/* Subs.c - Basic network handler support routines */

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* |_o_o|\\ Copyright (c) 1987 The Software Distillery.  All Rights Reserved */
/* |. o.| || This program may not be distributed without the permission of   */
/* | .  | || the author.                                           BBS:      */
/* | o  | ||   John Toebes                                   (919)-471-6436  */
/* |  . |//                                                                  */
/* ======                                                                    */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define NETCOMMON
#include "netcomm.h"
#include "proto.h"
/* misc.c  - support routines - Phillip Lindsay (C) Commodore 1986  
 *  You may freely distribute this source and use it for Amiga Development -
 *  as long as the Copyright notice is left intact.
 *
 * 30-SEP-86
 */

/* returnpkt() - packet support routine 
 * here is the guy who sends the packet back to the sender...
 */
 
void retpkt(global, packet)
NGLOBAL global;
struct DosPacket *packet;
{
 struct Message *mess;
 struct MsgPort *replyport;
 
 replyport                = packet->dp_Port;
 mess                     = packet->dp_Link;
 packet->dp_Port          = global->n.port;
 
 PutMsg(replyport,mess); 
}

/*
 * taskwait() ... Waits for a message to arrive at your port and 
 *   extracts the packet address which is returned to you.
 */

struct DosPacket *taskwait(global)
NGLOBAL global;
{
 struct Message *mymess;

 WaitPort(global->n.port); /* wait for packet */
 mymess = (struct Message *) GetMsg(global->n.port);

 global->pkt = (struct DosPacket *) mymess->mn_Node.ln_Name;

 return(global->pkt);
} 

char *DosAllocMem(global, len)
NGLOBAL global;
long len;
{
long *p;

if (( p = (long *)AllocMem(len+4, MEMF_PUBLIC | MEMF_CLEAR)) == NULL)
   {
   if (global->pkt != NULL)
      {
      global->pkt->dp_Res1 = DOS_FALSE;
      global->pkt->dp_Res2 = ERROR_NO_FREE_STORE;
      }
   else
      {
      /* Gee.  Out of memory AND there is nobody to tell about it ...  */
      /* Only choice is to GURU.  Maybe we could do something clever   */
      /* but I doubt it...                                             */
      BUG(("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n"));
      BUG(("!!!!!!!!!!!!               !!!!!!!!\n"));
      BUG(("!!!!!!!!!!!! OUT OF MEMORY !!!!!!!!\n"));
      BUG(("!!!!!!!!!!!!               !!!!!!!!\n"));
      BUG(("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n"));
      }
   }
else
   *p++ = len;

return((char *)p);
}

void DosFreeMem(p)
char *p;
{
long *lp;
long len;

   lp = (long *)p;
   len = *--lp;
   FreeMem((char *)lp, len);
}

LONG checksum(c, len)
char *c;
int len;
{
   int i, l;
   LONG sum, *lptr;
   unsigned char *uc;

   l = len/sizeof(LONG);
   lptr = (LONG *)c;
   for(i=0, sum=0; i<l; i++, lptr++) sum += *lptr;

   l = len % sizeof(LONG);
   uc = (unsigned char *)lptr;
   for(i=0; i<l; i++, uc++) sum += *uc;

   return(sum);
}

void CheckRP(r)
struct RPacket *r;
{
#ifndef SMALLPACKET
   /* Get checksum for RP */
   if(r->DLen)
      r->DCheck = checksum(r->Data, r->DLen);
   else
      r->DCheck = 0L;
 
   r->checksum = 0L;
   r->checksum = checksum((char *)r, RPSIZE);
#endif
}