390 lines
8.6 KiB
C
390 lines
8.6 KiB
C
/* unlzh.c -- decompress files in SCO compress -H (LZH) format.
|
|
* The code in this file is directly derived from the public domain 'ar002'
|
|
* written by Haruhiko Okumura.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char rcsid[] = "$Id: unlzh.c,v 1.2 1993/08/02 17:46:24 mycroft Exp $";
|
|
#endif /* not lint */
|
|
|
|
#include <stdio.h>
|
|
|
|
#include "tailor.h"
|
|
#include "gzip.h"
|
|
#include "lzw.h" /* just for consistency checking */
|
|
|
|
/* decode.c */
|
|
|
|
local unsigned decode OF((unsigned count, uch buffer[]));
|
|
local void decode_start OF((void));
|
|
|
|
/* huf.c */
|
|
local void huf_decode_start OF((void));
|
|
local unsigned decode_c OF((void));
|
|
local unsigned decode_p OF((void));
|
|
|
|
/* io.c */
|
|
local void fillbuf OF((int n));
|
|
local unsigned getbits OF((int n));
|
|
local void init_getbits OF((void));
|
|
|
|
#define DICBIT 13 /* 12(-lh4-) or 13(-lh5-) */
|
|
#define DICSIZ ((unsigned) 1 << DICBIT)
|
|
|
|
#ifndef CHAR_BIT
|
|
# define CHAR_BIT 8
|
|
#endif
|
|
|
|
#ifndef UCHAR_MAX
|
|
# define UCHAR_MAX 255
|
|
#endif
|
|
|
|
#define BITBUFSIZ (CHAR_BIT * 2 * sizeof(char))
|
|
/* Do not use CHAR_BIT * sizeof(bitbuf), does not work on machines
|
|
* for which short is not on 16 bits (Cray).
|
|
*/
|
|
|
|
/* encode.c and decode.c */
|
|
|
|
#define MAXMATCH 256 /* formerly F (not more than UCHAR_MAX + 1) */
|
|
#define THRESHOLD 3 /* choose optimal value */
|
|
|
|
/* huf.c */
|
|
|
|
#define NC (UCHAR_MAX + MAXMATCH + 2 - THRESHOLD)
|
|
/* alphabet = {0, 1, 2, ..., NC - 1} */
|
|
#define CBIT 9 /* $\lfloor \log_2 NC \rfloor + 1$ */
|
|
#define CODE_BIT 16 /* codeword length */
|
|
|
|
#define NP (DICBIT + 1)
|
|
#define NT (CODE_BIT + 3)
|
|
#define PBIT 4 /* smallest integer such that (1U << PBIT) > NP */
|
|
#define TBIT 5 /* smallest integer such that (1U << TBIT) > NT */
|
|
#if NT > NP
|
|
# define NPT NT
|
|
#else
|
|
# define NPT NP
|
|
#endif
|
|
|
|
/* local ush left[2 * NC - 1]; */
|
|
/* local ush right[2 * NC - 1]; */
|
|
#define left prev
|
|
#define right head
|
|
#if NC > 1<<(BITS-2)
|
|
error cannot overlay left+right and prev
|
|
#endif
|
|
|
|
/* local uch c_len[NC]; */
|
|
#define c_len outbuf
|
|
#if NC > OUTBUFSIZ
|
|
error cannot overlay c_len and outbuf
|
|
#endif
|
|
|
|
local uch pt_len[NPT];
|
|
local unsigned blocksize;
|
|
local ush pt_table[256];
|
|
|
|
/* local ush c_table[4096]; */
|
|
#define c_table d_buf
|
|
#if DIST_BUFSIZE < 4096
|
|
error cannot overlay c_table and d_buf
|
|
#endif
|
|
|
|
local ush bitbuf;
|
|
local unsigned subbitbuf;
|
|
local int bitcount;
|
|
|
|
local void fillbuf(n) /* Shift bitbuf n bits left, read n bits */
|
|
int n;
|
|
{
|
|
bitbuf <<= n;
|
|
while (n > bitcount) {
|
|
bitbuf |= subbitbuf << (n -= bitcount);
|
|
subbitbuf = (unsigned)try_byte();
|
|
if ((int)subbitbuf == EOF) subbitbuf = 0;
|
|
bitcount = CHAR_BIT;
|
|
}
|
|
bitbuf |= subbitbuf >> (bitcount -= n);
|
|
}
|
|
|
|
local unsigned getbits(n)
|
|
int n;
|
|
{
|
|
unsigned x;
|
|
|
|
x = bitbuf >> (BITBUFSIZ - n); fillbuf(n);
|
|
return x;
|
|
}
|
|
|
|
local void init_getbits()
|
|
{
|
|
