NetBSD-5.0.2/usr.bin/gzip/zuncompress.c
/* $NetBSD: zuncompress.c,v 1.6 2005/11/22 09:05:30 mrg 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: NetBSD: zopen.c,v 1.8 2003/08/07 11:13:29 agc Exp
*/
/* This file is #included by gzip.c */
static int zread(void *, char *, int);
#define tab_prefixof(i) (zs->zs_codetab[i])
#define tab_suffixof(i) ((char_type *)(zs->zs_htab))[i]
#define de_stack ((char_type *)&tab_suffixof(1 << BITS))
#define BITS 16 /* Default bits. */
#define HSIZE 69001 /* 95% occupancy */ /* XXX may not need HSIZE */
#define BIT_MASK 0x1f /* Defines for third byte of header. */
#define BLOCK_MASK 0x80
#define CHECK_GAP 10000 /* Ratio check interval. */
#define BUFSIZE (64 * 1024)
/*
* 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. */
/*
* 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. */
#define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
typedef long code_int;
typedef long count_int;
typedef u_char char_type;
static char_type magic_header[] =
{'\037', '\235'}; /* 1F 9D */
static char_type rmask[9] =
{0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
/* XXX zuncompress global */
off_t total_compressed_bytes;
size_t compressed_prelen;
char *compressed_pre;
struct s_zstate {
FILE *zs_fp; /* File stream for I/O */
char zs_mode; /* r or w */
enum {
S_START, 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;
int zs_offset;
long zs_in_count; /* Length of input. */
long zs_bytes_out; /* Length of compressed output. */
long zs_out_count; /* # of codes output (for debugging). */
char_type zs_buf[BITS];
union {
struct {
long zs_fcode;
code_int zs_ent;
code_int zs_hsize_reg;
int zs_hshift;
} w; /* Write paramenters */
struct {
char_type *zs_stackp;
int zs_finchar;
code_int zs_code, zs_oldcode, zs_incode;
int zs_roffset, zs_size;
char_type zs_gbuf[BITS];
} r; /* Read parameters */
} u;
};
static code_int getcode(struct s_zstate *zs);
static off_t
zuncompress(FILE *in, FILE *out, char *pre, size_t prelen,
off_t *compressed_bytes)
{
off_t bin, bout = 0;
char *buf;
buf = malloc(BUFSIZE);
if (buf == NULL)
return -1;
/* XXX */
compressed_prelen = prelen;
if (prelen != 0)
compressed_pre = pre;
else
compressed_pre = NULL;
while ((bin = fread(buf, 1, sizeof(buf), in)) != 0) {
if (tflag == 0 && fwrite(buf, 1, bin, out) != bin) {
free(buf);
return -1;
}
bout += bin;
}
if (compressed_bytes)
*compressed_bytes = total_compressed_bytes;
free(buf);
return bout;
}
static int
zclose(void *zs)
{
free(zs);
/* We leave the caller to close the fd passed to zdopen() */
return 0;
}
FILE *
zdopen(int fd)
{
struct s_zstate *zs;
if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
return (NULL);
zs->zs_state = S_START;
/* XXX we can get rid of some of these */
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; /* XXX we calloc()'d this structure why = 0? */
zs->zs_ratio = 0;
zs->zs_checkpoint = CHECK_GAP;
zs->zs_in_count = 1; /* Length of input. */
zs->zs_out_count = 0; /* # of codes output (for debugging). */
zs->u.r.zs_roffset = 0;
zs->u.r.zs_size = 0;
/*
* Layering compress on top of stdio in order to provide buffering,
* and ensure that reads and write work with the data specified.
*/
if ((zs->zs_fp = fdopen(fd, "r")) == NULL) {
free(zs);
return NULL;
}
return funopen(zs, zread, NULL, NULL, zclose);
}
/*
* 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.
