planet-strike/JM_LZH.C
2013-07-08 00:00:00 +00:00

1220 lines
26 KiB
C

//===========================================================================
//
// LZHUFF COMPRESSION ROUTINES
// VERSION 1.0
//
// Compression algrythim by Haruhiko OKUMURA
// Implementation by Jim T. Row
//
//
// Copyright (c) 1992 -
//
//===========================================================================
//
// Compiler #ifdef switches
//
// LZHUFF_COMPRESSION & LZHUFF_DECOMPRESSION - not yet functional!
//
// Usage Explanition :
//
// if LZHUFF_COMPRESSION is defined then the compression code & data is
// compiled and so-forth for the decompression code.
//
//---------------------------------------------------------------------------
#include <fcntl.h>
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <alloc.h>
#include <dos.h>
#include <mem.h>
#include "jm_cio.h"
#include "jm_lzh.h"
//===========================================================================
//
// SWITCHES
//
// NOTE : Make sure the appropriate switches are set in SOFT.c for Softlib
// archive support.
//
//===========================================================================
#define INCLUDE_LZH_COMP 1
#define INCLUDE_LZH_DECOMP 1
#define LZH_DYNAMIC_ALLOCATION
#define LZH_ID_MEMORY_ALLOCATION
#ifdef LZH_ID_MEMORY_ALLOCATION
#include "id_mm.h"
#endif
//===========================================================================
//
// DEFINES
//
//===========================================================================
#define EXIT_OK 0
#define EXIT_FAILED -1
/* LZSS Parameters */
#define N 4096 /* Size of string buffer */
#define F 30 /* Size of look-ahead buffer */
#define THRESHOLD 2
#define NIL N /* End of tree's node */
/* Huffman coding parameters */
#define N_CHAR (256 - THRESHOLD + F) /* character code (= 0..N_CHAR-1) */
#define T (N_CHAR * 2 - 1) /* Size of table */
#define R (T - 1) /* root position */
#define MAX_FREQ 0x8000 /* update when cumulative frequency */
/* reaches to this value */
//==========================================================================
//
// LOCAL PROTOTYPES
//
//==========================================================================
static void StartHuff(void);
static void reconst(void);
static void update(int c);
static void DeleteNode(int p); /* Deleting node from the tree */
static void InsertNode(int r); /* Inserting node to the tree */
static void InitTree(void); /* Initializing tree */
static void Putcode(long outfile_ptr, int l, unsigned c,unsigned PtrTypes); /* output c bits */
static void EncodeChar(long outfile_ptr, unsigned c, unsigned PtrTypes);
static void EncodePosition(long outfile_ptr, unsigned c, unsigned PtrTypes);
static void EncodeEnd(long outfile_ptr,unsigned PtrTypes);
static int GetByte(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes);
static int GetBit(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes); /* get one bit */
static int DecodeChar(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes);
static int DecodePosition(long infile_ptr,unsigned long *CompressLength, unsigned PtrTypes);
//==========================================================================
//
// USER AVAILABLE VECTORS
//
//==========================================================================
//---------------------------------------------------------------------------
//
// LZHUFF DISPLAY VECTORS
//
// These vectors allow you to hook up any form of display you desire for
// displaying the compression/decompression status.
//
// These routines are called inside of the compression/decompression routines
// and pass the orginal size of data and current position within that
// data. This allows for any kind of "% Done" messages.
//
// Your functions MUST have the following parameters in this order...
//
// void VectorRoutine(unsigned long OriginalSize,unsigned long CurPosition)
//
//
#if INCLUDE_LZH_COMP
void (*LZH_CompressDisplayVector)(unsigned long, unsigned long) = NULL;
#endif
#if INCLUDE_LZH_DECOMP
void (*LZH_DecompressDisplayVector)(unsigned long, unsigned long) = NULL;
#endif
//===========================================================================
//
// GLOBAL VARIABLES
//
//===========================================================================
/* pointing children nodes (son[], son[] + 1)*/
unsigned code, len;
unsigned long textsize = 0, codesize = 0, printcount = 0,datasize;
#ifdef LZH_DYNAMIC_ALLOCATION
int far *son=NULL;
//
// pointing parent nodes.
// area [T..(T + N_CHAR - 1)] are pointers for leaves
//
int far *prnt;
unsigned far *freq; /* cumulative freq table */
unsigned char far *text_buf;
#ifdef LZH_ID_MEMORY_ALLOCATION
memptr id_son,id_prnt,id_freq,id_text_buf;
#endif
#else
int son[T];
//
// pointing parent nodes.
