--- /dev/null
+/* gzio.c - decompression support for gzip */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 1999,2005 Free Software Foundation, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * Most of this file was originally the source file "inflate.c", written
+ * by Mark Adler. It has been very heavily modified. In particular, the
+ * original would run through the whole file at once, and this version can
+ * be stopped and restarted on any boundary during the decompression process.
+ *
+ * The license and header comments that file are included here.
+ */
+
+/* inflate.c -- Not copyrighted 1992 by Mark Adler
+ version c10p1, 10 January 1993 */
+
+/* You can do whatever you like with this source file, though I would
+ prefer that if you modify it and redistribute it that you include
+ comments to that effect with your name and the date. Thank you.
+ */
+
+#include <grub/err.h>
+#include <grub/types.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+#include <grub/fs.h>
+#include <grub/file.h>
+#include <grub/gzio.h>
+
+/*
+ * Window Size
+ *
+ * This must be a power of two, and at least 32K for zip's deflate method
+ */
+
+#define WSIZE 0x8000
+
+
+#define INBUFSIZ 0x2000
+
+/* The state stored in filesystem-specific data. */
+struct grub_gzio
+{
+ /* The underlyding file object. */
+ grub_file_t file;
+ /* The offset at which the data starts in the underlyding file. */
+ grub_ssize_t data_offset;
+ /* The type of current block. */
+ int block_type;
+ /* The length of current block. */
+ int block_len;
+ /* The flag of the last block. */
+ int last_block;
+ /* The flag of codes. */
+ int code_state;
+ /* The length of a copy. */
+ unsigned inflate_n;
+ /* The index of a copy. */
+ unsigned inflate_d;
+ /* The input buffer. */
+ grub_uint8_t inbuf[INBUFSIZ];
+ int inbuf_d;
+ /* The bit buffer. */
+ unsigned long bb;
+ /* The bits in the bit buffer. */
+ unsigned bk;
+ /* Ths sliding window in uncompressed data. */
+ grub_uint8_t slide[WSIZE];
+ /* Current position in the slide. */
+ unsigned wp;
+ /* The literal/length code table. */
+ struct huft *tl;
+ /* The distance code table. */
+ struct huft *td;
+ /* The lookup bits for the literal/length code table. */
+ int bl;
+ /* The lookup bits for the distance code table. */
+ int bd;
+ /* The original offset value. */
+ grub_ssize_t saved_offset;
+};
+typedef struct grub_gzio *grub_gzio_t;
+
+/* Declare the filesystem structure for grub_gzio_open. */
+static struct grub_fs grub_gzio_fs;
+
+/* Function prototypes */
+static void initialize_tables (grub_file_t file);
+
+/* Eat variable-length header fields. */
+static int
+eat_field (grub_file_t file, int len)
+{
+ char ch = 1;
+ int not_retval = 1;
+
+ do
+ {
+ if (len >= 0)
+ {
+ if (! (len--))
+ break;
+ }
+ else
+ {
+ if (! ch)
+ break;
+ }
+ }
+ while ((not_retval = grub_file_read (file, &ch, 1)) == 1);
+
+ return ! not_retval;
+}
+
+
+/* Little-Endian defines for the 2-byte magic numbers for gzip files. */
+#define GZIP_MAGIC grub_le_to_cpu16 (0x8B1F)
+#define OLD_GZIP_MAGIC grub_le_to_cpu16 (0x9E1F)
+
+/* Compression methods (see algorithm.doc) */
+#define STORED 0
+#define COMPRESSED 1
+#define PACKED 2
+#define LZHED 3
+/* methods 4 to 7 reserved */
+#define DEFLATED 8
+#define MAX_METHODS 9
+
+/* gzip flag byte */
+#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
+#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
+#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
+#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
+#define COMMENT 0x10 /* bit 4 set: file comment present */
+#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
+#define RESERVED 0xC0 /* bit 6,7: reserved */
+
+#define UNSUPPORTED_FLAGS (CONTINUATION | ENCRYPTED | RESERVED)
+
+/* inflate block codes */
+#define INFLATE_STORED 0
+#define INFLATE_FIXED 1
+#define INFLATE_DYNAMIC 2
+
+typedef unsigned char uch;
+typedef unsigned short ush;
+typedef unsigned long ulg;
+
+static int
+test_header (grub_file_t file)
+{
+ unsigned char buf[10];
+ grub_gzio_t gzio = file->data;
+
+ if (grub_file_tell (gzio->file) != 0)
+ grub_file_seek (gzio->file, 0);
+
+ /*
+ * This checks if the file is gzipped. If a problem occurs here
+ * (other than a real error with the disk) then we don't think it
+ * is a compressed file, and simply mark it as such.
