mempool.c

/*
 * Part of DNS zone file validator `validns`.
 *
 * Copyright 2011-2014 Anton Berezin <tobez@tobez.org>
 * Modified BSD license.
 * (See LICENSE file in the distribution.)
 *
 */
#include <stdlib.h>
#include <string.h>

#include "mempool.h"
#include "carp.h"

struct pool
{
    struct pool *next;
    size_t pool_size;
    size_t free_index;
    char mem[0];
};

static struct pool *freespace = NULL;
static struct pool *temp_freespace = NULL;

static void new_pool(size_t size)
{
    struct pool *pool;

    size = (size + sizeof(void *) - 1) / sizeof(void *);
    size *= sizeof(void *);
    pool = malloc(size + sizeof(struct pool));
    if (!pool)
        croak(1, "new_pool malloc");
    pool->next = freespace;
    pool->free_index = 0;
    pool->pool_size = size;
    freespace = pool;
}

void
mem_requirements_hint(size_t size)
{
    if (freespace) return;
    new_pool(size);
}

void *getmem(size_t size)
{
    void *ret;
    size = (size + sizeof(void *) - 1) / sizeof(void *);
    size *= sizeof(void *);
    if (!freespace) new_pool(size > 256000 ? size : 256000);
    if (freespace->pool_size - freespace->free_index < size)
        new_pool(size > 256000 ? size : 256000);
    ret = freespace->mem + freespace->free_index;
    freespace->free_index += size;
    return ret;
}

void *getmem_temp(size_t size)
{
    void *ret;
    size = (size + sizeof(void *) - 1) / sizeof(void *);
    size *= sizeof(void *);
    if (!temp_freespace) {
        size_t pool_size = size > 1024*1024 ? size : 1024*1024;
        pool_size = (pool_size + sizeof(void *) - 1) / sizeof(void *);
        pool_size *= sizeof(void *);
        temp_freespace = malloc(pool_size + sizeof(struct pool));
        if (!temp_freespace)
            croak(1, "getmem_temp malloc");
        temp_freespace->next = NULL;
        temp_freespace->free_index = 0;
        temp_freespace->pool_size = pool_size;
    }
    if (temp_freespace->pool_size - temp_freespace->free_index < size)
        croak(1, "getmem_temp request too large");
    ret = temp_freespace->mem + temp_freespace->free_index;
    temp_freespace->free_index += size;
    return ret;
}

int freeall_temp(void)
{
    if (temp_freespace) {
        temp_freespace->free_index = 0;
    }
    return 1;
}

char *quickstrdup(char *s)
{
    char *r = getmem(strlen(s)+1);
    return strcpy(r, s);
}

char *quickstrdup_temp(char *s)
{
    char *r = getmem_temp(strlen(s)+1);
    return strcpy(r, s);
}