// area [T..(T + N_CHAR - 1)] are pointers for leaves
//
int prnt[T + N_CHAR];
unsigned freq[T + 1]; /* cumulative freq table */
unsigned char text_buf[N + F - 1];
#endif
//
// COMPRESSION VARIABLES
//
#if INCLUDE_LZH_COMP
#ifdef LZH_DYNAMIC_ALLOCATION
static int far *lson, far *rson, far *dad;
#ifdef LZH_ID_MEMORY_ALLOCATION
memptr id_lson,id_rson,id_dad;
#endif
#else
static int lson[N + 1], rson[N + 257], dad[N + 1];
#endif
static int match_position,match_length;
unsigned putbuf = 0;
unsigned putlen = 0;
//
// Tables for encoding/decoding upper 6 bits of
// sliding dictionary pointer
//
//
// encoder table
//
unsigned char far 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
};
unsigned char far 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
};
#endif
//
// DECOMPRESSION VARIABLES
//
//
// decoder table
//
#if INCLUDE_LZH_DECOMP
unsigned char far 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,
};
unsigned char far 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,
};
unsigned getbuf = 0;
unsigned getlen = 0;
#endif
//===========================================================================
//
// COMPRESSION & DECOMPRESSION ROUTINES
//
//===========================================================================
//---------------------------------------------------------------------------
// LZH_Startup
//---------------------------------------------------------------------------
boolean LZH_Startup()
{
if (son)
return(true);
#ifdef LZH_DYNAMIC_ALLOCATION
#ifdef LZH_ID_MEMORY_ALLOCATION
MM_GetPtr(&id_son,T*sizeof(*son));
MM_GetPtr(&id_prnt,(T+N_CHAR)*sizeof(*prnt));
MM_GetPtr(&id_freq,(T+1)*sizeof(*freq));
MM_GetPtr(&id_text_buf,(N+F-1)*sizeof(*text_buf));
#else
if (!(son=farmalloc(T*sizeof(*son))))
return(false);
if (!(prnt=farmalloc((T+N_CHAR)*sizeof(*prnt))))
return(false);
if (!(freq=farmalloc((T+1)*sizeof(*freq))))
return(false);
if (!(text_buf=farmalloc((N+F-1)*sizeof(*text_buf))))
return(false);
#endif
#if INCLUDE_LZH_COMP
#ifdef LZH_ID_MEMORY_ALLOCATION
MM_GetPtr(&id_lson,(N+1)*sizeof(*lson));
MM_GetPtr(&id_rson,(N+257)*sizeof(*rson));
MM_GetPtr(&id_dad,(N+1)*sizeof(*dad));
#else
if (!(lson=farmalloc((N+1)*sizeof(*lson))))
return(false);
if (!(rson=farmalloc((N+257)*sizeof(*rson))))
return(false);
if (!(dad=farmalloc((N+1)*sizeof(*dad))))
return(false);
#endif
#endif
#endif
return(true);
}
//---------------------------------------------------------------------------
// LZH_Shutdown
//---------------------------------------------------------------------------
void LZH_Shutdown()
{
#ifdef LZH_DYNAMIC_ALLOCATION
#ifdef LZH_ID_MEMORY_ALLOCATION
if (id_son)
MM_FreePtr(&id_son);
if (id_prnt)
MM_FreePtr(&id_prnt);
if (id_freq)
MM_FreePtr(&id_freq);
if (id_text_buf)
MM_FreePtr(&id_text_buf);
#else
if (son)
farfree(son);
if (prnt)
farfree(prnt);
if (freq)
farfree(freq);
if (text_buf)
farfree(text_buf);
#endif
#if INCLUDE_LZH_COMP
#ifdef LZH_ID_MEMORY_ALLOCATION
if (id_lson)
MM_FreePtr(&id_lson);
if (id_rson)
MM_FreePtr(&id_rson);
if (id_dad)
MM_FreePtr(&id_dad);
#else
if (lson)
farfree(lson);
if (rson)
farfree(rson);
if (dad)
farfree(dad);
#endif
#endif
son=NULL; // Must be zeroed on shutdown!
#endif
}
//---------------------------------------------------------------------------
// StartHuff /* initialize freq tree */
//---------------------------------------------------------------------------
static void StartHuff()
{
int i, j;
#ifdef LZH_DYNAMIC_ALLOCATION
#ifdef LZH_ID_MEMORY_ALLOCATION
// Assign _seg pointers to far pointers, always initialized here in case
// the memory manager shifted things around after LZH_Startup() was called.
