// This file is part of ndppd.
//
// Copyright (C) 2011-2019  Daniel Adolfsson <daniel@ashen.se>
//
// ndppd 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 3 of the License, or
// (at your option) any later version.
//
// ndppd 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 ndppd.  If not, see <https://www.gnu.org/licenses/>.
#include <assert.h>
#include <stdlib.h>
#include <string.h>

#ifndef NDPPD_ALLOC_SIZE
#    define NDPPD_ALLOC_SIZE 16384
#endif

#include "alloc.h"
#include "ndppd.h"

typedef struct ndL_chunk ndL_chunk_t;

struct ndL_chunk
{
    ndL_chunk_t *next;
    size_t free;
    size_t size;
};

static ndL_chunk_t *ndL_chunks;
static size_t ndL_alloc_size = NDPPD_ALLOC_SIZE;

char *nd_strdup(const char *str)
{
    size_t len = strlen(str);
    char *buf = (char *)nd_alloc(len + 1);
    strcpy(buf, str);
    return buf;
}

void *nd_alloc(size_t size)
{
    assert(size > 0 && size < 512);

    // To keep everything properly aligned, we'll make sure it's multiple of 8.
    size = (size + 7U) & ~7U;

    for (ndL_chunk_t *chunk = ndL_chunks; chunk; chunk = chunk->next)
    {
        if (chunk->free >= size)
        {
            void *ptr = (void *)chunk + chunk->size - chunk->free;
            chunk->free -= size;
            return ptr;
        }
    }

    ndL_chunk_t *chunk = (ndL_chunk_t *)calloc(1, ndL_alloc_size);

    /* Should never happen. */
    if (chunk == NULL)
        abort();

    chunk->next = ndL_chunks;
    chunk->size = ndL_alloc_size;
    chunk->free = ndL_alloc_size - ((sizeof(ndL_chunk_t) + 7U) & ~7U);

    ndL_chunks = chunk;

    ndL_alloc_size *= 2;

    void *ptr = (void *)chunk + chunk->size - chunk->free;
    chunk->free -= size;
    return ptr;
}

void nd_alloc_cleanup()
{
    ND_LL_FOREACH_S(ndL_chunks, chunk, tmp, next)
    {
        free(chunk);
    }
}