/*
 ** Based on xwdtopnm.c - read and write an X11 or X10 window dump file
 **
 ** Modified heavily by Markus Baur (mbaur@ira.uka.de) for use as a part
 ** of xv-2.21, 12/30/92
 **
 ** Hacked up again to support xv-3.00 and XWDs from 64bit machines
 ** (e.g. DEC Alphas), 04/10/94
 **
 ** Copyright (C) 1989, 1991 by Jef Poskanzer.
 **
 ** Permission to use, copy, modify, and distribute this software and its
 ** documentation for any purpose and without fee is hereby granted, provided
 ** that the above copyright notice appear in all copies and that both that
 ** copyright notice and this permission notice appear in supporting
 ** documentation.  This software is provided "as is" without express or
 ** implied warranty.
 **
 */

#include "xv.h"
#include <limits.h>             /* for CHAR_BIT */

/* SJT: just in case ... */
#ifndef CHAR_BIT
#  define CHAR_BIT 8
#endif


/***************************** x11wd.h *****************************/
#define X11WD_FILE_VERSION 7
typedef struct {
  CARD32 header_size;         /* Size of the entire file header (bytes). */
  CARD32 file_version;        /* X11WD_FILE_VERSION */
  CARD32 pixmap_format;       /* Pixmap format */
  CARD32 pixmap_depth;        /* Pixmap depth */
  CARD32 pixmap_width;        /* Pixmap width */
  CARD32 pixmap_height;       /* Pixmap height */
  CARD32 xoffset;             /* Bitmap x offset */
  CARD32 byte_order;          /* MSBFirst, LSBFirst */
  CARD32 bitmap_unit;         /* Bitmap unit */
  CARD32 bitmap_bit_order;    /* MSBFirst, LSBFirst */
  CARD32 bitmap_pad;          /* Bitmap scanline pad */
  CARD32 bits_per_pixel;      /* Bits per pixel */
  CARD32 bytes_per_line;      /* Bytes per scanline */
  CARD32 visual_class;        /* Class of colormap */
  CARD32 red_mask;            /* Z red mask */
  CARD32 grn_mask;            /* Z green mask */
  CARD32 blu_mask;            /* Z blue mask */
  CARD32 bits_per_rgb;        /* Log base 2 of distinct color values */
  CARD32 colormap_entries;    /* Number of entries in colormap */
  CARD32 ncolors;             /* Number of Color structures */
  CARD32 window_width;        /* Window width */
  CARD32 window_height;       /* Window height */
  CARD32 window_x;            /* Window upper left X coordinate */
  CARD32 window_y;            /* Window upper left Y coordinate */
  CARD32 window_bdrwidth;     /* Window border width */
#ifdef WORD64
  CARD32 header_pad;
#endif
} X11WDFileHeader;

typedef struct {
  CARD32 num;
  CARD16 red, green, blue;
  CARD8  flags;               /* do_red, do_green, do_blue */
  CARD8  pad;
} X11XColor;


/*-------------------------------------------------------------------------*/

typedef byte pixel;

/* local functions */
static int    getinit         PARM((FILE *, int*, int*, int*, CARD32 *,
			                          CARD32, PICINFO *));
static CARD32 getpixnum       PARM((FILE *));
static int    xwdError        PARM((const char *));
static void   xwdWarning      PARM((const char *));
static int    bs_short        PARM((int));
static CARD32 bs_long         PARM((CARD32));
static int    readbigshort    PARM((FILE *, CARD16 *));
static int    readbiglong     PARM((FILE *, CARD32 *));
static int    readlittleshort PARM((FILE *, CARD16 *));
static int    readlittlelong  PARM((FILE *, CARD32 *));
#if 0 /* NOTUSED */
static int    writebigshort   PARM((FILE *, int));
static int    writebiglong    PARM((FILE *, CARD32));
#endif

static void   getcolorshift   PARM((CARD32, int *, int *)); /* SJT */

/* SJT: for 16bpp and 24bpp shifts */
static int    red_shift_right, red_justify_left,
              grn_shift_right, grn_justify_left,
              blu_shift_right, blu_justify_left;
static byte  *pic8, *pic24;
static CARD32 red_mask, grn_mask, blu_mask;
static int    bits_per_item, bits_used, bit_shift,
              bits_per_pixel, bits_per_rgb;
static char   buf[4];
static char   *byteP;
static CARD16 *shortP;
static CARD32 *longP;
static CARD32 pixel_mask;
static int    byte_swap, byte_order, bit_order, filesize;

static const char  *bname;