//
son=id_son;
prnt=id_prnt;
freq=id_freq;
text_buf=id_text_buf;
lson=id_lson;
rson=id_rson;
dad=id_dad;
#endif
#endif
for (i = 0; i < N_CHAR; i++) {
freq[i] = 1;
son[i] = i + T;
prnt[i + T] = i;
}
i = 0; j = N_CHAR;
while (j <= R) {
freq[j] = freq[i] + freq[i + 1];
son[j] = i;
prnt[i] = prnt[i + 1] = j;
i += 2; j++;
}
freq[T] = 0xffff;
prnt[R] = 0;
printcount=0;
putbuf=putlen=match_position=match_length=0;
}
//---------------------------------------------------------------------------
// reconst /* reconstruct freq tree */
//---------------------------------------------------------------------------
static void reconst()
{
int i, j, k;
unsigned f, l;
/* halven cumulative freq for leaf nodes */
j = 0;
for (i = 0; i < T; i++)
{
if (son[i] >= T)
{
freq[j] = (freq[i] + 1) / 2;
son[j] = son[i];
j++;
}
}
/* make a tree : first, connect children nodes */
for (i = 0, j = N_CHAR; j < T; i += 2, j++)
{
k = i + 1;
f = freq[j] = freq[i] + freq[k];
for (k = j - 1;f < freq[k]; k--);
k++;
l = (j - k) * 2;
_fmemcpy(&freq[k + 1], &freq[k], l);
freq[k] = f;
_fmemcpy(&son[k + 1], &son[k], l);
son[k] = i;
}
/* connect parent nodes */
for (i = 0; i < T; i++)
{
if ((k = son[i]) >= T)
{
prnt[k] = i;
}
else
{
prnt[k] = prnt[k + 1] = i;
}
}
}
//---------------------------------------------------------------------------
// update() update freq tree
//---------------------------------------------------------------------------
static void update(int c)
{
int i, j, k, l;
if (freq[R] == MAX_FREQ)
{
reconst();
}
c = prnt[c + T];
do {
k = ++freq[c];
//
// swap nodes to keep the tree freq-ordered
//
if (k > freq[l = c + 1])
{
while (k > freq[++l]);
l--;
freq[c] = freq[l];
freq[l] = k;
i = son[c];
prnt[i] = l;
if (i < T)
prnt[i + 1] = l;
j = son[l];
son[l] = i;
prnt[j] = c;
if (j < T)
prnt[j + 1] = c;
son[c] = j;
c = l;
}
} while ((c = prnt[c]) != 0); /* do it until reaching the root */
}
//===========================================================================
//
// COMPRESSION ROUTINES
//
//===========================================================================
#if INCLUDE_LZH_COMP
//---------------------------------------------------------------------------
// DeleteNode
//---------------------------------------------------------------------------
static void DeleteNode(int p) /* Deleting node from the tree */
{
int q;
if (dad[p] == NIL)
return; /* unregistered */
if (rson[p] == NIL)
q = lson[p];
else
if (lson[p] == NIL)
q = rson[p];
else
{
q = lson[p];
if (rson[q] != NIL)
{
do {
q = rson[q];
} while (rson[q] != NIL);
rson[dad[q]] = lson[q];
dad[lson[q]] = dad[q];
lson[q] = lson[p];
dad[lson[p]] = q;
}
rson[q] = rson[p];
dad[rson[p]] = q;
}
dad[q] = dad[p];
if (rson[dad[p]] == p)
rson[dad[p]] = q;
else
lson[dad[p]] = q;
dad[p] = NIL;
}
//---------------------------------------------------------------------------
// InsertNode
//---------------------------------------------------------------------------
static void InsertNode(int r) /* Inserting node to the tree */
{
int i, p, cmp;
unsigned char far *key;
unsigned c;
cmp = 1;
key = &text_buf[r];
p = N + 1 + key[0];
rson[r] = lson[r] = NIL;
match_length = 0;
for ( ; ; )
{
if (cmp >= 0)
{
if (rson[p] != NIL)
p = rson[p];
else
{
rson[p] = r;
dad[r] = p;
return;
}
}
else
{
if (lson[p] != NIL)
p = lson[p];
else
{
lson[p] = r;
dad[r] = p;
return;
}
}
for (i = 1; i < F; i++)
if ((cmp = key[i] - text_buf[p + i]) != 0)
break;
if (i > THRESHOLD)
{
if (i > match_length)
{
match_position = ((r - p) & (N - 1)) - 1;
if ((match_length = i) >= F)
break;
}
if (i == match_length)
{
if ((c = ((r - p) & (N - 1)) - 1) < match_position)
{
match_position = c;
}
}
}
}
dad[r] = dad[p];
lson[r] = lson[p];
rson[r] = rson[p];
dad[lson[p]] = r;