+ */
+ if (grub_file_read (gzio->file, buf, 10) != 10
+ || ((*((grub_uint16_t *) buf) != GZIP_MAGIC)
+ && (*((grub_uint16_t *) buf) != OLD_GZIP_MAGIC)))
+ {
+ grub_error (GRUB_ERR_BAD_FILE_TYPE, "no gzip magic found");
+ return 0;
+ }
+
+ /*
+ * This does consistency checking on the header data. If a
+ * problem occurs from here on, then we have corrupt or otherwise
+ * bad data, and the error should be reported to the user.
+ */
+ if (buf[2] != DEFLATED
+ || (buf[3] & UNSUPPORTED_FLAGS)
+ || ((buf[3] & EXTRA_FIELD)
+ && (grub_file_read (gzio->file, buf, 2) != 2
+ || eat_field (gzio->file,
+ grub_le_to_cpu16 (*((grub_uint16_t *) buf)))))
+ || ((buf[3] & ORIG_NAME) && eat_field (gzio->file, -1))
+ || ((buf[3] & COMMENT) && eat_field (gzio->file, -1)))
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA, "unsupported gzip format");
+ return 0;
+ }
+
+ gzio->data_offset = grub_file_tell (gzio->file);
+
+ grub_file_seek (gzio->file, grub_file_size (gzio->file) - 8);
+
+ if (grub_file_read (gzio->file, buf, 8) != 8)
+ {
+ grub_error (GRUB_ERR_BAD_FILE_TYPE, "unsupported gzip format");
+ return 0;
+ }
+
+ file->size = grub_le_to_cpu32 (*((grub_uint32_t *) (buf + 4)));
+
+ initialize_tables (file);
+
+ return 1;
+}
+
+
+/* Huffman code lookup table entry--this entry is four bytes for machines
+ that have 16-bit pointers (e.g. PC's in the small or medium model).
+ Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
+ means that v is a literal, 16 < e < 32 means that v is a pointer to
+ the next table, which codes e - 16 bits, and lastly e == 99 indicates
+ an unused code. If a code with e == 99 is looked up, this implies an
+ error in the data. */
+struct huft
+{
+ uch e; /* number of extra bits or operation */
+ uch b; /* number of bits in this code or subcode */
+ union
+ {
+ ush n; /* literal, length base, or distance base */
+ struct huft *t; /* pointer to next level of table */
+ }
+ v;
+};
+
+
+/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
+ stream to find repeated byte strings. This is implemented here as a
+ circular buffer. The index is updated simply by incrementing and then
+ and'ing with 0x7fff (32K-1). */
+/* It is left to other modules to supply the 32K area. It is assumed
+ to be usable as if it were declared "uch slide[32768];" or as just
+ "uch *slide;" and then malloc'ed in the latter case. The definition
+ must be in unzip.h, included above. */
+
+
+/* Tables for deflate from PKZIP's appnote.txt. */
+static unsigned bitorder[] =
+{ /* 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};
+static ush 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 ush 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 ush 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 ush 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};
+
+
+/*
+ Huffman code decoding is performed using a multi-level table lookup.
