Simplified version checking.
[oweals/busybox.git] / gunzip.c
index 1107bc75cbf92e4279f215b61966d1bb06454039..430bc630efc80daef9949eac46ab431d4fa9ab18 100644 (file)
--- a/gunzip.c
+++ b/gunzip.c
@@ -60,1005 +60,16 @@ static char *license_msg[] = {
 };
 #endif
 
-#include <getopt.h>
-#include <ctype.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <signal.h>
-//#include <errno.h>
-#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
-#include <memory.h>
 #include <unistd.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <time.h>
-#include <dirent.h>
+#include <getopt.h>
 #include "busybox.h"
-#define BB_DECLARE_EXTERN
-#define bb_need_memory_exhausted
-#define bb_need_name_too_long
-#include "messages.c"
-
-FILE *in_file, *out_file;
-
-static unsigned long *crc_table;
-static unsigned long crc = 0xffffffffL;        /* shift register contents */
-
-/* Return codes from gzip */
-static const int ERROR = 1;
-
-/*
- * window size--must be a power of two, and
- *  at least 32K for zip's deflate method 
- */
-static const int WSIZE = 0x8000;
-
-/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
-static const int BMAX = 16;            /* maximum bit length of any code (16 for explode) */
-static const int N_MAX = 288;          /* maximum number of codes in any set */
-
-static unsigned char *window;
-
-static long bytes_out;         /* number of output bytes */
-static unsigned long outcnt;   /* bytes in output buffer */
-
-unsigned hufts;                /* track memory usage */
-unsigned long bb;                      /* bit buffer */
-unsigned bk;           /* bits in bit buffer */
-
-typedef struct huft_s {
-       unsigned char e;                /* number of extra bits or operation */
-       unsigned char b;                /* number of bits in this code or subcode */
-       union {
-               unsigned short n;               /* literal, length base, or distance base */
-               struct huft_s *t;       /* pointer to next level of table */
-       } v;
-} huft_t;
-
-unsigned short mask_bits[] = {
-       0x0000,
-       0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
-       0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
-};
-
-//static int error_number = 0;
-/* ========================================================================
- * Signal and error handler.
- */
-static void abort_gzip()
-{
-       error_msg("gzip aborted\n");
-       exit(ERROR);
-}
-
-static void make_crc_table()
-{
-       unsigned long table_entry;      /* crc shift register */
-       unsigned long poly = 0;      /* polynomial exclusive-or pattern */
-       int i;                /* counter for all possible eight bit values */
-       int k;                /* byte being shifted into crc apparatus */
-
-       /* terms of polynomial defining this crc (except x^32): */
-       static int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
-
-       crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));
-
-       /* Make exclusive-or pattern from polynomial (0xedb88320) */
-       for (i = 0; i < sizeof(p)/sizeof(int); i++)
-               poly |= 1L << (31 - p[i]);
-
-       /* Compute and print table of CRC's, five per line */
-       for (i = 0; i < 256; i++) {
-               table_entry = i;
-          /* The idea to initialize the register with the byte instead of
-            * zero was stolen from Haruhiko Okumura's ar002
-            */
-               for (k = 8; k; k--) {
-                       table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
-               }
-               crc_table[i]=table_entry;
-       }
-}
-
-/* ===========================================================================
- * Write the output window window[0..outcnt-1] and update crc and bytes_out.
- * (Used for the decompressed data only.)
- */
-void flush_window()
-{
-       int n;
-
-       if (outcnt == 0)
-               return;
-
-       for (n = 0; n < outcnt; n++) {
-               crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
-       }
-
-       if (fwrite(window, 1, outcnt, out_file) != outcnt) {
-               error_msg_and_die("Couldnt write");
-       }
-       bytes_out += (unsigned long) outcnt;
-       outcnt = 0;
-}
-
-/*
- * Free the malloc'ed tables built by huft_build(), which makes a linked
- * list of the tables it made, with the links in a dummy first entry of
- * each table. 
- * t: table to free
- */
-static int huft_free(huft_t *t)
-{
-       huft_t *p, *q;
-
-       /* Go through linked list, freeing from the malloced (t[-1]) address. */
-       p = t;
-       while (p != (huft_t *) NULL) {
-               q = (--p)->v.t;
-               free((char *) p);
-               p = q;
-       }
-       return 0;
-}
-
-/* Given a list of code lengths and a maximum table size, make a set of
- * tables to decode that set of codes.  Return zero on success, one if
- * the given code set is incomplete (the tables are still built in this
- * case), two if the input is invalid (all zero length codes or an
- * oversubscribed set of lengths), and three if not enough memory.
