source: bootcd/isolinux/syslinux-6.03/gpxe/src/util/nrv2b.c @ 26ffad7

/**************************************************************
    Form adapted from lzhuf.c
    written by Haruyasu Yoshizaki 11/20/1988
    some minor changes 4/6/1989
    comments translated by Haruhiko Okumura 4/7/1989

    minor beautifications and adjustments for compiling under Linux
    by Markus Gutschke <gutschk@math.uni-muenster.de>
                                                1997-01-27

    Modifications to allow use as a filter by Ken Yap
    <ken_yap@users.sourceforge.net>.

                                                1997-07-01

    Small mod to cope with running on big-endian machines
    by Jim Hague <jim.hague@acm.org)
                                                1998-02-06

    Make compression statistics report shorter
    by Ken Yap <ken_yap@users.sourceforge.net>.
                                                2001-04-25

    Replaced algorithm with nrv2b from ucl the compression
    library from upx.  That code is:
    Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
    And is distributed under the terms of the GPL.
    The conversion was performed 
    by Eric Biederman <ebiederman@lnxi.com>.
                                             20 August 2002
                                                
**************************************************************/
#define UCLPACK_COMPAT 0
#define NDEBUG 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#ifdef __FreeBSD__
#include <inttypes.h>
#else
#include <stdint.h>
#endif
#include <limits.h>
#include <assert.h>
#if UCLPACK_COMPAT
#include <netinet/in.h>
#endif

#ifndef VERBOSE
#define Fprintf(x)
#define wterr     0
#else
#define Fprintf(x) fprintf x
#endif

#ifndef MAIN
extern
#endif
FILE  *infile, *outfile;

#if defined(ENCODE) || defined(DECODE)

#ifndef ENDIAN
#define ENDIAN   0
#endif
#ifndef BITSIZE
#define BITSIZE 32
#endif

static __inline__ void Error(char *message)
{
        Fprintf((stderr, "\n%s\n", message));
        exit(EXIT_FAILURE);
}

/* These will be a complete waste of time on a lo-endian */
/* system, but it only gets done once so WTF. */
static unsigned long i86ul_to_host(unsigned long ul)
{
        unsigned long res = 0;
        int i;
        union
        {
                unsigned char c[4];
                unsigned long ul;
        } u;

        u.ul = ul;
        for (i = 3; i >= 0; i--)
                res = (res << 8) + u.c[i];
        return res;
}

static unsigned long host_to_i86ul(unsigned long ul)
{
        int i;
        union
        {
                unsigned char c[4];
                unsigned long ul;
        } u;

        for (i = 0; i < 4; i++)
        {
                u.c[i] = ul & 0xff;
                ul >>= 8;
        }
        return u.ul;
}
#endif



#if UCLPACK_COMPAT
/* magic file header for compressed files */
static const unsigned char magic[8] =
{ 0x00, 0xe9, 0x55, 0x43, 0x4c, 0xff, 0x01, 0x1a };

#endif

#ifdef ENCODE
/********** NRV2B_99 compression **********/

/* Note by limiting the ring buffer I have limited the maximum
 * offset to 64K.  Since etherboot rarely gets that big it
 * is not a problem and it gives me a firm guarantee
 * that I will never get a 3 byte string match that is encodes
 * to more than 9/8 it's original size.
 * That guaranteee is important to for the inplace decompressor.
 * There are better ways to do this if a larger offset and buffer
 * would give better compression.
 */
#define N       (65536ul)           /* size of ring buffer */
#define THRESHOLD       1           /* lower limit for match length */
#define F            2048           /* upper limit for match length */
#define M2_MAX_OFFSET                 0xd00

/* note: to use default values pass -1, i.e. initialize
 * this struct by a memset(x,0xff,sizeof(x)) */
struct ucl_compress_config
{
        int bb_endian;
        int bb_size;
        unsigned int max_offset;
        unsigned int max_match;
        int s_level;
        int h_level;
        int p_level;
        int c_flags;
        unsigned int m_size;
};

struct ucl_compress
{
        int init;

        unsigned int look;          /* bytes in lookahead buffer */
        
        unsigned int m_len;
        unsigned int m_off;
        
        unsigned int last_m_len;
        unsigned int last_m_off;
        
        const unsigned char *bp;
        const unsigned char *ip;
        const unsigned char *in;
        const unsigned char *in_end;
        unsigned char *out;
        
        uint64_t bb_b;
        unsigned bb_k;
        unsigned bb_c_endian;
        unsigned bb_c_s;
        unsigned bb_c_s8;
        unsigned char *bb_p;
        unsigned char *bb_op;
        
        struct ucl_compress_config conf;
        unsigned int *result;

        unsigned int textsize;      /* text size counter */
        unsigned int codesize;      /* code size counter */
        unsigned int printcount; /* counter for reporting progress every 1K
                                    bytes */

        
        /* some stats */
        unsigned long lit_bytes;
        unsigned long match_bytes;
        unsigned long rep_bytes;
        unsigned long lazy;
};



#define getbyte(c)  ((c).ip < (c).in_end ? *((c).ip)++ : (-1))

#define UCL_E_OK               0
#define UCL_E_INVALID_ARGUMENT 1
#define UCL_E_OUT_OF_MEMORY    2
#define UCL_E_ERROR            3

/***********************************************************************
//
************************************************************************/

