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/* ------------------------------------------------------------------------ */
/* LHa for UNIX */
/* shuf.c -- extract static Huffman coding */
/* */
/* Modified Nobutaka Watazaki */
/* */
/* Ver. 1.14 Source All chagned 1995.01.14 N.Watazaki */
/* ------------------------------------------------------------------------ */
#include "lha.h"
/* ------------------------------------------------------------------------ */
#undef NP
#undef NP2
#define NP (8 * 1024 / 64)
#define NP2 (NP * 2 - 1)
/* ------------------------------------------------------------------------ */
static unsigned int np;
int fixed[2][16] = {
{3, 0x01, 0x04, 0x0c, 0x18, 0x30, 0}, /* old compatible */
{2, 0x01, 0x01, 0x03, 0x06, 0x0D, 0x1F, 0x4E, 0} /* 8K buf */
};
/* ------------------------------------------------------------------------ */
void
decode_start_st0( /*void*/ )
{
n_max = 286;
maxmatch = MAXMATCH;
init_getbits();
np = 1 << (MAX_DICBIT - 6);
}
/* ------------------------------------------------------------------------ */
void
encode_p_st0(j)
unsigned short j;
{
unsigned short i;
i = j >> 6;
putcode(pt_len[i], pt_code[i]);
putbits(6, j & 0x3f);
}
/* ------------------------------------------------------------------------ */
static void
ready_made(method)
int method;
{
int i, j;
unsigned int code, weight;
int *tbl;
tbl = fixed[method];
j = *tbl++;
weight = 1 << (16 - j);
code = 0;
for (i = 0; i < np; i++) {
while (*tbl == i) {
j++;
tbl++;
weight >>= 1;
}
pt_len[i] = j;
pt_code[i] = code;
code += weight;
}
}
/* ------------------------------------------------------------------------ */
void
encode_start_fix( /*void*/ )
{
n_max = 314;
maxmatch = 60;
np = 1 << (12 - 6);
init_putbits();
start_c_dyn();
ready_made(0);
}
/* ------------------------------------------------------------------------ */
static void
read_tree_c( /*void*/ )
{ /* read tree from file */
int i, c;
i = 0;
while (i < N1) {
if (getbits(1))
c_len[i] = getbits(LENFIELD) + 1;
else
c_len[i] = 0;
if (++i == 3 && c_len[0] == 1 && c_len[1] == 1 && c_len[2] == 1) {
c = getbits(CBIT);
for (i = 0; i < N1; i++)
c_len[i] = 0;
for (i = 0; i < 4096; i++)
c_table[i] = c;
return;
}
}
make_table(N1, c_len, 12, c_table);
}
/* ------------------------------------------------------------------------ */
static void
read_tree_p(/*void*/)
{ /* read tree from file */
int i, c;
i = 0;
while (i < NP) {
pt_len[i] = getbits(LENFIELD);
if (++i == 3 && pt_len[0] == 1 && pt_len[1] == 1 && pt_len[2] == 1) {
c = getbits(MAX_DICBIT - 6);
for (i = 0; i < NP; i++)
c_len[i] = 0;
for (i = 0; i < 256; i++)
c_table[i] = c;
return;
}
}
}
/* ------------------------------------------------------------------------ */
void
decode_start_fix(/*void*/)
{
n_max = 314;
maxmatch = 60;
init_getbits();
np = 1 << (12 - 6);
start_c_dyn();
ready_made(0);
make_table(np, pt_len, 8, pt_table);
}
/* ------------------------------------------------------------------------ */
unsigned short
decode_c_st0(/*void*/)
{
int i, j;
static unsigned short blocksize = 0;
if (blocksize == 0) { /* read block head */
blocksize = getbits(BUFBITS); /* read block blocksize */
read_tree_c();
if (getbits(1)) {
read_tree_p();
}
else {
ready_made(1);
}
make_table(NP, pt_len, 8, pt_table);
}
blocksize--;
j = c_table[bitbuf >> 4];
if (j < N1)
fillbuf(c_len[j]);
else {
fillbuf(12);
i = bitbuf;
do {
if ((short) i < 0)
j = right[j];
else
j = left[j];
i <<= 1;
} while (j >= N1);
fillbuf(c_len[j] - 12);
}
if (j == N1 - 1)
j += getbits(EXTRABITS);
return j;
}
/* ------------------------------------------------------------------------ */
unsigned short
decode_p_st0(/*void*/)
{
int i, j;
j = pt_table[bitbuf >> 8];
if (j < np) {
fillbuf(pt_len[j]);
}
else {
fillbuf(8);
i = bitbuf;
do {
if ((short) i < 0)
j = right[j];
else
j = left[j];
i <<= 1;
} while (j >= np);
fillbuf(pt_len[j] - 8);
}
return (j << 6) + getbits(6);
}
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