bitbuf = 0; subbitbuf = 0; bitcount = 0;
|
|
fillbuf(BITBUFSIZ);
|
|
}
|
|
|
|
/***********************************************************
|
|
maketbl.c -- make table for decoding
|
|
***********************************************************/
|
|
|
|
local void make_table(nchar, bitlen, tablebits, table)
|
|
int nchar;
|
|
uch bitlen[];
|
|
int tablebits;
|
|
ush table[];
|
|
{
|
|
ush count[17], weight[17], start[18], *p;
|
|
unsigned i, k, len, ch, jutbits, avail, nextcode, mask;
|
|
|
|
for (i = 1; i <= 16; i++) count[i] = 0;
|
|
for (i = 0; i < nchar; i++) count[bitlen[i]]++;
|
|
|
|
start[1] = 0;
|
|
for (i = 1; i <= 16; i++)
|
|
start[i + 1] = start[i] + (count[i] << (16 - i));
|
|
if (start[17] != (ush)((unsigned) 1 << 16))
|
|
error("Bad table\n");
|
|
|
|
jutbits = 16 - tablebits;
|
|
for (i = 1; i <= tablebits; i++) {
|
|
start[i] >>= jutbits;
|
|
weight[i] = (unsigned) 1 << (tablebits - i);
|
|
}
|
|
while (i <= 16) {
|
|
weight[i] = (unsigned) 1 << (16 - i);
|
|
i++;
|
|
}
|
|
|
|
i = start[tablebits + 1] >> jutbits;
|
|
if (i != (ush)((unsigned) 1 << 16)) {
|
|
k = 1 << tablebits;
|
|
while (i != k) table[i++] = 0;
|
|
}
|
|
|
|
avail = nchar;
|
|
mask = (unsigned) 1 << (15 - tablebits);
|
|
for (ch = 0; ch < nchar; ch++) {
|
|
if ((len = bitlen[ch]) == 0) continue;
|
|
nextcode = start[len] + weight[len];
|
|
if (len <= tablebits) {
|
|
for (i = start[len]; i < nextcode; i++) table[i] = ch;
|
|
} else {
|
|
k = start[len];
|
|
p = &table[k >> jutbits];
|
|
i = len - tablebits;
|
|
while (i != 0) {
|
|
if (*p == 0) {
|
|
right[avail] = left[avail] = 0;
|
|
*p = avail++;
|
|
}
|
|
if (k & mask) p = &right[*p];
|
|
else p = &left[*p];
|
|
k <<= 1; i--;
|
|
}
|
|
*p = ch;
|
|
}
|
|
start[len] = nextcode;
|
|
}
|
|
}
|
|
|
|
/***********************************************************
|
|
huf.c -- static Huffman
|
|
***********************************************************/
|
|
|
|
local void read_pt_len(nn, nbit, i_special)
|
|
int nn;
|
|
int nbit;
|
|
int i_special;
|
|
{
|
|
int i, c, n;
|
|
unsigned mask;
|
|
|
|
n = getbits(nbit);
|
|
if (n == 0) {
|
|
c = getbits(nbit);
|
|
for (i = 0; i < nn; i++) pt_len[i] = 0;
|
|
for (i = 0; i < 256; i++) pt_table[i] = c;
|
|
} else {
|
|
i = 0;
|
|
while (i < n) {
|
|
c = bitbuf >> (BITBUFSIZ - 3);
|
|
if (c == 7) {
|
|
mask = (unsigned) 1 << (BITBUFSIZ - 1 - 3);
|
|
while (mask & bitbuf) { mask >>= 1; c++; }
|
|
}
|
|
fillbuf((c < 7) ? 3 : c - 3);
|
|
pt_len[i++] = c;
|
|
if (i == i_special) {
|
|
c = getbits(2);
|
|
while (--c >= 0) pt_len[i++] = 0;
|
|
}
|
|
}
|
|
while (i < nn) pt_len[i++] = 0;
|
|
make_table(nn, pt_len, 8, pt_table);
|
|
}
|
|
}
|
|
|
|
local void read_c_len()
|
|
{
|
|
int i, c, n;
|
|
unsigned mask;
|
|
|
|
n = getbits(CBIT);
|
|
if (n == 0) {
|
|
c = getbits(CBIT);
|
|
for (i = 0; i < NC; i++) c_len[i] = 0;
|
|
for (i = 0; i < 4096; i++) c_table[i] = c;
|
|
} else {
|
|
i = 0;
|
|
while (i < n) {
|
|
c = pt_table[bitbuf >> (BITBUFSIZ - 8)];
|
|
if (c >= NT) {
|
|
mask = (unsigned) 1 << (BITBUFSIZ - 1 - 8);
|
|
do {
|
|
if (bitbuf & mask) c = right[c];
|
|
else c = left [c];
|
|
mask >>= 1;
|
|
} while (c >= NT);
|
|
}
|
|
fillbuf((int) pt_len[c]);
|
|
