+++ /dev/null
-/* $Id: tif_thunder.c,v 1.1 2005/06/17 13:54:52 vp153 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 THUNDER_SUPPORT
-/*
- * TIFF Library.
- *
- * ThunderScan 4-bit Compression Algorithm Support
- */
-
-/*
- * ThunderScan uses an encoding scheme designed for
- * 4-bit pixel values. Data is encoded in bytes, with
- * each byte split into a 2-bit code word and a 6-bit
- * data value. The encoding gives raw data, runs of
- * pixels, or pixel values encoded as a delta from the
- * previous pixel value. For the latter, either 2-bit
- * or 3-bit delta values are used, with the deltas packed
- * into a single byte.
- */
-#define THUNDER_DATA 0x3f /* mask for 6-bit data */
-#define THUNDER_CODE 0xc0 /* mask for 2-bit code word */
-/* code values */
-#define THUNDER_RUN 0x00 /* run of pixels w/ encoded count */
-#define THUNDER_2BITDELTAS 0x40 /* 3 pixels w/ encoded 2-bit deltas */
-#define DELTA2_SKIP 2 /* skip code for 2-bit deltas */
-#define THUNDER_3BITDELTAS 0x80 /* 2 pixels w/ encoded 3-bit deltas */
-#define DELTA3_SKIP 4 /* skip code for 3-bit deltas */
-#define THUNDER_RAW 0xc0 /* raw data encoded */
-
-static const int twobitdeltas[4] = { 0, 1, 0, -1 };
-static const int threebitdeltas[8] = { 0, 1, 2, 3, 0, -3, -2, -1 };
-
-#define SETPIXEL(op, v) { \
- lastpixel = (v) & 0xf; \
- if (npixels++ & 1) \
- *op++ |= lastpixel; \
- else \
- op[0] = (tidataval_t) (lastpixel << 4); \
-}
-
-static int
-ThunderDecode(TIFF* tif, tidata_t op, tsize_t maxpixels)
-{
- register unsigned char *bp;
- register tsize_t cc;
- unsigned int lastpixel;
- tsize_t npixels;
-
- bp = (unsigned char *)tif->tif_rawcp;
- cc = tif->tif_rawcc;
- lastpixel = 0;
- npixels = 0;
- while (cc > 0 && npixels < maxpixels) {
- int n, delta;
-
- n = *bp++, cc--;
- switch (n & THUNDER_CODE) {
- case THUNDER_RUN: /* pixel run */
- /*
- * Replicate the last pixel n times,
- * where n is the lower-order 6 bits.
- */
- if (npixels & 1) {
- op[0] |= lastpixel;
- lastpixel = *op++; npixels++; n--;
- } else
- lastpixel |= lastpixel << 4;
- npixels += n;
- if (npixels < maxpixels) {
- for (; n > 0; n -= 2)
- *op++ = (tidataval_t) lastpixel;
- }
- if (n == -1)
- *--op &= 0xf0;
- lastpixel &= 0xf;
- break;
- case THUNDER_2BITDELTAS: /* 2-bit deltas */
- if ((delta = ((n >> 4) & 3)) != DELTA2_SKIP)
- SETPIXEL(op, lastpixel + twobitdeltas[delta]);
- if ((delta = ((n >> 2) & 3)) != DELTA2_SKIP)
- SETPIXEL(op, lastpixel + twobitdeltas[delta]);
- if ((delta = (n & 3)) != DELTA2_SKIP)
- SETPIXEL(op, lastpixel + twobitdeltas[delta]);
- break;
- case THUNDER_3BITDELTAS: /* 3-bit deltas */
- if ((delta = ((n >> 3) & 7)) != DELTA3_SKIP)
- SETPIXEL(op, lastpixel + threebitdeltas[delta]);
- if ((delta = (n & 7)) != DELTA3_SKIP)
- SETPIXEL(op, lastpixel + threebitdeltas[delta]);
- break;
- case THUNDER_RAW: /* raw data */
- SETPIXEL(op, n);
- break;
- }
- }
- tif->tif_rawcp = (tidata_t) bp;
- tif->tif_rawcc = cc;
- if (npixels != maxpixels) {
- TIFFError(tif->tif_name,
- "ThunderDecode: %s data at scanline %ld (%lu != %lu)",
- npixels < maxpixels ? "Not enough" : "Too much",
- (long) tif->tif_row, (long) npixels, (long) maxpixels);
- return (0);
- }
- return (1);
-}
-
-static int
-ThunderDecodeRow(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
-{
- tidata_t row = buf;
-
- (void) s;
- while ((long)occ > 0) {
- if (!ThunderDecode(tif, row, tif->tif_dir.td_imagewidth))
- return (0);
- occ -= tif->tif_scanlinesize;
- row += tif->tif_scanlinesize;
- }
- return (1);
-}
-
-int
-TIFFInitThunderScan(TIFF* tif, int scheme)
-{
- (void) scheme;
- tif->tif_decoderow = ThunderDecodeRow;
- tif->tif_decodestrip = ThunderDecodeRow;
- return (1);
-}
-#endif /* THUNDER_SUPPORT */
-
-/* vim: set ts=8 sts=8 sw=8 noet: */
projects / opencv / blobdiff