/* * 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 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())<>=(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(""); 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(" 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(" 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(""); /* 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; }