/* command line interpretation, image loading etc. for Gforth


  Copyright (C) 1995 Free Software Foundation, Inc.

  This file is part of Gforth.

  Gforth is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "config.h"
#include <errno.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <assert.h>
#include <stdlib.h>
#include "forth.h"
#include "io.h"
#include "getopt.h"
#include "version.h"

#ifdef MSDOS
jmp_buf throw_jmp_buf;
#endif

/* Define FUZZ for better image positioning */
#define FUZZ 0x4000

#ifndef DEFAULTPATH
#  define DEFAULTPATH "/usr/local/lib/gforth:."
#endif

#ifdef DIRECT_THREADED
#  define CA(n)	(symbols[(n)])
#else
#  define CA(n)	((Cell)(symbols+(n)))
#endif

#define maxaligned(n)	(typeof(n))((((Cell)n)+sizeof(Float)-1)&-sizeof(Float))

static Cell dictsize=0;
static Cell dsize=0;
static Cell rsize=0;
static Cell fsize=0;
static Cell lsize=0;
char *progname;

/* image file format:
 *  "#! binary-path -i\n" (e.g., "#! /usr/local/bin/gforth-0.2.0 -i\n")
 *   padding to a multiple of 8
 *   magic: "Gforth1x" means format 0.2,
 *              where x is even for big endian and odd for little endian
 *              and x & ~1 is the size of the cell in bytes.
 *  padding to max alignment (no padding necessary on current machines)
 *  ImageHeader structure (see below)
 *  data (size in ImageHeader.image_size)
 *  tags ((if relocatable, 1 bit/data cell)
 *
 * tag==1 means that the corresponding word is an address;
 * If the word is >=0, the address is within the image;
 * addresses within the image are given relative to the start of the image.
 * If the word =-1 (CF_NIL), the address is NIL,
 * If the word is <CF_NIL and >CF(DODOES), it's a CFA (:, Create, ...)
 * If the word =CF(DODOES), it's a DOES> CFA
 * If the word =CF(DOESJUMP), it's a DOES JUMP (2 Cells after DOES>,
 *					possibly containing a jump to dodoes)
 * If the word is <CF(DOESJUMP), it's a primitive
 */

typedef struct {
  Address base;		/* base address of image (0 if relocatable) */
  UCell checksum;	/* checksum of ca's to protect against some
			   incompatible	binary/executable combinations
			   (0 if relocatable) */
  UCell image_size;	/* all sizes in bytes */
  UCell dict_size;
  UCell data_stack_size;
  UCell fp_stack_size;
  UCell return_stack_size;
  UCell locals_stack_size;
  Xt *boot_entry;	/* initial ip for booting (in BOOT) */
  Xt *throw_entry;	/* ip after signal (in THROW) */
} ImageHeader;
/* the image-header is created in main.fs */

void relocate(Cell *image, char *bitstring, int size, Label symbols[])
{
  int i=0, j, k, steps=(size/sizeof(Cell))/8;
  char bits;
/*   static char bits[8]={0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01};*/

/*  printf("relocating %x[%x]\n", image, size); */
   
  for(k=0; k<=steps; k++)
    for(j=0, bits=bitstring[k]; j<8; j++, i++, bits<<=1)
      if(bits & 0x80)
	if(image[i]<0)
	  switch(image[i])
	    {
	    case CF_NIL      : image[i]=0; break;
	    case CF(DOCOL)   :
	    case CF(DOVAR)   :
	    case CF(DOCON)   :
	    case CF(DOUSER)  : 
	    case CF(DODEFER) : 
	    case CF(DOFIELD) : MAKE_CF(image+i,symbols[CF(image[i])]); break;
	    case CF(DODOES)  : MAKE_DOES_CF(image+i,image[i+1]+((Cell)image));
	      break;
	    case CF(DOESJUMP): MAKE_DOES_HANDLER(image+i); break;
	    default          :
/*	      printf("Code field generation image[%x]:=CA(%x)\n",
		     i, CF(image[i]));
*/	      image[i]=(Cell)CA(CF(image[i]));
	    }
	else
	  image[i]+=(Cell)image;
}