/*************************************/
int LoadXWD(fname, pinfo)
     char *fname;
     PICINFO *pinfo;
{
  /* returns '1' on success */

  pixel *xP;
  int    col;
  int    rows=0, cols=0, padright=0, row, npixels, bufsize;
  CARD32 maxval=0, visualclass=0;
  FILE  *ifp;

  bname          = BaseName(fname);
  pinfo->pic     = (byte *) NULL;
  pinfo->comment = (char *) NULL;

  ifp = xv_fopen(fname, "r");
  if (!ifp) return (xwdError("can't open file"));

  /* figure out the file size (used to check colormap size) */
  fseek(ifp, 0L, 2);
  filesize = ftell(ifp);
  fseek(ifp, 0L, 0);


  if (getinit(ifp, &cols, &rows, &padright, &visualclass, maxval, pinfo))
    return 0;

  npixels = cols * rows;
  if (cols <= 0 || rows <= 0 || npixels/cols != rows) {
    xwdError("Image dimensions out of range");
    return 0;
  }


  switch (visualclass) {
  case StaticGray:
  case GrayScale:
    pinfo->colType = F_GREYSCALE;
    pic8 = (byte *) calloc((size_t) npixels, (size_t) 1);
    if (!pic8) {
      xwdError("couldn't malloc 'pic'");
      return 0;
    }

    for (row=0; row<rows; row++) {
      for (col=0, xP=pic8+(row*cols); col<cols; col++, xP++)
	*xP = getpixnum(ifp);

      for (col=0; col<padright; col++) getpixnum(ifp);
    }

    pinfo->type = PIC8;
    pinfo->pic  = pic8;
    break;

  case StaticColor:
  case PseudoColor:
    pinfo->colType = F_FULLCOLOR;
    pic8 = (byte *) calloc((size_t) npixels, (size_t) 1);
    if (!pic8) {
      xwdError("couldn't malloc 'pic'");
      return 0;
    }

    for (row=0; row<rows; row++) {
      for (col=0, xP=pic8+(row*cols); col<cols; col++, xP++)
	*xP = getpixnum(ifp);
      for (col=0; col<padright; col++) getpixnum(ifp);
    }

    pinfo->type = PIC8;
    pinfo->pic  = pic8;
    break;

  case TrueColor:
  case DirectColor:
    pinfo->colType = F_FULLCOLOR;
    bufsize = 3*npixels;
    if (bufsize/3 != npixels) {
      xwdError("Image dimensions out of range");
      return 0;
    }
    pic24 = (byte *) calloc((size_t) bufsize, (size_t) 1);
    if (!pic24) {
      xwdError("couldn't malloc 'pic24'");
      return 0;
    }

    for (row=0; row<rows; row++) {
      for (col=0, xP=pic24+(row*cols*3); col<cols; col++) {
	CARD32 ul;

	ul = getpixnum(ifp);
	switch (bits_per_pixel) {
        case 16:
        case 24:
        case 32:
          /* SJT: shift all the way to the right and then shift left. The
             pairs of shifts could be combined. There will be two right and
             one left shift, but it's unknown which will be which. It seems
             easier to do the shifts (which might be 0) separately than to
             have a complex set of tests. I believe this is independent of
             byte order but I have no way to test.
           */
          *xP++ = ((ul & red_mask) >> red_shift_right) << red_justify_left;
          *xP++ = ((ul & grn_mask) >> grn_shift_right) << grn_justify_left;
          *xP++ = ((ul & blu_mask) >> blu_shift_right) << blu_justify_left;
          break;