#define SWD_HSIZE       16384
#define SWD_MAX_CHAIN   2048
#define SWD_BEST_OFF    1

#define HEAD3(b,p) \
    (((0x9f5f*(((((uint32_t)b[p]<<5)^b[p+1])<<5)^b[p+2]))>>5) & (SWD_HSIZE-1))

#define HEAD2(b,p)      (b[p] ^ ((unsigned)b[p+1]<<8))
#define NIL2              UINT_MAX

struct ucl_swd
{
/* public - "built-in" */
        unsigned int n;
        unsigned int f;
        unsigned int threshold;
        
/* public - configuration */
        unsigned int max_chain;
        unsigned int nice_length;
        int use_best_off;
        unsigned int lazy_insert;
        
/* public - output */
        unsigned int m_len;
        unsigned int m_off;
        unsigned int look;
        int b_char;
#if defined(SWD_BEST_OFF)
        unsigned int best_off[ SWD_BEST_OFF ];
#endif
        
/* semi public */
        struct ucl_compress *c;
        unsigned int m_pos;
#if defined(SWD_BEST_OFF)
        unsigned int best_pos[ SWD_BEST_OFF ];
#endif
        
/* private */
        const uint8_t *dict;
        const uint8_t *dict_end;
        unsigned int dict_len;
        
/* private */
        unsigned int ip;                /* input pointer (lookahead) */
        unsigned int bp;                /* buffer pointer */
        unsigned int rp;                /* remove pointer */
        unsigned int b_size;
        
        unsigned char *b_wrap;
        
        unsigned int node_count;
        unsigned int first_rp;

        unsigned char b [ N + F + F ];
        unsigned int head3 [ SWD_HSIZE ];
        unsigned int succ3 [ N + F ];
        unsigned int best3 [ N + F ];
        unsigned int llen3 [ SWD_HSIZE ];
        unsigned int head2 [ 65536U ];
};

#define s_head3(s,key)        s->head3[key]


#if !defined( NDEBUG)
static void assert_match(const struct ucl_swd * swd, unsigned int m_len,
        unsigned int m_off )

{
        const struct ucl_compress *c = swd->c;
        unsigned int d_off;
        
        assert(m_len >= 2);
        if (m_off <= (unsigned int) (c->bp - c->in))
        {
                assert(c->bp - m_off + m_len < c->ip);
                assert(memcmp(c->bp, c->bp - m_off, m_len) == 0);
        }
        else
        {
                assert(swd->dict != NULL);
                d_off = m_off - (unsigned int) (c->bp - c->in);
                assert(d_off <= swd->dict_len);
                if (m_len > d_off)
                {
                        assert(memcmp(c->bp, swd->dict_end - d_off, d_off) ==
                                0);

                        assert(c->in + m_len - d_off < c->ip);
                        assert(memcmp(c->bp + d_off, c->in, m_len - d_off) ==
                                0);

                }
                else
                {
                        assert(memcmp(c->bp, swd->dict_end - d_off, m_len) ==
                                0);

                }
        }
}
#else
#  define assert_match(a,b,c)   ((void)0)
#endif

/***********************************************************************
//
************************************************************************/


static
void swd_initdict(struct ucl_swd *s, const uint8_t *dict, unsigned int dict_len)

{
        s->dict = s->dict_end = NULL;
        s->dict_len = 0;

        if (!dict || dict_len <= 0)
                return;
        if (dict_len > s->n)
        {
                dict += dict_len - s->n;
                dict_len = s->n;
        }

        s->dict = dict;
        s->dict_len = dict_len;
        s->dict_end = dict + dict_len;
        memcpy(s->b,dict,dict_len);
        s->ip = dict_len;
}


static
void swd_insertdict(struct ucl_swd *s, unsigned int node, unsigned int len)
{
        unsigned int key;

        s->node_count = s->n - len;
        s->first_rp = node;

        while (len-- > 0)
        {
                key = HEAD3(s->b,node);
                s->succ3[node] = s_head3(s,key);
                s->head3[key] = (unsigned int)(node);
                s->best3[node] = (unsigned int)(s->f + 1);
                s->llen3[key]++;
                assert(s->llen3[key] <= s->n);

                key = HEAD2(s->b,node);
                s->head2[key] = (unsigned int)(node);

                node++;
        }
}

/***********************************************************************
//
************************************************************************/


static
int swd_init(struct ucl_swd *s, const uint8_t *dict, unsigned int dict_len)
{
        unsigned int i = 0;
        int c = 0;

        if (s->n == 0)
                s->n = N;
        if (s->f == 0)
                s->f = F;
        s->threshold = THRESHOLD;
        if (s->n > N || s->f > F)
                return UCL_E_INVALID_ARGUMENT;

