| 1 | /**************************************************************************
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| 2 | *
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| 3 | * felics.c -- The main guts of the felics algorithm
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| 4 | * Copyright (C) 1994 Neil Sharman and Kerry Guise
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| 5 | *
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| 6 | * This program is free software; you can redistribute it and/or modify
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| 7 | * it under the terms of the GNU General Public License as published by
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| 8 | * the Free Software Foundation; either version 2 of the License, or
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| 9 | * (at your option) any later version.
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| 10 | *
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| 11 | * This program is distributed in the hope that it will be useful,
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| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | * GNU General Public License for more details.
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| 15 | *
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| 16 | * You should have received a copy of the GNU General Public License
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| 17 | * along with this program; if not, write to the Free Software
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| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 19 | *
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| 20 | * $Id: felics.c 3745 2003-02-20 21:20:24Z mdewsnip $
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| 21 | *
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| 22 | **************************************************************************/
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| 23 |
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| 24 | #include "sysfuncs.h"
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| 25 |
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| 26 | #include "bitio_m.h"
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| 27 | #include "bitio_m_stdio.h"
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| 28 |
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| 29 |
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| 30 | #undef putw
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| 31 | #define putw(x) { \
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| 32 | short z; \
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| 33 | byteptr = (unsigned char *)(x); \
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| 34 | for (z = 0; z < sizeof(int); z++) \
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| 35 | (void) putc((int) byteptr[z], fp_out); \
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| 36 | }
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| 37 | #define INTSIZE sizeof(int) * 8
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| 38 | #define BOOLEAN short
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| 39 | #define TRUE 1
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| 40 | #define FALSE 0
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| 41 |
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| 42 | #define IN_RANGE 0
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| 43 | #define OUT_OF_RANGE 1
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| 44 | #define BELOW_RANGE 0
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| 45 | #define ABOVE_RANGE 1
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| 46 |
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| 47 |
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| 48 | void
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| 49 | encode (unsigned int *line, int width, int height, int maxval, int maxk,
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| 50 | FILE * fp_in, FILE * fp_out, int (*get) (FILE *))
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| 51 | {
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| 52 | int x, y;
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| 53 | unsigned long P, L, H, N1, N2, delta;
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| 54 | unsigned long cumul_param[256][INTSIZE];
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| 55 | unsigned max_cumul;
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| 56 |
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| 57 | memset (cumul_param, '0', sizeof (cumul_param));
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| 58 |
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| 59 | if (maxk)
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| 60 | max_cumul = maxk;
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| 61 | else
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| 62 | CEILLOG_2 (maxval, max_cumul);
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| 63 |
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| 64 | ENCODE_START (fp_out)
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| 65 |
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| 66 | for (y = 0; y < height; y++)
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| 67 | for (x = 0; x < width; x++)
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| 68 | {
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| 69 | if (y > 0)
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| 70 | {
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| 71 | if (x > 0)
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| 72 | { /* ******** */
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| 73 | N1 = line[x]; /* ****1*** */
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| 74 | N2 = line[x - 1]; /* ***2P*** */
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| 75 | } /* ******** */
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| 76 | else
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| 77 | { /* |******* */
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| 78 | N1 = line[x]; /* |12***** */
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| 79 | N2 = line[x + 1]; /* |P***** */
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| 80 | } /* |******* */
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| 81 | }
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| 82 | else
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| 83 | {
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| 84 | if (x > 1)
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| 85 | {
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| 86 | N1 = line[x - 1]; /* -------- */
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| 87 | N2 = line[x - 2]; /* **12P*** */
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| 88 | } /* ******** */
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| 89 | else if (x > 0)
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| 90 | {
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| 91 | N1 = line[x - 1]; /* +------- */
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| 92 | N2 = N1; /* |3P***** */
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| 93 | } /* |******* */
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| 94 | else
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| 95 | {
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| 96 | line[x] = get (fp_in); /* +------- */
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| 97 | BINARY_ENCODE (line[x] + 1, maxval + 1); /* |P****** */
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| 98 | continue; /* |******* */
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| 99 | }
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| 100 | }
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| 101 |
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| 102 |
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| 103 | H = N1 > N2 ? N1 : N2;
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| 104 | L = N1 < N2 ? N1 : N2;
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| 105 | delta = H - L;
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| 106 |
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| 107 | line[x] = P = get (fp_in);
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| 108 |
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| 109 | if ((L <= P) && (P <= H))
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| 110 | {
