/* lzh.c */

/* Synchronet LZH compression library */

/* $Id$ */

/****************************************************************************
 * @format.tab-size 4       (Plain Text/Source Code File Header)            *
 * @format.use-tabs true    (see http://www.synchro.net/ptsc_hdr.html)      *
 *                                                                          *
 * Rob Swindell's conversion of 1988 LZH (LHarc) encoding functions         *
 * Based on Japanese version 29-NOV-1988                                    *
 * LZSS coded by Haruhiko Okumura                                           *
 * Adaptive Huffman Coding coded by Haruyasu Yoshizaki                      *
 *                                                                          *
 * Anonymous FTP access to the most recent released source is available at  *
 * ftp://vert.synchro.net, ftp://cvs.synchro.net and ftp://ftp.synchro.net  *
 *                                                                          *
 * Anonymous CVS access to the development source and modification history  *
 * is available at cvs.synchro.net:/cvsroot/sbbs, example:                  *
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 *     (just hit return, no password is necessary)                          *
 * cvs -d :pserver:anonymous@cvs.synchro.net:/cvsroot/sbbs checkout src     *
 *                                                                          *
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 * http://www.synchro.net/source.html                                       *
 *                                                                          *
 * You are encouraged to submit any modifications (preferably in Unix diff  *
 * format) via e-mail to mods@synchro.net                                   *
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 * Note: If this box doesn't appear square, then you need to fix your tabs. *
 ****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif

#include "lzh.h"

/****************************************************************************/
/* Memory allocation macros for various compilers and environments          */
/* MALLOC is used for allocations of 64k or less                            */
/* FREE is used to free buffers allocated with MALLOC                       */
/* LMALLOC is used for allocations of possibly larger than 64k              */
/* LFREE is used to free buffers allocated with LMALLOC                     */
/* REALLOC is used to re-size a previously MALLOCed or LMALLOCed buffer     */
/****************************************************************************/
#if defined(__COMPACT__) || defined(__LARGE__) || defined(__HUGE__)
    #if defined(__TURBOC__)
        #define REALLOC(x,y) farrealloc(x,y)
        #define LMALLOC(x) farmalloc(x)
        #define MALLOC(x) farmalloc(x)
        #define LFREE(x) farfree(x)
        #define FREE(x) farfree(x)
    #elif defined(__WATCOMC__)
        #define REALLOC realloc
        #define LMALLOC(x) halloc(x,1)  /* far heap, but slow */
        #define MALLOC malloc           /* far heap, but 64k max */
        #define LFREE hfree
        #define FREE free
    #else   /* Other 16-bit Compiler */
        #define REALLOC realloc
        #define LMALLOC malloc
        #define MALLOC malloc
        #define LFREE free
        #define FREE free
    #endif
#else       /* 32-bit Compiler or Small Memory Model */
    #define REALLOC realloc
    #define LMALLOC malloc
    #define MALLOC malloc
    #define LFREE free
    #define FREE free
#endif



/* LZSS Parameters */

#define LZH_N           4096    /* Size of string buffer */
#define LZH_F           60      /* Size of look-ahead buffer */
#define LZH_THRESHOLD   2
#define LZH_NIL         LZH_N   /* End of tree's node  */

#ifdef LZH_DYNAMIC_BUF

uint8_t *lzh_text_buf;
int16_t lzh_match_position, lzh_match_length,
        *lzh_lson, *lzh_rson, *lzh_dad;

#else

uint8_t lzh_text_buf[LZH_N + LZH_F - 1];
int16_t lzh_match_position, lzh_match_length,
        lzh_lson[LZH_N + 1], lzh_rson[LZH_N + 257], lzh_dad[LZH_N + 1];

#endif


void lzh_init_tree(void)  /* Initializing tree */
{
    int16_t i;

    for (i = LZH_N + 1; i <= LZH_N + 256; i++)
        lzh_rson[i] = LZH_NIL;          /* root */
    for (i = 0; i < LZH_N; i++)
        lzh_dad[i] = LZH_NIL;           /* node */
}