        /* defaults */
        s->max_chain = SWD_MAX_CHAIN;
        s->nice_length = s->f;
        s->use_best_off = 0;
        s->lazy_insert = 0;

        s->b_size = s->n + s->f;
        if (s->b_size + s->f >= UINT_MAX)
                return UCL_E_ERROR;
        s->b_wrap = s->b + s->b_size;
        s->node_count = s->n;

        memset(s->llen3, 0, sizeof(s->llen3[0]) * SWD_HSIZE);
        for (i = 0; i < 65536U; i++)
                s->head2[i] = NIL2;

        s->ip = 0;
        swd_initdict(s,dict,dict_len);
        s->bp = s->ip;
        s->first_rp = s->ip;

        assert(s->ip + s->f <= s->b_size);

        s->look = (unsigned int) (s->c->in_end - s->c->ip);
        if (s->look > 0)
        {
                if (s->look > s->f)
                        s->look = s->f;
                memcpy(&s->b[s->ip],s->c->ip,s->look);
                s->c->ip += s->look;
                s->ip += s->look;
        }
        if (s->ip == s->b_size)
                s->ip = 0;

        if (s->look >= 2 && s->dict_len > 0)
                swd_insertdict(s,0,s->dict_len);

        s->rp = s->first_rp;
        if (s->rp >= s->node_count)
                s->rp -= s->node_count;
        else
                s->rp += s->b_size - s->node_count;

        /* unused i */
        /* unused c */
        return UCL_E_OK;
}


static
void swd_exit(struct ucl_swd *s)
{
        /* unused s */

}

#define swd_pos2off(s,pos) \
        (s->bp > (pos) ? s->bp - (pos) : s->b_size - ((pos) - s->bp))

/***********************************************************************
//
************************************************************************/

static __inline__
void swd_getbyte(struct ucl_swd *s)
{
        int c;

        if ((c = getbyte(*(s->c))) < 0)
        {
                if (s->look > 0)
                        --s->look;
        }
        else
        {
                s->b[s->ip] = (uint8_t)(c);
                if (s->ip < s->f)
                        s->b_wrap[s->ip] = (uint8_t)(c);
        }
        if (++s->ip == s->b_size)
                s->ip = 0;
        if (++s->bp == s->b_size)
                s->bp = 0;
        if (++s->rp == s->b_size)
                s->rp = 0;
}
/***********************************************************************
// remove node from lists
************************************************************************/

static __inline__
void swd_remove_node(struct ucl_swd *s, unsigned int node)
{
        if (s->node_count == 0)
        {
                unsigned int key;
                
#ifdef UCL_DEBUG
                if (s->first_rp != UINT_MAX)
                {
                        if (node != s->first_rp)
                                printf("Remove %5d: %5d %5d %5d %5d %6d %6d\n",

                                        node, s->rp, s->ip, s->bp, s->first_rp,
                                        s->ip - node, s->ip - s->bp);
                        assert(node == s->first_rp);
                        s->first_rp = UINT_MAX;
                }
#endif
                
                key = HEAD3(s->b,node);
                assert(s->llen3[key] > 0);
                --s->llen3[key];
                
                key = HEAD2(s->b,node);
                assert(s->head2[key] != NIL2);
                if ((unsigned int) s->head2[key] == node)
                        s->head2[key] = NIL2;
        }
        else
                --s->node_count;
}


/***********************************************************************
//
************************************************************************/


static
void swd_accept(struct ucl_swd *s, unsigned int n)
{
        assert(n <= s->look);

        if (n > 0) do
        {
                unsigned int key;

                swd_remove_node(s,s->rp);

                /* add bp into HEAD3 */
                key = HEAD3(s->b,s->bp);
                s->succ3[s->bp] = s_head3(s,key);
                s->head3[key] = (unsigned int)(s->bp);
                s->best3[s->bp] = (unsigned int)(s->f + 1);
                s->llen3[key]++;
                assert(s->llen3[key] <= s->n);

                /* add bp into HEAD2 */
                key = HEAD2(s->b,s->bp);
                s->head2[key] = (unsigned int)(s->bp);

                swd_getbyte(s);
        } while (--n > 0);
}

/***********************************************************************
//
************************************************************************/

static
void swd_search(struct ucl_swd *s, unsigned int node, unsigned int cnt)
{
        const unsigned char *p1;
        const unsigned char *p2;
        const unsigned char *px;

        unsigned int m_len = s->m_len;
        const unsigned char * b  = s->b;
        const unsigned char * bp = s->b + s->bp;
        const unsigned char * bx = s->b + s->bp + s->look;
        unsigned char scan_end1;
        
        assert(s->m_len > 0);
        
        scan_end1 = bp[m_len - 1];
        for ( ; cnt-- > 0; node = s->succ3[node])
        {
                p1 = bp;
                p2 = b + node;
                px = bx;
                
                assert(m_len < s->look);
                
                if (
                        p2[m_len - 1] == scan_end1 &&
                        p2[m_len] == p1[m_len] &&
                        p2[0] == p1[0] &&
                        p2[1] == p1[1])
                {
                        unsigned int i;
                        assert(memcmp(bp,&b[node],3) == 0);
                        
                        p1 += 2; p2 += 2;
                        do {} while (++p1 < px && *p1 == *++p2);
                        i = p1 - bp;
                        
#ifdef UCL_DEBUG
                        if (memcmp(bp,&b[node],i) != 0)
                                printf("%5ld %5ld %02x%02x %02x%02x\n",
                                        (long)s->bp, (long) node,
                                        bp[0], bp[1], b[node], b[node+1]);
#endif
                        assert(memcmp(bp,&b[node],i) == 0);
                        
