/* $Id: tif_next.c,v 1.4 2005/11/19 16:02:59 malaterre Exp $ */

/*
 * Copyright (c) 1988-1997 Sam Leffler
 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

#include "tiffiop.h"
#ifdef NEXT_SUPPORT
/*
 * TIFF Library.
 *
 * NeXT 2-bit Grey Scale Compression Algorithm Support
 */

#define SETPIXEL(op, v) {      \
  switch (npixels++ & 3) {    \
  case 0:  op[0]  = (unsigned char) ((v) << 6); break;  \
  case 1:  op[0] |= (v) << 4; break;  \
  case 2:  op[0] |= (v) << 2; break;  \
  case 3:  *op++ |= (v);     break;  \
  }          \
}

#define LITERALROW  0x00
#define LITERALSPAN  0x40
#define WHITE     ((1<<2)-1)

static int
NeXTDecode(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
{
  register unsigned char *bp, *op;
  register tsize_t cc;
  register int n;
  tidata_t row;
  tsize_t scanline;

  (void) s;
  /*
   * Each scanline is assumed to start off as all
   * white (we assume a PhotometricInterpretation
   * of ``min-is-black'').
   */
  for (op = buf, cc = occ; cc-- > 0;)
    *op++ = 0xff;

  bp = (unsigned char *)tif->tif_rawcp;
  cc = tif->tif_rawcc;
  scanline = tif->tif_scanlinesize;
  for (row = buf; (long)occ > 0; occ -= scanline, row += scanline) {
    n = *bp++, cc--;
    switch (n) {
    case LITERALROW:
      /*
       * The entire scanline is given as literal values.
       */
      if (cc < scanline)
        goto bad;
      _TIFFmemcpy(row, bp, scanline);
      bp += scanline;
      cc -= scanline;
      break;
    case LITERALSPAN: {
      int off;
      /*
       * The scanline has a literal span
       * that begins at some offset.
       */
      off = (bp[0] * 256) + bp[1];
      n = (bp[2] * 256) + bp[3];
      if (cc < 4+n || off+n > scanline)
        goto bad;
      _TIFFmemcpy(row+off, bp+4, n);
      bp += 4+n;
      cc -= 4+n;
      break;
    }
    default: {
      register int npixels = 0, grey;
      unsigned long imagewidth = tif->tif_dir.td_imagewidth;

      /*
       * The scanline is composed of a sequence
       * of constant color ``runs''.  We shift
       * into ``run mode'' and interpret bytes
       * as codes of the form <color><npixels>
       * until we've filled the scanline.
       */
      op = row;
      for (;;) {
        grey = (n>>6) & 0x3;
        n &= 0x3f;
        while (n-- > 0)
          SETPIXEL(op, grey);
        if (npixels >= (int) imagewidth)
          break;
        if (cc == 0)
          goto bad;
        n = *bp++, cc--;
      }
      break;
    }
    }
  }
  tif->tif_rawcp = (tidata_t) bp;
  tif->tif_rawcc = cc;
  return (1);
bad:
  TIFFError(tif->tif_name, "NeXTDecode: Not enough data for scanline %ld",
      (long) tif->tif_row);
  return (0);
}

int
TIFFInitNeXT(TIFF* tif, int scheme)
{
  (void) scheme;
  tif->tif_decoderow = NeXTDecode;
  tif->tif_decodestrip = NeXTDecode;
  tif->tif_decodetile = NeXTDecode;
  return (1);
}
#endif /* NEXT_SUPPORT */