dad[rson[p]] = r;
if (rson[dad[p]] == p)
rson[dad[p]] = r;
else
lson[dad[p]] = r;
dad[p] = NIL; /* remove p */
}
//---------------------------------------------------------------------------
// InitTree
//---------------------------------------------------------------------------
static void InitTree(void) /* Initializing tree */
{
int i;
for (i = N + 1; i <= N + 256; i++)
rson[i] = NIL; /* root */
for (i = 0; i < N; i++)
dad[i] = NIL; /* node */
}
//---------------------------------------------------------------------------
// Putcode
//---------------------------------------------------------------------------
static void Putcode(long outfile_ptr, int l, unsigned c,unsigned PtrTypes) /* output c bits */
{
putbuf |= c >> putlen;
if ((putlen += l) >= 8)
{
CIO_WritePtr(outfile_ptr, putbuf >> 8, PtrTypes);
codesize++;
if ((putlen -= 8) >= 8)
{
CIO_WritePtr(outfile_ptr, putbuf, PtrTypes);
codesize++;
putlen -= 8;
putbuf = c << (l - putlen);
}
else
{
putbuf <<= 8;
}
}
}
//---------------------------------------------------------------------------
// EncodeChar
//---------------------------------------------------------------------------
static void EncodeChar(long outfile_ptr, unsigned c, unsigned PtrTypes)
{
unsigned i;
int j, k;
i = 0;
j = 0;
k = prnt[c + 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 = prnt[k]) != R);
Putcode(outfile_ptr, j, i, PtrTypes);
code = i;
len = j;
update(c);
}
//---------------------------------------------------------------------------
// EncodePosition
//---------------------------------------------------------------------------
static void EncodePosition(long outfile_ptr, unsigned c, unsigned PtrTypes)
{
unsigned i;
//
// output upper 6 bits with encoding
//
i = c >> 6;
Putcode(outfile_ptr, p_len[i], (unsigned)p_code[i] << 8,PtrTypes);
//
// output lower 6 bits directly
//
Putcode(outfile_ptr, 6, (c & 0x3f) << 10,PtrTypes);
}
//---------------------------------------------------------------------------
// EncodeEnd
//---------------------------------------------------------------------------
static void EncodeEnd(long outfile_ptr,unsigned PtrTypes)
{
if (putlen)
{
CIO_WritePtr(outfile_ptr,(putbuf >> 8),PtrTypes);
codesize++;
}
}
#endif
//===========================================================================
//
// DECOMPRESSION ROUTINES
//
//===========================================================================
#if INCLUDE_LZH_DECOMP
//---------------------------------------------------------------------------
// GetByte
//---------------------------------------------------------------------------
static int GetByte(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes)
{
unsigned i;
while (getlen <= 8)
{
if (*CompressLength)
{
i = CIO_ReadPtr(infile_ptr,PtrTypes);
(*CompressLength)--;
}
else
i = 0;
getbuf |= i << (8 - getlen);
getlen += 8;
}
i = getbuf;
getbuf <<= 8;
getlen -= 8;
return i>>8;
}
//---------------------------------------------------------------------------
// GetBit
//---------------------------------------------------------------------------
static int GetBit(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes) /* get one bit */
{
int i;
while (getlen <= 8)
{
if (*CompressLength)
{
i = CIO_ReadPtr(infile_ptr,PtrTypes);
(*CompressLength)--;
}
else
i = 0;
getbuf |= i << (8 - getlen);
getlen += 8;
}
i = getbuf;
getbuf <<= 1;
getlen--;
return (i < 0);
}
//---------------------------------------------------------------------------
// DecodeChar
//---------------------------------------------------------------------------
static int DecodeChar(long infile_ptr, unsigned long *CompressLength, unsigned PtrTypes)
{
unsigned c;
c = son[R];
/*
* start searching tree from the root to leaves.
