u6_lzw.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef NUVIE_FILES_U6_LZW_H
#define NUVIE_FILES_U6_LZW_H

#include "ultima/shared/std/string.h"

namespace Ultima {
namespace Nuvie {

class NuvieIOFileRead;

// LZW Stack

#define STACK_SIZE 10000

class U6LzwStack {
protected:
    unsigned char stack[STACK_SIZE];
    int contains;

public:
    U6LzwStack();

    void reset(void);
    bool is_empty(void);
    bool is_full(void);
    void push(unsigned char element);
    unsigned char pop(void);
    unsigned char gettop(void);
};

// LZW dictionary

#define DICT_SIZE 10000

typedef struct {
    unsigned char root;
    int codeword;
    int contains;
} dict_entry;

class U6LzwDict {
    dict_entry dict[DICT_SIZE];
    int contains;

public:

    U6LzwDict();

    void reset(void);
    void add(unsigned char root, int codeword);
    unsigned char get_root(int codeword) const;
    int get_codeword(int codeword) const;
};

class U6Lzw {
    U6LzwStack *stack;
    U6LzwDict *dict;
    const char *errstr; // error string
public:

    U6Lzw(void);
    ~U6Lzw(void);

    unsigned char *decompress_buffer(unsigned char *source, uint32 source_length, uint32 &destination_length);
    bool decompress_buffer(unsigned char *source, uint32 source_length, unsigned char *destination, uint32 destination_length);
    unsigned char *decompress_file(const Common::Path &filename, uint32 &destination_length);
    unsigned char *compress_buffer(unsigned char *src, uint32 src_len,
                                   uint32 &dest_len);
    const char *strerror() const {
        return errstr;    // get error string
    }
protected:

    bool is_valid_lzw_file(NuvieIOFileRead *input_file);
    bool is_valid_lzw_buffer(unsigned char *buf, uint32 length);

    long get_uncompressed_file_size(NuvieIOFileRead *input_file);
    long get_uncompressed_buffer_size(unsigned char *buf, uint32 length);

    int get_next_codeword(long *bits_read, unsigned char *source,
                          int codeword_size);
    void output_root(unsigned char root, unsigned char *destination,
                     long *position);
    void get_string(int codeword);
};

} // End of namespace Nuvie
} // End of namespace Ultima

#endif