OpenBSD-4.6/usr.bin/compress/zopen.c
/* $OpenBSD: zopen.c,v 1.17 2005/08/25 17:07:56 millert Exp $ */
/* $NetBSD: zopen.c,v 1.5 1995/03/26 09:44:53 glass Exp $ */
/*-
* Copyright (c) 1985, 1986, 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Diomidis Spinellis and 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. 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.
*
* From: @(#)zopen.c 8.1 (Berkeley) 6/27/93
*/
#if 0
static char sccsid[] = "@(#)zopen.c 8.1 (Berkeley) 6/27/93";
#else
const char z_rcsid[] =
"$OpenBSD: zopen.c,v 1.17 2005/08/25 17:07:56 millert Exp $";
#endif
/*-
* fcompress.c - File compression ala IEEE Computer, June 1984.
*
* Compress authors:
* Spencer W. Thomas (decvax!utah-cs!thomas)
* Jim McKie (decvax!mcvax!jim)
* Steve Davies (decvax!vax135!petsd!peora!srd)
* Ken Turkowski (decvax!decwrl!turtlevax!ken)
* James A. Woods (decvax!ihnp4!ames!jaw)
* Joe Orost (decvax!vax135!petsd!joe)
*
* Cleaned up and converted to library returning I/O streams by
* Diomidis Spinellis <dds@doc.ic.ac.uk>.
*
* zopen(filename, mode, bits)
* Returns a FILE * that can be used for read or write. The modes
* supported are only "r" and "w". Seeking is not allowed. On
* reading the file is decompressed, on writing it is compressed.
* The output is compatible with compress(1) with 16 bit tables.
* Any file produced by compress(1) can be read.
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "compress.h"
#define BITS 16 /* Default bits. */
#define HSIZE 69001 /* 95% occupancy */
#define ZBUFSIZ 8192 /* I/O buffer size */
/* A code_int must be able to hold 2**BITS values of type int, and also -1. */
typedef long code_int;
typedef long count_int;
static const u_char z_magic[] =
{'\037', '\235'}; /* 1F 9D */
#define BIT_MASK 0x1f /* Defines for third byte of header. */
#define BLOCK_MASK 0x80
/*
* 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. */
#define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
struct s_zstate {
int zs_fd; /* File stream for I/O */
char zs_mode; /* r or w */
enum {
S_START, S_MAGIC, S_MIDDLE, S_EOF
} zs_state; /* State of computation */
int zs_n_bits; /* Number of bits/code. */
int zs_maxbits; /* User settable max # bits/code. */
code_int zs_maxcode; /* Maximum code, given n_bits. */
code_int zs_maxmaxcode; /* Should NEVER generate this code. */
count_int zs_htab[HSIZE];
u_short zs_codetab[HSIZE];
code_int zs_hsize; /* For dynamic table sizing. */
code_int zs_free_ent; /* First unused entry. */
/*
* Block compression parameters -- after all codes are used up,
* and compression rate changes, start over.
*/
int zs_block_compress;
int zs_clear_flg;
long zs_ratio;
count_int zs_checkpoint;
long zs_in_count; /* Length of input. */
long zs_bytes_out; /* Length of output. */
long zs_out_count; /* # of codes output (for debugging).*/
u_char zs_buf[ZBUFSIZ]; /* I/O buffer */
u_char *zs_bp; /* Current I/O window in the zs_buf */
int zs_offset; /* Number of bits in the zs_buf */
union {
struct {
long zs_fcode;
code_int zs_ent;
code_int zs_hsize_reg;
int zs_hshift;
} w; /* Write parameters */
struct {
u_char *zs_stackp, *zs_ebp;
int zs_finchar;
code_int zs_code, zs_oldcode, zs_incode;
int zs_size;
} r; /* Read parameters */
} u;
};
/* Definitions to retain old variable names */
#define zs_fcode u.w.zs_fcode
#define zs_ent u.w.zs_ent
#define zs_hsize_reg u.w.zs_hsize_reg
#define zs_hshift u.w.zs_hshift
#define zs_stackp u.r.zs_stackp
#define zs_finchar u.r.zs_finchar
#define zs_code u.r.zs_code
#define zs_oldcode u.r.zs_oldcode
#define zs_incode u.r.zs_incode
#define zs_size u.r.zs_size
#define zs_ebp u.r.zs_ebp
/*
* To save much memory, we overlay the table used by compress() with those
* used by decompress(). The tab_prefix table is the same size and type as
* the codetab. The tab_suffix table needs 2**BITS characters. We get this
* from the beginning of htab. The output stack uses the rest of htab, and
* contains characters. There is plenty of room for any possible stack
* (stack used to be 8000 characters).