UCell checksum(Label symbols[])
{
  UCell r=0;
  Cell i;

  for (i=DOCOL; i<=DOESJUMP; i++) {
    r ^= (UCell)(symbols[i]);
    r = (r << 5) | (r >> (8*sizeof(Cell)-5));
  }
#ifdef DIRECT_THREADED
  /* we have to consider all the primitives */
  for (; symbols[i]!=(Label)0; i++) {
    r ^= (UCell)(symbols[i]);
    r = (r << 5) | (r >> (8*sizeof(Cell)-5));
  }
#else
  /* in indirect threaded code all primitives are accessed through the
     symbols table, so we just have to put the base address of symbols
     in the checksum */
  r ^= (UCell)symbols;
#endif
  return r;
}

Address loader(FILE *imagefile, char* filename)
/* returns the address of the image proper (after the preamble) */
{
  ImageHeader header;
  Address image;
  Address imp; /* image+preamble */
  Char magic[8];
  Cell wholesize;
  Cell imagesize; /* everything needed by the image */
  Cell preamblesize=0;
  Label *symbols=engine(0,0,0,0,0);
  UCell check_sum=checksum(symbols);

  static char* endianstring[]= { "big","little" };

  do
    {
      if(fread(magic,sizeof(Char),8,imagefile) < 8) {
	fprintf(stderr,"%s: image %s doesn't seem to be a Gforth (>=0.2) image.\n",
		progname, filename);
	exit(1);
      }
      preamblesize+=8;
#ifdef DEBUG
      fprintf(stderr,"Magic found: %-8s\n",magic);
#endif
    }
  while(memcmp(magic,"Gforth1",7));
  
  if(magic[7] != sizeof(Cell) +
#ifdef WORDS_BIGENDIAN
       '0'
#else
       '1'
#endif
       )
    { fprintf(stderr,"This image is %d bit %s-endian, whereas the machine is %d bit %s-endian.\n", 
	      ((magic[7]-'0')&~1)*8, endianstring[magic[7]&1],
	      sizeof(Cell)*8, endianstring[
#ifdef WORDS_BIGENDIAN
		      0
#else
		      1
#endif
		      ]);
      exit(-2);
    };

  fread((void *)&header,sizeof(ImageHeader),1,imagefile);
  if (dictsize==0)
    dictsize = header.dict_size;
  if (dsize==0)
    dsize=header.data_stack_size;
  if (rsize==0)
    rsize=header.return_stack_size;
  if (fsize==0)
    fsize=header.fp_stack_size;
  if (lsize==0)
    lsize=header.locals_stack_size;
  dictsize=maxaligned(dictsize);
  dsize=maxaligned(dsize);
  rsize=maxaligned(rsize);
  lsize=maxaligned(lsize);
  fsize=maxaligned(fsize);
  
  wholesize = preamblesize+dictsize+dsize+rsize+fsize+lsize;
  imagesize = preamblesize+header.image_size+((header.image_size-1)/sizeof(Cell))/8+1;
  image=malloc((wholesize>imagesize?wholesize:imagesize)
#ifdef FUZZ
	       +FUZZ
#endif
	       );
  /*image = maxaligned(image);*/
  /* memset(image,0,wholesize); */

#ifdef FUZZ
  if(header.base==0) image += FUZZ/2;
  else if((UCell)(header.base - (Cell)image + preamblesize) < FUZZ)
    image = header.base - preamblesize;
#endif  
  rewind(imagefile);  /* fseek(imagefile,0L,SEEK_SET); */
  fread(image,1,imagesize,imagefile);
  fclose(imagefile);
  imp=image+preamblesize;
  
  if(header.base==0) {
    relocate((Cell *)imp,imp+header.image_size,header.image_size,symbols);
    ((ImageHeader *)imp)->checksum=check_sum;
  }
  else if(header.base!=imp) {
    fprintf(stderr,"%s: Cannot load nonrelocatable image (compiled for address $%lx) at address $%lx\nThe Gforth installer should look into the INSTALL file\n",
	    progname, (unsigned long)header.base, (unsigned long)imp);
    exit(1);
  } else if (header.checksum != check_sum) {
    fprintf(stderr,"%s: Checksum of image ($%lx) does not match the executable ($%lx)\nThe Gforth installer should look into the INSTALL file\n",
	    progname, (unsigned long)(header.checksum),(unsigned long)check_sum);
    exit(1);
  }