#if defined(SWD_BEST_OFF)
                        if (i < SWD_BEST_OFF)
                        {
                                if (s->best_pos[i] == 0)
                                        s->best_pos[i] = node + 1;
                        }
#endif
                        if (i > m_len)
                        {
                                s->m_len = m_len = i;
                                s->m_pos = node;
                                if (m_len == s->look)
                                        return;
                                if (m_len >= s->nice_length)
                                        return;
                                if (m_len > (unsigned int) s->best3[node])
                                        return;
                                scan_end1 = bp[m_len - 1];
                        }
                }
        }
}

static int swd_search2(struct ucl_swd *s)
{
        unsigned int key;
        
        assert(s->look >= 2);
        assert(s->m_len > 0);
        
        key = s->head2[ HEAD2(s->b,s->bp) ];
        if (key == NIL2)
                return 0;
#ifdef UCL_DEBUG
        if (memcmp(&s->b[s->bp],&s->b[key],2) != 0)
                printf("%5ld %5ld %02x%02x %02x%02x\n", (long)s->bp, (long)key,
                        s->b[s->bp], s->b[s->bp+1], s->b[key], s->b[key+1]);
#endif
        assert(memcmp(&s->b[s->bp],&s->b[key],2) == 0);
#if defined(SWD_BEST_OFF)
        if (s->best_pos[2] == 0)
                s->best_pos[2] = key + 1;
#endif
        
        if (s->m_len < 2)
        {
                s->m_len = 2;
                s->m_pos = key;
        }
        return 1;
}

/***********************************************************************
//
************************************************************************/

static
void swd_findbest(struct ucl_swd *s)
{
        unsigned int key;
        unsigned int cnt, node;
        unsigned int len;

        assert(s->m_len > 0);

        /* get current head, add bp into HEAD3 */
        key = HEAD3(s->b,s->bp);
        node = s->succ3[s->bp] = s_head3(s,key);
        cnt = s->llen3[key]++;
        assert(s->llen3[key] <= s->n + s->f);
        if (cnt > s->max_chain && s->max_chain > 0)
                cnt = s->max_chain;
        s->head3[key] = (unsigned int)(s->bp);

        s->b_char = s->b[s->bp];
        len = s->m_len;
        if (s->m_len >= s->look)
        {
                if (s->look == 0)
                        s->b_char = -1;
                s->m_off = 0;
                s->best3[s->bp] = (unsigned int)(s->f + 1);
        }
        else
        {
                if (swd_search2(s))
                        if (s->look >= 3)
                                swd_search(s,node,cnt);
                if (s->m_len > len)
                        s->m_off = swd_pos2off(s,s->m_pos);
                s->best3[s->bp] = (unsigned int)(s->m_len);

#if defined(SWD_BEST_OFF)
                if (s->use_best_off)
                {
                        int i;
                        for (i = 2; i < SWD_BEST_OFF; i++)
                                if (s->best_pos[i] > 0)
                                        s->best_off[i] =
                                                swd_pos2off(s,s->best_pos[i]-1);

                                else
                                        s->best_off[i] = 0;
                }
#endif
        }

        swd_remove_node(s,s->rp);

        /* add bp into HEAD2 */
        key = HEAD2(s->b,s->bp);
        s->head2[key] = (unsigned int)(s->bp);
}


/***********************************************************************
//
************************************************************************/

static int
init_match ( struct ucl_compress *c, struct ucl_swd *s,
        const uint8_t *dict, unsigned int dict_len,
        uint32_t flags )
{
        int r;
        
        assert(!c->init);
        c->init = 1;
        
        s->c = c;
        
        c->last_m_len = c->last_m_off = 0;
        
        c->textsize = c->codesize = c->printcount = 0;
        c->lit_bytes = c->match_bytes = c->rep_bytes = 0;
        c->lazy = 0;
        
        r = swd_init(s,dict,dict_len);
        if (r != UCL_E_OK)
        {
                swd_exit(s);
                return r;
        }
        
        s->use_best_off = (flags & 1) ? 1 : 0;
        return UCL_E_OK;
}

static int
find_match ( struct ucl_compress *c, struct ucl_swd *s,
        unsigned int this_len, unsigned int skip )
{
        assert(c->init);
        
        if (skip > 0)
        {
                assert(this_len >= skip);
                swd_accept(s, this_len - skip);
                c->textsize += this_len - skip + 1;
        }
        else
        {
                assert(this_len <= 1);
                c->textsize += this_len - skip;
        }
        
        s->m_len = THRESHOLD;
#ifdef SWD_BEST_OFF
        if (s->use_best_off)
                memset(s->best_pos,0,sizeof(s->best_pos));
#endif
        swd_findbest(s);
        c->m_len = s->m_len;
        c->m_off = s->m_off;
        
        swd_getbyte(s);
        
        if (s->b_char < 0)
        {
                c->look = 0;
                c->m_len = 0;
                swd_exit(s);
        }
        else
        {
                c->look = s->look + 1;
        }
        c->bp = c->ip - c->look;
        
#if 0
        /* brute force match search */
        if (c->m_len > THRESHOLD && c->m_len + 1 <= c->look)
        {
                const uint8_t *ip = c->bp;
                const uint8_t *m  = c->bp - c->m_off;
                const uint8_t *in = c->in;
                
                if (ip - in > N)
                        in = ip - N;
                for (;;)
                {
                        while (*in != *ip)
                                in++;
                        if (in == ip)
                                break;
                        if (in != m)
                                if (memcmp(in,ip,c->m_len+1) == 0)
                                        printf("%p %p %p %5d\n",in,ip,m,c->m_len);