*/
#define htabof(i) zs->zs_htab[i]
#define codetabof(i) zs->zs_codetab[i]
#define tab_prefixof(i) codetabof(i)
#define tab_suffixof(i) ((u_char *)(zs->zs_htab))[i]
#define de_stack ((u_char *)&tab_suffixof(1 << BITS))
#define CHECK_GAP 10000 /* Ratio check interval. */
/*
* 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 int cl_block(struct s_zstate *);
static void cl_hash(struct s_zstate *, count_int);
static code_int getcode(struct s_zstate *);
static int output(struct s_zstate *, code_int);
/*-
* Algorithm from "A Technique for High Performance Data Compression",
* Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
*
* Algorithm:
* Modified Lempel-Ziv method (LZW). Basically finds common
* substrings and replaces them with a variable size code. This is
* deterministic, and can be done on the fly. Thus, the decompression
* procedure needs no input table, but tracks the way the table was built.
*/
/*-
* compress write
*
* 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
zwrite(void *cookie, const char *wbp, int num)
{
code_int i;
int c, disp;
struct s_zstate *zs;
const u_char *bp;
u_char tmp;
int count;
zs = cookie;
count = num;
bp = (u_char *)wbp;
switch (zs->zs_state) {
case S_MAGIC:
return -1;
case S_EOF:
return 0;
case S_START:
zs->zs_state = S_MIDDLE;
zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
if (write(zs->zs_fd, z_magic, sizeof(z_magic)) !=
sizeof(z_magic))
return (-1);
tmp = (u_char)(zs->zs_maxbits | zs->zs_block_compress);
if (write(zs->zs_fd, &tmp, sizeof(tmp)) != sizeof(tmp))
return (-1);
zs->zs_bp = zs->zs_buf;
zs->zs_offset = 0;
zs->zs_bytes_out = 3; /* Includes 3-byte header mojo. */
zs->zs_out_count = 0;
zs->zs_clear_flg = 0;
zs->zs_ratio = 0;
zs->zs_in_count = 1;
zs->zs_checkpoint = CHECK_GAP;
zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
zs->zs_free_ent = ((zs->zs_block_compress) ? FIRST : 256);
zs->zs_ent = *bp++;
--count;
zs->zs_hshift = 0;
for (zs->zs_fcode = (long)zs->zs_hsize; zs->zs_fcode < 65536L;
zs->zs_fcode *= 2L)
zs->zs_hshift++;
/* Set hash code range bound. */
zs->zs_hshift = 8 - zs->zs_hshift;
zs->zs_hsize_reg = zs->zs_hsize;
/* Clear hash table. */
cl_hash(zs, (count_int)zs->zs_hsize_reg);
case S_MIDDLE:
for (i = 0; count-- > 0;) {
c = *bp++;
zs->zs_in_count++;
zs->zs_fcode = (long)(((long)c << zs->zs_maxbits) +
zs->zs_ent);
/* Xor hashing. */
i = ((c << zs->zs_hshift) ^ zs->zs_ent);
if (htabof(i) == zs->zs_fcode) {
zs->zs_ent = codetabof(i);
continue;
} else if ((long)htabof(i) < 0) /* Empty slot. */
goto nomatch;
/* Secondary hash (after G. Knott). */
disp = zs->zs_hsize_reg - i;
if (i == 0)
disp = 1;
probe: if ((i -= disp) < 0)
i += zs->zs_hsize_reg;
if (htabof(i) == zs->zs_fcode) {
zs->zs_ent = codetabof(i);
continue;
}
if ((long)htabof(i) >= 0)
goto probe;
nomatch: if (output(zs, (code_int) zs->zs_ent) == -1)
return (-1);
zs->zs_out_count++;
zs->zs_ent = c;
if (zs->zs_free_ent < zs->zs_maxmaxcode) {
/* code -> hashtable */
codetabof(i) = zs->zs_free_ent++;
htabof(i) = zs->zs_fcode;
} else if ((count_int)zs->zs_in_count >=
zs->zs_checkpoint && zs->zs_block_compress) {
if (cl_block(zs) == -1)
return (-1);
}
}
}
return (num);