/******************************/
/* Inserting node to the tree */
/* Only used during encoding  */
/******************************/
void lzh_insert_node(int16_t r)
{
    int16_t   i, p, cmp;
    uint8_t   *key;
    uint32_t  c;

    cmp = 1;
    key = lzh_text_buf+r;
    p = LZH_N + 1 + key[0];
    lzh_rson[r] = lzh_lson[r] = LZH_NIL;
    lzh_match_length = 0;
    for ( ; ; ) {
        if (cmp >= 0) {
            if (lzh_rson[p] != LZH_NIL)
                p = lzh_rson[p];
            else {
                lzh_rson[p] = r;
                lzh_dad[r] = p;
                return;
            }
        } else {
            if (lzh_lson[p] != LZH_NIL)
                p = lzh_lson[p];
            else {
                lzh_lson[p] = r;
                lzh_dad[r] = p;
                return;
            }
        }
        for (i = 1; i < LZH_F; i++)
            if ((cmp = key[i] - lzh_text_buf[p + i]) != 0)
                break;
        if (i > LZH_THRESHOLD) {
            if (i > lzh_match_length) {
                lzh_match_position = ((r - p) & (LZH_N - 1)) - 1;
                if ((lzh_match_length = i) >= LZH_F)
                    break;
            }
            if (i == lzh_match_length) {
                if ((c = ((r - p) & (LZH_N - 1)) - 1)
                    < (uint32_t)lzh_match_position) {
                    lzh_match_position = c;
                }
            }
        }
    }
    lzh_dad[r] = lzh_dad[p];
    lzh_lson[r] = lzh_lson[p];
    lzh_rson[r] = lzh_rson[p];
    lzh_dad[lzh_lson[p]] = r;
    lzh_dad[lzh_rson[p]] = r;
    if (lzh_rson[lzh_dad[p]] == p)
        lzh_rson[lzh_dad[p]] = r;
    else
        lzh_lson[lzh_dad[p]] = r;
    lzh_dad[p] = LZH_NIL;  /* remove p */
}

void lzh_delete_node(int16_t p)  /* Deleting node from the tree */
{
    int16_t q;

    if (lzh_dad[p] == LZH_NIL)
        return;         /* unregistered */
    if (lzh_rson[p] == LZH_NIL)
        q = lzh_lson[p];
    else
    if (lzh_lson[p] == LZH_NIL)
        q = lzh_rson[p];
    else {
        q = lzh_lson[p];
        if (lzh_rson[q] != LZH_NIL) {
            do {
                q = lzh_rson[q];
            } while (lzh_rson[q] != LZH_NIL);
            lzh_rson[lzh_dad[q]] = lzh_lson[q];
            lzh_dad[lzh_lson[q]] = lzh_dad[q];
            lzh_lson[q] = lzh_lson[p];
            lzh_dad[lzh_lson[p]] = q;
        }
        lzh_rson[q] = lzh_rson[p];
        lzh_dad[lzh_rson[p]] = q;
    }
    lzh_dad[q] = lzh_dad[p];
    if (lzh_rson[lzh_dad[p]] == p)
        lzh_rson[lzh_dad[p]] = q;
    else
        lzh_lson[lzh_dad[p]] = q;
    lzh_dad[p] = LZH_NIL;
}

/* Huffman coding parameters */

#define LZH_N_CHAR      (256 - LZH_THRESHOLD + LZH_F)
                    /* character code (= 0..LZH_N_CHAR-1) */
#define LZH_T       (LZH_N_CHAR * 2 - 1)  /* Size of table */
#define LZH_R       (LZH_T - 1)           /* root position */
#define MAX_FREQ    0x8000
                    /* update when cumulative frequency */
                    /* reaches to this value */

/*
 * Tables for encoding/decoding upper 6 bits of
 * sliding dictionary pointer
 */
/* encoder table */
uint8_t lzh_p_len[64] = {
    0x03, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
    0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08
};

uint8_t lzh_p_code[64] = {
    0x00, 0x20, 0x30, 0x40, 0x50, 0x58, 0x60, 0x68,
    0x70, 0x78, 0x80, 0x88, 0x90, 0x94, 0x98, 0x9C,
    0xA0, 0xA4, 0xA8, 0xAC, 0xB0, 0xB4, 0xB8, 0xBC,
    0xC0, 0xC2, 0xC4, 0xC6, 0xC8, 0xCA, 0xCC, 0xCE,
    0xD0, 0xD2, 0xD4, 0xD6, 0xD8, 0xDA, 0xDC, 0xDE,
    0xE0, 0xE2, 0xE4, 0xE6, 0xE8, 0xEA, 0xEC, 0xEE,
    0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7,
    0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF
};

