/*
 * Copyright (C) 2012 Oracle.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "smatch.h"
#include "smatch_extra.h"
#include "smatch_slist.h"

static int my_id;

static struct symbol *get_cast_type(struct expression *expr)
{
        if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
                return NULL;
        expr = strip_parens(expr->unop);
        if (expr->type != EXPR_CAST)
                return NULL;
        return get_pointer_type(expr);
}

static void match_overflow(struct expression *expr)
{
        struct expression *ptr;
        struct symbol *type;
        int cast_size;
        int data_size;

        type = get_cast_type(expr->left);
        if (!type)
                return;
        cast_size = type_bytes(type);

        ptr = strip_expr(expr->left->unop);
        data_size = get_array_size_bytes_min(ptr);
        if (data_size <= 0)
                return;
        if (data_size >= cast_size)
                return;
        sm_warning("potential memory corrupting cast %d vs %d bytes",
               cast_size, data_size);
}

void check_cast_assign(int id)
{
        my_id = id;
        add_hook(&match_overflow, ASSIGNMENT_HOOK);
}