}
int
z_close(void *cookie, struct z_info *info, const char *name, struct stat *sb)
{
struct s_zstate *zs;
int rval;
zs = cookie;
if (zs->zs_mode == 'w') { /* Put out the final code. */
if (output(zs, (code_int) zs->zs_ent) == -1) {
(void)close(zs->zs_fd);
free(zs);
return (-1);
}
zs->zs_out_count++;
if (output(zs, (code_int) - 1) == -1) {
(void)close(zs->zs_fd);
free(zs);
return (-1);
}
}
if (info != NULL) {
info->mtime = 0;
info->crc = (u_int32_t)-1;
info->hlen = 0;
info->total_in = (off_t)zs->zs_in_count;
info->total_out = (off_t)zs->zs_bytes_out;
}
#ifndef SAVECORE
setfile(name, zs->zs_fd, sb);
#endif
rval = close(zs->zs_fd);
free(zs);
return (rval);
}
static int
zclose(void *cookie)
{
return z_close(cookie, NULL, NULL, NULL);
}
/*-
* 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 const u_char lmask[9] =
{0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
static const u_char rmask[9] =
{0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
static int
output(struct s_zstate *zs, code_int ocode)
{
int bits;
if (ocode >= 0) {
int r_off;
u_char *bp;
/* Get to the first byte. */
bp = zs->zs_bp + (zs->zs_offset >> 3);
r_off = zs->zs_offset & 7;
bits = zs->zs_n_bits;
/*
* Since ocode is always >= 8 bits, only need to mask the first
* hunk on the left.
*/
*bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
bp++;
bits -= (8 - r_off);
ocode >>= 8 - r_off;
/* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
if (bits >= 8) {
*bp++ = ocode;
ocode >>= 8;
bits -= 8;
}
/* Last bits. */
if (bits)
*bp = ocode;
zs->zs_offset += zs->zs_n_bits;
if (zs->zs_offset == (zs->zs_n_bits << 3)) {
zs->zs_bp += zs->zs_n_bits;
zs->zs_offset = 0;
}
/*
* If the next entry is going to be too big for the ocode size,
* then increase it, if possible.
*/
if (zs->zs_free_ent > zs->zs_maxcode ||
(zs->zs_clear_flg > 0)) {
/*
* Write the whole buffer, because the input side won't
* discover the size increase until after it has read it
*/
if (zs->zs_offset > 0) {
zs->zs_bp += zs->zs_n_bits;
zs->zs_offset = 0;
}
if (zs->zs_clear_flg) {
zs->zs_maxcode =
MAXCODE(zs->zs_n_bits = INIT_BITS);
zs->zs_clear_flg = 0;
} else {
zs->zs_n_bits++;
if (zs->zs_n_bits == zs->zs_maxbits)
zs->zs_maxcode = zs->zs_maxmaxcode;
else
zs->zs_maxcode =
MAXCODE(zs->zs_n_bits);
}
}
if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ]) {
bits = zs->zs_bp - zs->zs_buf;
if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
return (-1);
zs->zs_bytes_out += bits;
if (zs->zs_offset > 0)
fprintf (stderr, "zs_offset != 0\n");
zs->zs_bp = zs->zs_buf;
}
} else {
/* At EOF, write the rest of the buffer. */
if (zs->zs_offset > 0)
zs->zs_bp += (zs->zs_offset + 7) / 8;
if (zs->zs_bp > zs->zs_buf) {
bits = zs->zs_bp - zs->zs_buf;
if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
return (-1);
zs->zs_bytes_out += bits;
}
zs->zs_offset = 0;
zs->zs_bp = zs->zs_buf;
}
return (0);
}
/*
* Decompress read. This routine adapts to the codes in the file building
* the "string" table on-the-fly; requiring no table to be stored in the
* compressed file. The tables used herein are shared with those of the
* compress() routine. See the definitions above.