                        in++;
                }
        }
#endif
        
        return UCL_E_OK;
}


static int bbConfig(struct ucl_compress *c, int endian, int bitsize)
{
        if (endian != -1)
        {
                if (endian != 0)
                        return UCL_E_ERROR;
                c->bb_c_endian = endian;
        }
        if (bitsize != -1)
        {
                if (bitsize != 8 && bitsize != 16 && bitsize != 32 && bitsize != 64)
                        return UCL_E_ERROR;
                c->bb_c_s = bitsize;
                c->bb_c_s8 = bitsize / 8;
        }
        c->bb_b = 0; c->bb_k = 0;
        c->bb_p = NULL;
        c->bb_op = NULL;
        return UCL_E_OK;
}

static void bbWriteBits(struct ucl_compress *c)
{
        uint8_t *p = c->bb_p;
        uint64_t b = c->bb_b;

        p[0] = (uint8_t)(b >>  0);
        if (c->bb_c_s >= 16)
        {
                p[1] = (uint8_t)(b >>  8);
                if (c->bb_c_s >= 32)
                {
                        p[2] = (uint8_t)(b >> 16);
                        p[3] = (uint8_t)(b >> 24);
                        if (c->bb_c_s == 64)
                        {
                                p[4] = (uint8_t)(b >> 32);
                                p[5] = (uint8_t)(b >> 40);
                                p[6] = (uint8_t)(b >> 48);
                                p[7] = (uint8_t)(b >> 56);
                        }
                }
        }
}


static void bbPutBit(struct ucl_compress *c, unsigned bit)
{
        assert(bit == 0 || bit == 1);
        assert(c->bb_k <= c->bb_c_s);

        if (c->bb_k < c->bb_c_s)
        {
                if (c->bb_k == 0)
                {
                        assert(c->bb_p == NULL);
                        c->bb_p = c->bb_op;
                        c->bb_op += c->bb_c_s8;
                }
                assert(c->bb_p != NULL);
                assert(c->bb_p + c->bb_c_s8 <= c->bb_op);

                c->bb_b = (c->bb_b << 1) + bit;
                c->bb_k++;
        }
        else
        {
                assert(c->bb_p != NULL);
                assert(c->bb_p + c->bb_c_s8 <= c->bb_op);

                bbWriteBits(c);
                c->bb_p = c->bb_op;
                c->bb_op += c->bb_c_s8;
                c->bb_b = bit;
                c->bb_k = 1;
        }
}


static void bbPutByte(struct ucl_compress *c, unsigned b)
{
        /**printf("putbyte %p %p %x  (%d)\n", op, bb_p, x, bb_k);*/
        assert(c->bb_p == NULL || c->bb_p + c->bb_c_s8 <= c->bb_op);
        *c->bb_op++ = (uint8_t)(b);
}

static void bbFlushBits(struct ucl_compress *c, unsigned filler_bit)
{
        if (c->bb_k > 0)
        {
                assert(c->bb_k <= c->bb_c_s);
                while (c->bb_k != c->bb_c_s)
                        bbPutBit(c, filler_bit);
                bbWriteBits(c);
                c->bb_k = 0;
        }
        c->bb_p = NULL;
}



/***********************************************************************
//
************************************************************************/


static void code_prefix_ss11(struct ucl_compress *c, uint32_t i)
{
        if (i >= 2)
        {
                uint32_t t = 4;
                i += 2;
                do {
                        t <<= 1;
                } while (i >= t);
                t >>= 1;
                do {
                        t >>= 1;
                        bbPutBit(c, (i & t) ? 1 : 0);
                        bbPutBit(c, 0);
                } while (t > 2);
        }
        bbPutBit(c, (unsigned)i & 1);
        bbPutBit(c, 1);
}

static void
code_match(struct ucl_compress *c, unsigned int m_len, const unsigned int m_off)

{
        while (m_len > c->conf.max_match)
        {
                code_match(c, c->conf.max_match - 3, m_off);
                m_len -= c->conf.max_match - 3;
        }
        
        c->match_bytes += m_len;
        if (m_len > c->result[3])
                c->result[3] = m_len;
        if (m_off > c->result[1])
                c->result[1] = m_off;

        bbPutBit(c, 0);

        if (m_off == c->last_m_off)
        {
                bbPutBit(c, 0);
                bbPutBit(c, 1);
        }
        else
        {
                code_prefix_ss11(c, 1 + ((m_off - 1) >> 8));
                bbPutByte(c, (unsigned)m_off - 1);
        }
        m_len = m_len - 1 - (m_off > M2_MAX_OFFSET);
        if (m_len >= 4)
        {
                bbPutBit(c,0);
                bbPutBit(c,0);
                code_prefix_ss11(c, m_len - 4);
        }
        else
        {
                bbPutBit(c, m_len > 1);
                bbPutBit(c, (unsigned)m_len & 1);
        }

        c->last_m_off = m_off;
}

static void
code_run(struct ucl_compress *c, const uint8_t *ii, unsigned int lit)
{
        if (lit == 0)
                return;
        c->lit_bytes += lit;
        if (lit > c->result[5])
                c->result[5] = lit;
        do {
                bbPutBit(c, 1);
                bbPutByte(c, *ii++);
        } while (--lit > 0);
}

/***********************************************************************
//
************************************************************************/

static int
len_of_coded_match(struct ucl_compress *c, unsigned int m_len, unsigned int
        m_off)