*/
static int
zread(void *cookie, char *rbp, int num)
{
u_int count, i;
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;
break;
case S_MIDDLE:
goto middle;
case S_EOF:
goto eof;
}
/* Check the magic number */
for (i = 0; i < 3 && compressed_prelen; i++, compressed_prelen--)
header[i] = *compressed_pre++;
if (fread(header + i, 1, sizeof(header) - i, zs->zs_fp) !=
sizeof(header) - i ||
memcmp(header, magic_header, sizeof(magic_header)) != 0) {
errno = EFTYPE;
return (-1);
}
total_compressed_bytes = 0;
zs->zs_maxbits = header[2]; /* Set -b from file. */
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->u.r.zs_code = 255; zs->u.r.zs_code >= 0; zs->u.r.zs_code--) {
tab_prefixof(zs->u.r.zs_code) = 0;
tab_suffixof(zs->u.r.zs_code) = (char_type) zs->u.r.zs_code;
}
zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
zs->u.r.zs_finchar = zs->u.r.zs_oldcode = getcode(zs);
if (zs->u.r.zs_oldcode == -1) /* EOF already? */
return (0); /* Get out of here */
/* First code must be 8 bits = char. */
*bp++ = (u_char)zs->u.r.zs_finchar;
count--;
zs->u.r.zs_stackp = de_stack;
while ((zs->u.r.zs_code = getcode(zs)) > -1) {
if ((zs->u.r.zs_code == CLEAR) && zs->zs_block_compress) {
for (zs->u.r.zs_code = 255; zs->u.r.zs_code >= 0;
zs->u.r.zs_code--)
tab_prefixof(zs->u.r.zs_code) = 0;
zs->zs_clear_flg = 1;
zs->zs_free_ent = FIRST - 1;
if ((zs->u.r.zs_code = getcode(zs)) == -1) /* O, untimely death! */
break;
}
zs->u.r.zs_incode = zs->u.r.zs_code;
/* Special case for KwKwK string. */
if (zs->u.r.zs_code >= zs->zs_free_ent) {
*zs->u.r.zs_stackp++ = zs->u.r.zs_finchar;
zs->u.r.zs_code = zs->u.r.zs_oldcode;
}
/* Generate output characters in reverse order. */
while (zs->u.r.zs_code >= 256) {
*zs->u.r.zs_stackp++ = tab_suffixof(zs->u.r.zs_code);
zs->u.r.zs_code = tab_prefixof(zs->u.r.zs_code);
}
*zs->u.r.zs_stackp++ = zs->u.r.zs_finchar = tab_suffixof(zs->u.r.zs_code);
/* And put them out in forward order. */
middle: do {
if (count-- == 0)
return (num);
*bp++ = *--zs->u.r.zs_stackp;
} while (zs->u.r.zs_stackp > de_stack);
/* Generate the new entry. */
if ((zs->u.r.zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
tab_prefixof(zs->u.r.zs_code) = (u_short) zs->u.r.zs_oldcode;
tab_suffixof(zs->u.r.zs_code) = zs->u.r.zs_finchar;
zs->zs_free_ent = zs->u.r.zs_code + 1;
}
/* Remember previous code. */
zs->u.r.zs_oldcode = zs->u.r.zs_incode;
}
zs->zs_state = S_EOF;
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, i;
char_type *bp;
bp = zs->u.r.zs_gbuf;
if (zs->zs_clear_flg > 0 || zs->u.r.zs_roffset >= zs->u.r.zs_size ||
zs->zs_free_ent > zs->zs_maxcode) {
/*
* 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;
}
/* XXX */
for (i = 0; i < zs->zs_n_bits && compressed_prelen; i++, compressed_prelen--)
zs->u.r.zs_gbuf[i] = *compressed_pre++;
zs->u.r.zs_size = fread(zs->u.r.zs_gbuf + i, 1, zs->zs_n_bits - i, zs->zs_fp);
zs->u.r.zs_size += i;
if (zs->u.r.zs_size <= 0) /* End of file. */
return (-1);
zs->u.r.zs_roffset = 0;
total_compressed_bytes += zs->u.r.zs_size;
/* Round size down to integral number of codes. */
zs->u.r.zs_size = (zs->u.r.zs_size << 3) - (zs->zs_n_bits - 1);
}
r_off = zs->u.r.zs_roffset;
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->u.r.zs_roffset += zs->zs_n_bits;
return (gcode);
}