	default:
	  xwdError("True/Direct supports only 16, 24, and 32 bits");
	  return 0;
	}
      }

      for (col=0; col<padright; col++) getpixnum(ifp);
    }

    pinfo->type = PIC24;
    pinfo->pic  = pic24;
    break;

  default:
    xwdError("unknown visual class");
    return 0;
  }

  sprintf(pinfo->fullInfo, "XWD, %d-bit %s.  (%d bytes)",
	  bits_per_pixel,
	  ((visualclass == StaticGray ) ? "StaticGray"  :
	   (visualclass == GrayScale  ) ? "GrayScale"   :
	   (visualclass == StaticColor) ? "StaticColor" :
	   (visualclass == PseudoColor) ? "PseudoColor" :
	   (visualclass == TrueColor  ) ? "TrueColor"   :
	   (visualclass == DirectColor) ? "DirectColor" : "<unknown>"),
	  filesize);

  sprintf(pinfo->shrtInfo, "%dx%d XWD.", cols, rows);

  pinfo->normw = pinfo->w = cols;
  pinfo->normh = pinfo->h = rows;

  fclose(ifp);
  return 1;
}


/*********************/
static int getinit(file, colsP, rowsP, padrightP, visualclassP, maxv, pinfo)
     FILE* file;
     int* colsP;
     int* rowsP;
     int* padrightP;
     CARD32 * visualclassP;
     CARD32   maxv;
     PICINFO *pinfo;
{
  int              i;
  int              grayscale;
  char             errstr[200];
  byte             header[sizeof(X11WDFileHeader)];
  X11WDFileHeader *h11P;
  X11XColor       *x11colors;
  CARD32           pad;
  int              word64 = 0;

  x11colors = (X11XColor *) NULL;

  byte_swap = 0;
  maxv = 255L;

  h11P = (X11WDFileHeader*) header;

  if (fread(&header[0], sizeof(*h11P), (size_t) 1, file) != 1)
    return(xwdError("couldn't read X11 XWD file header"));

  if (h11P->file_version != X11WD_FILE_VERSION) {
    byte_swap = 1;
    h11P->header_size      = bs_long(h11P->header_size);
    h11P->file_version     = bs_long(h11P->file_version);
    h11P->pixmap_format    = bs_long(h11P->pixmap_format);
    h11P->pixmap_depth     = bs_long(h11P->pixmap_depth);
    h11P->pixmap_width     = bs_long(h11P->pixmap_width);
    h11P->pixmap_height    = bs_long(h11P->pixmap_height);
    h11P->xoffset          = bs_long(h11P->xoffset);
    h11P->byte_order       = bs_long(h11P->byte_order);
    h11P->bitmap_unit      = bs_long(h11P->bitmap_unit);
    h11P->bitmap_bit_order = bs_long(h11P->bitmap_bit_order);
    h11P->bitmap_pad       = bs_long(h11P->bitmap_pad);
    h11P->bits_per_pixel   = bs_long(h11P->bits_per_pixel);
    h11P->bytes_per_line   = bs_long(h11P->bytes_per_line);
    h11P->visual_class     = bs_long(h11P->visual_class);
    h11P->red_mask         = bs_long(h11P->red_mask);
    h11P->grn_mask         = bs_long(h11P->grn_mask);
    h11P->blu_mask         = bs_long(h11P->blu_mask);
    h11P->bits_per_rgb     = bs_long(h11P->bits_per_rgb);
    h11P->colormap_entries = bs_long(h11P->colormap_entries);
    h11P->ncolors          = bs_long(h11P->ncolors);
    h11P->window_width     = bs_long(h11P->window_width);
    h11P->window_height    = bs_long(h11P->window_height);
    h11P->window_x         = bs_long(h11P->window_x);
    h11P->window_y         = bs_long(h11P->window_y);
    h11P->window_bdrwidth  = bs_long(h11P->window_bdrwidth);
  }

  for (i=0; i<h11P->header_size - sizeof(*h11P); i++)
    if (getc(file) == EOF)
      return(xwdError("couldn't read rest of X11 XWD file header"));

