/*
**  ixstacksize.c
**
**  Change the stack size for an already compiled ixemul-program
**
**  Compile:
**  vc vlib:minstart.o ixstacksize.c -sc -sd -lamigas -lvcs -nostdlib
**     -o ixstacksize
**
**  Written by Frank Wille 02-Jan-97
**
*/


#include <exec/libraries.h>
#include <exec/memory.h>
#include <dos/dos.h>
#include <dos/rdargs.h>
#include <clib/exec_protos.h>
#include <clib/dos_protos.h>


static void setstack(ULONG *,UWORD *,ULONG,char *);

struct Library *DOSBase=NULL;
static char *rev_string = "$VER: ixstacksize 1.0 (02.02.97)\r\n";


int main()
{
  LONG argv[] = { 0,0 };
  struct RDArgs *rda;
  struct FileInfoBlock fib;
  BPTR fh;
  UWORD *buf;

  if (!(DOSBase = OpenLibrary("dos.library",37)))
    exit(20);
  if (rda = ReadArgs("NAME/A,STACK/K/N",argv,NULL)) {
    if (fh = Open((STRPTR)argv[0],MODE_OLDFILE)) {
      if (ExamineFH(fh,&fib)) {
        if (buf = (UWORD *)AllocVec((unsigned long)fib.fib_Size,
            MEMF_PUBLIC)) {
          if (Read(fh,buf,fib.fib_Size) >= 0) {
            Close(fh);
            setstack((ULONG *)argv[1],buf,fib.fib_Size,(char *)argv[0]);
          }
          else {
            Close(fh);
            Printf("Read error!\n");
          }
          FreeVec(buf);
        }
        else {
          Close(fh);
          Printf("Out of memory!\n");
        }
      }
      else {
        Close(fh);
        Printf("Can't determine size of %s.\n",(char *)argv[0]);
      }
    }
    else
      Printf("Could not open %s.\n",(char *)argv[0]);
    FreeArgs(rda);
  }
  else
    PrintFault(IoErr(),NULL);
  CloseLibrary(DOSBase);
}


static void setstack(stacksize,buf,bufsize,filename)
ULONG *stacksize;
UWORD *buf;
ULONG bufsize;
char *filename;
{
  UWORD *p=buf;
  ULONG i;
  BPTR fh;

  for (i=0; i<=(bufsize-12); i+=2,p++)
    if (*(ULONG *)p==0x5374436b && *(ULONG *)(p+4)==0x7354634b) {
      i = 0;
      break;
    }
  if (i==0) {
    p += 2;
    if (stacksize) {
      if ((i = (*stacksize + 3) & ~3) < 4096) {
        Printf("Stack size must be at least 4096 bytes.\n");
        i = 4096;
      }
      if (fh = Open((STRPTR)filename,MODE_NEWFILE)) {
        *(ULONG *)p = i;
        if (Write(fh,buf,bufsize) < 0) {
          Printf("*** Write error!!! ***\n");
          Close(fh);
          return;
        }
        Close(fh);
      }
      else
        Printf("Can't open %s for writing!\n",filename);
    }
    Printf("Stack size of %s: %ld bytes.\n",filename,*(long *)p);
  }
  else
    Printf("%s doesn't allow to change its stack size.\n",filename);
}