/* decoder table */
uint8_t lzh_d_code[256] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
    0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09,
    0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A,
    0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B,
    0x0C, 0x0C, 0x0C, 0x0C, 0x0D, 0x0D, 0x0D, 0x0D,
    0x0E, 0x0E, 0x0E, 0x0E, 0x0F, 0x0F, 0x0F, 0x0F,
    0x10, 0x10, 0x10, 0x10, 0x11, 0x11, 0x11, 0x11,
    0x12, 0x12, 0x12, 0x12, 0x13, 0x13, 0x13, 0x13,
    0x14, 0x14, 0x14, 0x14, 0x15, 0x15, 0x15, 0x15,
    0x16, 0x16, 0x16, 0x16, 0x17, 0x17, 0x17, 0x17,
    0x18, 0x18, 0x19, 0x19, 0x1A, 0x1A, 0x1B, 0x1B,
    0x1C, 0x1C, 0x1D, 0x1D, 0x1E, 0x1E, 0x1F, 0x1F,
    0x20, 0x20, 0x21, 0x21, 0x22, 0x22, 0x23, 0x23,
    0x24, 0x24, 0x25, 0x25, 0x26, 0x26, 0x27, 0x27,
    0x28, 0x28, 0x29, 0x29, 0x2A, 0x2A, 0x2B, 0x2B,
    0x2C, 0x2C, 0x2D, 0x2D, 0x2E, 0x2E, 0x2F, 0x2F,
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
    0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
};

uint8_t lzh_d_len[256] = {
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
    0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
    0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
};

#ifdef LZH_DYNAMIC_BUF

uint16_t  *lzh_freq = NULL;     /* cumulative freq table */

/*
 * pointing parent nodes.
 * area [LZH_T..(LZH_T + LZH_N_CHAR - 1)] are pointers for leaves
 */
int16_t   *lzh_prnt = NULL;

/* pointing children nodes (son[], son[] + 1)*/
int16_t   *lzh_son = NULL;

#else   /* STATIC */

uint16_t  lzh_freq[LZH_T + 1];  /* cumulative freq table */
int16_t   lzh_prnt[LZH_T + LZH_N_CHAR];
int16_t   lzh_son[LZH_T + 1];   /* bug fixed by Digital Dynamics */

#endif


uint16_t  lzh_getbuf = 0;       /* Was just "unsigned" fixed 04/12/95 */
uint8_t   lzh_getlen = 0;

int lzh_getbit(uint8_t *inbuf, int32_t *incnt, int32_t inlen)    /* get one bit */
{
    int16_t i;

    while (lzh_getlen <= 8) {
        if((*incnt)>=inlen)
            i=0;
        else
            i=inbuf[(*incnt)++];
        lzh_getbuf |= i << (8 - lzh_getlen);
        lzh_getlen += 8;
    }
    i = lzh_getbuf;
    lzh_getbuf <<= 1;
    lzh_getlen--;
    return (i < 0);
}

int16_t lzh_getbyte(uint8_t *inbuf, int32_t *incnt, int32_t inlen)   /* get a byte */
{
    uint16_t i;

    while (lzh_getlen <= 8) {
        if((*incnt)>=inlen)
            i=0;
        else
            i=inbuf[(*incnt)++];
        lzh_getbuf |= i << (8 - lzh_getlen);
        lzh_getlen += 8;
    }
    i = lzh_getbuf;
    lzh_getbuf <<= 8;
    lzh_getlen -= 8;
    return i >> 8;
}

uint32_t  lzh_putbuf = 0;
uint8_t   lzh_putlen = 0;

/* output c bits */
void lzh_putcode(int16_t l, uint16_t c, uint8_t *outbuf, int32_t *outlen)
{
    lzh_putbuf |= c >> lzh_putlen;
    if ((lzh_putlen += l) >= 8) {
        outbuf[(*outlen)++]=(lzh_putbuf >> 8);
        if ((lzh_putlen -= 8) >= 8) {
            outbuf[(*outlen)++]=lzh_putbuf;
            lzh_putlen -= 8;
            lzh_putbuf = c << (l - lzh_putlen);
        } else {
            lzh_putbuf <<= 8;
        }
    }
}


