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lib/inflate.c
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#define DEBG(x) #define DEBG1(x) /* 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 * |
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* Nicolas Pitre <nico@fluxnic.net>, 1999/04/14 : |
1da177e4c Linux-2.6.12-rc2 |
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* Little mods for all variable to reside either into rodata or bss segments * by marking constant variables with 'const' and initializing all the others * at run-time only. This allows for the kernel uncompressor to run * directly from Flash or ROM memory on embedded systems. */ /* Inflate deflated (PKZIP's method 8 compressed) data. The compression method searches for as much of the current string of bytes (up to a length of 258) in the previous 32 K bytes. If it doesn't find any matches (of at least length 3), it codes the next byte. Otherwise, it codes the length of the matched string and its distance backwards from the current position. There is a single Huffman code that codes both single bytes (called "literals") and match lengths. A second Huffman code codes the distance information, which follows a length code. Each length or distance code actually represents a base value and a number of "extra" (sometimes zero) bits to get to add to the base value. At the end of each deflated block is a special end-of-block (EOB) literal/ length code. The decoding process is basically: get a literal/length code; if EOB then done; if a literal, emit the decoded byte; if a length then get the distance and emit the referred-to bytes from the sliding window of previously emitted data. There are (currently) three kinds of inflate blocks: stored, fixed, and dynamic. The compressor deals with some chunk of data at a time, and decides which method to use on a chunk-by-chunk basis. A chunk might typically be 32 K or 64 K. If the chunk is incompressible, then the "stored" method is used. In this case, the bytes are simply stored as is, eight bits per byte, with none of the above coding. The bytes are preceded by a count, since there is no longer an EOB code. If the data is compressible, then either the fixed or dynamic methods are used. In the dynamic method, the compressed data is preceded by an encoding of the literal/length and distance Huffman codes that are to be used to decode this block. The representation is itself Huffman coded, and so is preceded by a description of that code. These code descriptions take up a little space, and so for small blocks, there is a predefined set of codes, called the fixed codes. The fixed method is used if the block codes up smaller that way (usually for quite small chunks), otherwise the dynamic method is used. In the latter case, the codes are customized to the probabilities in the current block, and so can code it much better than the pre-determined fixed codes. The Huffman codes themselves are decoded using a multi-level table lookup, in order to maximize the speed of decoding plus the speed of building the decoding tables. See the comments below that precede the lbits and dbits tuning parameters. */ /* Notes beyond the 1.93a appnote.txt: 1. Distance pointers never point before the beginning of the output stream. 2. Distance pointers can point back across blocks, up to 32k away. 3. There is an implied maximum of 7 bits for the bit length table and 15 bits for the actual data. 4. If only one code exists, then it is encoded using one bit. (Zero would be more efficient, but perhaps a little confusing.) If two codes exist, they are coded using one bit each (0 and 1). 5. There is no way of sending zero distance codes--a dummy must be sent if there are none. (History: a pre 2.0 version of PKZIP would store blocks with no distance codes, but this was discovered to be too harsh a criterion.) Valid only for 1.93a. 2.04c does allow zero distance codes, which is sent as one code of zero bits in length. 6. There are up to 286 literal/length codes. Code 256 represents the end-of-block. Note however that the static length tree defines 288 codes just to fill out the Huffman codes. Codes 286 and 287 cannot be used though, since there is no length base or extra bits defined for them. Similarly, there are up to 30 distance codes. However, static trees define 32 codes (all 5 bits) to fill out the Huffman codes, but the last two had better not show up in the data. 7. Unzip can check dynamic Huffman blocks for complete code sets. The exception is that a single code would not be complete (see #4). 8. The five bits following the block type is really the number of literal codes sent minus 257. 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits (1+6+6). Therefore, to output three times the length, you output three codes (1+1+1), whereas to output four times the same length, you only need two codes (1+3). Hmm. 10. In the tree reconstruction algorithm, Code = Code + Increment only if BitLength(i) is not zero. (Pretty obvious.) 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) 12. Note: length code 284 can represent 227-258, but length code 285 really is 258. The last length deserves its own, short code since it gets used a lot in very redundant files. The length 258 is special since 258 - 3 (the min match length) is 255. 13. The literal/length and distance code bit lengths are read as a single stream of lengths. It is possible (and advantageous) for a repeat code (16, 17, or 18) to go across the boundary between the two sets of lengths. */ #include <linux/compiler.h> #ifdef RCSID static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #"; #endif #ifndef STATIC #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H) # include <sys/types.h> # include <stdlib.h> #endif #include "gzip.h" #define STATIC #endif /* !STATIC */ #ifndef INIT #define INIT #endif #define slide window /* 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; }; /* Function prototypes */ STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned, const ush *, const ush *, struct huft **, int *)); STATIC int INIT huft_free OF((struct huft *)); STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int)); STATIC int INIT inflate_stored OF((void)); STATIC int INIT inflate_fixed OF((void)); STATIC int INIT inflate_dynamic OF((void)); STATIC int INIT inflate_block OF((int *)); STATIC int INIT inflate OF((void)); /* The inflate algorithm uses a sliding 32 K 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 ANDing with 0x7fff (32K-1). */ /* It is left to other modules to supply the 32 K 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. */ /* unsigned wp; current position in slide */ #define wp outcnt #define flush_output(w) (wp=(w),flush_window()) /* Tables for deflate from PKZIP's appnote.txt. */ static const 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 const 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 const 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 const 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 const 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}; /* 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 ulg bb; /* bit buffer */ STATIC unsigned bk; /* bits in bit buffer */ STATIC const ush mask_bits[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff }; #define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; }) #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}} #define DUMPBITS(n) {b>>=(n);k-=(n);} |