+ The fastest way to decode is to simply build a lookup table whose
+ size is determined by the longest code. However, the time it takes
+ to build this table can also be a factor if the data being decoded
+ is not very long. The most common codes are necessarily the
+ shortest codes, so those codes dominate the decoding time, and hence
+ the speed. The idea is you can have a shorter table that decodes the
+ shorter, more probable codes, and then point to subsidiary tables for
+ the longer codes. The time it costs to decode the longer codes is
+ then traded against the time it takes to make longer tables.
+
+ This results of this trade are in the variables lbits and dbits
+ below. lbits is the number of bits the first level table for literal/
+ length codes can decode in one step, and dbits is the same thing for
+ the distance codes. Subsequent tables are also less than or equal to
+ those sizes. These values may be adjusted either when all of the
+ codes are shorter than that, in which case the longest code length in
+ bits is used, or when the shortest code is *longer* than the requested
+ table size, in which case the length of the shortest code in bits is
+ used.
+
+ There are two different values for the two tables, since they code a
+ different number of possibilities each. The literal/length table
+ codes 286 possible values, or in a flat code, a little over eight
+ bits. The distance table codes 30 possible values, or a little less
+ than five bits, flat. The optimum values for speed end up being
+ about one bit more than those, so lbits is 8+1 and dbits is 5+1.
+ The optimum values may differ though from machine to machine, and
+ possibly even between compilers. Your mileage may vary.
+ */
+
+
+static int lbits = 9; /* bits in base literal/length lookup table */
+static int dbits = 6; /* bits in base distance lookup table */
+
+
+/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
+#define BMAX 16 /* maximum bit length of any code (16 for explode) */
+#define N_MAX 288 /* maximum number of codes in any set */
+
+
+/* Macros for inflate() bit peeking and grabbing.
+ The usage is:
+
+ NEEDBITS(j)
+ x = b & mask_bits[j];
+ DUMPBITS(j)
+
+ where NEEDBITS makes sure that b has at least j bits in it, and
+ DUMPBITS removes the bits from b. The macros use the variable k
+ for the number of bits in b. Normally, b and k are register
+ variables for speed, and are initialized at the beginning of a
+ routine that uses these macros from a global bit buffer and count.
+
+ If we assume that EOB will be the longest code, then we will never
+ ask for bits with NEEDBITS that are beyond the end of the stream.
+ So, NEEDBITS should not read any more bytes than are needed to
+ meet the request. Then no bytes need to be "returned" to the buffer
+ at the end of the last block.
+
+ However, this assumption is not true for fixed blocks--the EOB code
+ is 7 bits, but the other literal/length codes can be 8 or 9 bits.
+ (The EOB code is shorter than other codes because fixed blocks are
+ generally short. So, while a block always has an EOB, many other
+ literal/length codes have a significantly lower probability of
+ showing up at all.) However, by making the first table have a
+ lookup of seven bits, the EOB code will be found in that first
+ lookup, and so will not require that too many bits be pulled from
+ the stream.