- *
- * b:  code lengths in bits (all assumed <= BMAX)
- * n:  number of codes (assumed <= N_MAX)
- * s:  number of simple-valued codes (0..s-1)
- * d:  list of base values for non-simple codes
- * e:  list of extra bits for non-simple codes
- * t:  result: starting table
- * m:  maximum lookup bits, returns actual
- */
-static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s, 
-       const unsigned short *d, const unsigned short *e, huft_t **t, int *m)
-{
-       unsigned a;             /* counter for codes of length k */
-       unsigned c[BMAX + 1];   /* bit length count table */
-       unsigned f;             /* i repeats in table every f entries */
-       int g;                  /* maximum code length */
-       int h;                  /* table level */
-       register unsigned i;    /* counter, current code */
-       register unsigned j;    /* counter */
-       register int k;         /* number of bits in current code */
-       int l;                  /* bits per table (returned in m) */
-       register unsigned *p;           /* pointer into c[], b[], or v[] */
-       register huft_t *q;     /* points to current table */
-       huft_t r;               /* table entry for structure assignment */
-       huft_t *u[BMAX];        /* table stack */
-       unsigned v[N_MAX];      /* values in order of bit length */
-       register int w;         /* bits before this table == (l * h) */
-       unsigned x[BMAX + 1];   /* bit offsets, then code stack */
-       unsigned *xp;           /* pointer into x */
-       int y;                  /* number of dummy codes added */
-       unsigned z;             /* number of entries in current table */
-
-       /* Generate counts for each bit length */
-       memset ((void *)(c), 0, sizeof(c));
-       p = b;
-       i = n;
-       do {
-               c[*p]++;        /* assume all entries <= BMAX */
-               p++;            /* Can't combine with above line (Solaris bug) */
-       } while (--i);
-       if (c[0] == n) {        /* null input--all zero length codes */
-               *t = (huft_t *) NULL;
-               *m = 0;
-               return 0;
-       }
-
-       /* Find minimum and maximum length, bound *m by those */
-       l = *m;
-       for (j = 1; j <= BMAX; j++)
-               if (c[j])
-                       break;
-       k = j;                          /* minimum code length */
-       if ((unsigned) l < j)
-               l = j;
-       for (i = BMAX; i; i--)
-               if (c[i])
-                       break;
-       g = i;                          /* maximum code length */
-       if ((unsigned) l > i)
-               l = i;
-       *m = l;
-
-       /* Adjust last length count to fill out codes, if needed */
-       for (y = 1 << j; j < i; j++, y <<= 1)
-               if ((y -= c[j]) < 0)
-                       return 2;       /* bad input: more codes than bits */
-       if ((y -= c[i]) < 0)
-               return 2;
-       c[i] += y;
-
-       /* Generate starting offsets into the value table for each length */
-       x[1] = j = 0;
-       p = c + 1;
-       xp = x + 2;
-       while (--i) {                   /* note that i == g from above */
-               *xp++ = (j += *p++);
-       }
-
-       /* Make a table of values in order of bit lengths */
-       p = b;
-       i = 0;
-       do {
-               if ((j = *p++) != 0)
-                       v[x[j]++] = i;
-       } while (++i < n);
-
-       /* Generate the Huffman codes and for each, make the table entries */
-       x[0] = i = 0;                   /* first Huffman code is zero */
-       p = v;                          /* grab values in bit order */
-       h = -1;                         /* no tables yet--level -1 */
-       w = -l;                         /* bits decoded == (l * h) */
-       u[0] = (huft_t *) NULL; /* just to keep compilers happy */
-       q = (huft_t *) NULL;    /* ditto */
-       z = 0;                          /* ditto */
-
-       /* go through the bit lengths (k already is bits in shortest code) */
-       for (; k <= g; k++) {
-               a = c[k];
-               while (a--) {
-                       /* here i is the Huffman code of length k bits for value *p */
-                       /* make tables up to required level */
-                       while (k > w + l) {
-                               h++;
-                               w += l;         /* previous table always l bits */
-
-                               /* compute minimum size table less than or equal to l bits */
-                               z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
-                               if ((f = 1 << (j = k - w)) > a + 1) {   /* try a k-w bit table *//* too few codes for k-w bit table */
-                                       f -= a + 1;     /* deduct codes from patterns left */
-                                       xp = c + k;
-                                       while (++j < z) {       /* try smaller tables up to z bits */
-                                               if ((f <<= 1) <= *++xp)
-                                                       break;  /* enough codes to use up j bits */
-                                               f -= *xp;       /* else deduct codes from patterns */
-                                       }
-                               }
-                               z = 1 << j;             /* table entries for j-bit table */
-
-                               /* allocate and link in new table */
-                               if ((q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t))) == NULL) {
-                                       if (h) {
-                                               huft_free(u[0]);
-                                       }
-                                       return 3;       /* not enough memory */
-                               }
-                               hufts += z + 1; /* track memory usage */
-                               *t = q + 1;             /* link to list for huft_free() */
-                               *(t = &(q->v.t)) = NULL;
-                               u[h] = ++q;             /* table starts after link */
-
-                               /* connect to last table, if there is one */
-                               if (h) {
-                                       x[h] = i;       /* save pattern for backing up */
-                                       r.b = (unsigned char) l;        /* bits to dump before this table */
