/*
 * nanowasm, a tiny WebAssembly/Wasm interpreter
 * Copyright (C) 2023-2025  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 <nanowasm/nw.h>
#include <nw/interp.h>
#include <nw/io.h>
#include <nw/log.h>
#include <nw/ops.h>
#include <nw/routines.h>
#include <nw/stack.h>

static enum nw_state pop(struct nw_interp *const i)
{
    struct nw_i_sm_gm *const gm = &i->sm.gm;
    const unsigned long max = i->cfg.m->out.linear.max;
    const enum nw_state n = nwp_stack_pop(i, &gm->io);

    if (n)
        return n;
    else if (gm->pages > max || i->linear.n_pages > max - gm->pages)
    {
        static const char *const exc = "cannot grow linear memory pages";

        i->exception = exc;
#ifdef NW_LOG
        nwp_log("%s: %#lx\n", exc, (unsigned long)gm->pages);
#endif
        return NW_FATAL;
    }

    i->linear.n_pages += gm->pages;
    nwp_interp_resume(i);
    return NW_AGAIN;
}

static enum nw_state get_reserved(struct nw_interp *const i)
{
    nw_varuint1 reserved;
    struct nw_i_sm_gm *const gm = &i->sm.gm;
    const struct nw_io_cfg *const cfg = &i->cfg.io;
    const enum nw_state n = nwp_varuint1(cfg, &gm->leb128, &reserved, cfg->user);

    if (n)
        return n;
    else if (reserved)
    {
        static const char *const exc = "invalid reserved value";

        i->exception = exc;
#ifdef NW_LOG
        nwp_log("%s: %#x\n", exc, (unsigned)reserved);
#endif
        return NW_FATAL;
    }
    else
    {
        struct nw_sm_io io = {0};

        io.buf = &gm->pages;
        io.n = sizeof gm->pages;
        gm->io = io;
    }

    i->next = pop;
    return NW_AGAIN;
}

void nwp_op_grow_memory(struct nw_interp *const i)
{
    static const struct nw_i_sm_gm gm;
    struct nw_i_sm_gm *const pgm = &i->sm.gm;

    *pgm = gm;
    i->next = get_reserved;
}