+ */
+
+static ush mask_bits[] =
+{
+ 0x0000,
+ 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
+ 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
+};
+
+#define NEEDBITS(n) do {while(k<(n)){b|=((ulg)get_byte(file))<<k;k+=8;}} while (0)
+#define DUMPBITS(n) do {b>>=(n);k-=(n);} while (0)
+
+static int
+get_byte (grub_file_t file)
+{
+ grub_gzio_t gzio = file->data;
+
+ if (grub_file_tell (gzio->file) == gzio->data_offset
+ || gzio->inbuf_d == INBUFSIZ)
+ {
+ gzio->inbuf_d = 0;
+ grub_file_read (gzio->file, gzio->inbuf, INBUFSIZ);
+ }
+
+ return gzio->inbuf[gzio->inbuf_d++];
+}
+
+/* more function prototypes */
+static int huft_build (unsigned *, unsigned, unsigned, ush *, ush *,
+ struct huft **, int *);
+static int huft_free (struct huft *);
+static int inflate_codes_in_window (grub_file_t);
+
+
+/* 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. */
+
+static int
+huft_build (unsigned *b, /* code lengths in bits (all assumed <= BMAX) */
+ unsigned n, /* number of codes (assumed <= N_MAX) */
+ unsigned s, /* number of simple-valued codes (0..s-1) */
+ ush * d, /* list of base values for non-simple codes */
+ ush * e, /* list of extra bits for non-simple codes */
+ struct huft **t, /* result: starting table */
+ int *m) /* maximum lookup bits, returns actual */
+{
+ 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 struct huft *q; /* points to current table */
+ struct huft r; /* table entry for structure assignment */
+ struct huft *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 */
+ grub_memset ((char *) 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 = (struct huft *) 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] = (struct huft *) NULL; /* just to keep compilers happy */
+ q = (struct huft *) 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 = (unsigned) (g - w)) > (unsigned) l ? (unsigned) 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 */
+ q = (struct huft *) grub_malloc ((z + 1) * sizeof (struct huft));
+ if (! q)
+ {
+ if (h)
+ huft_free (u[0]);
+ return 3;
+ }
+
+ *t = q + 1; /* link to list for huft_free() */
+ *(t = &(q->v.t)) = (struct huft *) 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 = (uch) l; /* bits to dump before this table */
+ r.e = (uch) (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 = (uch) (k - w);
+ if (p >= v + n)
+ r.e = 99; /* out of values--invalid code */
+ else if (*p < s)
+ {
+ r.e = (uch) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
+ r.v.n = (ush) (*p); /* simple code is just the value */
+ p++; /* one compiler does not like *p++ */
+ }
+ else
+ {
+ r.e = (uch) 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;
+}
+
+
+/* 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. */
+static int
+huft_free (struct huft *t)
+{
+ register struct huft *p, *q;
+
+
+ /* Go through linked list, freeing from the malloced (t[-1]) address. */
+ p = t;
+ while (p != (struct huft *) NULL)
+ {
+ q = (--p)->v.t;
+ grub_free ((char *) p);
+ p = q;
+ }
+ return 0;
+}
+
+
+/*
+ * inflate (decompress) the codes in a deflated (compressed) block.
+ * Return an error code or zero if it all goes ok.
+ */
+
+static int
+inflate_codes_in_window (grub_file_t file)
