/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997, 1998
 *      Sleepycat Software.  All rights reserved.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)os_alloc.c    10.10 (Sleepycat) 10/12/98";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#include <string.h>
#include <stdlib.h>
#endif

#include "db_int.h"
#include "os_jump.h"

/*
 * !!!
 * Correct for systems that return NULL when you allocate 0 bytes of memory.
 * There are several places in DB where we allocate the number of bytes held
 * by the key/data item, and it can be 0.  Correct here so that malloc never
 * returns a NULL for that reason (which behavior is permitted by ANSI).  We
 * could make these calls macros on non-Alpha architectures (that's where we
 * saw the problem), but it's probably not worth the autoconf complexity.
 *
 * !!!
 * Correct for systems that don't set errno when malloc and friends fail.
 *
 *      Out of memory.
 *      We wish to hold the whole sky,
 *      But we never will.
 */

/*
 * __os_strdup --
 *      The strdup(3) function for DB.
 *
 * PUBLIC: int __os_strdup __P((const char *, void *));
 */
int
__os_strdup(str, storep)
        const char *str;
        void *storep;
{
        size_t size;
        int ret;
        void *p;

        *(void **)storep = NULL;

        size = strlen(str) + 1;
        if ((ret = __os_malloc(size, NULL, &p)) != 0)
                return (ret);

        memcpy(p, str, size);

        *(void **)storep = p;
        return (0);
}

/*
 * __os_calloc --
 *      The calloc(3) function for DB.
 *
 * PUBLIC: int __os_calloc __P((size_t, size_t, void *));
 */
int
__os_calloc(num, size, storep)
        size_t num, size;
        void *storep;
{
        void *p;
        int ret;

        size *= num;
        if ((ret = __os_malloc(size, NULL, &p)) != 0)
                return (ret);

        memset(p, 0, size);
        *(void **)storep = p;

        return (0);
}

/*
 * __os_malloc --
 *      The malloc(3) function for DB.
 *
 * PUBLIC: int __os_malloc __P((size_t, void *(*)(size_t), void *));
 */
int
__os_malloc(size, db_malloc, storep)
        size_t size;
        void *(*db_malloc) __P((size_t)), *storep;
{
        void *p;

        *(void **)storep = NULL;

        /* Never allocate 0 bytes -- some C libraries don't like it. */
        if (size == 0)
                ++size;

        /* Some C libraries don't correctly set errno when malloc(3) fails. */
        errno = 0;
        if (db_malloc != NULL)
                p = db_malloc(size);
        else if (__db_jump.j_malloc != NULL)
                p = __db_jump.j_malloc(size);
        else
                p = malloc(size);
        if (p == NULL) {
                if (errno == 0)
                        errno = ENOMEM;
                return (errno);
        }

#ifdef DIAGNOSTIC
        memset(p, 0xdb, size);
#endif
        *(void **)storep = p;

        return (0);
}

/*
 * __os_realloc --
 *      The realloc(3) function for DB.
 *
 * PUBLIC: int __os_realloc __P((void *, size_t));
 */
int
__os_realloc(storep, size)
        void *storep;
        size_t size;
{
        void *p, *ptr;

        ptr = *(void **)storep;

        /* If we haven't yet allocated anything yet, simply call malloc. */
        if (ptr == NULL)
                return (__os_malloc(size, NULL, storep));

        /* Never allocate 0 bytes -- some C libraries don't like it. */
        if (size == 0)
                ++size;

        /*
         * Some C libraries don't correctly set errno when realloc(3) fails.
         *
         * Don't overwrite the original pointer, there are places in DB we
         * try to continue after realloc fails.
         */
        errno = 0;
        if (__db_jump.j_realloc != NULL)
                p = __db_jump.j_realloc(ptr, size);
        else
                p = realloc(ptr, size);
        if (p == NULL) {
                if (errno == 0)
                        errno = ENOMEM;
                return (errno);
        }

        *(void **)storep = p;

        return (0);
}

/*
 * __os_free --
 *      The free(3) function for DB.
 *
 * PUBLIC: void __os_free __P((void *, size_t));
 */
void
__os_free(ptr, size)
        void *ptr;
        size_t size;
{
#ifdef DIAGNOSTIC
        if (size != 0)
                memset(ptr, 0xdb, size);
#endif

        if (__db_jump.j_free != NULL)
                __db_jump.j_free(ptr);
        else
                free(ptr);
}

/*
 * __os_freestr --
 *      The free(3) function for DB, freeing a string.
 *
 * PUBLIC: void __os_freestr __P((void *));
 */
void
__os_freestr(ptr)
        void *ptr;
{
#ifdef DIAGNOSTIC
        memset(ptr, 0xdb, strlen(ptr) + 1);
#endif

        if (__db_jump.j_free != NULL)
                __db_jump.j_free(ptr);
        else
                free(ptr);
}