/*
* inflate.c -- Not copyrighted 1992 by Mark Adler
* version c10p1, 10 January 1993
*/
/*
* Adapted for booting Linux by Hannu Savolainen 1993
* based on gzip-1.0.3
*/
#include "gzip.h"
#define slide window
#include <linux/types.h>
extern void *malloc(size_t size);
extern void free(void *ptr);
#if 0
#define DEBG(x) {register long sp asm("30"); \
printf("%s (sp=%lx)\n", x, sp);}
#define DEBG1(x) {register long sp asm("30"); \
printf(" %s (sp=%lx)\n", x, sp);}
#else
#define DEBG(x)
#define DEBG1(x)
#endif
struct huft {
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 *t; /* pointer to next level of table */
} v;
};
/* Function prototypes */
int huft_build (unsigned *, unsigned, unsigned, unsigned short *,
unsigned short *, struct huft **, int *);
int huft_free (struct huft *);
int inflate_codes (struct huft *, struct huft *, int, int);
int inflate_stored (void);
int inflate_fixed (void);
int inflate_dynamic (void);
int inflate_block (int *);
int inflate (void);
#define wp outcnt
#define flush_output(w) (wp=(w),flush_window())
/* 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
};
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
};
unsigned long bb; /* bit buffer */
unsigned bk; /* bits in bit buffer */
unsigned short mask_bits[] = {
0x0000,
0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
#define NEXTBYTE() (unsigned char)get_byte()
#define NEEDBITS(n) {while(k<(n)){b|=((unsigned long)NEXTBYTE())<<k;k+=8;}}
#define DUMPBITS(n) {b>>=(n);k-=(n);}
int lbits = 9; /* bits in base literal/length lookup table */
int dbits = 6; /* bits in base distance lookup table */
/*
* If BMAX needs to be larger than 16, then h and x[] should be
* unsigned long.
*/
#define BMAX 16 /* maximum bit length of any code (16 for explode) */
#define N_MAX 288 /* maximum number of codes in any set */
unsigned hufts; /* track memory usage */
/*
* 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.
*/
int
huft_build(b, n, s, d, e, t, m)
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) */
unsigned short *d; /* list of base values for non-simple codes */
unsigned short *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 */
DEBG("huft1 ");
/* Generate counts for each bit length */
memzero(c, sizeof(c));
p = b; i = n;
do {
c[*p++]++; /* assume all entries <= BMAX */
} while (--i);
if (c[0] == n) /* null input--all zero length codes */
{
*t = (struct huft *)NULL;
*m = 0;
return 0;
}
DEBG("huft2 ");
/* 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;
DEBG("huft3 ");
/* 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;
DEBG("huft4 ");
/* 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++);
}
DEBG("huft5 ");
/* 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);
DEBG("h6 ");
/* 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 */
DEBG("h6a ");
/* go through the bit lengths (k already is bits in shortest code) */
for (; k <= g; k++)
{
DEBG("h6b ");
a = c[k];
while (a--)
{
DEBG("h6b1 ");
/* here i is the Huffman code of length k bits for value *p */
/* make tables up to required level */
while (k > w + l)
{
DEBG1("1 ");
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 */
DEBG1("2 ");
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 */
}
}
DEBG1("3 ");
z = 1 << j; /* table entries for j-bit table */
/* allocate and link in new table */
q = (struct huft *)malloc((z + 1)*sizeof(struct huft));
DEBG1("4 ");
hufts += z + 1; /* track memory usage */
*t = q + 1; /* link to list for huft_free() */
*(t = &(q->v.t)) = (struct huft *)NULL;
u[h] = ++q; /* table starts after link */
DEBG1("5 ");
/* 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 */
}
DEBG1("6 ");
}
DEBG("h6c ");
/* 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 = *p++; /* simple code is just the value */
}
else
{
r.e = (unsigned char)e[*p - s]; /* non-simple--look up in lists */
r.v.n = d[*p++ - s];
}
DEBG("h6d ");
/* 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;
}
DEBG("h6e ");
}
DEBG("h6f ");
}
DEBG("huft7 ");
/* Return true (1) if we were given an incomplete table */
return y != 0 && g != 1;
}
int huft_free(t)
struct huft *t; /* table to free */
/* 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. */
{
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;
free(p);
p = q;
}
return 0;
}
int inflate_codes(tl, td, bl, bd)
struct huft *tl, *td; /* literal/length and distance decoder tables */
int bl, bd; /* number of bits decoded by tl[] and td[] */
/* inflate (decompress) the codes in a deflated (compressed) block.
