/*
 * nanowasm, a tiny WebAssembly/Wasm interpreter
 * Copyright (C) 2023-2024  Xavier Del Campo Romero
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include <nw/log.h>
#include <nw/ops.h>
#include <nanowasm/nw.h>
#include <nw/interp.h>
#include <nw/types.h>
#include <stddef.h>
#include <stdio.h>

static int load(struct nw_interp *const i, const varuint32 flags,
    const varuint32 offset)
{
    enum {ALIGN = 2};
    int32_t value_le;

    if (flags != ALIGN)
    {
        LOG("%s: expected 32-bit alignment (%d), got %lu\n",
            __func__, ALIGN, (unsigned long)flags);
        i->exception = "unaligned access";
        return -1;
    }
    else if (interp_heap_load(i, offset, &value_le, sizeof value_le))
    {
        LOG("%s: interp_heap_load failed\n", __func__);
        return -1;
    }

    const int32_t value = ntohi32(value_le);

    if (interp_stack_push(i, &value, sizeof value))
    {
        LOG("%s: interp_stack_push failed\n", __func__);
        return -1;
    }

    return 0;
}

static int op(struct nw_interp *const i, FILE *const f)
{
    varint32 flags, offset;

    if (varint32_read(f, &flags))
    {
        LOG("%s: varint32_read flags failed\n", __func__);
        return 1;
    }
    else if (varint32_read(f, &offset))
    {
        LOG("%s: varint32_read offset failed\n", __func__);
        return 1;
    }
    else if (i && load(i, flags, offset))
    {
        LOG("%s: load failed\n", __func__);
        return -1;
    }

    return 0;
}

int op_i32_load(struct nw_interp *const i)
{
    return op(i, i->f);
}

int check_i32_load(FILE *const f)
{
    return op(NULL, f);
}