if (c <= 2) {
|
|
if (c == 0) c = 1;
|
|
else if (c == 1) c = getbits(4) + 3;
|
|
else c = getbits(CBIT) + 20;
|
|
while (--c >= 0) c_len[i++] = 0;
|
|
} else c_len[i++] = c - 2;
|
|
}
|
|
while (i < NC) c_len[i++] = 0;
|
|
make_table(NC, c_len, 12, c_table);
|
|
}
|
|
}
|
|
|
|
local unsigned decode_c()
|
|
{
|
|
unsigned j, mask;
|
|
|
|
if (blocksize == 0) {
|
|
blocksize = getbits(16);
|
|
if (blocksize == 0) {
|
|
return NC; /* end of file */
|
|
}
|
|
read_pt_len(NT, TBIT, 3);
|
|
read_c_len();
|
|
read_pt_len(NP, PBIT, -1);
|
|
}
|
|
blocksize--;
|
|
j = c_table[bitbuf >> (BITBUFSIZ - 12)];
|
|
if (j >= NC) {
|
|
mask = (unsigned) 1 << (BITBUFSIZ - 1 - 12);
|
|
do {
|
|
if (bitbuf & mask) j = right[j];
|
|
else j = left [j];
|
|
mask >>= 1;
|
|
} while (j >= NC);
|
|
}
|
|
fillbuf((int) c_len[j]);
|
|
return j;
|
|
}
|
|
|
|
local unsigned decode_p()
|
|
{
|
|
unsigned j, mask;
|
|
|
|
j = pt_table[bitbuf >> (BITBUFSIZ - 8)];
|
|
if (j >= NP) {
|
|
mask = (unsigned) 1 << (BITBUFSIZ - 1 - 8);
|
|
do {
|
|
if (bitbuf & mask) j = right[j];
|
|
else j = left [j];
|
|
mask >>= 1;
|
|
} while (j >= NP);
|
|
}
|
|
fillbuf((int) pt_len[j]);
|
|
if (j != 0) j = ((unsigned) 1 << (j - 1)) + getbits((int) (j - 1));
|
|
return j;
|
|
}
|
|
|
|
local void huf_decode_start()
|
|
{
|
|
init_getbits(); blocksize = 0;
|
|
}
|
|
|
|
/***********************************************************
|
|
decode.c
|
|
***********************************************************/
|
|
|
|
local int j; /* remaining bytes to copy */
|
|
local int done; /* set at end of input */
|
|
|
|
local void decode_start()
|
|
{
|
|
huf_decode_start();
|
|
j = 0;
|
|
done = 0;
|
|
}
|
|
|
|
/* Decode the input and return the number of decoded bytes put in buffer
|
|
*/
|
|
local unsigned decode(count, buffer)
|
|
unsigned count;
|
|
uch buffer[];
|
|
/* The calling function must keep the number of
|
|
bytes to be processed. This function decodes
|
|
either 'count' bytes or 'DICSIZ' bytes, whichever
|
|
is smaller, into the array 'buffer[]' of size
|
|
'DICSIZ' or more.
|
|
Call decode_start() once for each new file
|
|
before calling this function.
|
|
*/
|
|
{
|
|
local unsigned i;
|
|
unsigned r, c;
|
|
|
|
r = 0;
|
|
while (--j >= 0) {
|
|
buffer[r] = buffer[i];
|
|
i = (i + 1) & (DICSIZ - 1);
|
|
if (++r == count) return r;
|
|
}
|
|
for ( ; ; ) {
|
|
c = decode_c();
|
|
if (c == NC) {
|
|
done = 1;
|
|
return r;
|
|
}
|
|
if (c <= UCHAR_MAX) {
|
|
buffer[r] = c;
|
|
if (++r == count) return r;
|
|
} else {
|
|
j = c - (UCHAR_MAX + 1 - THRESHOLD);
|
|
i = (r - decode_p() - 1) & (DICSIZ - 1);
|
|
while (--j >= 0) {
|
|
buffer[r] = buffer[i];
|
|
i = (i + 1) & (DICSIZ - 1);
|
|
if (++r == count) return r;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* ===========================================================================
|
|
* Unlzh in to out. Return OK or ERROR.
|
|
*/
|
|
int unlzh(in, out)
|
|
int in;
|
|
int out;
|
|
{
|
|
unsigned n;
|
|
ifd = in;
|
|
ofd = out;
|
|
|
|
decode_start();
|
|
while (!done) {
|
|
n = decode((unsigned) DICSIZ, window);
|
|
if (!test && n > 0) {
|
|
write_buf(out, (char*)window, n);
|
|
}
|
|
}
|
|
return OK;
|
|
}
|