/*  DNR.c - DNR library for MPW

    (c) Copyright 1988 by Apple Computer.  All rights reserved

*/

#define MPW3.0 true

#include <OSUtils.h>

#include <Errors.h>

#include <Files.h>

#include <Resources.h>

#ifdef MPW3.0

#include <Memory.h>

#endif

#define OPENRESOLVER    1

#define CLOSERESOLVER   2

#define STRTOADDR       3

#define ADDRTOSTR       4

#define ENUMCACHE       5

#define ADDRTONAME      6

Handle codeHndl = nil;

typedef OSErr (*OSErrProcPtr)();

OSErrProcPtr dnr = nil;

/* OpenOurRF is called to open the MacTCP driver resources */

short OpenOurRF() {

    SysEnvRec info;

    HParamBlockRec fi;

    Str255 filename;

    SysEnvirons(1, &info);

    fi.fileParam.ioCompletion   = nil;

    fi.fileParam.ioNamePtr      = &filename;

    fi.fileParam.ioVRefNum      = info.sysVRefNum;

    fi.fileParam.ioDirID        = 0;

    fi.fileParam.ioFDirIndex    = 1;

    while (PBHGetFInfo(&fi, false) == noErr) {

        /* scan system folder for driver resource files of specific type & creator */

        if (fi.fileParam.ioFlFndrInfo.fdType == 'cdev' && fi.fileParam.ioFlFndrInfo.fdCreator == 'mtcp') {

            /* found the MacTCP driver file */

            SetVol(0,info.sysVRefNum);

            return(OpenResFile(&filename));

        }

        /* check next file in system folder */

        fi.fileParam.ioFDirIndex++;

        fi.fileParam.ioDirID = 0;

    }

    return(-1);

}

OSErr OpenResolver(fileName)

char *fileName;

{

    short refnum;

    OSErr rc;

    if (dnr != nil)

        /* resolver already loaded in */

        return(noErr);

    /* open the MacTCP driver to get DNR resources. Search for it based on

       creator & type rather than simply file name */   

    refnum = OpenOurRF();

    /* ignore failures since the resource may have been installed in the 

       System file if running on a Mac 512Ke */

    /* load in the DNR resource package */

    codeHndl = GetIndResource('dnrp', 1);

    if (codeHndl == nil) {

        /* can't open DNR */

        return(ResError());

        }

    DetachResource(codeHndl);

    if (refnum != -1) {

        CloseResFile(refnum);

        }

    /* lock the DNR resource since it cannot be reloated while opened */

    HLock(codeHndl);

    dnr = (OSErrProcPtr) *codeHndl;

    /* call open resolver */

    rc = (*dnr)(OPENRESOLVER, fileName);

    if (rc != noErr) {

        /* problem with open resolver, flush it */

        HUnlock(codeHndl);

        DisposHandle(codeHndl);

        dnr = nil;

        }

    return(rc);

    }

OSErr CloseResolver()

{

    if (dnr == nil)

        /* resolver not loaded error */

        return(notOpenErr);

    /* call close resolver */

    (void) (*dnr)(CLOSERESOLVER);

    /* release the DNR resource package */

    HUnlock(codeHndl);

    DisposHandle(codeHndl);

    dnr = nil;

    return(noErr);

    }

OSErr StrToAddr(hostName, rtnStruct, resultproc, userDataPtr)

char *hostName;

struct hostInfo *rtnStruct;

long resultproc;

char *userDataPtr;

{

    if (dnr == nil)

        /* resolver not loaded error */

        return(notOpenErr);

    return((*dnr)(STRTOADDR, hostName, rtnStruct, resultproc, userDataPtr));

    }

OSErr AddrToStr(addr, addrStr)

unsigned long addr;

char *addrStr;                                  

{

    if (dnr == nil)

        /* resolver not loaded error */

        return(notOpenErr);

    (*dnr)(ADDRTOSTR, addr, addrStr);

    return(noErr);

    }

OSErr EnumCache(resultproc, userDataPtr)

long resultproc;

char *userDataPtr;

{

    if (dnr == nil)

        /* resolver not loaded error */

        return(notOpenErr);

    return((*dnr)(ENUMCACHE, resultproc, userDataPtr));

    }

OSErr AddrToName(addr, rtnStruct, resultproc, userDataPtr)

unsigned long addr;

struct hostInfo *rtnStruct;

long resultproc;

char *userDataPtr;                                  

{

    if (dnr == nil)

        /* resolver not loaded error */

        return(notOpenErr);

    return((*dnr)(ADDRTONAME, addr, rtnStruct, resultproc, userDataPtr));

    }