-                                       r.e = (unsigned char) (16 + j); /* bits in this table */
-                                       r.v.t = q;      /* pointer to this table */
-                                       j = i >> (w - l);       /* (get around Turbo C bug) */
-                                       u[h - 1][j] = r;        /* connect to last table */
-                               }
-                       }
-
-                       /* set up table entry in r */
-                       r.b = (unsigned char) (k - w);
-                       if (p >= v + n)
-                               r.e = 99;               /* out of values--invalid code */
-                       else if (*p < s) {
-                               r.e = (unsigned char) (*p < 256 ? 16 : 15);     /* 256 is end-of-block code */
-                               r.v.n = (unsigned short) (*p);  /* simple code is just the value */
-                               p++;                    /* one compiler does not like *p++ */
-                       } else {
-                               r.e = (unsigned char) e[*p - s];        /* non-simple--look up in lists */
-                               r.v.n = d[*p++ - s];
-                       }
-
-                       /* fill code-like entries with r */
-                       f = 1 << (k - w);
-                       for (j = i >> w; j < z; j += f)
-                               q[j] = r;
-
-                       /* backwards increment the k-bit code i */
-                       for (j = 1 << (k - 1); i & j; j >>= 1)
-                               i ^= j;
-                       i ^= j;
-
-                       /* backup over finished tables */
-                       while ((i & ((1 << w) - 1)) != x[h]) {
-                               h--;                    /* don't need to update q */
-                               w -= l;
-                       }
-               }
-       }
-       /* Return true (1) if we were given an incomplete table */
-       return y != 0 && g != 1;
-}
-
-/*
- * inflate (decompress) the codes in a deflated (compressed) block.
- * Return an error code or zero if it all goes ok.
- *
- * tl, td: literal/length and distance decoder tables
- * bl, bd: number of bits decoded by tl[] and td[]
- */
-static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
-{
-       register unsigned long e;               /* table entry flag/number of extra bits */
-       unsigned long n, d;                             /* length and index for copy */
-       unsigned long w;                                /* current window position */
-       huft_t *t;                              /* pointer to table entry */
-       unsigned ml, md;                        /* masks for bl and bd bits */
-       register unsigned long b;                               /* bit buffer */
-       register unsigned k;            /* number of bits in bit buffer */
-
-       /* make local copies of globals */
-       b = bb;                                 /* initialize bit buffer */
-       k = bk;
-       w = outcnt;                             /* initialize window position */
-
-       /* inflate the coded data */
-       ml = mask_bits[bl];                     /* precompute masks for speed */
-       md = mask_bits[bd];
-       for (;;) {                              /* do until end of block */
-               while (k < (unsigned) bl) {
-                       b |= ((unsigned long)fgetc(in_file)) << k;
-                       k += 8;
-               }
-               if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
-               do {
-                       if (e == 99) {
-                               return 1;
-                       }
-                       b >>= t->b;
-                       k -= t->b;
-                       e -= 16;
-                       while (k < e) {
-                               b |= ((unsigned long)fgetc(in_file)) << k;
-                               k += 8;
-                       }
-               } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
-               b >>= t->b;
-               k -= t->b;
-               if (e == 16) {          /* then it's a literal */
-                       window[w++] = (unsigned char) t->v.n;
-                       if (w == WSIZE) {
-                               outcnt=(w),
-                               flush_window();
-                               w = 0;
-                       }
-               } else {                                /* it's an EOB or a length */
-
-                       /* exit if end of block */
-                       if (e == 15) {
-                               break;
-                       }
-
-                       /* get length of block to copy */
-                       while (k < e) {
-                               b |= ((unsigned long)fgetc(in_file)) << k;
-                               k += 8;
-                       }
-                       n = t->v.n + ((unsigned) b & mask_bits[e]);
-                       b >>= e;
-                       k -= e;
-
-                       /* decode distance of block to copy */
-                       while (k < (unsigned) bd) {
-                               b |= ((unsigned long)fgetc(in_file)) << k;
-                               k += 8;
-                       }
-
-                       if ((e = (t = td + ((unsigned) b & md))->e) > 16)
-                               do {
-                                       if (e == 99)
-                                               return 1;
-                                       b >>= t->b;
-                                       k -= t->b;
-                                       e -= 16;
-                                       while (k < e) {
-                                               b |= ((unsigned long)fgetc(in_file)) << k;
-                                               k += 8;
-                                       }
-                               } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
-                       b >>= t->b;
-                       k -= t->b;
-                       while (k < e) {
-                               b |= ((unsigned long)fgetc(in_file)) << k;
-                               k += 8;
-                       }
-                       d = w - t->v.n - ((unsigned) b & mask_bits[e]);
-                       b >>= e;
-                       k -= e;
-
-                       /* do the copy */
-                       do {
-                               n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