Return an error code or zero if it all goes ok. */
{
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 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 = wp; /* 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 */
{
NEEDBITS((unsigned)bl)
if ((e = (t = tl + ((unsigned)b & ml))->e) > 16)
do {
if (e == 99)
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 */
{
slide[w++] = (unsigned char)t->v.n;
if (w == WSIZE)
{
flush_output(w);
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 */
NEEDBITS(e)
n = t->v.n + ((unsigned)b & mask_bits[e]);
DUMPBITS(e);
/* decode distance of block to copy */
NEEDBITS((unsigned)bd)
if ((e = (t = td + ((unsigned)b & md))->e) > 16)
do {
if (e == 99)
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)
/* 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(slide + w, slide + d, e);
w += e;
d += e;
}
else /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
do {
slide[w++] = slide[d++];
} while (--e);
if (w == WSIZE)
{
flush_output(w);
w = 0;
}
} while (n);
}
}
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
bk = k;
/* done */
return 0;
}
int inflate_stored()
/* "decompress" an inflated type 0 (stored) block. */
{
unsigned n; /* number of bytes in block */
unsigned w; /* current window position */
register unsigned long b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
DEBG("<stor");
/* make local copies of globals */
b = bb; /* initialize bit buffer */
k = bk;
w = wp; /* initialize window position */
/* go to byte boundary */
n = k & 7;
DUMPBITS(n);
/* get the length and its complement */
NEEDBITS(16)
n = ((unsigned)b & 0xffff);
DUMPBITS(16)
NEEDBITS(16)
if (n != (unsigned)((~b) & 0xffff))
return 1; /* error in compressed data */
DUMPBITS(16)
/* read and output the compressed data */
while (n--)
{
NEEDBITS(8)
slide[w++] = (unsigned char)b;
if (w == WSIZE)
{
flush_output(w);
w = 0;
}
DUMPBITS(8)
}
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
bk = k;
DEBG(">");
return 0;
}
int 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 */
struct huft *tl; /* literal/length code table */
struct huft *td; /* distance code table */
int bl; /* lookup bits for tl */
int bd; /* lookup bits for td */
unsigned l[288]; /* length list for huft_build */
DEBG("<fix");
/* 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);
DEBG(">");
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;
}
int inflate_dynamic()
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
{
int i; /* temporary variables */
unsigned j;
unsigned l; /* last length */
unsigned m; /* mask for bit lengths table */
unsigned n; /* number of lengths to get */
struct huft *tl; /* literal/length code table */
struct huft *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 */
#ifdef PKZIP_BUG_WORKAROUND
unsigned ll[288+32]; /* literal/length and distance code lengths */
#else
unsigned ll[286+30]; /* literal/length and distance code lengths */
#endif
register unsigned long b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
DEBG("<dyn");
/* make local bit buffer */
b = bb;
k = 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)
#ifdef PKZIP_BUG_WORKAROUND
if (nl > 288 || nd > 32)
#else
if (nl > 286 || nd > 30)
#endif
return 1; /* bad lengths */
DEBG("dyn1 ");
/* read in bit-length-code lengths */
for (j = 0; j < nb; j++)
{
NEEDBITS(3)
ll[border[j]] = (unsigned)b & 7;
DUMPBITS(3)
}
for (; j < 19; j++)
ll[border[j]] = 0;
DEBG("dyn2 ");
/* 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 */
}
DEBG("dyn3 ");
/* read in literal and distance code lengths */
n = nl + nd;
m = mask_bits[bl];
i = l = 0;
while ((unsigned)i < n)
{
NEEDBITS((unsigned)bl)
j = (td = tl + ((unsigned)b & m))->b;
DUMPBITS(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 */
{
NEEDBITS(2)
j = 3 + ((unsigned)b & 3);
DUMPBITS(2)
if ((unsigned)i + j > n)
return 1;
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)
return 1;
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)
return 1;
while (j--)
ll[i++] = 0;
l = 0;
}
}
DEBG("dyn4 ");
/* free decoding table for trees */
huft_free(tl);
DEBG("dyn5 ");
/* restore the global bit buffer */
bb = b;
bk = k;
DEBG("dyn5a ");
/* build the decoding tables for literal/length and distance codes */
bl = lbits;
if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
{
DEBG("dyn5b ");
if (i == 1) {
unzip_error("incomplete literal tree");
huft_free(tl);
}
return i; /* incomplete code set */
}
DEBG("dyn5c ");
bd = dbits;
if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
{
DEBG("dyn5d ");
if (i == 1) {
unzip_error("incomplete distance tree");
#ifdef PKZIP_BUG_WORKAROUND
i = 0;
}
#else
huft_free(td);
}
huft_free(tl);
return i; /* incomplete code set */
#endif
}
DEBG("dyn6 ");
/* decompress until an end-of-block code */
if (inflate_codes(tl, td, bl, bd))
return 1;
DEBG("dyn7 ");
/* free the decoding tables, return */
huft_free(tl);
huft_free(td);
DEBG(">");
return 0;
}
int inflate_block(e)
int *e; /* last block flag */
/* decompress an inflated block */
{
unsigned t; /* block type */
register unsigned long b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
DEBG("<blk");
/* make local bit buffer */
b = bb;
k = bk;
/* read in last block bit */
NEEDBITS(1)
*e = (int)b & 1;
DUMPBITS(1)
/* read in block type */
NEEDBITS(2)
t = (unsigned)b & 3;
DUMPBITS(2)
/* restore the global bit buffer */
bb = b;
bk = k;
/* inflate that block type */
if (t == 2)
return inflate_dynamic();
if (t == 0)
return inflate_stored();
if (t == 1)
return inflate_fixed();
DEBG(">");
/* bad block type */
return 2;
}
int inflate()
/* decompress an inflated entry */
{
int e; /* last block flag */
int r; /* result code */
unsigned h; /* maximum struct huft's malloc'ed */
/* initialize window, bit buffer */
wp = 0;
bk = 0;
bb = 0;
/* decompress until the last block */
h = 0;
do {
hufts = 0;
if ((r = inflate_block(&e)) != 0)
return r;
if (hufts > h)
h = hufts;
} while (!e);
/* Undo too much lookahead. The next read will be byte aligned so we
* can discard unused bits in the last meaningful byte.
*/
while (bk >= 8) {
bk -= 8;
inptr--;
}
/* flush out slide */
flush_output(wp);
/* return success */
return 0;
}