{
        int b;
        if (m_len < 2 || (m_len == 2 && (m_off > M2_MAX_OFFSET))
                || m_off > c->conf.max_offset)
                return -1;
        assert(m_off > 0);
        
        m_len = m_len - 2 - (m_off > M2_MAX_OFFSET);
        
        if (m_off == c->last_m_off)
                b = 1 + 2;
        else
        {
                b = 1 + 10;
                m_off = (m_off - 1) >> 8;
                while (m_off > 0)
                {
                        b += 2;
                        m_off >>= 1;
                }
        }

        b += 2;
        if (m_len < 3)
                return b;
        m_len -= 3;

        do {
                b += 2;
                m_len >>= 1;
        } while (m_len > 0);

        return b;
}

int ucl_nrv2b_99_compress(
        const uint8_t *in, unsigned long in_len,
        uint8_t *out, unsigned long *out_len,
        unsigned int *result)
{
        const uint8_t *ii;
        unsigned int lit;
        unsigned int m_len, m_off;
        struct ucl_compress c_buffer;
        struct ucl_compress * const c = &c_buffer;
        struct ucl_swd *swd;
        unsigned int result_buffer[16];
        int r;

/* max compression */
#define SC_TRY_LAZY    2
#define SC_GOOD_LENGTH F
#define SC_MAX_LAZY    F
#define SC_NICE_LENGTH F
#define SC_MAX_CHAIN   4096
#define SC_FLAGS       1
#define SC_MAX_OFFSET  N
        
        memset(c, 0, sizeof(*c));
        c->ip = c->in = in;
        c->in_end = in + in_len;
        c->out = out;
        c->result = result ? result : result_buffer;
        memset(c->result, 0, 16*sizeof(*c->result));
        c->result[0] = c->result[2] = c->result[4] = UINT_MAX;
        result = NULL;
        memset(&c->conf, 0xff, sizeof(c->conf));
        r = bbConfig(c, ENDIAN, BITSIZE);
        if (r == 0)
                r = bbConfig(c, c->conf.bb_endian, c->conf.bb_size);
        if (r != 0)
                return UCL_E_INVALID_ARGUMENT;
        c->bb_op = out;
        
        ii = c->ip;             /* point to start of literal run */
        lit = 0;
        

        swd = (struct ucl_swd *) malloc(sizeof(*swd));
        if (!swd)
                return UCL_E_OUT_OF_MEMORY;

        swd->f = F;
        swd->n = N;
        if (in_len >= 256 && in_len < swd->n)
                swd->n = in_len;
        if (swd->f < 8 || swd->n < 256)
                return UCL_E_INVALID_ARGUMENT;

        r = init_match(c,swd,NULL,0, SC_FLAGS);
        if (r != UCL_E_OK)
        {
                free(swd);
                return r;
        }
        if (SC_MAX_CHAIN > 0)
                swd->max_chain = SC_MAX_CHAIN;
        if (SC_NICE_LENGTH > 0)
                swd->nice_length = SC_NICE_LENGTH;
        if (c->conf.max_match < swd->nice_length)
                swd->nice_length = c->conf.max_match;
        
        c->last_m_off = 1;
        r = find_match(c,swd,0,0);
        if (r != UCL_E_OK)
                return r;
        while (c->look > 0)
        {
                unsigned int ahead;
                unsigned int max_ahead;
                int l1, l2;
                
                c->codesize = c->bb_op - out;
                
                m_len = c->m_len;
                m_off = c->m_off;
                
                assert(c->bp == c->ip - c->look);
                assert(c->bp >= in);
                if (lit == 0)
                        ii = c->bp;
                assert(ii + lit == c->bp);
                assert(swd->b_char == *(c->bp));
                
                if (m_len < 2 || (m_len == 2 && (m_off > M2_MAX_OFFSET))
                        || m_off > c->conf.max_offset)
                {
                        /* a literal */
                        lit++;
                        swd->max_chain = SC_MAX_CHAIN;
                        r = find_match(c,swd,1,0);
                        assert(r == 0);
                        continue;
                }
                
                /* a match */
                assert_match(swd,m_len,m_off);
                
                /* shall we try a lazy match ? */
                ahead = 0;
                if (SC_TRY_LAZY <= 0 || m_len >= SC_MAX_LAZY || m_off ==
                        c->last_m_off)

                {
                        /* no */
                        l1 = 0;
                        max_ahead = 0;
                }
                else
                {
                        /* yes, try a lazy match */
                        l1 = len_of_coded_match(c,m_len,m_off);
                        assert(l1 > 0);
                        max_ahead = SC_TRY_LAZY;
                        if ((m_len - 1) < max_ahead) {
                                max_ahead = m_len -1;
                        }
                }
                
                while (ahead < max_ahead && c->look > m_len)
                {
                        if (m_len >= SC_GOOD_LENGTH)
                                swd->max_chain = SC_MAX_CHAIN >> 2;
                        else
                                swd->max_chain = SC_MAX_CHAIN;
                        r = find_match(c,swd,1,0);
                        ahead++;
                        
                        assert(r == 0);
                        assert(c->look > 0);
                        assert(ii + lit + ahead == c->bp);
                        