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| 111 | /* IN-RANGE */
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| 112 | unsigned long range, logofrange, thresh, numlong;
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| 113 | int nbits;
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| 114 |
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| 115 | ENCODE_BIT (IN_RANGE);
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| 116 |
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| 117 | P -= L;
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| 118 |
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| 119 | range = delta + 1;
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| 120 |
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| 121 | if (range > 1)
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| 122 | {
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| 123 | /* 2**i <= delta + 1 < 2**(i+1) ; find i ... */
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| 124 | CEILLOG_2 (range, logofrange);
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| 125 |
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| 126 | /* number of n-bit values in the range */
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| 127 | thresh = (1 << logofrange) - range;
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| 128 |
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| 129 | /* number of n+1-bit values in the range */
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| 130 | numlong = range - thresh;
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| 131 |
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| 132 | /* rotate the n-bit codes into the centre */
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| 133 | P -= (numlong >> 1);
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| 134 | if ((long) P < 0)
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| 135 | P += range;
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| 136 |
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| 137 | if (P < thresh)
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| 138 | nbits = logofrange - 1;
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| 139 | else
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| 140 | {
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| 141 | nbits = logofrange;
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| 142 | P += thresh;
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| 143 | }
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| 144 | while (--nbits >= 0)
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| 145 | ENCODE_BIT ((P >> nbits) & 1);
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| 146 | }
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| 147 | }
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| 148 | else
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| 149 | {
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| 150 | /* OUT_OF_RANGE */
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| 151 | unsigned long diff, parm, i, min;
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| 152 |
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| 153 | ENCODE_BIT (OUT_OF_RANGE);
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| 154 |
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| 155 | if (P < L)
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| 156 | {
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| 157 | ENCODE_BIT (BELOW_RANGE);
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| 158 | diff = L - P - 1;
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| 159 | }
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| 160 | else
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| 161 | {
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| 162 | ENCODE_BIT (ABOVE_RANGE);
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| 163 | diff = P - H - 1;
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| 164 | }
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| 165 |
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| 166 | /* Now code 'diff' as a Golomb-Rice code */
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| 167 |
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| 168 | parm = 0;
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| 169 | min = cumul_param[delta][0];
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| 170 | for (i = 1; i < max_cumul; i++)
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| 171 | if (cumul_param[delta][i] < min)
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| 172 | {
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| 173 | min = cumul_param[delta][i];
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| 174 | parm = i;
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| 175 | }
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| 176 |
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| 177 | UNARY_ENCODE ((diff >> parm) + 1);
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| 178 | BINARY_ENCODE ((diff & ((1 << parm) - 1)) + 1, 1 << parm);
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| 179 |
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| 180 | for (i = 0; i < max_cumul; i++)
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| 181 | cumul_param[delta][i] += (diff >> i) + 1 + i;
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| 182 | }
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| 183 |
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| 184 | }
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| 185 |
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| 186 | ENCODE_DONE
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| 187 |
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| 188 | }
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| 189 |
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| 190 |
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| 191 |
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| 192 |
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| 193 |
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| 194 |
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| 195 | void
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| 196 | decode (unsigned int *line, int width, int height, int maxval, int maxk,
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| 197 | FILE * fp_in, FILE * fp_out)
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| 198 | {
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| 199 | int x, y;
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| 200 | unsigned int P, L, H, N1, N2, delta;
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| 201 | unsigned long cumul_param[256][INTSIZE];
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| 202 | unsigned max_cumul;
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| 203 |
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| 204 | memset (cumul_param, '0', sizeof (cumul_param));
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| 205 |
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| 206 | if (maxk)
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| 207 | max_cumul = maxk;
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| 208 | else
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| 209 | CEILLOG_2 (maxval, max_cumul);
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| 210 |
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| 211 | DECODE_START (fp_in);
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| 212 |
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| 213 | for (y = 0; y < height; y++)
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| 214 | for (x = 0; x < width; x++)
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| 215 | {
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| 216 | if (y > 0)
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| 217 | {
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| 218 | if (x > 0)
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| 219 | { /* ******** */
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| 220 | N1 = line[x]; /* ****1*** */
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| 221 | N2 = line[x - 1]; /* ***2P*** */
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| 222 | } /* ******** */
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| 223 | else
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| 224 | { /* |******* */
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| 225 | N1 = line[x]; /* |12***** */
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| 226 | N2 = line[x + 1]; /* |P***** */
