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HUF.C
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C/C++ Source or Header
|
1994-02-04
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8KB
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492 lines
/***********************************************************
huf.c -- new static Huffman
***********************************************************/
#include "lh386.h"
#include <stdlib.h>
#include <dos.h>
#include "slidehuf.h"
#ifdef __HIGHC__
# pragma On(Print_reg_vars);
# pragma On(Align_labels);
#endif
#ifdef __HIGHC__
# ifndef PASCAL
# define PASCAL (_DEFAULT_CALLING_CONVENTION | _CALLEE_POPS_STACK)
# endif
#endif
#ifdef __HIGHC__
# pragma Calling_convention(PASCAL);
#endif
static void write_pt_len(short n, short nbit, short i_special);
static void write_c_len(void);
static void encode_c(short c);
static void encode_p(ushort p);
static void send_block(void);
static void read_pt_len(short nn, short nbit, short i_special);
static void read_c_len(void);
#ifdef __HIGHC__
# pragma Calling_convention();
#endif
#define NP (MAX_DICBIT + 1)
#define NT (USHRT_BIT + 3)
#define PBIT 4 /* smallest integer such that (1U << PBIT) > * NP */
#define TBIT 5 /* smallest integer such that (1U << TBIT) > * NT */
#define NPT 0x80
ushort left[2 * NC - 1], right[2 * NC - 1];
uchar c_len[NC], pt_len[NPT];
ushort c_freq[2 * NC - 1], c_table[4096], c_code[NC], p_freq[2 * NP - 1],
pt_table[256], pt_code[NPT], t_freq[2 * NT - 1];
static uchar *buf = NULL;
static ushort bufsiz = 0;
static ushort blocksize = 0;
/***** encoding *****/
static void count_t_freq(void)
{
REG short i;
short n;
for (i = 0; i < NT; i++)
t_freq[i] = 0;
n = NC;
while (n > 0 && c_len[n - 1] == 0)
n--;
i = 0;
while (i < n)
{
short k;
k = c_len[i++];
if (k == 0)
{
short count;
count = 1;
while (i < n && c_len[i] == 0)
{
i++;
count++;
}
if (count <= 2)
t_freq[0] += count;
else if (count <= 18)
t_freq[1]++;
else if (count == 19)
{
t_freq[0]++;
t_freq[1]++;
} else
t_freq[2]++;
} else
t_freq[k + 2]++;
}
}
static void write_pt_len(short n, short nbit, short i_special)
{
REG short i;
while (n > 0 && pt_len[n - 1] == 0)
n--;
putbits(nbit, n);
i = 0;
while (i < n)
{
REG short k;
k = pt_len[i++];
if (k <= 6)
putbits(3, k);
else
putbits(k - 3, USHRT_MAX << 1);
if (i == i_special)
{
while (i < 6 && pt_len[i] == 0)
i++;
putbits(2, i - 3);
}
}
}
static void write_c_len(void)
{
REG short i;
short n;
n = NC;
while (n > 0 && c_len[n - 1] == 0)
n--;
putbits(CBIT, n);
i = 0;
while (i < n)
{
short k;
k = c_len[i++];
if (k == 0)
{
short count;
count = 1;
while (i < n && c_len[i] == 0)
{
i++;
count++;
}
if (count <= 2)
{
for (k = 0; k < count; k++)
putcode(pt_len[0], pt_code[0]);
} else if (count <= 18)
{
putcode(pt_len[1], pt_code[1]);
putbits(4, count - 3);
} else if (count == 19)
{
putcode(pt_len[0], pt_code[0]);
putcode(pt_len[1], pt_code[1]);
putbits(4, 15);
} else
{
putcode(pt_len[2], pt_code[2]);
putbits(CBIT, count - 20);
}
} else
putcode(pt_len[k + 2], pt_code[k + 2]);
}
}
static void encode_c(short c)
{
putcode(c_len[c], c_code[c]);
}
static void encode_p(ushort p)
{
REG ushort c, q;
c = 0;
q = p;
while (q)
{
q >>= 1;
c++;
}
putcode(pt_len[c], pt_code[c]);
if (c > 1)
putbits(c - 1, p);
}
static void send_block(void)