  /* Check whether we can handle this dump. */
  if (h11P->pixmap_depth > 24)
    return(xwdError("can't handle X11 pixmap_depth > 24"));

  if (h11P->bits_per_rgb > 24)
    return(xwdError("can't handle X11 bits_per_rgb > 24"));

  if (h11P->pixmap_format != ZPixmap && h11P->pixmap_depth != 1)  {
    sprintf(errstr, "can't handle X11 pixmap_format %ld with depth != 1",
	    (long)h11P->pixmap_format);
    return(xwdError(errstr));
  }

  if (h11P->bitmap_unit != 8 && h11P->bitmap_unit != 16 &&
      h11P->bitmap_unit != 32)  {
    sprintf(errstr, "X11 bitmap_unit (%ld) is non-standard - can't handle",
	    (long)h11P->bitmap_unit);
    return(xwdError(errstr));
  }

  grayscale = 1;
  if (h11P->ncolors > 0) {      /* Read X11 colormap. */
    int bufsize = h11P->ncolors * sizeof(X11XColor);

    if (bufsize/sizeof(X11XColor) != h11P->ncolors)
      return(xwdError("too many colors"));
    x11colors = (X11XColor*) malloc(bufsize);
    if (!x11colors) return(xwdError("out of memory"));

    if (h11P->header_size + bufsize
	+ h11P->pixmap_height * h11P->bytes_per_line + h11P->ncolors * 4
	== filesize ) word64 = 1;

    if (word64) {
      for (i = 0; i < h11P->ncolors; ++i) {
	if (fread(&pad, sizeof(pad), (size_t) 1, file ) != 1)
	  return(xwdError("couldn't read X11 XWD colormap"));

	if (fread( &x11colors[i], sizeof(X11XColor), (size_t) 1, file) != 1)
	  return(xwdError("couldn't read X11 XWD colormap"));
      }
    }
    else {
      if (fread(x11colors, sizeof(X11XColor), (size_t) h11P->ncolors, file)
	  != h11P->ncolors)
	return(xwdError("couldn't read X11 XWD colormap"));
    }

    for (i = 0; i < h11P->ncolors; ++i) {
      if (byte_swap) {
	x11colors[i].red   = (CARD16) bs_short(x11colors[i].red);
	x11colors[i].green = (CARD16) bs_short(x11colors[i].green);
	x11colors[i].blue  = (CARD16) bs_short(x11colors[i].blue);
      }

      if (maxv != 65535L) {
	x11colors[i].red   = (u_short) ((x11colors[i].red   * maxv) / 65535);
	x11colors[i].green = (u_short) ((x11colors[i].green * maxv) / 65535);
	x11colors[i].blue  = (u_short) ((x11colors[i].blue  * maxv) / 65535);
      }
      if (x11colors[i].red != x11colors[i].green ||
	  x11colors[i].green != x11colors[i].blue)
	grayscale = 0;
    }
  }

  *visualclassP = h11P->visual_class;
  /* SJT: FIXME. If bits_per_pixel == 16, maxv could be either 31 or 63.
     It doesn't matter, though, because maxv is never used beyond here.
   */
  if (*visualclassP == TrueColor || *visualclassP == DirectColor) {
    if (h11P->bits_per_pixel == 16) maxv = 31;
    else maxv = 255;
  }

  else if (*visualclassP == StaticGray && h11P->bits_per_pixel == 1) {
    maxv = 1;
    /* B/W bitmaps have a two entry colormap */
    pinfo->r[0] = pinfo->g[0] = pinfo->b[0] = 255;   /* 0 = white */
    pinfo->r[1] = pinfo->g[1] = pinfo->b[1] = 0;     /* 1 = black */
  }