                        if (c->m_len < 2)
                                continue;
                        l2 = len_of_coded_match(c,c->m_len,c->m_off);
                        if (l2 < 0)
                                continue;
                        if (l1 + (int)(ahead + c->m_len - m_len) * 5 > l2 +
                                (int)(ahead) * 9)
                        {
                                c->lazy++;
                                assert_match(swd,c->m_len,c->m_off);
                                lit += ahead;
                                assert(ii + lit == c->bp);
                                goto lazy_match_done;
                        }
                }
                
                assert(ii + lit + ahead == c->bp);
                
                /* 1 - code run */
                code_run(c,ii,lit);
                lit = 0;
                
                /* 2 - code match */
                code_match(c,m_len,m_off);
                swd->max_chain = SC_MAX_CHAIN;
                r = find_match(c,swd,m_len,1+ahead);
                assert(r == 0);
                
        lazy_match_done: ;
        }
        
        /* store final run */
        code_run(c,ii,lit);
        
        /* EOF */
        bbPutBit(c, 0);
        code_prefix_ss11(c, 0x1000000U);
        bbPutByte(c, 0xff);

        bbFlushBits(c, 0);
        
        assert(c->textsize == in_len);
        c->codesize = c->bb_op - out;
        *out_len = c->bb_op - out;
        
#if 0
        printf("%7ld %7ld -> %7ld   %7ld %7ld   %ld  (max: %d %d %d)\n",
                (long) c->textsize, (long) in_len, (long) c->codesize,
                c->match_bytes, c->lit_bytes,  c->lazy,
                c->result[1], c->result[3], c->result[5]);
#endif
        assert(c->lit_bytes + c->match_bytes == in_len);
        
        swd_exit(swd);
        free(swd);

        return UCL_E_OK;
}


void Encode(void)  /* compression */
{
        uint8_t *in, *out;
        unsigned long in_len, out_len;
        uint32_t tw;
        int r;
        fseek(infile, 0, SEEK_END);
        in_len = ftell(infile);
#ifdef VERBOSE
        if ((signed long)in_len < 0)
                Fprintf((stderr, "Errno: %d", errno));
#endif
#if UCLPACK_COMPAT
        {
                uint8_t byte;
                if (fwrite(magic, sizeof(magic), 1, outfile) != 1)
                        Error("Can't write.");
                tw = htonl(0); /* flags */
                if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                        Error("Can't write.");
                byte = 0x2b;            /* method */
                if (fwrite(&byte, sizeof(byte), 1, outfile) != 1)
                        Error("Can't write.");
                byte = 10;              /* level */
                if (fwrite(&byte, sizeof(byte), 1, outfile) != 1)
                        Error("Can't write.");
                tw = htonl(256*1024);           /* block_size */
                if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                        Error("Can't write.");
                tw = htonl(in_len);
                if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                        Error("Can't write.");  /* output size of text */
        }
#else
        tw = host_to_i86ul(in_len);
        if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                Error("Can't write.");  /* output size of text */
#endif  
        if (in_len == 0)
                return;
        rewind(infile);

        in = malloc(in_len);
        out_len = in_len + (in_len/8) + 256;
        out = malloc(out_len);
        if (!in || !out) {
                Error("Can't malloc");
        }
        if (fread(in, in_len, 1, infile) != 1) {
                Error("Can't read");
        }
        r = ucl_nrv2b_99_compress(in, in_len, out, &out_len, 0 );
        if (r != UCL_E_OK)
                Error("Compression failure\n");
#if UCLPACK_COMPAT
        tw = htonl(out_len);
        if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                Error("Can't write.");  /* file size of text */

#endif
        if (fwrite(out, out_len, 1, outfile) != 1) {
                Error("Write error\n");
        }
#if UCLPACK_COMPAT
        tw = htonl(0); /* EOF marker */
        if (fwrite(&tw, sizeof(tw), 1, outfile) != 1)
                Error("Can't write.");

#endif

#ifdef  LONG_REPORT
        Fprintf((stdout, "input size    %ld bytes\n", in_len));
        Fprintf((stdout, "output size   %ld bytes\n", out_len));
        Fprintf((stdout, "input/output  %.3f\n", (double)in_len / out_len));
#else
        Fprintf((stdout, "input/output = %ld/%ld = %.3f\n", in_len, out_len,
                (double)in_len / out_len));
#endif
        
}

#endif

#ifdef DECODE

#define GETBIT_8(bb, src, ilen) \
    (((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)

#define GETBIT_LE16(bb, src, ilen) \
    (bb*=2,bb&0xffff ? (bb>>16)&1 : (ilen+=2,((bb=(src[ilen-2]+src[ilen-1]*256u)*2+1)>>16)&1))

#define GETBIT_LE32(bb, src, ilen) \
    (bc > 0 ? ((bb>>--bc)&1) : (bc=31,\
    bb=*(const uint32_t *)((src)+ilen),ilen+=4,(bb>>31)&1))

#define GETBIT_LE64(bb, src, ilen) \
    (bc > 0 ? ((bb>>--bc)&1) : (bc=63, \
    bb=*(const uint64_t *)((src)+ilen),ilen+=8,(bb>>63)&1))

#if ENDIAN == 0 && BITSIZE == 8
#define GETBIT(bb, src, ilen) GETBIT_8(bb, src, ilen)
#endif
#if ENDIAN == 0 && BITSIZE == 16
#define GETBIT(bb, src, ilen) GETBIT_LE16(bb, src, ilen)
#endif
#if ENDIAN == 0 && BITSIZE == 32
#define GETBIT(bb, src, ilen) GETBIT_LE32(bb, src, ilen)
#endif
#if ENDIAN == 0 && BITSIZE == 64
#define GETBIT(bb, src, ilen) GETBIT_LE64(bb, src, ilen)
#endif
#ifndef GETBIT
#error "Bad Combination of ENDIAN and BITSIZE values specified"
#endif

