sets.c

来自「db.* (pronounced dee-be star) is an adva」· C语言 代码 · 共 656 行 · 第 1/2 页

    /* Make sure we have a current record */
    if (!task->curr_rec)
        return (dberr(S_NOCR));

    /* Read current record */
    if (dio_read(task->curr_rec, (char **) &task->crloc, NOPGHOLD, task) != S_OKAY)
        return (task->db_status);

    /* Get the member ptr for this set */
    stat = r_gmem(set, task->crloc, &mem, task);

    if (dio_release(task->curr_rec, NOPGFREE, task) != S_OKAY)
        return (task->db_status);

    if (stat != S_OKAY)
        return (task->db_status = stat);

    if (mem.owner == NULL_DBA)            /* Record not connected to set */
        return (dberr(S_NOTCON));

    /* set the new current owner and member */
    task->curr_own[set] = mem.owner;
    task->curr_mem[set] = task->curr_rec;
    task->curr_rec = mem.owner;

    /* set any timestamps */
    if (task->db_tsrecs)
    {
        dutscr(&task->cr_time, task, dbn);
        dutscm(nset, &task->cm_time[set], task, dbn);
        task->co_time[set] = task->cr_time;
    }

    if (task->db_tssets)
        dutscs(nset, &task->cs_time[set], task, dbn);

    return (task->db_status);
}


/* ======================================================================
    Find first member of set
*/
int INTERNAL_FCN dfindfm(int nset, DB_TASK *task, int dbn)
{
    SET_PTR setp;
    char *recp;
    int set;
    int stat;
    short crt;
    SET_ENTRY *set_ptr;

    if (nset_check(nset, &set, &set_ptr, task) != S_OKAY)
        return (task->db_status);

    /* make sure we have a current owner */
    if (!task->curr_own[set])
        return (dberr(S_NOCO));

    /* read current owner of set */
    if (dio_read(task->curr_own[set], (char **) &recp, NOPGHOLD, task) != S_OKAY)
        return (task->db_status);

    /* Test whether current owner has been deleted */
    memcpy(&crt, recp, sizeof(short));

    if (crt < 0)
    {
        /* record is deleted */
        stat = S_DELETED;
    }
    else
    {
        /* get set pointer from record */
        stat = r_gset(set, recp, &setp, task);
    }

    if (dio_release(task->curr_own[set], NOPGFREE, task) != S_OKAY)
        return (task->db_status);

    if (stat != S_OKAY)
        return (task->db_status = stat);

    /* set current record and member */
    task->curr_mem[set] = setp.first;

    if (!setp.first)                       /* end of set if no first member */
        return (task->db_status = S_EOS);

    task->curr_rec = setp.first;

    /* set timestamps */
    if (task->db_tsrecs)
    {
        dutscr(&task->cr_time, task, dbn);
        task->cm_time[set] = task->cr_time;
    }

    if (task->db_tssets)
    {
        /* only needed for system record support */
        dutscs(nset, &task->cs_time[set], task, dbn);
    }

    return (task->db_status);
}


/* ======================================================================
    Find last member of set
*/
int INTERNAL_FCN dfindlm(int nset, DB_TASK *task, int dbn)
{
    SET_PTR setp;
    char *recp;
    int set;
    int stat;
    short crt;
    SET_ENTRY *set_ptr;

    if (nset_check(nset, &set, &set_ptr, task) != S_OKAY)
        return (task->db_status);

    /* make sure we have a current owner */
    if (!task->curr_own[set])
        return (dberr(S_NOCO));

    /* read current owner of set */
    if (dio_read(task->curr_own[set], (char **) &recp, NOPGHOLD, task) != S_OKAY)
        return (task->db_status);

    /* Test whether current owner has been deleted */
    memcpy(&crt, recp, sizeof(short));

    if (crt < 0)
    {
        /* record is deleted */
        stat = S_DELETED;
    }
    else
    {
        /* get set pointer from record */
        stat = r_gset(set, recp, &setp, task);
    }

    if (dio_release(task->curr_own[set], NOPGFREE, task) != S_OKAY)
        return (task->db_status);

    if (stat != S_OKAY)
        return (task->db_status = stat);

    /* set current record and member */
    task->curr_mem[set] = setp.last;

    if (!setp.last)                           /* end of set if no first member */
        return (task->db_status = S_EOS);

    task->curr_rec = setp.last;