  else if (*visualclassP == StaticGray) {
    maxv = (1 << h11P->bits_per_pixel) - 1;
    for (i=0; i<=maxv; i++)
      pinfo->r[i] = pinfo->g[i] = pinfo->b[i] = x11colors[i].red;
  }

  else {
    if (grayscale) {
      for (i=0; i<=h11P->ncolors; i++)
	pinfo->r[i] = pinfo->g[i] = pinfo->b[i] = x11colors[i].red;
    }
    else {
      for (i = 0; i < h11P->ncolors; ++i) {
	pinfo->r[i] = x11colors[i].red;
	pinfo->g[i] = x11colors[i].green;
	pinfo->b[i] = x11colors[i].blue;
      }
    }
  }

  *colsP = h11P->pixmap_width;
  *rowsP = h11P->pixmap_height;
  *padrightP = h11P->bytes_per_line * 8 / h11P->bits_per_pixel -
    h11P->pixmap_width;

  bits_per_item  = h11P->bitmap_unit;
  bits_per_pixel = h11P->bits_per_pixel;
  byte_order     = h11P->byte_order;
  bit_order      = h11P->bitmap_bit_order;
  bits_per_rgb   = h11P->bits_per_rgb;


  /* add sanity-code for freako 'exceed' server, where bitmapunit = 8
     and bitsperpix = 32 (and depth=24)... */

  if (bits_per_item < bits_per_pixel) {
    bits_per_item = bits_per_pixel;

    /* round bits_per_item up to next legal value, if necc */
    if      (bits_per_item <  8) bits_per_item = 8;
    else if (bits_per_item < 16) bits_per_item = 16;
    else                         bits_per_item = 32;
  }


  /* which raises the question:  how (can?) you ever have a 24 bits per pix,
     (i.e., 3 bytes, no alpha/padding) */


  bits_used  = bits_per_item;

  if (bits_per_pixel == sizeof(pixel_mask) * 8)  pixel_mask = (CARD32) -1;
  else pixel_mask = (1 << bits_per_pixel) - 1;

  red_mask = h11P->red_mask;
  grn_mask = h11P->grn_mask;
  blu_mask = h11P->blu_mask;

  getcolorshift(red_mask, &red_shift_right, &red_justify_left);
  getcolorshift(grn_mask, &grn_shift_right, &grn_justify_left);
  getcolorshift(blu_mask, &blu_shift_right, &blu_justify_left);

  byteP  = (char   *) buf;
  shortP = (CARD16 *) buf;
  longP  = (CARD32 *) buf;

  return 0;
}


/* SJT: figure out the proper shifts */
static void getcolorshift (CARD32 mask, int *rightshift, int *leftshift)
{
  int lshift, rshift;
  unsigned int uu;

  if (mask == 0)
  {
    *rightshift = *leftshift = 0;
    return;
  }

  uu = mask;
  lshift = rshift = 0;
  while ((uu & 0xf) == 0)
  {
      rshift += 4;
      uu >>= 4;
  }
  while ((uu & 1) == 0)
  {
      rshift++;
      uu >>= 1;
  }

  while (uu != 0)
  {
      if (uu & 1)
      {
          lshift++;
          uu >>= 1;
      }
  }
  *rightshift = rshift;
  *leftshift = CHAR_BIT * sizeof(pixel) - lshift;
  return;
}