* choose node #(son[]) if input bit == 0
* else choose #(son[]+1) (input bit == 1)
*/
while (c < T)
{
c += GetBit(infile_ptr,CompressLength,PtrTypes);
c = son[c];
}
c -= T;
update(c);
return c;
}
//---------------------------------------------------------------------------
// DecodePosition
//---------------------------------------------------------------------------
static int DecodePosition(long infile_ptr,unsigned long *CompressLength, unsigned PtrTypes)
{
unsigned i, j, c;
//
// decode upper 6 bits from given table
//
i = GetByte(infile_ptr, CompressLength, PtrTypes);
c = (unsigned)d_code[i] << 6;
j = d_len[i];
//
// input lower 6 bits directly
//
j -= 2;
while (j--)
{
i = (i << 1) + GetBit(infile_ptr, CompressLength, PtrTypes);
}
return c | i & 0x3f;
}
#endif
//===========================================================================
//
// EXTERNAL REFERENCED
// COMPRESSION & DECOMPRESSION
// ROUTINES
//
//===========================================================================
#if INCLUDE_LZH_DECOMP
//---------------------------------------------------------------------------
// LZH_Decompress()
//---------------------------------------------------------------------------
long LZH_Decompress(void far *infile, void far *outfile, unsigned long OriginalLength, unsigned long CompressLength, unsigned PtrTypes)
{
int i, j, k, r, c;
long count;
datasize = textsize = OriginalLength;
getbuf = 0;
getlen = 0;
if (textsize == 0)
return(0);
StartHuff();
for (i = 0; i < N - F; i++)
text_buf[i] = ' ';
r = N - F;
for (count = 0; count < textsize; )
{
c = DecodeChar((long)&infile,&CompressLength,PtrTypes);
if (c < 256)
{
CIO_WritePtr((long)&outfile,c,PtrTypes);
datasize--; // Dec # of bytes to write
text_buf[r++] = c;
r &= (N - 1);
count++; // inc count of bytes written
}
else
{
i = (r - DecodePosition((long)&infile,&CompressLength,PtrTypes) - 1) & (N - 1);
j = c - 255 + THRESHOLD;
for (k = 0; k < j; k++)
{
c = text_buf[(i + k) & (N - 1)];
CIO_WritePtr((long)&outfile,c,PtrTypes);
datasize--; // dec count of bytes to write
text_buf[r++] = c;
r &= (N - 1);
count++; // inc count of bytes written
}
}
if (LZH_DecompressDisplayVector && (count > printcount))
{
LZH_DecompressDisplayVector(OriginalLength,OriginalLength-datasize);
printcount += 1024;
}
}
if (LZH_DecompressDisplayVector)
LZH_DecompressDisplayVector(OriginalLength,OriginalLength);
return(count);
}
#endif
#if INCLUDE_LZH_COMP
//---------------------------------------------------------------------------
// LZH_Compress()
//---------------------------------------------------------------------------
long LZH_Compress(void far *infile, void far *outfile,unsigned long DataLength,unsigned PtrTypes)
{
int i, c, len, r, s, last_match_length;
textsize = DataLength;
if (textsize == 0)
return(0);
getbuf = 0;
getlen = 0;
textsize = 0; /* rewind and rescan */
codesize = 0;
datasize = 0; // Init our counter of ReadData...
StartHuff();
InitTree();
s = 0;
r = N - F;
for (i = s; i < r; i++)
text_buf[i] = ' ';
for (len = 0; len < F && (DataLength > datasize); len++)
{
c = CIO_ReadPtr((long)&infile,PtrTypes);
datasize++; // Dec num of bytes to compress
text_buf[r + len] = c;
}
textsize = len;
for (i = 1; i <= F; i++)
InsertNode(r - i);
InsertNode(r);
do {
if (match_length > len)
match_length = len;
if (match_length <= THRESHOLD)
{
match_length = 1;
EncodeChar((long)&outfile,text_buf[r],PtrTypes);
}
else
{
EncodeChar((long)&outfile, 255 - THRESHOLD + match_length,PtrTypes);
EncodePosition((long)&outfile, match_position,PtrTypes);
}
last_match_length = match_length;
for (i = 0; i < last_match_length && (DataLength > datasize); i++)
{
c = CIO_ReadPtr((long)&infile,PtrTypes);
datasize++;
DeleteNode(s);
text_buf[s] = c;
if (s < F - 1)
text_buf[s + N] = c;
s = (s + 1) & (N - 1);
r = (r + 1) & (N - 1);
InsertNode(r);
}
if (LZH_CompressDisplayVector && ((textsize += i) > printcount))
{
LZH_CompressDisplayVector(DataLength,datasize);
printcount += 1024;
}
while (i++ < last_match_length)
{
DeleteNode(s);
s = (s + 1) & (N - 1);
r = (r + 1) & (N - 1);
if (--len)
InsertNode(r);
}
} while (len > 0);
EncodeEnd((long)&outfile,PtrTypes);
if (LZH_CompressDisplayVector)
LZH_CompressDisplayVector(DataLength,DataLength);
return(codesize);
}
#endif