You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
552 lines
14 KiB
552 lines
14 KiB
/*
|
|
* Copyright (c) 1985, 1986 The Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* James A. Woods, derived from original work by Spencer Thomas
|
|
* and Joseph Orost.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "cmcompress.h"
|
|
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
|
|
static const char_type magic_header[] = { "\037\235" }; /* 1F 9D */
|
|
|
|
/* Defines for third byte of header */
|
|
#define BIT_MASK 0x1f
|
|
#define BLOCK_MASK 0x80
|
|
#define CHECK_GAP 10000 /* ratio check interval */
|
|
/* Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is
|
|
a fourth header byte (for expansion).
|
|
*/
|
|
#define INIT_BITS 9 /* initial number of bits/code */
|
|
|
|
#ifdef COMPATIBLE /* But wrong! */
|
|
# define MAXCODE(n_bits) (1 << (n_bits) - 1)
|
|
#else
|
|
# define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
|
|
#endif /* COMPATIBLE */
|
|
|
|
#define htabof(i) cdata->htab[i]
|
|
#define codetabof(i) cdata->codetab[i]
|
|
|
|
/*
|
|
* the next two codes should not be changed lightly, as they must not
|
|
* lie within the contiguous general code space.
|
|
*/
|
|
#define FIRST 257 /* first free entry */
|
|
#define CLEAR 256 /* table clear output code */
|
|
|
|
#ifdef DEBUG
|
|
static void prratio( FILE *stream, long int num, long int den);
|
|
#endif
|
|
|
|
int cmcompress_compress_initialize(struct cmcompress_stream* cdata)
|
|
{
|
|
cdata->maxbits = BITS; /* user settable max # bits/code */
|
|
cdata->maxmaxcode = 1 << BITS; /* should NEVER generate this code */
|
|
cdata->hsize = HSIZE; /* for dynamic table sizing */
|
|
cdata->free_ent = 0; /* first unused entry */
|
|
cdata->nomagic = 0; /* Use a 3-byte magic number header, unless old file */
|
|
cdata->block_compress = BLOCK_MASK;
|
|
cdata->clear_flg = 0;
|
|
cdata->ratio = 0;
|
|
cdata->checkpoint = CHECK_GAP;
|
|
|
|
cdata->input_stream = 0;
|
|
cdata->output_stream = 0;
|
|
cdata->client_data = 0;
|
|
return 1;
|
|
}
|
|
|
|
static void cl_hash(struct cmcompress_stream* cdata, count_int hsize) /* reset code table */
|
|
{
|
|
register count_int *htab_p = cdata->htab+hsize;
|
|
register long i;
|
|
register long m1 = -1;
|
|
|
|
i = hsize - 16;
|
|
do
|
|
{ /* might use Sys V memset(3) here */
|
|
*(htab_p-16) = m1;
|
|
*(htab_p-15) = m1;
|
|
*(htab_p-14) = m1;
|
|
*(htab_p-13) = m1;
|
|
*(htab_p-12) = m1;
|
|
*(htab_p-11) = m1;
|
|
*(htab_p-10) = m1;
|
|
*(htab_p-9) = m1;
|
|
*(htab_p-8) = m1;
|
|
*(htab_p-7) = m1;
|
|
*(htab_p-6) = m1;
|
|
*(htab_p-5) = m1;
|
|
*(htab_p-4) = m1;
|
|
*(htab_p-3) = m1;
|
|
*(htab_p-2) = m1;
|
|
*(htab_p-1) = m1;
|
|
htab_p -= 16;
|
|
}
|
|
while ((i -= 16) >= 0);
|
|
for ( i += 16; i > 0; i-- )
|
|
{
|
|
*--htab_p = m1;
|
|
}
|
|
}
|
|
|
|
/*-
|
|
* Output the given code.
|
|
* Inputs:
|
|
* code: A n_bits-bit integer. If == -1, then EOF. This assumes
|
|
* that n_bits =< (long)wordsize - 1.
|
|
* Outputs:
|
|
* Outputs code to the file.
|
|
* Assumptions:
|
|
* Chars are 8 bits long.
|
|
* Algorithm:
|
|
* Maintain a BITS character long buffer (so that 8 codes will
|
|
* fit in it exactly). Use the VAX insv instruction to insert each
|
|
* code in turn. When the buffer fills up empty it and start over.