/******************************/
static CARD32 getpixnum(file)
     FILE* file;
{
  int n;

  if (bits_used == bits_per_item) {
    switch (bits_per_item) {
    case 8:
      *byteP = getc(file);
      break;

    case 16:
      if (byte_order == MSBFirst) {
	if (readbigshort(file, shortP) == -1)
	  xwdWarning("unexpected EOF");
      }
      else {
	if (readlittleshort(file, shortP) == -1)
	  xwdWarning("unexpected EOF");
      }
      break;

    case 32:
      if (byte_order == MSBFirst) {
	if (readbiglong(file, longP) == -1)
	  xwdWarning("unexpected EOF");
      }
      else {
	if (readlittlelong(file, longP) == -1)
	  xwdWarning("unexpected EOF");
      }
      break;

    default:
      xwdWarning("can't happen");
    }
    bits_used = 0;

    if (bit_order == MSBFirst)
      bit_shift = bits_per_item - bits_per_pixel;
    else
      bit_shift = 0;
  }

  switch (bits_per_item) {
  case 8:
    n = (*byteP >> bit_shift) & pixel_mask;
    break;

  case 16:
    n = (*shortP >> bit_shift) & pixel_mask;
    break;

  case 32:
    n = (*longP >> bit_shift) & pixel_mask;
    break;

  default:
    n = 0;
    xwdWarning("can't happen");
  }

  if (bit_order == MSBFirst) bit_shift -= bits_per_pixel;
                        else bit_shift += bits_per_pixel;

  bits_used += bits_per_pixel;

  return n;
}


/***************************/
static int xwdError(st)
     const char *st;
{
  if (pic8  != NULL) free(pic8);
  if (pic24 != NULL) free(pic24);

  SetISTR(ISTR_WARNING,"%s:  %s", bname, st);
  return 0;
}


/***************************/
static void xwdWarning(st)
     const char *st;
{
  SetISTR(ISTR_WARNING,"%s:  %s", bname, st);
}





/*
 * Byte-swapping junk.
 */

union cheat {
  CARD32 l;
  CARD16 s;
  CARD8  c[sizeof(CARD32)];
};

static int bs_short(s)
     int s;
{
  union cheat u;
  unsigned char t;

  u.s = (CARD16) s;
  t = u.c[0];  u.c[0] = u.c[1];  u.c[1] = t;
  return (int) u.s;
}

static CARD32 bs_long(l)
     CARD32 l;
{
  union cheat u;
  unsigned char t;

  u.l = l;
  t = u.c[0];  u.c[0] = u.c[3];  u.c[3] = t;
  t = u.c[1];  u.c[1] = u.c[2];  u.c[2] = t;
  return u.l;
}






/*
 * Endian I/O.
 */

static int readbigshort(in, sP)
     FILE  *in;
     CARD16 *sP;
{
  *sP = (getc(in) & 0xff) << 8;
  *sP |= getc(in) & 0xff;

  if (ferror(in)) return -1;
  return 0;
}

static int readbiglong(in, lP)
     FILE *in;
     CARD32 *lP;
{
  *lP  = (getc(in) & 0xff) << 24;
  *lP |= (getc(in) & 0xff) << 16;
  *lP |= (getc(in) & 0xff) << 8;
  *lP |=  getc(in) & 0xff;

  if (ferror(in)) return -1;
  return 0;
}


static int readlittleshort(in, sP)
     FILE  *in;
     CARD16 *sP;
{
  *sP  =  getc(in) & 0xff;
  *sP |= (getc(in) & 0xff) << 8;

  if (ferror(in)) return -1;
  return 0;
}


static int readlittlelong(in, lP)
     FILE *in;
     CARD32 *lP;
{
  *lP  =  getc(in) & 0xff;
  *lP |= (getc(in) & 0xff) << 8;
  *lP |= (getc(in) & 0xff) << 16;
  *lP |= (getc(in) & 0xff) << 24;

  if (ferror(in)) return -1;
  return 0;
}


#if 0 /* NOTUSED */
static int writebiglong(out, l)
     FILE* out;
     CARD32 l;
{
  putc((l>>24) & 0xff, out);
  putc((l>>16) & 0xff, out);
  putc((l>> 8) & 0xff, out);
  putc( l      & 0xff, out);
  return 0;
}


static int writebigshort(out, s)
     FILE* out;
     int   s;
{
  putc((s>>8)&0xff, out);
  putc(s&0xff, out);
  return 0;
}
#endif /* 0 (NOTUSED) */