+{
+ register unsigned e; /* table entry flag/number of extra bits */
+ unsigned n, d; /* length and index for copy */
+ unsigned w; /* current window position */
+ struct huft *t; /* pointer to table entry */
+ unsigned ml, md; /* masks for bl and bd bits */
+ register ulg b; /* bit buffer */
+ register unsigned k; /* number of bits in bit buffer */
+ grub_gzio_t gzio = file->data;
+
+ /* make local copies of globals */
+ d = gzio->inflate_d;
+ n = gzio->inflate_n;
+ b = gzio->bb; /* initialize bit buffer */
+ k = gzio->bk;
+ w = gzio->wp; /* initialize window position */
+
+ /* inflate the coded data */
+ ml = mask_bits[gzio->bl]; /* precompute masks for speed */
+ md = mask_bits[gzio->bd];
+ for (;;) /* do until end of block */
+ {
+ if (! gzio->code_state)
+ {
+ NEEDBITS ((unsigned) gzio->bl);
+ if ((e = (t = gzio->tl + ((unsigned) b & ml))->e) > 16)
+ do
+ {
+ if (e == 99)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "an unused code found");
+ return 1;
+ }
+ DUMPBITS (t->b);
+ e -= 16;
+ NEEDBITS (e);
+ }
+ while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
+ DUMPBITS (t->b);
+
+ if (e == 16) /* then it's a literal */
+ {
+ gzio->slide[w++] = (uch) t->v.n;
+ if (w == WSIZE)
+ break;
+ }
+ else
+ /* it's an EOB or a length */
+ {
+ /* exit if end of block */
+ if (e == 15)
+ {
+ gzio->block_len = 0;
+ break;
+ }
+
+ /* get length of block to copy */
+ NEEDBITS (e);
+ n = t->v.n + ((unsigned) b & mask_bits[e]);
+ DUMPBITS (e);
+
+ /* decode distance of block to copy */
+ NEEDBITS ((unsigned) gzio->bd);
+ if ((e = (t = gzio->td + ((unsigned) b & md))->e) > 16)
+ do
+ {
+ if (e == 99)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "an unused code found");
+ return 1;
+ }
+ DUMPBITS (t->b);
+ e -= 16;
+ NEEDBITS (e);
+ }
+ while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e)
+ > 16);
+ DUMPBITS (t->b);
+ NEEDBITS (e);
+ d = w - t->v.n - ((unsigned) b & mask_bits[e]);
+ DUMPBITS (e);
+ gzio->code_state++;
+ }
+ }
+
+ if (gzio->code_state)
+ {
+ /* do the copy */
+ do
+ {
+ n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n
+ : e);
+
+ if (w - d >= e)
+ {
+ grub_memmove (gzio->slide + w, gzio->slide + d, e);
+ w += e;
+ d += e;
+ }
+ else
+ /* purposefully use the overlap for extra copies here!! */
+ {
+ while (e--)
+ gzio->slide[w++] = gzio->slide[d++];
+ }
+
+ if (w == WSIZE)
+ break;
+ }
+ while (n);
+
+ if (! n)
+ gzio->code_state--;
+
+ /* did we break from the loop too soon? */
+ if (w == WSIZE)
+ break;
+ }
+ }
+
+ /* restore the globals from the locals */
+ gzio->inflate_d = d;
+ gzio->inflate_n = n;
+ gzio->wp = w; /* restore global window pointer */
+ gzio->bb = b; /* restore global bit buffer */
+ gzio->bk = k;
+
+ return ! gzio->block_len;
+}
+
+
+/* get header for an inflated type 0 (stored) block. */
+
+static void
+init_stored_block (grub_file_t file)
+{
+ register ulg b; /* bit buffer */
+ register unsigned k; /* number of bits in bit buffer */
+ grub_gzio_t gzio = file->data;
+
+ /* make local copies of globals */
+ b = gzio->bb; /* initialize bit buffer */
+ k = gzio->bk;
+
+ /* go to byte boundary */
+ DUMPBITS (k & 7);
+
+ /* get the length and its complement */
+ NEEDBITS (16);