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| 227 | } /* |******* */
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| 228 | }
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| 229 | else
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| 230 | {
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| 231 | if (x > 1)
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| 232 | {
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| 233 | N1 = line[x - 1]; /* -------- */
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| 234 | N2 = line[x - 2]; /* **12P*** */
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| 235 | } /* ******** */
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| 236 | else if (x > 0)
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| 237 | {
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| 238 | N1 = line[x - 1]; /* +------- */
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| 239 | N2 = N1; /* |3P***** */
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| 240 | } /* |******* */
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| 241 | else
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| 242 | {
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| 243 | BINARY_DECODE (line[x], maxval + 1);
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| 244 | line[x]--;
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| 245 | if (maxval < 256)
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| 246 | putc (line[x], fp_out); /* +------- */
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| 247 | else /* |P****** */
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| 248 | fprintf (fp_out, "%u ", line[x]); /* |******* */
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| 249 | continue;
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| 250 | }
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| 251 | }
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| 252 |
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| 253 |
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| 254 | H = N1 > N2 ? N1 : N2;
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| 255 | L = N1 < N2 ? N1 : N2;
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| 256 | delta = H - L;
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| 257 |
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| 258 | if (DECODE_BIT == IN_RANGE)
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| 259 | {
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| 260 | unsigned long i, range, logofrange, thresh, numlong;
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| 261 | unsigned xx, l;
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| 262 |
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| 263 | range = delta + 1;
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| 264 |
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| 265 | if (range > 1)
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| 266 | {
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| 267 | /* 2**i <= delta + 1 < 2**(i+1) ; find i ... */
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| 268 | CEILLOG_2 (range, logofrange);
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| 269 |
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| 270 | /* number of n-bit values in the range */
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| 271 | thresh = (1 << logofrange) - range;
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| 272 | for (P = i = 0; i < logofrange - 1; i++)
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| 273 | DECODE_ADD (P);
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| 274 | xx = P;
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| 275 | l = logofrange - 1;
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| 276 | if (P >= thresh)
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| 277 | {
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| 278 | DECODE_ADD (P);
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| 279 | xx = P;
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| 280 | l++;
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| 281 | P -= thresh;
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| 282 | }
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| 283 |
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| 284 | /* number of n+1-bit values in the range */
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| 285 | numlong = range - thresh;
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| 286 |
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| 287 | /* rotate the n-bit codes into the centre */
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| 288 | P += (numlong >> 1);
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| 289 | if ((long) P >= range)
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| 290 | P -= range;
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| 291 |
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| 292 | P += L;
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| 293 | }
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| 294 | else
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| 295 | P = L;
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| 296 | }
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| 297 | else
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| 298 | {
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| 299 | int out_of_range = DECODE_BIT;
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| 300 | unsigned long diff, unary, binary, i, min, parm;
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| 301 |
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| 302 | /* Now code 'diff' as a Golomb-Rice code */
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| 303 |
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| 304 | parm = 0;
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| 305 | min = cumul_param[delta][0];
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| 306 | for (i = 1; i < max_cumul; i++)
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| 307 | if (cumul_param[delta][i] < min)
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| 308 | {
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| 309 | min = cumul_param[delta][i];
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| 310 | parm = i;
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| 311 | }
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| 312 |
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| 313 | UNARY_DECODE (unary);
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| 314 | diff = (unary - 1) << parm;
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| 315 | BINARY_DECODE (binary, 1 << parm);
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| 316 | diff |= binary - 1;
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| 317 |
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| 318 | for (i = 0; i < max_cumul; i++)
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| 319 | cumul_param[delta][i] += (diff >> i) + 1 + i;
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| 320 |
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| 321 | if (out_of_range == BELOW_RANGE)
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| 322 | {
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| 323 | P = L - diff - 1;
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| 324 | }
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| 325 | else
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| 326 | {
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| 327 | P = diff + H + 1;
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| 328 | }
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| 329 | }
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| 330 |
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| 331 | line[x] = P;
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| 332 |
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| 333 | if (maxval < 256)
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| 334 | (void) putc (P, fp_out);
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| 335 | else
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| 336 | fprintf (fp_out, "%u ", P);
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| 337 | }
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| 338 |
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| 339 | DECODE_DONE
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| 340 | }
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