  ((ImageHeader *)imp)->dict_size=dictsize;
  ((ImageHeader *)imp)->data_stack_size=dsize;
  ((ImageHeader *)imp)->return_stack_size=rsize;
  ((ImageHeader *)imp)->fp_stack_size=fsize;
  ((ImageHeader *)imp)->locals_stack_size=lsize;

  CACHE_FLUSH(imp, header.image_size);

  return imp;
}

int go_forth(Address image, int stack, Cell *entries)
{
  Cell *sp=(Cell*)(image+dictsize+dsize);
  Address lp=(Address)((void *)sp+lsize);
  Float *fp=(Float *)((void *)lp+fsize);
  Cell *rp=(Cell*)((void *)fp+rsize);
  Xt *ip=(Xt *)(((ImageHeader *)image)->boot_entry);
  int throw_code;
  
  for(;stack>0;stack--)
    *--sp=entries[stack-1];

#if !defined(MSDOS) && !defined(_WIN32) && !defined(__EMX__)
  get_winsize();
#endif
   
  install_signal_handlers(); /* right place? */
  
  if ((throw_code=setjmp(throw_jmp_buf))) {
    static Cell signal_data_stack[8];
    static Cell signal_return_stack[8];
    static Float signal_fp_stack[1];
    
    signal_data_stack[7]=throw_code;
    
    return((int)engine(((ImageHeader *)image)->throw_entry,signal_data_stack+7,
		       signal_return_stack+8,signal_fp_stack,0));
  }

  return((int)engine(ip,sp,rp,fp,lp));
}

int convsize(char *s, int elemsize)
/* converts s of the format #+u (e.g. 25k) into the number of bytes.
   the unit u can be one of bekM, where e stands for the element
   size. default is e */
{
  char *endp;
  int n,m;

  m = elemsize;
  n = strtoul(s,&endp,0);
  if (endp!=NULL) {
    if (strcmp(endp,"b")==0)
      m=1;
    else if (strcmp(endp,"k")==0)
      m=1024;
    else if (strcmp(endp,"M")==0)
      m=1024*1024;
    else if (strcmp(endp,"e")!=0 && strcmp(endp,"")!=0) {
      fprintf(stderr,"%s: cannot grok size specification %s: invalid unit \"%s\"\n", progname, s, endp);
      exit(1);
    }
  }
  return n*m;
}

int main(int argc, char **argv, char **env)
{
  char *path, *path1;
  char *imagename="gforth.fi";
  FILE *image_file;
  int c, retvalue;
	  
#if defined(i386) && defined(ALIGNMENT_CHECK) && !defined(DIRECT_THREADED)
  /* turn on alignment checks on the 486.
   * on the 386 this should have no effect. */
  __asm__("pushfl; popl %eax; orl $0x40000, %eax; pushl %eax; popfl;");
  /* this is unusable with Linux' libc.4.6.27, because this library is
     not alignment-clean; we would have to replace some library
     functions (e.g., memcpy) to make it work */
#endif

  progname = argv[0];
  if ((path1=getenv("GFORTHPATH"))==NULL)
    path1 = DEFAULTPATH;
  
  opterr=0;
  while (1) {
    int option_index=0;
    static struct option opts[] = {
      {"image-file", required_argument, NULL, 'i'},
      {"dictionary-size", required_argument, NULL, 'm'},
      {"data-stack-size", required_argument, NULL, 'd'},
      {"return-stack-size", required_argument, NULL, 'r'},
      {"fp-stack-size", required_argument, NULL, 'f'},
      {"locals-stack-size", required_argument, NULL, 'l'},
      {"path", required_argument, NULL, 'p'},
      {"version", no_argument, NULL, 'v'},
      {"help", no_argument, NULL, 'h'},
      {0,0,0,0}
      /* no-init-file, no-rc? */
    };
    