+ gzio->block_len = ((unsigned) b & 0xffff);
+ DUMPBITS (16);
+ NEEDBITS (16);
+ if (gzio->block_len != (int) ((~b) & 0xffff))
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "the length of a stored block does not match");
+ DUMPBITS (16);
+
+ /* restore global variables */
+ gzio->bb = b;
+ gzio->bk = k;
+}
+
+
+/* get header for an inflated type 1 (fixed Huffman codes) block. We should
+ either replace this with a custom decoder, or at least precompute the
+ Huffman tables. */
+
+static void
+init_fixed_block (grub_file_t file)
+{
+ int i; /* temporary variable */
+ unsigned l[288]; /* length list for huft_build */
+ grub_gzio_t gzio = file->data;
+
+ /* 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;
+ gzio->bl = 7;
+ if (huft_build (l, 288, 257, cplens, cplext, &gzio->tl, &gzio->bl) != 0)
+ {
+ if (grub_errno == GRUB_ERR_NONE)
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "failed in building a Huffman code table");
+ return;
+ }
+
+ /* set up distance table */
+ for (i = 0; i < 30; i++) /* make an incomplete code set */
+ l[i] = 5;
+ gzio->bd = 5;
+ if (huft_build (l, 30, 0, cpdist, cpdext, &gzio->td, &gzio->bd) > 1)
+ {
+ if (grub_errno == GRUB_ERR_NONE)
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "failed in building a Huffman code table");
+ huft_free (gzio->tl);
+ gzio->tl = 0;
+ return;
+ }
+
+ /* indicate we're now working on a block */
+ gzio->code_state = 0;
+ gzio->block_len++;
+}
+
+
+/* get header for an inflated type 2 (dynamic Huffman codes) block. */
+
+static void
+init_dynamic_block (grub_file_t file)
+{
+ int i; /* temporary variables */
+ unsigned j;
+ unsigned l; /* last length */
+ unsigned m; /* mask for bit lengths table */
+ unsigned n; /* number of lengths to get */
+ 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 ulg b; /* bit buffer */
+ register unsigned k; /* number of bits in bit buffer */
+ grub_gzio_t gzio = file->data;
+
+ /* make local bit buffer */
+ b = gzio->bb;
+ k = gzio->bk;
+
+ /* read in table lengths */
+ NEEDBITS (5);
+ nl = 257 + ((unsigned) b & 0x1f); /* number of literal/length codes */
+ DUMPBITS (5);
+ NEEDBITS (5);
+ nd = 1 + ((unsigned) b & 0x1f); /* number of distance codes */
+ DUMPBITS (5);
+ NEEDBITS (4);
+ nb = 4 + ((unsigned) b & 0xf); /* number of bit length codes */
+ DUMPBITS (4);
+ if (nl > 286 || nd > 30)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA, "too much data");
+ return;
+ }
+
+ /* read in bit-length-code lengths */
+ for (j = 0; j < nb; j++)
+ {
+ NEEDBITS (3);
+ ll[bitorder[j]] = (unsigned) b & 7;
+ DUMPBITS (3);
+ }
+ for (; j < 19; j++)
+ ll[bitorder[j]] = 0;
+
+ /* build decoding table for trees--single level, 7 bit lookup */
+ gzio->bl = 7;
+ if (huft_build (ll, 19, 19, NULL, NULL, &gzio->tl, &gzio->bl) != 0)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "failed in building a Huffman code table");
+ return;
+ }
+
+ /* read in literal and distance code lengths */
+ n = nl + nd;
+ m = mask_bits[gzio->bl];
+ i = l = 0;
+ while ((unsigned) i < n)
+ {
+ NEEDBITS ((unsigned) gzio->bl);
+ j = (gzio->td = gzio->tl + ((unsigned) b & m))->b;
+ DUMPBITS (j);
+ j = gzio->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 */
+ {
+ NEEDBITS (2);