-#if !defined(NOMEMCPY) && !defined(DEBUG)
-                               if (w - d >= e) {       /* (this test assumes unsigned comparison) */
-                                       memcpy(window + w, window + d, e);
-                                       w += e;
-                                       d += e;
-                               } else                  /* do it slow to avoid memcpy() overlap */
-#endif                                                 /* !NOMEMCPY */
-                                       do {
-                                               window[w++] = window[d++];
-                                       } while (--e);
-                               if (w == WSIZE) {
-                                       outcnt=(w),
-                                       flush_window();
-                                       w = 0;
-                               }
-                       } while (n);
-               }
-       }
-
-       /* restore the globals from the locals */
-       outcnt = w;                     /* restore global window pointer */
-       bb = b;                         /* restore global bit buffer */
-       bk = k;
-
-       /* done */
-       return 0;
-}
-
-/*
- * decompress an inflated block
- * e: last block flag
- *
- * GLOBAL VARIABLES: bb, kk,
- */
-static int inflate_block(int *e)
-{
-       unsigned t;                     /* block type */
-       register unsigned long b;                       /* bit buffer */
-       register unsigned k;            /* number of bits in bit buffer */
-       static unsigned short cplens[] = {              /* Copy lengths for literal codes 257..285 */
-               3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
-               35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
-       };
-       /* note: see note #13 above about the 258 in this list. */
-       static unsigned short cplext[] = {              /* Extra bits for literal codes 257..285 */
-               0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
-               3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
-       };                              /* 99==invalid */
-       static unsigned short cpdist[] = {              /* Copy offsets for distance codes 0..29 */
-               1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
-               257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
-               8193, 12289, 16385, 24577
-       };
-       static unsigned short cpdext[] = {              /* Extra bits for distance codes */
-               0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
-               7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
-               12, 12, 13, 13
-       };
-
-       /* make local bit buffer */
-       b = bb;
-       k = bk;
-
-       /* read in last block bit */
-       while (k < 1) {
-               b |= ((unsigned long)fgetc(in_file)) << k;
-               k += 8;
-       }
-       *e = (int) b & 1;
-       b >>= 1;
-       k -= 1;
-
-       /* read in block type */
-       while (k < 2) {
-               b |= ((unsigned long)fgetc(in_file)) << k;
-               k += 8;
-       }
-       t = (unsigned) b & 3;
-       b >>= 2;
-       k -= 2;
-
-       /* restore the global bit buffer */
-       bb = b;
-       bk = k;
-
-       /* inflate that block type */
-       switch (t) {
-       case 0: /* Inflate stored */
-               {
-                       unsigned long n;                        /* number of bytes in block */
-                       unsigned long w;                        /* current window position */
-                       register unsigned long b_stored;                        /* bit buffer */
-                       register unsigned long k_stored;                /* number of bits in bit buffer */
-
-                       /* make local copies of globals */
-                       b_stored = bb;                          /* initialize bit buffer */
-                       k_stored = bk;
-                       w = outcnt;                     /* initialize window position */
-
-                       /* go to byte boundary */
-                       n = k_stored & 7;
-                       b_stored >>= n;
-                       k_stored -= n;
-
-                       /* get the length and its complement */
-                       while (k_stored < 16) {
-                               b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
-                               k_stored += 8;
-                       }
-                       n = ((unsigned) b_stored & 0xffff);
-                       b_stored >>= 16;
-                       k_stored -= 16;
-                       while (k_stored < 16) {
-                               b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
-                               k_stored += 8;
-                       }
-                       if (n != (unsigned) ((~b_stored) & 0xffff)) {
-                               return 1;               /* error in compressed data */
-                       }
-                       b_stored >>= 16;
-                       k_stored -= 16;
-
-                       /* read and output the compressed data */
-                       while (n--) {
-                               while (k_stored < 8) {
-                                       b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
-                                       k_stored += 8;
-                               }
-                               window[w++] = (unsigned char) b_stored;
-                               if (w == (unsigned long)WSIZE) {
-                                       outcnt=(w),
-                                       flush_window();
-                                       w = 0;
-                               }
-                               b_stored >>= 8;
-                               k_stored -= 8;
-                       }
-
-                       /* restore the globals from the locals */
-                       outcnt = w;                     /* restore global window pointer */
-                       bb = b_stored;                          /* restore global bit buffer */
-                       bk = k_stored;
-                       return 0;
-               }
-       case 1: /* Inflate fixed 
-                        * decompress an inflated type 1 (fixed Huffman codes) block.  We should
-                        * either replace this with a custom decoder, or at least precompute the
-                        * Huffman tables.