|
|
*/
|
|
|
|
static char buf[BITS];
|
|
|
|
#ifndef vax
|
|
char_type lmask[9] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
|
|
char_type rmask[9] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
|
|
#endif /* vax */
|
|
|
|
static int output(struct cmcompress_stream* cdata, code_int code)
|
|
{
|
|
#ifdef DEBUG
|
|
static int col = 0;
|
|
#endif /* DEBUG */
|
|
|
|
/*
|
|
* On the VAX, it is important to have the register declarations
|
|
* in exactly the order given, or the asm will break.
|
|
*/
|
|
register int r_off = cdata->offset, bits= cdata->n_bits;
|
|
register char * bp = buf;
|
|
|
|
#ifdef DEBUG
|
|
if ( verbose )
|
|
{
|
|
fprintf( stderr, "%5d%c", code,
|
|
(col+=6) >= 74 ? (col = 0, '\n') : ' ' );
|
|
}
|
|
#endif /* DEBUG */
|
|
if ( code >= 0 )
|
|
{
|
|
#if defined(vax) && !defined(__GNUC__)
|
|
/*
|
|
* VAX and PCC DEPENDENT!! Implementation on other machines is
|
|
* below.
|
|
*
|
|
* Translation: Insert BITS bits from the argument starting at
|
|
* cdata->offset bits from the beginning of buf.
|
|
*/
|
|
0; /* Work around for pcc -O bug with asm and if stmt */
|
|
asm( "insv 4(ap),r11,r10,(r9)" );
|
|
#else
|
|
/*
|
|
* byte/bit numbering on the VAX is simulated by the following code
|
|
*/
|
|
/*
|
|
* Get to the first byte.
|
|
*/
|
|
bp += (r_off >> 3);
|
|
r_off &= 7;
|
|
/*
|
|
* Since code is always >= 8 bits, only need to mask the first
|
|
* hunk on the left.
|
|
*/
|
|
*bp = (char)((*bp & rmask[r_off]) | ((code << r_off) & lmask[r_off]));
|
|
bp++;
|
|
bits -= (8 - r_off);
|
|
code >>= 8 - r_off;
|
|
/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
|
|
if ( bits >= 8 )
|
|
{
|
|
*bp++ = (char)(code);
|
|
code >>= 8;
|
|
bits -= 8;
|
|
}
|
|
/* Last bits. */
|
|
if(bits)
|
|
{
|
|
*bp = (char)(code);
|
|
}
|
|
#endif /* vax */
|
|
cdata->offset += cdata->n_bits;
|
|
if ( cdata->offset == (cdata->n_bits << 3) )
|
|
{
|
|
bp = buf;
|
|
bits = cdata->n_bits;
|
|
cdata->bytes_out += bits;
|
|
do
|
|
{
|
|
if ( cdata->output_stream(cdata, bp, 1) != 1 )
|
|
{
|
|
return 0;
|
|
}
|
|
bp++;
|
|
}
|
|
while(--bits);
|
|
cdata->offset = 0;
|
|
}
|
|
|
|
/*
|
|
* If the next entry is going to be too big for the code size,
|
|
* then increase it, if possible.
|
|
*/
|
|
if ( cdata->free_ent > cdata->maxcode || (cdata->clear_flg > 0))
|
|
{
|
|
/*
|
|
* Write the whole buffer, because the input side won't
|
|
* discover the size increase until after it has read it.
|
|
*/
|
|
if ( cdata->offset > 0 )
|
|
{
|
|
if ( cdata->output_stream(cdata, buf, cdata->n_bits) != cdata->n_bits )
|
|
{
|
|
return 0;
|
|
}
|
|
cdata->bytes_out += cdata->n_bits;
|
|
}
|
|
cdata->offset = 0;
|
|
|
|
if ( cdata->clear_flg )
|
|
{
|
|
cdata->maxcode = MAXCODE (cdata->n_bits = INIT_BITS);
|
|
cdata->clear_flg = 0;
|
|
}
|
|
else
|
|
{
|
|
cdata->n_bits++;
|
|
if ( cdata->n_bits == cdata->maxbits )
|
|
{
|
|
cdata->maxcode = cdata->maxmaxcode;
|
|
}
|
|
else
|
|
{
|
|
cdata->maxcode = MAXCODE(cdata->n_bits);
|
|
}
|
|
}
|
|
#ifdef DEBUG
|
|
if ( debug )
|
|
{
|
|
fprintf( stderr, "\nChange to %d bits\n", cdata->n_bits );
|
|
col = 0;
|
|
}
|
|
#endif /* DEBUG */
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/*
|
|
* At EOF, write the rest of the buffer.