#undef SAFE

#ifdef SAFE
#define FAIL(x,r)   if (x) { Error(r); }
#else
#define FAIL(x,r)
#endif

void Decode(void)  /* recover */
{
        uint32_t tw;
        uint8_t *src, *dst;
        unsigned long max_src_len, src_len, dst_len;
        unsigned long ilen = 0, olen = 0, last_m_off =  1;
#if BITSIZE <= 32
        uint32_t bb = 0;
#elif BITSIZE == 64
        uint64_t bb = 0;
#endif
        unsigned bc = 0;
#if UCLPACK_COMPAT
        if (fseek(infile, sizeof(magic) + sizeof(tw) + 1 + 1 + sizeof(tw),
                SEEK_SET) != 0)

                Error("Seek Error");
        if (fread(&tw, sizeof(tw), 1, infile) < 1)
                Error("Can't read"); /* read size of text */
        dst_len = ntohl(tw);
        if (fread(&tw, sizeof(tw), 1, infile) < 1)
                Error("Can't read"); /* read size of file */
        max_src_len = ntohl(tw);
#else
        if (fread(&tw, sizeof(tw), 1, infile) < 1)
                Error("Can't read"); /* read size of text */
        dst_len = i86ul_to_host(tw);
        max_src_len = dst_len + (dst_len/8) + 256;
#endif
        if (dst_len == 0)
                return;
        dst = malloc(dst_len);
        if (!dst)
                Error("Can't malloc");
        src = malloc(max_src_len);
        if (!src)
                Error("Can't malloc");
        src_len = fread(src, 1, max_src_len, infile);
        if (src_len <= 0) 
                Error("Can't read");

        for(;;) {
                unsigned int m_off, m_len;
                while(GETBIT(bb, src, ilen)) {
                        FAIL(ilen >= src_len, "input overrun");
                        FAIL(olen >= dst_len, "output  overrun");
                        dst[olen++] = src[ilen++];
                }
                m_off = 1;
                do {
                        m_off = m_off*2 + GETBIT(bb, src, ilen);
                        FAIL(ilen >= src_len, "input overrun");
                        FAIL(m_off > 0xffffffU +3, "lookbehind overrun");
                } while (!GETBIT(bb, src, ilen));
                if (m_off == 2)
                {
                        m_off = last_m_off;
                }
                else
                {
                        FAIL(ilen >= src_len, "input overrun");
                        m_off = (m_off - 3)*256 + src[ilen++];
                        if (m_off == 0xffffffffU)
                                break;
                        last_m_off = ++m_off;
                }
                m_len = GETBIT(bb, src, ilen);
                m_len = m_len*2 + GETBIT(bb, src, ilen);
                if (m_len == 0) 
                {
                        m_len++;
                        do {
                                m_len = m_len*2 + GETBIT(bb, src, ilen);
                                FAIL(ilen >= src_len, "input overrun");
                                FAIL(m_len >= dst_len, "output overrun");
                        } while(!GETBIT(bb, src, ilen));
                        m_len += 2;
                }
                m_len += (m_off > 0xd00);
                FAIL(olen + m_len > dst_len, "output overrun");
                FAIL(m_off > olen, "lookbeind overrun");
                {
                        const uint8_t *m_pos;
                        m_pos = dst + olen - m_off;
                        dst[olen++] = *m_pos++;
                        do {
                                dst[olen++] = *m_pos++;
                        } while(--m_len > 0);
                }
        }
        FAIL(ilen < src_len, "input not consumed");
        FAIL(ilen > src_len, "input overrun");
        assert(ilen == src_len);
        Fprintf((stderr, "%12ld\n", olen));
        if (dst_len != olen) {
                fprintf(stderr, "length != expected length\n");
        }
        if (fwrite(dst, olen, 1, outfile) != 1)
                Error("Write error\n");
        free(src);
        free(dst);
}
#endif

#ifdef MAIN
int main(int argc, char *argv[])
{
        char  *s;
        FILE  *f;
        int    c;
        
        if (argc == 2) {
                outfile = stdout;
                if ((f = tmpfile()) == NULL) {
                        perror("tmpfile");
                        return EXIT_FAILURE;
                }
                while ((c = getchar()) != EOF)
                        fputc(c, f);
                rewind(infile = f);
        }
        else if (argc != 4) {
                Fprintf((stderr, "'nrv2b e file1 file2' encodes file1 into file2.\n"
                        "'nrv2b d file2 file1' decodes file2 into file1.\n"));
                return EXIT_FAILURE;
        }
        if (argc == 4) {
                if ((s = argv[1], s[1] || strpbrk(s, "DEde") == NULL)
                        || (s = argv[2], (infile  = fopen(s, "rb")) == NULL)
                        || (s = argv[3], (outfile = fopen(s, "wb")) == NULL)) {
                        Fprintf((stderr, "??? %s\n", s));
                        return EXIT_FAILURE;
                }
        }
        if (toupper(*argv[1]) == 'E')
                Encode();
        else
                Decode();
        fclose(infile);
        fclose(outfile);
        return EXIT_SUCCESS;
}
#endif