*/
int
zread(void *cookie, char *rbp, int num)
{
u_int count;
struct s_zstate *zs;
u_char *bp, header[3];
if (num == 0)
return (0);
zs = cookie;
count = num;
bp = (u_char *)rbp;
switch (zs->zs_state) {
case S_START:
zs->zs_state = S_MIDDLE;
zs->zs_bp = zs->zs_buf;
header[0] = header[1] = header[2] = '\0';
read(zs->zs_fd, header, sizeof(header));
break;
case S_MAGIC:
zs->zs_state = S_MIDDLE;
zs->zs_bp = zs->zs_buf;
header[0] = z_magic[0];
header[1] = z_magic[1];
header[2] = '\0';
read(zs->zs_fd, &header[2], 1);
break;
case S_MIDDLE:
goto middle;
case S_EOF:
goto eof;
}
/* Check the magic number */
if (header[0] != z_magic[0] || header[1] != z_magic[1]) {
errno = EFTYPE;
return (-1);
}
zs->zs_maxbits = header[2]; /* Set -b from file. */
zs->zs_in_count += sizeof(header);
zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;
zs->zs_maxbits &= BIT_MASK;
zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
if (zs->zs_maxbits > BITS) {
errno = EFTYPE;
return (-1);
}
/* As above, initialize the first 256 entries in the table. */
zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
for (zs->zs_code = 255; zs->zs_code >= 0; zs->zs_code--) {
tab_prefixof(zs->zs_code) = 0;
tab_suffixof(zs->zs_code) = (u_char) zs->zs_code;
}
zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
zs->zs_finchar = zs->zs_oldcode = getcode(zs);
if (zs->zs_oldcode == -1) /* EOF already? */
return (0); /* Get out of here */
/* First code must be 8 bits = char. */
*bp++ = (u_char)zs->zs_finchar;
count--;
zs->zs_stackp = de_stack;
while ((zs->zs_code = getcode(zs)) > -1) {
if ((zs->zs_code == CLEAR) && zs->zs_block_compress) {
for (zs->zs_code = 255; zs->zs_code >= 0;
zs->zs_code--)
tab_prefixof(zs->zs_code) = 0;
zs->zs_clear_flg = 1;
zs->zs_free_ent = FIRST - 1;
if ((zs->zs_code = getcode(zs)) == -1) /* O, untimely death! */
break;
}
zs->zs_incode = zs->zs_code;
/* Special case for KwKwK string. */
if (zs->zs_code >= zs->zs_free_ent) {
*zs->zs_stackp++ = zs->zs_finchar;
zs->zs_code = zs->zs_oldcode;
}
/* Generate output characters in reverse order. */
while (zs->zs_code >= 256) {
/*
* Bad input file may cause zs_stackp to overflow
* zs_htab; check here and abort decompression,
* that's better than dumping core.
*/
if (zs->zs_stackp >= (u_char *)&zs->zs_htab[HSIZE]) {
errno = EINVAL;
return (-1);
}
*zs->zs_stackp++ = tab_suffixof(zs->zs_code);
zs->zs_code = tab_prefixof(zs->zs_code);
}
*zs->zs_stackp++ = zs->zs_finchar = tab_suffixof(zs->zs_code);
/* And put them out in forward order. */
middle: do {
if (count-- == 0) {
zs->zs_bytes_out += num;
return (num);
}
*bp++ = *--zs->zs_stackp;
} while (zs->zs_stackp > de_stack);
/* Generate the new entry. */
if ((zs->zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
tab_prefixof(zs->zs_code) = (u_short) zs->zs_oldcode;
tab_suffixof(zs->zs_code) = zs->zs_finchar;
zs->zs_free_ent = zs->zs_code + 1;
}
/* Remember previous code. */
zs->zs_oldcode = zs->zs_incode;
}
zs->zs_state = S_EOF;
zs->zs_bytes_out += num - count;
eof: return (num - count);
}
/*-
* Read one code from the standard input. If EOF, return -1.
* Inputs:
* stdin
* Outputs:
* code or -1 is returned.
*/
static code_int
getcode(struct s_zstate *zs)
{
code_int gcode;
int r_off, bits;
u_char *bp;
if (zs->zs_clear_flg > 0 || zs->zs_offset >= zs->zs_size ||
zs->zs_free_ent > zs->zs_maxcode) {
zs->zs_bp += zs->zs_n_bits;
/*
* If the next entry will be too big for the current gcode
* size, then we must increase the size. This implies reading
* a new buffer full, too.
