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-rw-r--r--busybox/archival/libunarchive/decompress_uncompress.c293
1 files changed, 293 insertions, 0 deletions
diff --git a/busybox/archival/libunarchive/decompress_uncompress.c b/busybox/archival/libunarchive/decompress_uncompress.c
new file mode 100644
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--- /dev/null
+++ b/busybox/archival/libunarchive/decompress_uncompress.c
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+#include "config.h"
+#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 ...]
+ *
+ */
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Default input buffer size */
+#define IBUFSIZ 2048
+
+/* Default output buffer size */
+#define OBUFSIZ 2048
+
+/* Defines for third byte of header */
+#define MAGIC_1 (char_type)'\037' /* First byte of compressed file */
+#define MAGIC_2 (char_type)'\235' /* Second byte of compressed file */
+#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 compresssion 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 FAST
+
+#define HBITS 17 /* 50% occupancy */
+#define HSIZE (1<<HBITS)
+#define HMASK (HSIZE-1)
+#define HPRIME 9941
+#define BITS 16
+#undef MAXSEG_64K
+#define MAXCODE(n) (1L << (n))
+
+/* Block compress mode -C compatible with 2.0 */
+int block_mode = BLOCK_MODE;
+
+/* user settable max # bits/code */
+int maxbits = BITS;
+
+/* Exitcode of compress (-1 no file compressed) */
+int exit_code = -1;
+
+/* Input buffer */
+unsigned char inbuf[IBUFSIZ + 64];
+
+/* Output buffer */
+unsigned char outbuf[OBUFSIZ + 2048];
+
+
+long int htab[HSIZE];
+unsigned short codetab[HSIZE];
+
+#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_htab() memset(htab, -1, sizeof(htab))
+#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. The tables used herein are shared
+ * with those of the compress() routine. See the definitions above.
+ */
+
+extern int uncompress(int fd_in, int fd_out)
+{
+ unsigned char *stackp;
+ long int code;
+ int finchar;
+ long int oldcode;
+ long int incode;
+ int inbits;
+ int posbits;
+ int outpos;
+ int insize;
+ int bitmask;
+ long int free_ent;
+ long int maxcode;
+ long int maxmaxcode;
+ int n_bits;
+ int rsize = 0;
+
+ insize = 0;
+
+ inbuf[0] = bb_xread_char(fd_in);
+
+ 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 %d bits", maxbits,
+ BITS);
+ return -1;
+ }
+
+ maxcode = MAXCODE(n_bits = INIT_BITS) - 1;
+ bitmask = (1 << n_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();
+
+ for (code = 255; code >= 0; --code) {
+ tab_suffixof(code) = (unsigned char) code;
+ }
+
+ do {
+ resetbuf:;
+ {
+ int i;
+ int e;
+ int o;
+
+ e = insize - (o = (posbits >> 3));
+
+ for (i = 0; i < e; ++i)
+ inbuf[i] = inbuf[i + o];
+
+ insize = e;
+ posbits = 0;
+ }
+
+ if (insize < (int) sizeof(inbuf) - IBUFSIZ) {
+ rsize = safe_read(fd_in, inbuf + insize, IBUFSIZ);
+ 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) {
+ outbuf[outpos++] = (unsigned char) (finchar =
+ (int) (oldcode = code));
+ 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)));
+ maxcode = MAXCODE(n_bits = INIT_BITS) - 1;
+ bitmask = (1 << n_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");
+ return -1;
+ }
+
+ *--stackp = (unsigned char) finchar;
+ code = oldcode;
+ }
+
+ /* Generate output characters in reverse order */
+ while ((long int) code >= (long int) 256) {
+ *--stackp = tab_suffixof(code);
+ code = tab_prefixof(code);
+ }
+
+ *--stackp = (unsigned char) (finchar = tab_suffixof(code));
+
+ /* And put them out in forward order */
+ {
+ int i;
+
+ if (outpos + (i = (de_stack - stackp)) >= OBUFSIZ) {
+ do {
+ if (i > OBUFSIZ - outpos) {
+ i = OBUFSIZ - outpos;
+ }
+
+ if (i > 0) {
+ memcpy(outbuf + outpos, stackp, i);
+ outpos += i;
+ }
+
+ if (outpos >= OBUFSIZ) {
+ write(fd_out, outbuf, outpos);
+ outpos = 0;
+ }
+ stackp += i;
+ } while ((i = (de_stack - stackp)) > 0);
+ } else {
+ memcpy(outbuf + outpos, stackp, i);
+ outpos += i;
+ }
+ }
+
+ /* Generate the new entry. */
+ if ((code = free_ent) < 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) {
+ write(fd_out, outbuf, outpos);
+ }
+
+ return 0;
+}
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