-                        */
-               {
-                       int i;                                  /* temporary variable */
-                       huft_t *tl;                             /* literal/length code table */
-                       huft_t *td;                             /* distance code table */
-                       int bl;                                 /* lookup bits for tl */
-                       int bd;                                 /* lookup bits for td */
-                       unsigned int l[288];    /* length list for huft_build */
-
-                       /* set up literal table */
-                       for (i = 0; i < 144; i++) {
-                               l[i] = 8;
-                       }
-                       for (; i < 256; i++) {
-                               l[i] = 9;
-                       }
-                       for (; i < 280; i++) {
-                               l[i] = 7;
-                       }
-                       for (; i < 288; i++) {  /* make a complete, but wrong code set */
-                               l[i] = 8;
-                       }
-                       bl = 7;
-                       if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
-                               return i;
-                       }
-
-                       /* set up distance table */
-                       for (i = 0; i < 30; i++) {      /* make an incomplete code set */
-                               l[i] = 5;
-                       }
-                       bd = 5;
-                       if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
-                               huft_free(tl);
-                               return i;
-                       }
-
-                       /* decompress until an end-of-block code */
-                       if (inflate_codes(tl, td, bl, bd))
-                               return 1;
-
-                       /* free the decoding tables, return */
-                       huft_free(tl);
-                       huft_free(td);
-                       return 0;
-               }
-       case 2: /* Inflate dynamic */
-               {
-                       /* Tables for deflate from PKZIP's appnote.txt. */
-                       static unsigned border[] = {    /* Order of the bit length code lengths */
-                               16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
-                       };
-                       int dbits = 6;                                  /* bits in base distance lookup table */
-                       int lbits = 9;                                  /* bits in base literal/length lookup table */
-
-                       int i;                                          /* temporary variables */
-                       unsigned j;
-                       unsigned l;                                     /* last length */
-                       unsigned m;                                     /* mask for bit lengths table */
-                       unsigned n;                                     /* number of lengths to get */
-                       huft_t *tl;                     /* literal/length code table */
-                       huft_t *td;                     /* distance code table */
-                       int bl;                                         /* lookup bits for tl */
-                       int bd;                                         /* lookup bits for td */
-                       unsigned nb;                            /* number of bit length codes */
-                       unsigned nl;                            /* number of literal/length codes */
-                       unsigned nd;                            /* number of distance codes */
-
-                       unsigned ll[286 + 30];          /* literal/length and distance code lengths */
-                       register unsigned long b_dynamic;       /* bit buffer */
-                       register unsigned k_dynamic;            /* number of bits in bit buffer */
-
-                       /* make local bit buffer */
-                       b_dynamic = bb;
-                       k_dynamic = bk;
-
-                       /* read in table lengths */
-                       while (k_dynamic < 5) {
-                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                               k_dynamic += 8;
-                       }
-                       nl = 257 + ((unsigned) b_dynamic & 0x1f);       /* number of literal/length codes */
-                       b_dynamic >>= 5;
-                       k_dynamic -= 5;
-                       while (k_dynamic < 5) {
-                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                               k_dynamic += 8;
-                       }
-                       nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
-                       b_dynamic >>= 5;
-                       k_dynamic -= 5;
-                       while (k_dynamic < 4) {
-                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                               k_dynamic += 8;
-                       }
-                       nb = 4 + ((unsigned) b_dynamic & 0xf);  /* number of bit length codes */
-                       b_dynamic >>= 4;
-                       k_dynamic -= 4;
-                       if (nl > 286 || nd > 30) {
-                               return 1;       /* bad lengths */
-                       }
-
-                       /* read in bit-length-code lengths */
-                       for (j = 0; j < nb; j++) {
-                               while (k_dynamic < 3) {
-                                       b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                                       k_dynamic += 8;
-                               }
-                               ll[border[j]] = (unsigned) b_dynamic & 7;
-                               b_dynamic >>= 3;
-                               k_dynamic -= 3;
-                       }
-                       for (; j < 19; j++) {
-                               ll[border[j]] = 0;
-                       }
-
-                       /* build decoding table for trees--single level, 7 bit lookup */
-                       bl = 7;
-                       if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
-                               if (i == 1) {
-                                       huft_free(tl);
-                               }
-                               return i;                       /* incomplete code set */
