| 1 | /**************************************************************************
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| 2 | *
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| 3 | * huffman.h -- Huffman coding functions
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| 4 | * Copyright (C) 1994 Neil Sharman
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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 | **************************************************************************/
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| 21 |
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| 22 | #ifndef H_HUFFMAN
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| 23 | #define H_HUFFMAN
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| 24 |
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| 25 | #include "sysfuncs.h"
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| 26 | #include "bitio_m_abstract.h"
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| 27 |
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| 28 | #define MAX_HUFFCODE_LEN 31
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| 29 |
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| 30 | struct huff_data {
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| 31 | int num_codes;
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| 32 | int mincodelen;
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| 33 | int maxcodelen;
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| 34 | int lencount[MAX_HUFFCODE_LEN + 1];
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| 35 | unsigned long min_code[MAX_HUFFCODE_LEN + 1];
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| 36 | char *clens;
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| 37 | };
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| 38 |
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| 39 |
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| 40 | huff_data *Generate_Huffman_Data (int num, long *freqs, huff_data * data,
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| 41 | u_long * mem);
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| 42 |
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| 43 | unsigned long *Generate_Huffman_Codes (huff_data * data, u_long * mem);
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| 44 |
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| 45 | unsigned long **Generate_Huffman_Vals (huff_data * data, u_long * mem);
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| 46 |
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| 47 | int Write_Huffman_Data (FILE * f, huff_data * hd);
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| 48 |
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| 49 | int Read_Huffman_Data (FILE * f, huff_data * hd, u_long * mem, u_long * disk);
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| 50 |
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| 51 | /* Calculate the number of bits required to code the data with the
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| 52 | specified frequencies. Normally freqs and counts should point to
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| 53 | the same array. */
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| 54 | double Calculate_Huffman_Size (int num, long *freqs, long *counts);
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| 55 |
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| 56 |
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| 57 | #endif
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