    /* set timestamps */
    if (task->db_tsrecs)
    {
        dutscr(&task->cr_time, task, dbn);
        task->cm_time[set] = task->cr_time;
    }

    if (task->db_tssets)
    {
        /* only needed for system record support */
        dutscs(nset, &task->cs_time[set], task, dbn);
    }

    return (task->db_status);
}


/* ======================================================================
    Find next member of set
*/
int INTERNAL_FCN dfindnm(int nset, DB_TASK *task, int dbn)
{
    int set;
    short crt;
    MEM_PTR memp;
    int stat;
    char *recp;
    DB_ADDR *cm_ptr;
    DB_ADDR mem_dba;
    SET_ENTRY *set_ptr;

    if (nset_check(nset, &set, &set_ptr, task) != S_OKAY)
        return (task->db_status);

    /* make sure we have a current owner */
    if (!task->curr_own[set])
        return (dberr(S_NOCO));

    /* find first member if no current member */
    if (!*(cm_ptr = &task->curr_mem[set]))
        return (dfindfm(nset, task, dbn));

    mem_dba = *cm_ptr;

    /* read current member of set and get member pointer from record */
    if (dio_read(mem_dba, (char **) &recp, NOPGHOLD, task) != S_OKAY)
        return (task->db_status);

    /* Test whether current member has been deleted */
    memcpy(&crt, recp, sizeof(short));

    if (crt < 0)
    {
        /* record is deleted */
        stat = S_DELETED;
    }
    else
    {
        stat = r_gmem(set, recp, &memp, task);
        if (memp.owner != task->curr_own[set])
        {
            /* set consistancy clash with another user between locks */
            *cm_ptr = NULL_DBA;
            stat = S_SETCLASH;
        }
    }

    if (dio_release(mem_dba, NOPGFREE, task) != S_OKAY)
        return (task->db_status);

    if (stat != S_OKAY)
        return (task->db_status = stat);

    /* set current record and member */
    *cm_ptr = memp.next;

    if (!memp.next)                           /* end of set */
        return (task->db_status = S_EOS);

    task->curr_rec = memp.next;

    /* set timestamps */
    if (task->db_tsrecs)
    {
        dutscr(&task->cr_time, task, dbn);
        task->cm_time[set] = task->cr_time;
    }

    return (task->db_status);
}


/* ======================================================================
    Find previous member of set
*/
int INTERNAL_FCN dfindpm(int nset, DB_TASK *task, int dbn)
{
    int set;
    int stat;
    short crt;
    MEM_PTR memp;
    char *recp;
    DB_ADDR *cm_ptr;
    DB_ADDR mem_dba;
    SET_ENTRY *set_ptr;

    if (nset_check(nset, &set, &set_ptr, task) != S_OKAY)
        return (task->db_status);

    /* make sure we have a current owner */
    if (!task->curr_own[set])
        return (dberr(S_NOCO));

    /* find last member if no current member */
    if (!*(cm_ptr = &task->curr_mem[set]))
        return (dfindlm(nset, task, dbn));

    mem_dba = *cm_ptr;

    /* read current member of set and get member pointer from record */
    if (dio_read(mem_dba, (char **) &recp, NOPGHOLD, task) != S_OKAY)
        return (task->db_status);

    /* Test whether current member has been deleted */
    memcpy(&crt, recp, sizeof(short));

    if (crt < 0)
    {
        /* record is deleted */
        stat = S_DELETED;
    }
    else
    {
        stat = r_gmem(set, recp, &memp, task);
        if (memp.owner != task->curr_own[set])
        {
            /* set consistancy clash with another user between locks */
            *cm_ptr = NULL_DBA;
            stat = S_SETCLASH;
        }
    }

    if (dio_release(mem_dba, NOPGFREE, task) != S_OKAY)
        return (task->db_status);

    if (stat != S_OKAY)
        return (task->db_status = stat);

    /* set current record and member */
    *cm_ptr = memp.prev;

    if (!memp.prev)                           /* end of set */
        return (task->db_status = S_EOS);

    task->curr_rec = memp.prev;

    /* set timestamps */
    if (task->db_tsrecs)
    {
        dutscr(&task->cr_time, task, dbn);
        task->cm_time[set] = task->cr_time;
    }

    return (task->db_status);
}