|
|
*/
|
|
if ( cdata->offset > 0 )
|
|
{
|
|
cdata->offset = (cdata->offset + 7) / 8;
|
|
if ( cdata->output_stream(cdata, buf, cdata->offset ) != cdata->offset )
|
|
{
|
|
return 0;
|
|
}
|
|
cdata->bytes_out += cdata->offset;
|
|
}
|
|
cdata->offset = 0;
|
|
(void)fflush( stdout );
|
|
if( ferror( stdout ) )
|
|
{
|
|
return 0;
|
|
}
|
|
#ifdef DEBUG
|
|
if ( verbose )
|
|
{
|
|
fprintf( stderr, "\n" );
|
|
}
|
|
#endif
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* compress stdin to stdout
|
|
*
|
|
* Algorithm: use open addressing double hashing (no chaining) on the
|
|
* prefix code / next character combination. We do a variant of Knuth's
|
|
* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
|
|
* secondary probe. Here, the modular division first probe is gives way
|
|
* to a faster exclusive-or manipulation. Also do block compression with
|
|
* an adaptive reset, whereby the code table is cleared when the compression
|
|
* ratio decreases, but after the table fills. The variable-length output
|
|
* codes are re-sized at this point, and a special CLEAR code is generated
|
|
* for the decompressor. Late addition: construct the table according to
|
|
* file size for noticeable speed improvement on small files. Please direct
|
|
* questions about this implementation to ames!jaw.
|
|
*/
|
|
|
|
int cmcompress_compress_start(struct cmcompress_stream* cdata)
|
|
{
|
|
#ifndef COMPATIBLE
|
|
if (cdata->nomagic == 0)
|
|
{
|
|
char headLast = (char)(cdata->maxbits | cdata->block_compress);
|
|
cdata->output_stream(cdata, (const char*)magic_header, 2);
|
|
cdata->output_stream(cdata, &headLast, 1);
|
|
if(ferror(stdout))
|
|
{
|
|
printf("Error...\n");
|
|
}
|
|
}
|
|
#endif /* COMPATIBLE */
|
|
|
|
cdata->offset = 0;
|
|
cdata->bytes_out = 3; /* includes 3-byte header mojo */
|
|
cdata->out_count = 0;
|
|
cdata->clear_flg = 0;
|
|
cdata->ratio = 0;
|
|
cdata->in_count = 1;
|
|
cdata->checkpoint = CHECK_GAP;
|
|
cdata->maxcode = MAXCODE(cdata->n_bits = INIT_BITS);
|
|
cdata->free_ent = ((cdata->block_compress) ? FIRST : 256 );
|
|
|
|
cdata->first_pass = 1;
|
|
|
|
cdata->hshift = 0;
|
|
for ( cdata->fcode = (long) cdata->hsize; cdata->fcode < 65536L; cdata->fcode *= 2L )
|
|
{
|
|
cdata->hshift++;
|
|
}
|
|
cdata->hshift = 8 - cdata->hshift; /* set hash code range bound */
|
|
|
|
cdata->hsize_reg = cdata->hsize;
|
|
cl_hash(cdata, (count_int) cdata->hsize_reg); /* clear hash table */
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int cl_block (struct cmcompress_stream* cdata) /* table clear for block compress */
|
|
{
|
|
register long int rat;
|
|
|
|
cdata->checkpoint = cdata->in_count + CHECK_GAP;
|
|
#ifdef DEBUG
|
|
if ( cdata->debug )
|
|
{
|
|
fprintf ( stderr, "count: %ld, ratio: ", cdata->in_count );
|
|
prratio ( stderr, cdata->in_count, cdata->bytes_out );
|
|
fprintf ( stderr, "\n");
|
|
}
|
|
#endif /* DEBUG */
|
|
|
|
if(cdata->in_count > 0x007fffff)
|
|
{ /* shift will overflow */
|
|
rat = cdata->bytes_out >> 8;
|
|
if(rat == 0)
|
|
{ /* Don't divide by zero */
|
|
rat = 0x7fffffff;
|
|
}
|
|
else
|
|
{
|
|
rat = cdata->in_count / rat;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
rat = (cdata->in_count << 8) / cdata->bytes_out; /* 8 fractional bits */
|
|
}