+ j = 3 + ((unsigned) b & 3);
+ DUMPBITS (2);
+ if ((unsigned) i + j > n)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA, "too many codes found");
+ return;
+ }
+ while (j--)
+ ll[i++] = l;
+ }
+ else if (j == 17) /* 3 to 10 zero length codes */
+ {
+ NEEDBITS (3);
+ j = 3 + ((unsigned) b & 7);
+ DUMPBITS (3);
+ if ((unsigned) i + j > n)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA, "too many codes found");
+ return;
+ }
+ while (j--)
+ ll[i++] = 0;
+ l = 0;
+ }
+ else
+ /* j == 18: 11 to 138 zero length codes */
+ {
+ NEEDBITS (7);
+ j = 11 + ((unsigned) b & 0x7f);
+ DUMPBITS (7);
+ if ((unsigned) i + j > n)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA, "too many codes found");
+ return;
+ }
+ while (j--)
+ ll[i++] = 0;
+ l = 0;
+ }
+ }
+
+ /* free decoding table for trees */
+ huft_free (gzio->tl);
+ gzio->td = 0;
+ gzio->tl = 0;
+
+ /* restore the global bit buffer */
+ gzio->bb = b;
+ gzio->bk = k;
+
+ /* build the decoding tables for literal/length and distance codes */
+ gzio->bl = lbits;
+ if (huft_build (ll, nl, 257, cplens, cplext, &gzio->tl, &gzio->bl) != 0)
+ {
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "failed in building a Huffman code table");
+ return;
+ }
+ gzio->bd = dbits;
+ if (huft_build (ll + nl, nd, 0, cpdist, cpdext, &gzio->td, &gzio->bd) != 0)
+ {
+ huft_free (gzio->tl);
+ gzio->tl = 0;
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "failed in building a Huffman code table");
+ return;
+ }
+
+ /* indicate we're now working on a block */
+ gzio->code_state = 0;
+ gzio->block_len++;
+}
+
+
+static void
+get_new_block (grub_file_t file)
+{
+ register ulg b; /* bit buffer */
+ register unsigned k; /* number of bits in bit buffer */
+ grub_gzio_t gzio = file->data;
+
+ /* make local bit buffer */
+ b = gzio->bb;
+ k = gzio->bk;
+
+ /* read in last block bit */
+ NEEDBITS (1);
+ gzio->last_block = (int) b & 1;
+ DUMPBITS (1);
+
+ /* read in block type */
+ NEEDBITS (2);
+ gzio->block_type = (unsigned) b & 3;
+ DUMPBITS (2);
+
+ /* restore the global bit buffer */
+ gzio->bb = b;
+ gzio->bk = k;
+
+ switch (gzio->block_type)
+ {
+ case INFLATE_STORED:
+ init_stored_block (file);
+ break;
+ case INFLATE_FIXED:
+ init_fixed_block (file);
+ break;
+ case INFLATE_DYNAMIC:
+ init_dynamic_block (file);
+ break;
+ default:
+ break;
+ }
+}
+
+
+static void
+inflate_window (grub_file_t file)
+{
+ grub_gzio_t gzio = file->data;
+
+ /* initialize window */
+ gzio->wp = 0;
+
+ /*
+ * Main decompression loop.
+ */
+
+ while (gzio->wp < WSIZE && grub_errno == GRUB_ERR_NONE)
+ {
+ if (! gzio->block_len)
+ {
+ if (gzio->last_block)
+ break;
+
+ get_new_block (file);
+ }
+
+ if (gzio->block_type > INFLATE_DYNAMIC)
+ grub_error (GRUB_ERR_BAD_GZIP_DATA,
+ "unknown block type %d", gzio->block_type);
+
+ if (grub_errno != GRUB_ERR_NONE)
+ return;
+
+ /*
+ * Expand stored block here.
+ */
+ if (gzio->block_type == INFLATE_STORED)
+ {
+ int w = gzio->wp;
+
+ /*
+ * This is basically a glorified pass-through
+ */
+
+ while (gzio->block_len && w < WSIZE && grub_errno == GRUB_ERR_NONE)
+ {
+ gzio->slide[w++] = get_byte (file);
+ gzio->block_len--;
+ }
+
+ gzio->wp = w;
+
+ continue;
+ }
+
+ /*
+ * Expand other kind of block.