    c = getopt_long(argc, argv, "+i:m:d:r:f:l:p:vh", opts, &option_index);
    
    if (c==EOF)
      break;
    if (c=='?') {
      optind--;
      break;
    }
    switch (c) {
    case 'i': imagename = optarg; break;
    case 'm': dictsize = convsize(optarg,sizeof(Cell)); break;
    case 'd': dsize = convsize(optarg,sizeof(Cell)); break;
    case 'r': rsize = convsize(optarg,sizeof(Cell)); break;
    case 'f': fsize = convsize(optarg,sizeof(Float)); break;
    case 'l': lsize = convsize(optarg,sizeof(Cell)); break;
    case 'p': path1 = optarg; break;
    case 'v': fprintf(stderr, "gforth %s\n", gforth_version); exit(0);
    case 'h': 
      fprintf(stderr, "Usage: %s [engine options] [image arguments]\n\
Engine Options:\n\
 -d SIZE, --data-stack-size=SIZE    Specify data stack size\n\
 -f SIZE, --fp-stack-size=SIZE	    Specify floating point stack size\n\
 -h, --help			    Print this message and exit\n\
 -i FILE, --image-file=FILE	    Use image FILE instead of `gforth.fi'\n\
 -l SIZE, --locals-stack-size=SIZE  Specify locals stack size\n\
 -m SIZE, --dictionary-size=SIZE    Specify Forth dictionary size\n\
 -p PATH, --path=PATH		    Search path for finding image and sources\n\
 -r SIZE, --return-stack-size=SIZE  Specify return stack size\n\
 -v, --version			    Print version and exit\n\
SIZE arguments consists of an integer followed by a unit. The unit can be\n\
  `b' (bytes), `e' (elements), `k' (kilobytes), or `M' (Megabytes).\n\
\n\
Arguments of default image `gforth.fi':\n\
 FILE				    load FILE (with `require')\n\
 -e STRING, --evaluate STRING       interpret STRING (with `EVALUATE')\n",
	      argv[0]); exit(0);
    }
  }
  path=path1;
  
  if(strchr(imagename, '/')==NULL)
    {
      do {
	char *pend=strchr(path, PATHSEP);
	if (pend==NULL)
	  pend=path+strlen(path);
	if (strlen(path)==0) {
	  fprintf(stderr,"%s: cannot open image file %s in path %s for reading\n",
		  progname, imagename, path1);
	  exit(1);
	}
	{
	  int dirlen=pend-path;
	  char fullfilename[dirlen+strlen(imagename)+2];
	  memcpy(fullfilename, path, dirlen);
	  if (fullfilename[dirlen-1]!='/')
	    fullfilename[dirlen++]='/';
	  strcpy(fullfilename+dirlen,imagename);
	  image_file=fopen(fullfilename,"rb");
	}
	path=pend+(*pend==PATHSEP);
      } while (image_file==NULL);
    }
  else
    {
      image_file=fopen(imagename,"rb");
    }

  {
    char path2[strlen(path1)+1];
    char *p1, *p2;
    Cell environ[]= {
      (Cell)argc-(optind-1),
      (Cell)(argv+(optind-1)),
      (Cell)strlen(path1),
      (Cell)path2};
    argv[optind-1] = progname;
    /*
       for (i=0; i<environ[0]; i++)
       printf("%s\n", ((char **)(environ[1]))[i]);
       */
    /* make path OS-independent by replacing path separators with NUL */
    for (p1=path1, p2=path2; *p1!='\0'; p1++, p2++)
      if (*p1==PATHSEP)
	*p2 = '\0';
      else
	*p2 = *p1;
    *p2='\0';
    retvalue=go_forth(loader(image_file, imagename),4,environ);
    deprep_terminal();
    exit(retvalue);
  }
}