-                       }
-
-                       /* read in literal and distance code lengths */
-                       n = nl + nd;
-                       m = mask_bits[bl];
-                       i = l = 0;
-                       while ((unsigned) i < n) {
-                               while (k_dynamic < (unsigned) bl) {
-                                       b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                                       k_dynamic += 8;
-                               }
-                               j = (td = tl + ((unsigned) b_dynamic & m))->b;
-                               b_dynamic >>= j;
-                               k_dynamic -= j;
-                               j = td->v.n;
-                               if (j < 16) {                   /* length of code in bits (0..15) */
-                                       ll[i++] = l = j;        /* save last length in l */
-                               }
-                               else if (j == 16) {             /* repeat last length 3 to 6 times */
-                                       while (k_dynamic < 2) {
-                                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                                               k_dynamic += 8;
-                                       }
-                                       j = 3 + ((unsigned) b_dynamic & 3);
-                                       b_dynamic >>= 2;
-                                       k_dynamic -= 2;
-                                       if ((unsigned) i + j > n) {
-                                               return 1;
-                                       }
-                                       while (j--) {
-                                               ll[i++] = l;
-                                       }
-                               } else if (j == 17) {   /* 3 to 10 zero length codes */
-                                       while (k_dynamic < 3) {
-                                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                                               k_dynamic += 8;
-                                       }
-                                       j = 3 + ((unsigned) b_dynamic & 7);
-                                       b_dynamic >>= 3;
-                                       k_dynamic -= 3;
-                                       if ((unsigned) i + j > n) {
-                                               return 1;
-                                       }
-                                       while (j--) {
-                                               ll[i++] = 0;
-                                       }
-                                       l = 0;
-                               } else {                /* j == 18: 11 to 138 zero length codes */
-                                       while (k_dynamic < 7) {
-                                               b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
-                                               k_dynamic += 8;
-                                       }
-                                       j = 11 + ((unsigned) b_dynamic & 0x7f);
-                                       b_dynamic >>= 7;
-                                       k_dynamic -= 7;
-                                       if ((unsigned) i + j > n) {
-                                               return 1;
-                                       }
-                                       while (j--) {
-                                               ll[i++] = 0;
-                                       }
-                                       l = 0;
-                               }
-                       }
-
-                       /* free decoding table for trees */
-                       huft_free(tl);
-
-                       /* restore the global bit buffer */
-                       bb = b_dynamic;
-                       bk = k_dynamic;
-
-                       /* build the decoding tables for literal/length and distance codes */
-                       bl = lbits;
-                       if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
-                               if (i == 1) {
-                                       error_msg("Incomplete literal tree");
-                                       huft_free(tl);
-                               }
-                               return i;                       /* incomplete code set */
-                       }
-                       bd = dbits;
-                       if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
-                               if (i == 1) {
-                                       error_msg("incomplete distance tree");
-                                       huft_free(td);
-                               }
-                               huft_free(tl);
-                               return i;                       /* incomplete code set */
-                       }
-
-                       /* decompress until an end-of-block code */
-                       if (inflate_codes(tl, td, bl, bd))
-                               return 1;
-
-                       /* free the decoding tables, return */
-                       huft_free(tl);
-                       huft_free(td);
-                       return 0;
-               }
-       default:
-               /* bad block type */
-               return 2;
-       }
-}
-
-/*
- * decompress an inflated entry
- *
- * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
- */
-static int inflate()
-{
-       int e;                          /* last block flag */
-       int r;                          /* result code */
-       unsigned h = 0;         /* maximum struct huft's malloc'ed */
-
-       /* initialize window, bit buffer */
-       outcnt = 0;
-       bk = 0;
-       bb = 0;
-
-       /* decompress until the last block */
-       do {
-               hufts = 0;
-               if ((r = inflate_block(&e)) != 0) {
-                       return r;
-               }
-               if (hufts > h) {
-                       h = hufts;
-               }
-       } while (!e);
-
-       /* flush out window */
-       flush_window();
-
-       /* return success */
-       return 0;
-}
-
-/* ===========================================================================
- * Unzip in to out.  This routine works on both gzip and pkzip files.
- *
- * IN assertions: the buffer inbuf contains already the beginning of
- *   the compressed data, from offsets inptr to insize-1 included.