/* initialize freq tree */

void lzh_start_huff(void)
{
    int16_t i, j;

    lzh_getbuf = 0;   /* Added by Digital Dynamics for repeating operations */
    lzh_getlen = 0;
    lzh_putbuf = 0;
    lzh_putlen = 0;

    for (i = 0; i < LZH_N_CHAR; i++) {
        lzh_freq[i] = 1;
        lzh_son[i] = i + LZH_T;
        lzh_prnt[i + LZH_T] = i;
    }
    i = 0; j = LZH_N_CHAR;
    while (j <= LZH_R) {
        lzh_freq[j] = lzh_freq[i] + lzh_freq[i + 1];
        lzh_son[j] = i;
        lzh_prnt[i] = lzh_prnt[i + 1] = j;
        i += 2; j++;
    }
    lzh_freq[LZH_T] = 0xffff;
    lzh_prnt[LZH_R] = 0;
}


/* reconstruct freq tree */

void lzh_reconst(void)
{
    int16_t   i, j, k;
    uint16_t  f, l;

    /* halven cumulative freq for leaf nodes */
    j = 0;
    for (i = 0; i < LZH_T; i++) {
        if (lzh_son[i] >= LZH_T) {
            lzh_freq[j] = (lzh_freq[i] + 1) / 2;
            lzh_son[j] = lzh_son[i];
            j++;
        }
    }
    /* make a tree : first, connect children nodes */
    for (i = 0, j = LZH_N_CHAR; j < LZH_T; i += 2, j++) {
        k = i + 1;
        f = lzh_freq[j] = lzh_freq[i] + lzh_freq[k];
        for (k = j - 1; f < lzh_freq[k]; k--);
        k++;
        l = (j - k) * 2;

        /* movmem() is Turbo-C dependent
           rewritten to memmove() by Kenji */

        /* movmem(&lzh_freq[k], &lzh_freq[k + 1], l); */
        (void)memmove(lzh_freq+k+1,lzh_freq+k, l);
        lzh_freq[k] = f;
        /* movmem(&lzh_son[k], &lzh_son[k + 1], l); */
        (void)memmove(lzh_son+k+1,lzh_son+k, l);
        lzh_son[k] = i;
    }
    /* connect parent nodes */
    for (i = 0; i < LZH_T; i++) {
        if ((k = lzh_son[i]) >= LZH_T) {
            lzh_prnt[k] = i;
        } else {
            lzh_prnt[k] = lzh_prnt[k + 1] = i;
        }
    }
}

/* update freq tree */

void lzh_update(int16_t c)
{
    int16_t i, j, k, l;

    if (lzh_freq[LZH_R] == MAX_FREQ) {
        lzh_reconst();
    }
    c = lzh_prnt[c + LZH_T];
    do {
        k = ++lzh_freq[c];

        /* swap nodes to keep the tree freq-ordered */
        if (k > lzh_freq[l = c + 1]) {
            while (k > lzh_freq[++l]);
            l--;
            lzh_freq[c] = lzh_freq[l];
            lzh_freq[l] = k;

            i = lzh_son[c];
            lzh_prnt[i] = l;
            if (i < LZH_T) lzh_prnt[i + 1] = l;

            j = lzh_son[l];
            lzh_son[l] = i;

            lzh_prnt[j] = c;
            if (j < LZH_T) lzh_prnt[j + 1] = c;
            lzh_son[c] = j;

            c = l;
        }
    } while ((c = lzh_prnt[c]) != 0);   /* do it until reaching the root */
}

uint16_t  lzh_code, lzh_len;

void lzh_encode_char(uint16_t c, uint8_t *outbuf, int32_t *outlen)
{
    uint16_t  i;
    int16_t   j, k;

    i = 0;
    j = 0;
    k = lzh_prnt[c + LZH_T];

    /* search connections from leaf node to the root */
    do {
        i >>= 1;

        /*
        if node's address is odd, output 1
        else output 0
        */
        if (k & 1) i += 0x8000;

        j++;
    } while ((k = lzh_prnt[k]) != LZH_R);
    lzh_putcode(j, i, outbuf, outlen);
    lzh_code = i;
    lzh_len = j;
    lzh_update(c);
}

void lzh_encode_position(uint16_t c, uint8_t *outbuf, int32_t *outlen)
{
    uint16_t  i;

    /* output upper 6 bits with encoding */
    i = c >> 6;
    lzh_putcode(lzh_p_len[i], (uint16_t)(lzh_p_code[i] << 8), outbuf, outlen);