|
|
if ( rat > cdata->ratio )
|
|
{
|
|
cdata->ratio = rat;
|
|
}
|
|
else
|
|
{
|
|
cdata->ratio = 0;
|
|
#ifdef DEBUG
|
|
if(cdata->verbose)
|
|
{
|
|
dump_tab(); /* dump string table */
|
|
}
|
|
#endif
|
|
cl_hash (cdata, (count_int) cdata->hsize );
|
|
cdata->free_ent = FIRST;
|
|
cdata->clear_flg = 1;
|
|
if ( !output (cdata, (code_int) CLEAR ) )
|
|
{
|
|
return 0;
|
|
}
|
|
#ifdef DEBUG
|
|
if(cdata->debug)
|
|
{
|
|
fprintf ( stderr, "clear\n" );
|
|
}
|
|
#endif /* DEBUG */
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
|
|
int cmcompress_compress(struct cmcompress_stream* cdata, void* buff, size_t n)
|
|
{
|
|
register code_int i;
|
|
register int c;
|
|
register int disp;
|
|
|
|
unsigned char* input_buffer = (unsigned char*)buff;
|
|
|
|
size_t cc;
|
|
|
|
/*printf("cmcompress_compress(%p, %p, %d)\n", cdata, buff, n);*/
|
|
|
|
if ( cdata->first_pass )
|
|
{
|
|
cdata->ent = input_buffer[0];
|
|
++ input_buffer;
|
|
-- n;
|
|
cdata->first_pass = 0;
|
|
}
|
|
|
|
for ( cc = 0; cc < n; ++ cc )
|
|
{
|
|
c = input_buffer[cc];
|
|
cdata->in_count++;
|
|
cdata->fcode = (long) (((long) c << cdata->maxbits) + cdata->ent);
|
|
i = ((c << cdata->hshift) ^ cdata->ent); /* xor hashing */
|
|
|
|
if ( htabof (i) == cdata->fcode )
|
|
{
|
|
cdata->ent = codetabof (i);
|
|
continue;
|
|
}
|
|
else if ( (long)htabof (i) < 0 ) /* empty slot */
|
|
{
|
|
goto nomatch;
|
|
}
|
|
disp = (int)(cdata->hsize_reg - i); /* secondary hash (after G. Knott) */
|
|
if ( i == 0 )
|
|
{
|
|
disp = 1;
|
|
}
|
|
probe:
|
|
if ( (i -= disp) < 0 )
|
|
{
|
|
i += cdata->hsize_reg;
|
|
}
|
|
|
|
if ( htabof (i) == cdata->fcode )
|
|
{
|
|
cdata->ent = codetabof (i);
|
|
continue;
|
|
}
|
|
if ( (long)htabof (i) > 0 )
|
|
{
|
|
goto probe;
|
|
}
|
|
nomatch:
|
|
if ( !output(cdata, (code_int) cdata->ent ) )
|
|
{
|
|
return 0;
|
|
}
|
|
cdata->out_count++;
|
|
cdata->ent = c;
|
|
if (
|
|
#ifdef SIGNED_COMPARE_SLOW
|
|
(unsigned) cdata->free_ent < (unsigned) cdata->maxmaxcode
|
|
#else
|
|
cdata->free_ent < cdata->maxmaxcode
|
|
#endif
|
|
)
|
|
{
|
|
codetabof (i) = (unsigned short)(cdata->free_ent++); /* code -> hashtable */
|
|
htabof (i) = cdata->fcode;
|
|
}
|
|
else if ( (count_int)cdata->in_count >= cdata->checkpoint && cdata->block_compress )
|
|
{
|
|
if ( !cl_block (cdata) )
|
|
{
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int cmcompress_compress_finalize(struct cmcompress_stream* cdata)
|
|
{
|
|
/*
|
|
* Put out the final code.
|
|
*/
|
|
if ( !output(cdata, (code_int)cdata->ent ) )
|
|
{
|
|
return 0;
|
|
}
|
|
cdata->out_count++;
|
|
if ( !output(cdata, (code_int)-1 ) )
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
if(cdata->bytes_out > cdata->in_count) /* exit(2) if no savings */
|
|
{
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
|
|
#if defined(DEBUG)
|
|
static void prratio(FILE *stream, long int num, long int den)
|
|
{
|
|
register int q; /* Doesn't need to be long */
|
|
|
|
if(num > 214748L)
|
|
{ /* 2147483647/10000 */
|
|
q = num / (den / 10000L);
|
|
}
|
|
else
|
|
{
|
|
q = 10000L * num / den; /* Long calculations, though */
|
|
}
|
|
if (q < 0)
|
|
{
|
|
putc('-', stream);
|
|
q = -q;
|
|
}
|
|
fprintf(stream, "%d.%02d%%", q / 100, q % 100);
|
|
}
|
|
#endif
|
|
|