Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 | /* vi: set sw=4 ts=4: */
#include "libbb.h"
/* uncompress for busybox -- (c) 2002 Robert Griebl
*
* based on the original compress42.c source
* (see disclaimer below)
*/
/* (N)compress42.c - File compression ala IEEE Computer, Mar 1992.
*
* Authors:
* Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!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)
* Dave Mack (csu@alembic.acs.com)
* Peter Jannesen, Network Communication Systems
* (peter@ncs.nl)
*
* marc@suse.de : a small security fix for a buffer overflow
*
* [... History snipped ...]
*
*/
/* Default input buffer size */
#define IBUFSIZ 2048
/* Default output buffer size */
#define OBUFSIZ 2048
/* Defines for third byte of header */
#define BIT_MASK 0x1f /* Mask for 'number of compresssion bits' */
/* Masks 0x20 and 0x40 are free. */
/* I think 0x20 should mean that there is */
/* a fourth header byte (for expansion). */
#define BLOCK_MODE 0x80 /* Block compression if table is full and */
/* compression rate is dropping flush tables */
/* 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 INIT_BITS 9 /* initial number of bits/code */
/* machine variants which require cc -Dmachine: pdp11, z8000, DOS */
#define HBITS 17 /* 50% occupancy */
#define HSIZE (1<<HBITS)
#define HMASK (HSIZE-1) /* unused */
#define HPRIME 9941 /* unused */
#define BITS 16
#define BITS_STR "16"
#undef MAXSEG_64K /* unused */
#define MAXCODE(n) (1L << (n))
#define htabof(i) htab[i]
#define codetabof(i) codetab[i]
#define tab_prefixof(i) codetabof(i)
#define tab_suffixof(i) ((unsigned char *)(htab))[i]
#define de_stack ((unsigned char *)&(htab[HSIZE-1]))
#define clear_tab_prefixof() memset(codetab, 0, 256)
/*
* Decompress stdin to stdout. 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.
*/
USE_DESKTOP(long long) int
uncompress(int fd_in, int fd_out)
{
USE_DESKTOP(long long total_written = 0;)
USE_DESKTOP(long long) int retval = -1;
unsigned char *stackp;
long code;
int finchar;
long oldcode;
long incode;
int inbits;
int posbits;
int outpos;
int insize;
int bitmask;
long free_ent;
long maxcode;
long maxmaxcode;
int n_bits;
int rsize = 0;
unsigned char *inbuf; /* were eating insane amounts of stack - */
unsigned char *outbuf; /* bad for some embedded targets */
unsigned char *htab;
unsigned short *codetab;
/* Hmm, these were statics - why?! */
/* user settable max # bits/code */
int maxbits; /* = BITS; */
/* block compress mode -C compatible with 2.0 */
int block_mode; /* = BLOCK_MODE; */
inbuf = xzalloc(IBUFSIZ + 64);
outbuf = xzalloc(OBUFSIZ + 2048);
htab = xzalloc(HSIZE); /* wsn't zeroed out before, maybe can xmalloc? */
codetab = xzalloc(HSIZE * sizeof(codetab[0]));
insize = 0;
/* xread isn't good here, we have to return - caller may want
* to do some cleanup (e.g. delete incomplete unpacked file etc) */
if (full_read(fd_in, inbuf, 1) != 1) {
bb_error_msg("short read");
goto err;
}
maxbits = inbuf[0] & BIT_MASK;
block_mode = inbuf[0] & BLOCK_MODE;
maxmaxcode = MAXCODE(maxbits);
if (maxbits > BITS) {
bb_error_msg("compressed with %d bits, can only handle "
BITS_STR" bits", maxbits);
goto err;
}
n_bits = INIT_BITS;
maxcode = MAXCODE(INIT_BITS) - 1;
bitmask = (1 << INIT_BITS) - 1;
oldcode = -1;
finchar = 0;
outpos = 0;
posbits = 0 << 3;
free_ent = ((block_mode) ? FIRST : 256);
/* As above, initialize the first 256 entries in the table. */
/*clear_tab_prefixof(); - done by xzalloc */
for (code = 255; code >= 0; --code) {
tab_suffixof(code) = (unsigned char) code;
}
do {
resetbuf:
{
int i;
int e;
int o;
o = posbits >> 3;
e = insize - o;
for (i = 0; i < e; ++i)
inbuf[i] = inbuf[i + o];
insize = e;
posbits = 0;
}
if (insize < (int) (IBUFSIZ + 64) - IBUFSIZ) {
rsize = safe_read(fd_in, inbuf + insize, IBUFSIZ);
//error check??