- *   The magic header has already been checked. The output buffer is cleared.
- * in, out: input and output file descriptors
- */
-extern int unzip(FILE *l_in_file, FILE *l_out_file)
-{
-       const int extra_field = 0x04;   /* bit 2 set: extra field present */
-       const int orig_name = 0x08;     /* bit 3 set: original file name present */
-       const int comment = 0x10;       /* bit 4 set: file comment present */
-       unsigned char buf[8];   /* extended local header */
-       unsigned char flags;    /* compression flags */
-       char magic[2];                  /* magic header */
-       int method;
-       typedef void (*sig_type) (int);
-       int exit_code=0;        /* program exit code */
-
-       in_file = l_in_file;
-       out_file = l_out_file;
-
-       if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
-               (void) signal(SIGINT, (sig_type) abort_gzip);
-       }
-#ifdef SIGTERM
-       if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
-               (void) signal(SIGTERM, (sig_type) abort_gzip);
-       }
-#endif
-#ifdef SIGHUP
-       if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
-               (void) signal(SIGHUP, (sig_type) abort_gzip);
-       }
-#endif
-
-       /* Allocate all global buffers (for DYN_ALLOC option) */
-       window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
-       outcnt = 0;
-       bytes_out = 0L;
-
-       /* set the buffer size */
-       setvbuf(in_file, NULL, _IOFBF, 0x8000);
-
-       magic[0] = fgetc(in_file);
-       magic[1] = fgetc(in_file);
-
-       /* Magic header for gzip files, 1F 8B = \037\213 */
-       if (memcmp(magic, "\037\213", 2) != 0) {
-               error_msg("Invalid gzip magic");
-               return EXIT_FAILURE;
-       }
-
-       method = (int) fgetc(in_file);
-       if (method != 8) {
-               error_msg("unknown method %d -- get newer version of gzip", method);
-               exit_code = 1;
-               return -1;
-       }
-
-       flags = (unsigned char) fgetc(in_file);
-
-       /* Ignore time stamp(4), extra flags(1), OS type(1) */
-       fseek(in_file, 6, SEEK_CUR);
-
-       if ((flags & extra_field) != 0) {
-               fseek(in_file, (size_t) fgetc(in_file) + ((size_t)fgetc(in_file) << 8), SEEK_CUR);
-       }
-
-       /* Discard original name if any */
-       if ((flags & orig_name) != 0) {
-               while (fgetc(in_file) != 0);    /* null */
-       }
-
-       /* Discard file comment if any */
-       if ((flags & comment) != 0) {
-               while (fgetc(in_file) != 0);    /* null */
-       }
-
-       if (method < 0) {
-               printf("it failed\n");
-               return(exit_code);              /* error message already emitted */
-       }
-
-       make_crc_table();
-
-       /* Decompress */
-       if (method == 8) {
-
-               int res = inflate();
-
-               if (res == 3) {
-                       error_msg(memory_exhausted);
-               } else if (res != 0) {
-                       error_msg("invalid compressed data--format violated");
-               }
-
-       } else {
-               error_msg("internal error, invalid method");
-       }
-
-       /* Get the crc and original length
-        * crc32  (see algorithm.doc)
-        * uncompressed input size modulo 2^32
-        */
-       fread(buf, 1, 8, in_file);
-
-       /* Validate decompression - crc */
-       if (((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
-               error_msg("invalid compressed data--crc error");
-       }
-       /* Validate decompression - size */
-       if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
-               error_msg("invalid compressed data--length error");
-       }
-
-       free(window);
-       free(crc_table);
-
-       return 0;
-}
-
-extern int gz_open(FILE *compressed_file, int *pid)
-{
-       int unzip_pipe[2];
-
-       if (pipe(unzip_pipe)!=0) {
-               error_msg("pipe error");
-               return(EXIT_FAILURE);
-       }
-       if ((*pid = fork()) == -1) {
-               error_msg("fork failured");
-               return(EXIT_FAILURE);
-       }
-       if (*pid==0) {
-               /* child process */
-               close(unzip_pipe[0]);
-               unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
-               printf("finished unzipping\n");
-               fflush(NULL);
-               fclose(compressed_file);
-               close(unzip_pipe[1]);
-               exit(EXIT_SUCCESS);
-       }
-       
-       close(unzip_pipe[1]);
-       return(unzip_pipe[0]);
-}
-
-extern void gz_close(int gunzip_pid)
-{
-       if (kill(gunzip_pid, SIGTERM) == -1) {
-               error_msg_and_die("***  Couldnt kill old gunzip process *** aborting");
-       }
-
-       if (waitpid(gunzip_pid, NULL, 0) == -1) {
-               printf("Couldnt wait ?");
-       }
-       free(window);
-       free(crc_table);
-}
 
 extern int gunzip_main(int argc, char **argv)
 {
+       FILE *in_file = stdin;
+       FILE *out_file = NULL;
