data;
    for ( n = 0 ; n < wdef->priv_data_size ; n++ ) {
	*cp++ = 0;
    }
printf ( "  pd cleared\n" );
    /* set default values for all attributes */
    adef = wdef->attribs;
    if ( adef != NULL ) {
	while ( adef->name != NULL ) {
	    if ( convert_attrib(adef, adef->deflt, widget->priv_data) != 0 ) {
		printf ( "(internal error) widget %s: %s\n", wdef->name, errbuf );
		free_widget(widget);
		return NULL;
	    }
	    adef++;
	}
    }
printf ( "  defaulted\n" );
    /* parse remainder of widget */
    while (1) {
	item_name = tf_get_token(tf);
	if ( item_name == NULL ) {
	    printf ( "line %d: unexpected EOF in widget '%s'\n",
		tf->tokenline, wdef->name );
	    free_widget(widget);
	    return NULL;
	} else if ( item_name[0] == '}' ) {
	    /* end of widget, check for any string attribs without values */
	    adef = widget->type->attribs;
	    if ( adef != NULL ) {
		while ( adef->name != NULL ) {
		    if ( adef->datatype == ATTRIB_STRING ) {
			/* point to attribute value */
			cp = *((char **)(widget->priv_data + adef->offset));
			if ( cp == NULL ) {
			    printf ( "line %d: attribute '%s' must be supplied for widget '%s'\n",
				tf->tokenline, adef->name, wdef->name );
			    free_widget(widget);
			    return NULL;
			}
		    }
		    adef++;
		}
	    }
	    return widget;
	} else if ( !isalnum(item_name[0]) ) {
	    printf ( "line %d: bad widget or attribute name: '%s'\n",
		tf->tokenline, item_name );
	    free_widget(widget);
	    return NULL;
	}
	delim = tf_get_token(tf);
	if ( delim == NULL ) {
	    printf ( "line %d: unexpected EOF in widget '%s'\n",
		tf->tokenline, wdef->name );
	    free_widget(widget);
	    return NULL;
	} else if ( delim[0] == '=' ) {
	    /* name is a attribute */
	    if ( get_attrib(widget, item_name, tf) != 0 ) {
		/* message already printed inside get_attrib() */
		free_widget(widget);
		return NULL;
	    }
	} else if ( delim[0] == '{' ) {
	    /* recurse deeper */
	    if ( get_child_widget(widget, item_name, tf) == NULL ) {
		/* message already printed inside get_child_widget() */
		free_widget(widget);
		return NULL;
	    }
	} else {
	    printf ( "line %d: expected '=' or '{' after '%s'\n",
			tf->tokenline, item_name );
	    free_widget(widget);
	    return NULL;
	}
    }
}


static int get_attrib(vcp_widget_t *widget, char *name, token_file_t *tf)
{
    vcp_widget_def_t *wdef;
    vcp_attrib_def_t *adef;
    char *value;

    wdef = widget->type;
    adef = wdef->attribs;
    if ( adef == NULL ) {
	printf ( "line %d: widget '%s' accepts no attributes\n",
	    tf->tokenline, wdef->name );
	return -1;
    }
    while (( adef->name != NULL ) && ( strcmp(adef->name, name) ) != 0 ) {
	adef++;
    }
    if ( adef->name == NULL ) {
	printf ( "line %d: attribute '%s' is invalid for widget '%s'\n",
	    tf->tokenline, name, wdef->name );
	return -1;
    }
    /* found a match for name */
    value = tf_get_token(tf);
    if ( value == NULL ) {
	printf ( "line %d: missing value for attribute '%s'\n",
	    tf->tokenline, name );
	return -1;
    }
    if ( convert_attrib(adef, value, widget->priv_data) != 0 ) {
	printf ( "line %d: %s\n", tf->tokenline, errbuf );
	return -1;
    }
    return 0;
}

static int convert_attrib(vcp_attrib_def_t *adef, char *value, void *base_addr)
{
    char *cp;
    double float_value;
    int int_value, bool_value;

