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CMake/Utilities/cmcompress/cmcompress.c

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/*
* 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 */
static void cl_hash(struct cmcompress_stream* cdata, count_int hsize); /* reset code table */
static void cl_block (struct cmcompress_stream* cdata); /* table clear for block compress */
static void prratio( FILE *stream, long int num, long int den);
static void output(struct cmcompress_stream* cdata, code_int code);
static void writeerr();
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;
}
/*
* 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, 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;
}
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 = 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:
output(cdata, (code_int) cdata->ent );
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) = cdata->free_ent++; /* code -> hashtable */
htabof (i) = cdata->fcode;
}
else if ( (count_int)cdata->in_count >= cdata->checkpoint && cdata->block_compress )
{
cl_block (cdata);
}
}
return 1;
}
int cmcompress_compress_finalize(struct cmcompress_stream* cdata)
{
/*
* Put out the final code.
*/
output(cdata, (code_int)cdata->ent );
cdata->out_count++;
output(cdata, (code_int)-1 );
if(cdata->bytes_out > cdata->in_count) /* exit(2) if no savings */
{
return 0;
}
return 1;
}
void 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;
output (cdata, (code_int) CLEAR );
#ifdef DEBUG
if(cdata->debug)
{
fprintf ( stderr, "clear\n" );
}
#endif /* DEBUG */
}
}
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;
}
}
#if defined(DEBUG)
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
/*-
* 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 */
void 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 = (*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++ = code;
code >>= 8;
bits -= 8;
}
/* Last bits. */
if(bits)
{
*bp = 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 )
//putchar(*bp++);
//if (ferror(stdout))
{
writeerr();
}
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 )
//if( fwrite( buf, 1, cdata->n_bits, stdout ) != cdata->n_bits)
{
writeerr();
}
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 )
//if( fwrite( buf, 1, cdata->offset, stdout ) != cdata->offset )
{
writeerr();
}
cdata->bytes_out += cdata->offset;
}
cdata->offset = 0;
(void)fflush( stdout );
if( ferror( stdout ) )
{
writeerr();
}
#ifdef DEBUG
if ( verbose )
{
fprintf( stderr, "\n" );
}
#endif
}
}
void writeerr()
{
(void)fprintf(stderr, "compress: %s\n",
strerror(errno));
exit(1);
}
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