+ */
+
+ if (inflate_codes_in_window (file))
+ {
+ huft_free (gzio->tl);
+ huft_free (gzio->td);
+ gzio->tl = 0;
+ gzio->td = 0;
+ }
+ }
+
+ gzio->saved_offset += WSIZE;
+
+ /* XXX do CRC calculation here! */
+}
+
+
+static void
+initialize_tables (grub_file_t file)
+{
+ grub_gzio_t gzio = file->data;
+
+ gzio->saved_offset = 0;
+ grub_file_seek (gzio->file, gzio->data_offset);
+
+ /* Initialize the bit buffer. */
+ gzio->bk = 0;
+ gzio->bb = 0;
+
+ /* Reset partial decompression code. */
+ gzio->last_block = 0;
+ gzio->block_len = 0;
+
+ /* Reset memory allocation stuff. */
+ huft_free (gzio->tl);
+ huft_free (gzio->td);
+}
+
+
+/* Open a new decompressing object on the top of IO. If TRANSPARENT is true,
+ even if IO does not contain data compressed by gzip, return a valid file
+ object. Note that this function won't close IO, even if an error occurs. */
+grub_file_t
+grub_gzio_open (grub_file_t io, int transparent)
+{
+ grub_file_t file;
+ grub_gzio_t gzio = 0;
+
+ file = (grub_file_t) grub_malloc (sizeof (*file));
+ if (! file)
+ return 0;
+
+ gzio = grub_malloc (sizeof (*gzio));
+ if (! gzio)
+ {
+ grub_free (file);
+ return 0;
+ }
+
+ grub_memset (gzio, 0, sizeof (*gzio));
+ gzio->file = io;
+
+ file->device = io->device;
+ file->offset = 0;
+ file->data = gzio;
+ file->read_hook = 0;
+ file->fs = &grub_gzio_fs;
+
+ if (! test_header (file))
+ {
+ grub_free (gzio);
+ grub_free (file);
+ grub_file_seek (io, 0);
+
+ if (grub_errno == GRUB_ERR_BAD_FILE_TYPE && transparent)
+ {
+ grub_errno = GRUB_ERR_NONE;
+ return io;
+ }
+ else
+ return 0;
+ }
+
+ return file;
+}
+
+/* This is similar to grub_gzio_open, but takes a file name as an argument. */
+grub_file_t
+grub_gzfile_open (const char *name, int transparent)
+{
+ grub_file_t io, file;
+
+ io = grub_file_open (name);
+ if (! io)
+ return 0;
+
+ file = grub_gzio_open (io, transparent);
+ if (! file)
+ {
+ grub_file_close (io);
+ return 0;
+ }
+
+ return file;
+}
+
+static grub_ssize_t
+grub_gzio_read (grub_file_t file, char *buf, grub_ssize_t len)
+{
+ grub_ssize_t ret = 0;
+ grub_gzio_t gzio = file->data;
+ grub_ssize_t offset;
+
+ /* Do we reset decompression to the beginning of the file? */
+ if (gzio->saved_offset > file->offset + WSIZE)
+ initialize_tables (file);
+
+ /*
+ * This loop operates upon uncompressed data only. The only
+ * special thing it does is to make sure the decompression
+ * window is within the range of data it needs.
+ */
+
+ offset = file->offset;
+
+ while (len > 0 && grub_errno == GRUB_ERR_NONE)
+ {
+ register grub_ssize_t size;
+ register char *srcaddr;
+
+ while (offset >= gzio->saved_offset)
+ inflate_window (file);
+
+ srcaddr = (char *) ((offset & (WSIZE - 1)) + gzio->slide);
+ size = gzio->saved_offset - file->offset;
+ if (size > len)
+ size = len;
+
+ grub_memmove (buf, srcaddr, size);
+
+ buf += size;
+ len -= size;
+ ret += size;
+ offset += size;
+ }
+
+ if (grub_errno != GRUB_ERR_NONE)
+ ret = -1;
+
+ return ret;
+}
+
+/* Release everything, including the underlying file object. */
+static grub_err_t
+grub_gzio_close (grub_file_t file)
+{
+ grub_gzio_t gzio = file->data;
+
+ grub_file_close (gzio->file);
+ huft_free (gzio->tl);
+ huft_free (gzio->td);
+ grub_free (gzio);
+
+ /* No need to close the same device twice. */
+ file->device = 0;
+
+ return grub_errno;
+}
+
+\f
+
+static struct grub_fs grub_gzio_fs =
+ {
+ .name = "gzio",
+ .dir = 0,
+ .open = 0,
+ .read = grub_gzio_read,
+ .close = grub_gzio_close,
+ .label = 0,
+ .next = 0
+ };
projects / thirdparty / grub.git / commitdiff