    /* output lower 6 bits directly */
    lzh_putcode(6, (uint16_t)((c & 0x3f) << 10), outbuf, outlen);
}

void lzh_encode_end(uint8_t *outbuf, int32_t *outlen)
{
    if (lzh_putlen) {
        outbuf[(*outlen)++]=(lzh_putbuf >> 8);
    }
}

int16_t lzh_decode_char(uint8_t *inbuf, int32_t *incnt, int32_t inlen)
{
    uint16_t  c;

    c = lzh_son[LZH_R];

    /*
     * start searching tree from the root to leaves.
     * choose node #(lzh_son[]) if input bit == 0
     * else choose #(lzh_son[]+1) (input bit == 1)
     */
    while (c < LZH_T) {
        c += lzh_getbit(inbuf,incnt,inlen);
        c = lzh_son[c];
    }
    c -= LZH_T;
    lzh_update(c);
    return c;
}

int16_t lzh_decode_position(uint8_t *inbuf, int32_t *incnt, int32_t inlen)
{
    uint16_t  i, j, c;

    /* decode upper 6 bits from given table */
    i = lzh_getbyte(inbuf,incnt,inlen);
    c = (uint32_t)lzh_d_code[i] << 6;
    j = lzh_d_len[i];

    /* input lower 6 bits directly */
    j -= 2;
    while (j--) {
        i = (i << 1) + lzh_getbit(inbuf,incnt,inlen);
    }
    return c | (i & 0x3f);
}

/* Compression */

/* Encoding/Compressing */
/* Returns length of outbuf */
int32_t LZHCALL lzh_encode(uint8_t *inbuf, int32_t inlen, uint8_t *outbuf)
{
    int16_t i, c, len, r, s, last_match_length;
    int32_t incnt, outlen; /* textsize=0; */

#ifdef LZH_DYNAMIC_BUF

    if((lzh_text_buf=(uint8_t *)MALLOC(LZH_N + LZH_F - 1))==NULL)
        return(-1);
    if((lzh_freq=(uint16_t *)MALLOC((LZH_T + 1)*sizeof(uint16_t)))==NULL) {
        FREE(lzh_text_buf);
        return(-1); }
    if((lzh_prnt=(int16_t *)MALLOC((LZH_T + LZH_N_CHAR)*sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_freq);
        return(-1); }
    if((lzh_son=(int16_t *)MALLOC((LZH_T + 1) * sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        return(-1); }
    if((lzh_lson=(int16_t *)MALLOC((LZH_N + 1)*sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        FREE(lzh_son);
        return(-1); }
    if((lzh_rson=(int16_t *)MALLOC((LZH_N + 257)*sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        FREE(lzh_son);
        FREE(lzh_lson);
        return(-1); }
    if((lzh_dad=(int16_t *)MALLOC((LZH_N + 1)*sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        FREE(lzh_son);
        FREE(lzh_lson);
        FREE(lzh_rson);
        return(-1); }
#endif

    incnt=0;
    memcpy(outbuf,&inlen,sizeof(inlen));
    outlen=sizeof(inlen);
    if(!inlen) {
#ifdef LZH_DYNAMIC_BUF
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        FREE(lzh_son);
        FREE(lzh_lson);
        FREE(lzh_rson);
        FREE(lzh_dad);
#endif
        return(outlen); }
    lzh_start_huff();
    lzh_init_tree();
    s = 0;
    r = LZH_N - LZH_F;
    for (i = s; i < r; i++)
        lzh_text_buf[i] = ' ';
    for (len = 0; len < LZH_F && incnt<inlen; len++)
        lzh_text_buf[r + len] = inbuf[incnt++];
    /* textsize = len; */
    for (i = 1; i <= LZH_F; i++)
        lzh_insert_node((int16_t)(r - i));
    lzh_insert_node(r);
    do {
        if (lzh_match_length > len)
            lzh_match_length = len;
        if (lzh_match_length <= LZH_THRESHOLD) {
            lzh_match_length = 1;
            lzh_encode_char(lzh_text_buf[r],outbuf,&outlen);
        } else {
            lzh_encode_char((uint16_t)(255 - LZH_THRESHOLD + lzh_match_length)
                ,outbuf,&outlen);
            lzh_encode_position(lzh_match_position
                ,outbuf,&outlen);
        }
        last_match_length = lzh_match_length;
        for (i = 0; i < last_match_length && incnt<inlen; i++) {
            lzh_delete_node(s);
            c=inbuf[incnt++];
            lzh_text_buf[s] = (uint8_t)c;
            if (s < LZH_F - 1)
                lzh_text_buf[s + LZH_N] = (uint8_t)c;
            s = (s + 1) & (LZH_N - 1);
            r = (r + 1) & (LZH_N - 1);
            lzh_insert_node(r);
        }
/***
        if ((textsize += i) > printcount) {
            printf("%12ld\r", textsize);
            printcount += 1024;
        }
***/
        while (i++ < last_match_length) {
            lzh_delete_node(s);
            s = (s + 1) & (LZH_N - 1);
            r = (r + 1) & (LZH_N - 1);
            if (--len) lzh_insert_node(r);
        }
    } while (len > 0);
    lzh_encode_end(outbuf,&outlen);
/*
    printf("input: %ld (%ld) bytes\n", inlen,textsize);
    printf("output: %ld bytes\n", outlen);
    printf("output/input: %.3f\n", (double)outlen / inlen);
*/

