#include "ipf.h"

#define EMM_MAGIC       0x97dd8b3a

void eMrwlock_read_enter(rw, file, line)
eMrwlock_t *rw;
char *file;
int line;
{
        if (rw->eMrw_magic != EMM_MAGIC) {
                fprintf(stderr, "%s:eMrwlock_read_enter(%p): bad magic: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        if (rw->eMrw_read != 0 || rw->eMrw_write != 0) {
                fprintf(stderr,
                        "%s:eMrwlock_read_enter(%p): already locked: %d/%d\n",
                        rw->eMrw_owner, rw, rw->eMrw_read, rw->eMrw_write);
                abort();
        }
        rw->eMrw_read++;
        rw->eMrw_heldin = file;
        rw->eMrw_heldat = line;
}


void eMrwlock_write_enter(rw, file, line)
eMrwlock_t *rw;
char *file;
int line;
{
        if (rw->eMrw_magic != EMM_MAGIC) {
                fprintf(stderr, "%s:eMrwlock_write_enter(%p): bad magic: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        if (rw->eMrw_read != 0 || rw->eMrw_write != 0) {
                fprintf(stderr,
                        "%s:eMrwlock_write_enter(%p): already locked: %d/%d\n",
                        rw->eMrw_owner, rw, rw->eMrw_read, rw->eMrw_write);
                abort();
        }
        rw->eMrw_write++;
        rw->eMrw_heldin = file;
        rw->eMrw_heldat = line;
}


void eMrwlock_downgrade(rw, file, line)
eMrwlock_t *rw;
char *file;
int line;
{
        if (rw->eMrw_magic != EMM_MAGIC) {
                fprintf(stderr, "%s:eMrwlock_write_enter(%p): bad magic: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        if (rw->eMrw_read != 0 || rw->eMrw_write != 1) {
                fprintf(stderr,
                        "%s:eMrwlock_write_enter(%p): already locked: %d/%d\n",
                        rw->eMrw_owner, rw, rw->eMrw_read, rw->eMrw_write);
                abort();
        }
        rw->eMrw_write--;
        rw->eMrw_read++;
        rw->eMrw_heldin = file;
        rw->eMrw_heldat = line;
}


void eMrwlock_exit(rw)
eMrwlock_t *rw;
{
        if (rw->eMrw_magic != EMM_MAGIC) {
                fprintf(stderr, "%s:eMrwlock_exit(%p): bad magic: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        if (rw->eMrw_read != 1 && rw->eMrw_write != 1) {
                fprintf(stderr, "%s:eMrwlock_exit(%p): not locked: %d/%d\n",
                        rw->eMrw_owner, rw, rw->eMrw_read, rw->eMrw_write);
                abort();
        }
        if (rw->eMrw_read == 1)
                rw->eMrw_read--;
        else if (rw->eMrw_write == 1)
                rw->eMrw_write--;
        rw->eMrw_heldin = NULL;
        rw->eMrw_heldat = 0;
}


void eMrwlock_init(rw, who)
eMrwlock_t *rw;
char *who;
{
        if (rw->eMrw_magic == EMM_MAGIC) {      /* safe bet ? */
                fprintf(stderr,
                        "%s:eMrwlock_init(%p): already initialised?: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        rw->eMrw_magic = EMM_MAGIC;
        rw->eMrw_read = 0;
        rw->eMrw_write = 0;
        if (who != NULL)
                rw->eMrw_owner = strdup(who);
        else
                rw->eMrw_owner = NULL;
}


void eMrwlock_destroy(rw)
eMrwlock_t *rw;
{
        if (rw->eMrw_magic != EMM_MAGIC) {
                fprintf(stderr, "%s:eMrwlock_destroy(%p): bad magic: %#x\n",
                        rw->eMrw_owner, rw, rw->eMrw_magic);
                abort();
        }
        memset(rw, 0xa5, sizeof(*rw));
}