    switch ( adef->datatype ) {
    case ATTRIB_FLOAT:
	float_value = strtod(value, &cp);
	if ( *cp != '\0' ) {
	    snprintf ( errbuf, ERRBUFLEN,
		"bad value for float attribute '%s': '%s'\n", adef->name, value );
	    return -1;
	}
	/* is this the default value */
	if ( value != adef->deflt ) {
	    /* no, token from an input file, free it */
	    free(value);
	}
	/* store value */
	*((double *)(base_addr + adef->offset)) = float_value;
	break;
    case ATTRIB_INT:
	int_value = strtol(value, &cp, 0);
	if ( *cp != '\0' ) {
	    snprintf ( errbuf, ERRBUFLEN,
		"bad value for integer attribute '%s': '%s'\n", adef->name, value );
	    return -1;
	}
	/* is this the default value */
	if ( value != adef->deflt ) {
	    /* no, token from an input file, free it */
	    free(value);
	}
	/* store value */
	*((int *)(base_addr + adef->offset)) = int_value;
	break;
    case ATTRIB_BOOL:
	if ( strcasecmp(value, "true" ) == 0 ) {
	    bool_value = 1;
	} else if ( strcasecmp(value, "t" ) == 0 ) {
	    bool_value = 1;
	} else if ( strcasecmp(value, "1" ) == 0 ) {
	    bool_value = 1;
	} else if ( strcasecmp(value, "false" ) == 0 ) {
	    bool_value = 0;
	} else if ( strcasecmp(value, "f" ) == 0 ) {
	    bool_value = 0;
	} else if ( strcasecmp(value, "0" ) == 0 ) {
	    bool_value = 0;
	} else {
	    snprintf ( errbuf, ERRBUFLEN,
		"bad value for boolean attribute '%s': '%s'\n", adef->name, value );
	    return -1;
	}
	/* is this the default value */
	if ( value != adef->deflt ) {
	    /* no, token from an input file, free it */
	    free(value);
	}
	/* store value */
	*((int *)(base_addr + adef->offset)) = bool_value;
	break;
    case ATTRIB_STRING:
	/* get previous value, if any */
	cp = *((char **)(base_addr + adef->offset));
	/* was there a non-default previous value? */
	if (( cp != NULL ) && ( cp != adef->deflt )) {
	    /* yes, it was a token from an input file, free it */
	    free(cp);
	}
	/* store value */
	*((char **)(base_addr + adef->offset)) = value;
	break;
    default:
	snprintf ( errbuf, ERRBUFLEN,
	    "(internal error) bad type for attribute '%s'\n", adef->name );
	return -1;
	break;
    }
    return 0;
}

static void free_widget(vcp_widget_t *widget)
{
    vcp_attrib_def_t *adef;
    char *cp;
    vcp_widget_t *wp;
    
    if ( widget == NULL ) {
	return;
    }
    /* first free any children */
    if ( widget->child != NULL ) {
	free_widget(widget->child);
    }
    /* then any younger siblings */
    if ( widget->sibling != NULL ) {
	free_widget(widget->sibling);
    }
    /* free any string attribute values */
    adef = widget->type->attribs;
    if (( adef != NULL ) && ( widget->priv_data != NULL )) {
	while ( adef->name != NULL ) {
	    if ( adef->datatype == ATTRIB_STRING ) {
		/* point to attribute value */
		cp = *((char **)(widget->priv_data + adef->offset));
		/* was there a non-default previous value? */
		if (( cp != NULL ) && ( cp != adef->deflt )) {
		    /* yes, it was a token from an input file, free it */
		    free(cp);
		}
	    }
	    adef++;
	}
    }
    /* free widget's private data */
    if ( widget->priv_data != NULL ) {
	free(widget->priv_data);
    }
    /* unlink widget from parent or older sibling */
    if (( widget->parent != NULL ) && ( widget->parent->child != NULL )) {
	if ( widget->parent->child == widget ) {
	    widget->parent->child = NULL;
	} else {
	    wp = widget->parent->child;
	    while ( wp->sibling != NULL ) {
		if ( wp->sibling == widget ) {
		    wp->sibling = NULL;
		} else {
		    wp = wp->sibling;
		}
	    }
	}
    }
    /* and finally free the widget structure itself */
    free(widget);
}