*/
if (zs->zs_free_ent > zs->zs_maxcode) {
zs->zs_n_bits++;
if (zs->zs_n_bits == zs->zs_maxbits) {
/* Won't get any bigger now. */
zs->zs_maxcode = zs->zs_maxmaxcode;
} else
zs->zs_maxcode = MAXCODE(zs->zs_n_bits);
}
if (zs->zs_clear_flg > 0) {
zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
zs->zs_clear_flg = 0;
}
/* fill the buffer up to the neck */
if (zs->zs_bp + zs->zs_n_bits > zs->zs_ebp) {
for (bp = zs->zs_buf; zs->zs_bp < zs->zs_ebp;
*bp++ = *zs->zs_bp++);
if ((bits = read(zs->zs_fd, bp, ZBUFSIZ -
(bp - zs->zs_buf))) < 0)
return -1;
zs->zs_in_count += bits;
zs->zs_bp = zs->zs_buf;
zs->zs_ebp = bp + bits;
}
zs->zs_offset = 0;
zs->zs_size = MIN(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp);
if (zs->zs_size == 0)
return -1;
/* Round size down to integral number of codes. */
zs->zs_size = (zs->zs_size << 3) - (zs->zs_n_bits - 1);
}
bp = zs->zs_bp;
r_off = zs->zs_offset;
bits = zs->zs_n_bits;
/* Get to the first byte. */
bp += (r_off >> 3);
r_off &= 7;
/* Get first part (low order bits). */
gcode = (*bp++ >> r_off);
bits -= (8 - r_off);
r_off = 8 - r_off; /* Now, roffset into gcode word. */
/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
if (bits >= 8) {
gcode |= *bp++ << r_off;
r_off += 8;
bits -= 8;
}
/* High order bits. */
gcode |= (*bp & rmask[bits]) << r_off;
zs->zs_offset += zs->zs_n_bits;
return (gcode);
}
/* Table clear for block compress. */
static int
cl_block(struct s_zstate *zs)
{
long rat;
zs->zs_checkpoint = zs->zs_in_count + CHECK_GAP;
if (zs->zs_in_count > 0x007fffff) { /* Shift will overflow. */
rat = zs->zs_bytes_out >> 8;
if (rat == 0) /* Don't divide by zero. */
rat = 0x7fffffff;
else
rat = zs->zs_in_count / rat;
} else {
/* 8 fractional bits. */
rat = (zs->zs_in_count << 8) / zs->zs_bytes_out;
}
if (rat > zs->zs_ratio)
zs->zs_ratio = rat;
else {
zs->zs_ratio = 0;
cl_hash(zs, (count_int) zs->zs_hsize);
zs->zs_free_ent = FIRST;
zs->zs_clear_flg = 1;
if (output(zs, (code_int) CLEAR) == -1)
return (-1);
}
return (0);
}
/* Reset code table. */
static void
cl_hash(struct s_zstate *zs, count_int cl_hsize)
{
count_int *htab_p;
long i, m1;
m1 = -1;
htab_p = zs->zs_htab + cl_hsize;
i = cl_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;
}
FILE *
zopen(const char *name, const char *mode, int bits)
{
int fd;
void *cookie;
if ((fd = open(name, (*mode=='r'? O_RDONLY:O_WRONLY|O_CREAT),
S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) == -1)
return NULL;
if ((cookie = z_open(fd, mode, NULL, bits, 0, 0)) == NULL) {
close(fd);
return NULL;
}
return funopen(cookie, (*mode == 'r'?zread:NULL),
(*mode == 'w'?zwrite:NULL), NULL, zclose);
}
void *
z_open(int fd, const char *mode, char *name, int bits,
u_int32_t mtime, int gotmagic)
{
struct s_zstate *zs;
if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
bits < 0 || bits > BITS) {
errno = EINVAL;
return (NULL);
}
if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
return (NULL);
/* User settable max # bits/code. */
zs->zs_maxbits = bits ? bits : BITS;
/* Should NEVER generate this code. */
zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
zs->zs_hsize = HSIZE; /* For dynamic table sizing. */
zs->zs_free_ent = 0; /* First unused entry. */
zs->zs_block_compress = BLOCK_MASK;
zs->zs_clear_flg = 0;
zs->zs_ratio = 0;
zs->zs_checkpoint = CHECK_GAP;
zs->zs_in_count = 0; /* Length of input. */
zs->zs_out_count = 0; /* # of codes output (for debugging).*/
zs->zs_state = gotmagic ? S_MAGIC : S_START;
zs->zs_offset = 0;
zs->zs_size = 0;
zs->zs_mode = mode[0];
zs->zs_bp = zs->zs_ebp = zs->zs_buf;
zs->zs_fd = fd;
return zs;
}