        struct stat stat_buf;
 
        char *if_name = NULL;
@@ -1066,82 +77,74 @@ extern int gunzip_main(int argc, char **argv)
        char *delete_file_name = NULL;
 
        const int gunzip_to_stdout = 1;
-       const int gunzip_from_stdin = 2;
-       const int gunzip_force = 4;
-       const int gunzip_test = 8;
+       const int gunzip_force = 2;
+       const int gunzip_test = 4;
 
        int flags = 0;
        int opt = 0;
        int delete_old_file = FALSE;
 
        /* if called as zcat */
-       if (strcmp(applet_name, "zcat") == 0) {
-               if (argc != 2) {
-                       show_usage();
-               }
-               optind = 1;
-               flags |= (gunzip_force | gunzip_to_stdout);
-       } else {
-               /* workout flags as regular gunzip */
-               /* set default flags */
-               if (argc == 1) {
-                       flags |= (gunzip_from_stdin | gunzip_to_stdout);
-               } else {
-                       /* Parse any options */
-                       while ((opt = getopt(argc, argv, "ctfh")) != -1) {
-                               switch (opt) {
-                               case 'c':
-                                       flags |= gunzip_to_stdout;
-                                       break;
-                               case 'f':
-                                       flags |= gunzip_force;
-                                       break;
-                               case 't':
-                                       flags |= gunzip_test;
-                                       break;
-                               case 'h':
-                               default:
-                                       show_usage(); /* exit's inside usage */
-                               }
-                       }
+       if (strcmp(applet_name, "zcat") == 0)
+               flags |= gunzip_to_stdout;
+
+       while ((opt = getopt(argc, argv, "ctfhdq")) != -1) {
+               switch (opt) {
+               case 'c':
+                       flags |= gunzip_to_stdout;
+                       break;
+               case 'f':
+                       flags |= gunzip_force;
+                       break;
+               case 't':
+                       flags |= gunzip_test;
+                       break;
+               case 'd': /* Used to convert gzip to gunzip. */
+                       break;
+               case 'q':
+                       error_msg("-q option not supported, ignored");
+                       break;
+               case 'h':
+               default:
+                       show_usage(); /* exit's inside usage */
                }
        }
 
        /* Set input filename and number */
-       if (flags & gunzip_from_stdin) {
-               in_file = stdin;
-               if ((flags & gunzip_force) == 0) {
-                       error_msg_and_die("data not written to terminal. Use -f to force it.");
-               }
+       if (argv[optind] == NULL || strcmp(argv[optind], "-") == 0) {
+               flags |= gunzip_to_stdout;
        } else {
                if_name = strdup(argv[optind]);
                /* Open input file */
                in_file = xfopen(if_name, "r");
 
+               /* set the buffer size */
+               setvbuf(in_file, NULL, _IOFBF, 0x8000);
+
                /* Get the time stamp on the input file. */
                if (stat(if_name, &stat_buf) < 0) {
-                       error_msg_and_die("Couldnt stat file %s",if_name);
+                       error_msg_and_die("Couldn't stat file %s", if_name);
                }
        }
 
+       /* Check that the input is sane.  */
+       if (isatty(fileno(in_file)) && (flags & gunzip_force) == 0)
+               error_msg_and_die("compressed data not read from terminal.  Use -f to force it.");
+
        /* Set output filename and number */
-       if (flags & gunzip_to_stdout) {
-               out_file = stdout;
-               /* whats the best way to do this with streams ? */
-               if (isatty(fileno(out_file)) && ((flags & gunzip_force) == 0)) {
-                       error_msg_and_die("data not written to terminal. Use -f to force it.");
-               }
-       } else if (flags & gunzip_test) {
+       if (flags & gunzip_test) {
                out_file = xfopen("/dev/null", "w"); /* why does test use filenum 2 ? */
+       } else if (flags & gunzip_to_stdout) {
+               out_file = stdout;
        } else {
                char *extension;
                int length = strlen(if_name);
 
                delete_old_file = TRUE;
                extension = strrchr(if_name, '.');
-               if (strcmp(extension, ".gz") == 0) {
+               if (extension && strcmp(extension, ".gz") == 0) {
                        length -= 3;
-               } else if (strcmp(extension, ".tgz") == 0) {
+               } else if (extension && strcmp(extension, ".tgz") == 0) {
                        length -= 4;
                } else {
                        error_msg_and_die("Invalid extension");