{
REG ushort i;
ushort root, pos, size;
root = make_tree(NC, c_freq, c_len, c_code);
size = c_freq[root];
putbits(16, size);
if (root >= NC)
{
count_t_freq();
root = make_tree(NT, t_freq, pt_len, pt_code);
if (root >= NT)
{
write_pt_len(NT, TBIT, 3);
} else
{
putbits(TBIT, 0);
putbits(TBIT, root);
}
write_c_len();
} else
{
putbits(TBIT, 0);
putbits(TBIT, 0);
putbits(CBIT, 0);
putbits(CBIT, root);
}
root = make_tree(NP, p_freq, pt_len, pt_code);
if (root >= NP)
{
write_pt_len(NP, PBIT, -1);
} else
{
putbits(PBIT, 0);
putbits(PBIT, root);
}
pos = 0;
for (i = 0; i < size; i++)
{
REG uchar flags;
if (i % CHAR_BIT == 0)
flags = buf[pos++];
else
flags <<= 1;
if (flags & (1U << (CHAR_BIT - 1)))
{
ushort k;
encode_c(buf[pos++] + (1U << CHAR_BIT));
k = buf[pos++] << CHAR_BIT;
k += buf[pos++];
encode_p(k);
} else
encode_c(buf[pos++]);
if (unpackable)
return;
}
for (i = 0; i < NC; i++)
c_freq[i] = 0;
for (i = 0; i < NP; i++)
p_freq[i] = 0;
}
static ushort output_pos = 0, output_mask = 0;
void output_st1(ushort c, ushort p)
{
static ushort cpos;
if ((output_mask >>= 1) == 0)
{
output_mask = 1U << (CHAR_BIT - 1);
if (output_pos >= bufsiz - 3 * CHAR_BIT)
{
send_block();
if (unpackable)
return;
output_pos = 0;
}
cpos = output_pos++;
buf[cpos] = 0;
}
buf[output_pos++] = (uchar) c;
c_freq[c]++;
if (c >= (1U << CHAR_BIT))
{
buf[cpos] |= output_mask;
buf[output_pos++] = (uchar) (p >> CHAR_BIT);
buf[output_pos++] = (uchar) p;
c = 0;
while (p)
{
p >>= 1;
c++;
}
p_freq[c]++;
}
}
void *alloc_buf(void)
{
bufsiz = 0xFFF0u; /* 16 * 1024u; */
while ((buf = malloc(bufsiz)) == NULL)
{
bufsiz = (bufsiz / 10U) * 9U;
if (bufsiz < 4 * 1024U)
break;
}
return buf;
}
void encode_start_st1(void)
{
REG int i;
for (i = 0; i < NC; i++)
c_freq[i] = 0;
for (i = 0; i < NP; i++)
p_freq[i] = 0;
output_pos = output_mask = 0;
init_putbits();
buf[0] = 0;
}
void encode_end_st1(void)
{
if (!unpackable)
{
send_block();
putbits(CHAR_BIT - 1, 0); /* flush remaining bits */
}
}
/***** decoding *****/
static void read_pt_len(short nn, short nbit, short i_special)
{
REG short i, c, n;
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 >> (16 - 3);
if (c == 7)
{
ushort mask = 1U << (16 - 4);
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);
}
}
static void read_c_len(void)
{
REG short i, c, n;
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 >> (16 - 8)];
if (c >= NT)
{
ushort mask = 1U << (16 - 9);
do
{
if (bitbuf & mask)
c = right[c];
else
c = left[c];
mask >>= 1;
} while (c >= NT);
}
fillbuf(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);
}
}
ushort decode_c_st1(void)
{
REG ushort j, mask;
if (blocksize == 0)
{
blocksize = getbits(16);
read_pt_len(NT, TBIT, 3);
read_c_len();
read_pt_len(NP, PBIT, -1);
}
blocksize--;
j = c_table[bitbuf >> 4];
if (j < NC)
fillbuf(c_len[j]);
else
{
fillbuf(12);
mask = 1U << (16 - 1);
do
{
if (bitbuf & mask)
j = right[j];
else
j = left[j];
mask >>= 1;
} while (j >= NC);
fillbuf(c_len[j] - 12);
}
return j;
}
ushort decode_p_st1(void)
{
REG ushort j, mask;
j = pt_table[bitbuf >> (16 - 8)];
if (j < NP)
fillbuf(pt_len[j]);
else
{
fillbuf(8);
mask = 1U << (16 - 1);
do
{
if (bitbuf & mask)
j = right[j];
else
j = left[j];
mask >>= 1;
} while (j >= NP);
fillbuf(pt_len[j] - 8);
}
if (j != 0)
j = (1U << (j