#ifndef _XCA_H
#define _XCA_H

/*
 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

/**
* @file
*
* Xpress Compression Algorithm (MS-XCA) decompression
*
*/

#include <stdint.h>
#include "huffman.h"

/** Number of XCA codes */
#define XCA_CODES 512

/** XCA decompressor */
struct xca
{
    /** Huffman alphabet */
    struct huffman_alphabet alphabet;
    /** Raw symbols
     *
     * Must immediately follow the Huffman alphabet.
     */
    huffman_raw_symbol_t raw[XCA_CODES];
    /** Code lengths */
    uint8_t lengths[XCA_CODES];
};

/** XCA symbol Huffman lengths table */
struct xca_huf_len
{
    /** Lengths of each symbol */
    uint8_t nibbles[XCA_CODES / 2];
} __attribute__ ((packed));

/**
 * Extract Huffman-coded length of a raw symbol
 *
 * @v lengths		Huffman lengths table
 * @v symbol		Raw symbol
 * @ret len		Huffman-coded length
 */
static inline unsigned int
xca_huf_len (const struct xca_huf_len *lengths, unsigned int symbol)
{
    return (((lengths->nibbles[ symbol / 2 ]) >>
        (4 * (symbol % 2))) & 0x0f);
}

/** Get word from source data stream */
#define XCA_GET16(src) \
({ \
    const uint16_t *src16 = src; \
    src += sizeof (*src16); \
    *src16; \
})

/** Get byte from source data stream */
#define XCA_GET8(src) \
({ \
    const uint8_t *src8 = src; \
    src += sizeof (*src8); \
    *src8; \
})

/** XCA source data stream end marker */
#define XCA_END_MARKER 256

/** XCA block size */
#define XCA_BLOCK_SIZE (64 * 1024)

extern ssize_t
xca_decompress (const void *data, size_t len, void *buf);

#endif /* _XCA_H */