143 lines
3.7 KiB
C
143 lines
3.7 KiB
C
/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_next.c,v 1.2 1999-11-27 21:43:28 warmerda Exp $ */
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/*
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* Copyright (c) 1988-1997 Sam Leffler
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* Copyright (c) 1991-1997 Silicon Graphics, Inc.
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*
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* Permission to use, copy, modify, distribute, and sell this software and
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* its documentation for any purpose is hereby granted without fee, provided
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* that (i) the above copyright notices and this permission notice appear in
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* all copies of the software and related documentation, and (ii) the names of
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* Sam Leffler and Silicon Graphics may not be used in any advertising or
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* publicity relating to the software without the specific, prior written
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* permission of Sam Leffler and Silicon Graphics.
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*
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* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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*
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* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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* OF THIS SOFTWARE.
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*/
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#include "tiffiop.h"
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#ifdef NEXT_SUPPORT
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/*
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* TIFF Library.
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*
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* NeXT 2-bit Grey Scale Compression Algorithm Support
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*/
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#define SETPIXEL(op, v) { \
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switch (npixels++ & 3) { \
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case 0: op[0] = (v) << 6; break; \
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case 1: op[0] |= (v) << 4; break; \
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case 2: op[0] |= (v) << 2; break; \
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case 3: *op++ |= (v); break; \
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} \
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}
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#define LITERALROW 0x00
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#define LITERALSPAN 0x40
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#define WHITE ((1<<2)-1)
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static int
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NeXTDecode(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
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{
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register u_char *bp, *op;
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register tsize_t cc;
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register int n;
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tidata_t row;
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tsize_t scanline;
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(void) s;
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/*
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* Each scanline is assumed to start off as all
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* white (we assume a PhotometricInterpretation
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* of ``min-is-black'').
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*/
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for (op = buf, cc = occ; cc-- > 0;)
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*op++ = 0xff;
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bp = (u_char *)tif->tif_rawcp;
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cc = tif->tif_rawcc;
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scanline = tif->tif_scanlinesize;
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for (row = buf; (long)occ > 0; occ -= scanline, row += scanline) {
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n = *bp++, cc--;
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switch (n) {
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case LITERALROW:
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/*
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* The entire scanline is given as literal values.
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*/
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if (cc < scanline)
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goto bad;
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_TIFFmemcpy(row, bp, scanline);
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bp += scanline;
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cc -= scanline;
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break;
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case LITERALSPAN: {
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int off;
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/*
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* The scanline has a literal span
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* that begins at some offset.
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*/
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off = (bp[0] * 256) + bp[1];
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n = (bp[2] * 256) + bp[3];
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if (cc < 4+n)
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goto bad;
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_TIFFmemcpy(row+off, bp+4, n);
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bp += 4+n;
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cc -= 4+n;
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break;
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}
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default: {
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register int npixels = 0, grey;
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u_long imagewidth = tif->tif_dir.td_imagewidth;
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/*
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* The scanline is composed of a sequence
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* of constant color ``runs''. We shift
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* into ``run mode'' and interpret bytes
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* as codes of the form <color><npixels>
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* until we've filled the scanline.
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*/
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op = row;
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for (;;) {
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grey = (n>>6) & 0x3;
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n &= 0x3f;
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while (n-- > 0)
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SETPIXEL(op, grey);
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if (npixels >= (int) imagewidth)
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break;
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if (cc == 0)
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goto bad;
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n = *bp++, cc--;
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}
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break;
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}
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}
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}
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tif->tif_rawcp = (tidata_t) bp;
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tif->tif_rawcc = cc;
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return (1);
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bad:
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TIFFError(tif->tif_name, "NeXTDecode: Not enough data for scanline %ld",
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(long) tif->tif_row);
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return (0);
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}
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int
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TIFFInitNeXT(TIFF* tif, int scheme)
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{
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(void) scheme;
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tif->tif_decoderow = NeXTDecode;
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tif->tif_decodestrip = NeXTDecode;
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tif->tif_decodetile = NeXTDecode;
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return (1);
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}
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#endif /* NEXT_SUPPORT */
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