insize += rsize;
}
inbits = ((rsize > 0) ? (insize - insize % n_bits) << 3 :
(insize << 3) - (n_bits - 1));
while (inbits > posbits) {
if (free_ent > maxcode) {
posbits =
((posbits - 1) +
((n_bits << 3) -
(posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
++n_bits;
if (n_bits == maxbits) {
maxcode = maxmaxcode;
} else {
maxcode = MAXCODE(n_bits) - 1;
}
bitmask = (1 << n_bits) - 1;
goto resetbuf;
}
{
unsigned char *p = &inbuf[posbits >> 3];
code = ((((long) (p[0])) | ((long) (p[1]) << 8) |
((long) (p[2]) << 16)) >> (posbits & 0x7)) & bitmask;
}
posbits += n_bits;
if (oldcode == -1) {
oldcode = code;
finchar = (int) oldcode;
outbuf[outpos++] = (unsigned char) finchar;
continue;
}
if (code == CLEAR && block_mode) {
clear_tab_prefixof();
free_ent = FIRST - 1;
posbits =
((posbits - 1) +
((n_bits << 3) -
(posbits - 1 + (n_bits << 3)) % (n_bits << 3)));
n_bits = INIT_BITS;
maxcode = MAXCODE(INIT_BITS) - 1;
bitmask = (1 << INIT_BITS) - 1;
goto resetbuf;
}
incode = code;
stackp = de_stack;
/* Special case for KwKwK string. */
if (code >= free_ent) {
if (code > free_ent) {
unsigned char *p;
posbits -= n_bits;
p = &inbuf[posbits >> 3];
bb_error_msg
("insize:%d posbits:%d inbuf:%02X %02X %02X %02X %02X (%d)",
insize, posbits, p[-1], p[0], p[1], p[2], p[3],
(posbits & 07));
bb_error_msg("uncompress: corrupt input");
goto err;
}
*--stackp = (unsigned char) finchar;
code = oldcode;
}
/* Generate output characters in reverse order */
while ((long) code >= (long) 256) {
*--stackp = tab_suffixof(code);
code = tab_prefixof(code);
}
finchar = tab_suffixof(code);
*--stackp = (unsigned char) finchar;
/* And put them out in forward order */
{
int i;
i = de_stack - stackp;
if (outpos + i >= OBUFSIZ) {
do {
if (i > OBUFSIZ - outpos) {
i = OBUFSIZ - outpos;
}
if (i > 0) {
memcpy(outbuf + outpos, stackp, i);
outpos += i;
}
if (outpos >= OBUFSIZ) {
full_write(fd_out, outbuf, outpos);
//error check??
USE_DESKTOP(total_written += outpos;)
outpos = 0;
}
stackp += i;
i = de_stack - stackp;
} while (i > 0);
} else {
memcpy(outbuf + outpos, stackp, i);
outpos += i;
}
}
/* Generate the new entry. */
code = free_ent;
if (code < maxmaxcode) {
tab_prefixof(code) = (unsigned short) oldcode;
tab_suffixof(code) = (unsigned char) finchar;
free_ent = code + 1;
}
/* Remember previous code. */
oldcode = incode;
}
} while (rsize > 0);
if (outpos > 0) {
full_write(fd_out, outbuf, outpos);
//error check??
USE_DESKTOP(total_written += outpos;)
}
retval = USE_DESKTOP(total_written) + 0;
err:
free(inbuf);
free(outbuf);
free(htab);
free(codetab);
return retval;
}
|