#ifdef LZH_DYNAMIC_BUF
    FREE(lzh_text_buf);
    FREE(lzh_prnt);
    FREE(lzh_freq);
    FREE(lzh_son);
    FREE(lzh_lson);
    FREE(lzh_rson);
    FREE(lzh_dad);
#endif

    return(outlen);
}

/* Decoding/Uncompressing */
/* Returns length of outbuf */
int32_t LZHCALL lzh_decode(uint8_t *inbuf, int32_t inlen, uint8_t *outbuf)
{
    int16_t   i, j, k, r, c;
    uint32_t  count;
    int32_t   incnt, textsize;

#ifdef LZH_DYNAMIC_BUF

    if((lzh_text_buf=(uint8_t *)MALLOC((LZH_N + LZH_F - 1)*2))==NULL)
        return(-1);
    if((lzh_freq=(uint16_t *)MALLOC((LZH_T + 1)*sizeof(uint16_t)))
        ==NULL) {
        FREE(lzh_text_buf);
        return(-1); }
    if((lzh_prnt=(int16_t *)MALLOC((LZH_T + LZH_N_CHAR)*sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_freq);
        return(-1); }
    if((lzh_son=(int16_t *)MALLOC((LZH_T + 1) * sizeof(int16_t)))==NULL) {
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        return(-1); }

#endif

    incnt=0;
    memcpy(&textsize,inbuf,sizeof(textsize));
    incnt+=sizeof(textsize);
    if (textsize == 0) {
#ifdef LZH_DYNAMIC_BUF
        FREE(lzh_text_buf);
        FREE(lzh_prnt);
        FREE(lzh_freq);
        FREE(lzh_son);
#endif
        return(textsize); }
    lzh_start_huff();
    for (i = 0; i < LZH_N - LZH_F; i++)
        *(lzh_text_buf+i) = ' ';
    r = LZH_N - LZH_F;
    for (count = 0; count < (uint32_t)textsize; ) {
        c = lzh_decode_char(inbuf,&incnt,inlen);
        if (c < 256) {
            outbuf[count]=(uint8_t)c;
#if 0
            if(r>(LZH_N + LZH_F - 1) || r<0) {
                printf("Overflow! (%d)\n",r);
                getch();
                exit(-1); }
#endif
            *(lzh_text_buf+r) = (uint8_t)c;
            r++;
            r &= (LZH_N - 1);
            count++;
        } else {
            i = (r - lzh_decode_position(inbuf,&incnt,inlen) - 1)
                & (LZH_N - 1);
            j = c - 255 + LZH_THRESHOLD;
            for (k = 0; k < j && count<(uint32_t)textsize; k++) {
                c = lzh_text_buf[(i + k) & (LZH_N - 1)];
                outbuf[count]=(uint8_t)c;
#if 0
                if(r>(LZH_N + LZH_F - 1) || r<0) {
                    printf("Overflow! (%d)\n",r);
                    exit(-1); }
#endif
                *(lzh_text_buf+r) = (uint8_t)c;
                r++;
                r &= (LZH_N - 1);
                count++;
            }
        }
    }
/***
    printf("%12ld\n", count);
***/

#ifdef LZH_DYNAMIC_BUF
    FREE(lzh_text_buf);
    FREE(lzh_prnt);
    FREE(lzh_freq);
    FREE(lzh_son);
#endif

return(count);
}


