1 | /* $Id: tif_next.c,v 1.6 2005/12/21 12:23:13 joris Exp $ */
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2 |
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3 | /*
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4 | * Copyright (c) 1988-1997 Sam Leffler
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5 | * Copyright (c) 1991-1997 Silicon Graphics, Inc.
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6 | *
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7 | * Permission to use, copy, modify, distribute, and sell this software and
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8 | * its documentation for any purpose is hereby granted without fee, provided
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9 | * that (i) the above copyright notices and this permission notice appear in
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10 | * all copies of the software and related documentation, and (ii) the names of
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11 | * Sam Leffler and Silicon Graphics may not be used in any advertising or
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12 | * publicity relating to the software without the specific, prior written
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13 | * permission of Sam Leffler and Silicon Graphics.
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14 | *
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15 | * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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16 | * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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17 | * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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18 | *
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19 | * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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20 | * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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21 | * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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22 | * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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23 | * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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24 | * OF THIS SOFTWARE.
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25 | */
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26 |
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27 | #include "tiffiop.h"
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28 | #ifdef NEXT_SUPPORT
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29 | /*
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30 | * TIFF Library.
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31 | *
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32 | * NeXT 2-bit Grey Scale Compression Algorithm Support
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33 | */
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34 |
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35 | #define SETPIXEL(op, v) { \
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36 | switch (npixels++ & 3) { \
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37 | case 0: op[0] = (unsigned char) ((v) << 6); break; \
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38 | case 1: op[0] |= (v) << 4; break; \
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39 | case 2: op[0] |= (v) << 2; break; \
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40 | case 3: *op++ |= (v); break; \
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41 | } \
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42 | }
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43 |
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44 | #define LITERALROW 0x00
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45 | #define LITERALSPAN 0x40
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46 | #define WHITE ((1<<2)-1)
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47 |
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48 | static int
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49 | NeXTDecode(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
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50 | {
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51 | register unsigned char *bp, *op;
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52 | register tsize_t cc;
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53 | register int n;
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54 | tidata_t row;
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55 | tsize_t scanline;
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56 |
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57 | (void) s;
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58 | /*
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59 | * Each scanline is assumed to start off as all
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60 | * white (we assume a PhotometricInterpretation
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61 | * of ``min-is-black'').
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62 | */
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63 | for (op = buf, cc = occ; cc-- > 0;)
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64 | *op++ = 0xff;
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65 |
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66 | bp = (unsigned char *)tif->tif_rawcp;
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67 | cc = tif->tif_rawcc;
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68 | scanline = tif->tif_scanlinesize;
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69 | for (row = buf; (long)occ > 0; occ -= scanline, row += scanline) {
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70 | n = *bp++, cc--;
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71 | switch (n) {
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72 | case LITERALROW:
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73 | /*
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74 | * The entire scanline is given as literal values.
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75 | */
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76 | if (cc < scanline)
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77 | goto bad;
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78 | _TIFFmemcpy(row, bp, scanline);
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79 | bp += scanline;
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80 | cc -= scanline;
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81 | break;
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82 | case LITERALSPAN: {
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83 | int off;
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84 | /*
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85 | * The scanline has a literal span
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86 | * that begins at some offset.
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87 | */
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88 | off = (bp[0] * 256) + bp[1];
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89 | n = (bp[2] * 256) + bp[3];
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90 | if (cc < 4+n || off+n > scanline)
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91 | goto bad;
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92 | _TIFFmemcpy(row+off, bp+4, n);
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93 | bp += 4+n;
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94 | cc -= 4+n;
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95 | break;
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96 | }
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97 | default: {
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98 | register int npixels = 0, grey;
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99 | unsigned long imagewidth = tif->tif_dir.td_imagewidth;
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100 |
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101 | /*
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102 | * The scanline is composed of a sequence
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103 | * of constant color ``runs''. We shift
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104 | * into ``run mode'' and interpret bytes
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105 | * as codes of the form <color><npixels>
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106 | * until we've filled the scanline.
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107 | */
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108 | op = row;
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109 | for (;;) {
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110 | grey = (n>>6) & 0x3;
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111 | n &= 0x3f;
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112 | while (n-- > 0)
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113 | SETPIXEL(op, grey);
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114 | if (npixels >= (int) imagewidth)
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115 | break;
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116 | if (cc == 0)
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117 | goto bad;
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118 | n = *bp++, cc--;
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119 | }
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120 | break;
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121 | }
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122 | }
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123 | }
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124 | tif->tif_rawcp = (tidata_t) bp;
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125 | tif->tif_rawcc = cc;
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126 | return (1);
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127 | bad:
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128 | TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "NeXTDecode: Not enough data for scanline %ld",
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129 | (long) tif->tif_row);
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130 | return (0);
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131 | }
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132 |
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133 | int
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134 | TIFFInitNeXT(TIFF* tif, int scheme)
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135 | {
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136 | (void) scheme;
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137 | tif->tif_decoderow = NeXTDecode;
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138 | tif->tif_decodestrip = NeXTDecode;
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139 | tif->tif_decodetile = NeXTDecode;
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140 | return (1);
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141 | }
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142 | #endif /* NEXT_SUPPORT */
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143 |
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144 | /* vim: set ts=8 sts=8 sw=8 noet: */
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