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#ifndef NO_INFLATE_MALLOC /* A trivial malloc implementation, adapted from * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 */ static unsigned long malloc_ptr; static int malloc_count; static void *malloc(int size) { void *p; if (size < 0) error("Malloc error"); if (!malloc_ptr) malloc_ptr = free_mem_ptr; malloc_ptr = (malloc_ptr + 3) & ~3; /* Align */ p = (void *)malloc_ptr; malloc_ptr += size; if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr) error("Out of memory"); malloc_count++; return p; } static void free(void *where) { malloc_count--; if (!malloc_count) malloc_ptr = free_mem_ptr; } #else #define malloc(a) kmalloc(a, GFP_KERNEL) #define free(a) kfree(a) #endif |
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/* 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 const int lbits = 9; /* bits in base literal/length lookup table */ STATIC const 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 */ STATIC unsigned hufts; /* track memory usage */ STATIC int INIT 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) */ const ush *d, /* list of base values for non-simple codes */ const ush *e, /* list of extra bits for non-simple codes */ struct huft **t, /* result: starting table */ int *m /* maximum lookup bits, returns actual */ ) /* 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. */ { unsigned a; /* counter for codes of length k */ |
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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 */ |
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register int w; /* bits before this table == (l * h) */ |
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unsigned *xp; /* pointer into x */ int y; /* number of dummy codes added */ unsigned z; /* number of entries in current table */ |
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struct { unsigned c[BMAX+1]; /* bit length count table */ struct huft *u[BMAX]; /* table stack */ unsigned v[N_MAX]; /* values in order of bit length */ unsigned x[BMAX+1]; /* bit offsets, then code stack */ } *stk; unsigned *c, *v, *x; struct huft **u; int ret; |
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DEBG("huft1 "); |
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stk = malloc(sizeof(*stk)); if (stk == NULL) return 3; /* out of memory */ c = stk->c; v = stk->v; x = stk->x; u = stk->u; |
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/* Generate counts for each bit length */ |
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memzero(stk->c, sizeof(stk->c)); |
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p = b; i = n; do { Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d " : "0x%x %d "), n-i, *p)); 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; |
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ret = 2; goto out; |
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} 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) |
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if ((y -= c[j]) < 0) { ret = 2; /* bad input: more codes than bits */ goto out; } if ((y -= c[i]) < 0) { ret = 2; goto out; } |
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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); |
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n = x[g]; /* set n to length of v */ |
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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; |
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if (j < z) 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 */ } |
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} DEBG1("3 "); z = 1 << j; /* table entries for j-bit table */ /* allocate and link in new table */ if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == (struct huft *)NULL) { if (h) huft_free(u[0]); |
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ret = 3; /* not enough memory */ goto out; |
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} 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 = (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 */ } DEBG1("6 "); } DEBG("h6c "); /* 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]; } 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 */ |
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ret = y != 0 && g != 1; out: free(stk); return ret; |
1da177e4c Linux-2.6.12-rc2 |
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} STATIC int INIT huft_free( 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((char*)p); p = q; } return 0; } STATIC int INIT inflate_codes( struct huft *tl, /* literal/length decoder tables */ struct huft *td, /* distance decoder tables */ int bl, /* number of bits decoded by tl[] */ int bd /* number of bits decoded by 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 ulg 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++] = (uch)t->v.n; Tracevv((stderr, "%c", slide[w-1])); 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) Tracevv((stderr,"\\[%d,%d]", w-d, n)); /* 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++]; Tracevv((stderr, "%c", slide[w-1])); } 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; underrun: return 4; /* Input underrun */ } STATIC int INIT inflate_stored(void) /* "decompress" an inflated type 0 (stored) block. */ { unsigned n; /* number of bytes in block */ unsigned w; /* current window position */ register ulg 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++] = (uch)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; underrun: return 4; /* Input underrun */ } /* * We use `noinline' here to prevent gcc-3.5 from using too much stack space */ STATIC int noinline INIT inflate_fixed(void) /* 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 */ |
35c742264 [PATCH] x86: defl... |
770 |
unsigned *l; /* length list for huft_build */ |
1da177e4c Linux-2.6.12-rc2 |
771 772 |
DEBG("<fix"); |
35c742264 [PATCH] x86: defl... |
773 774 775 |
l = malloc(sizeof(*l) * 288); if (l == NULL) return 3; /* out of memory */ |
1da177e4c Linux-2.6.12-rc2 |
776 777 778 779 780 781 782 783 784 785 |
/* 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; |
35c742264 [PATCH] x86: defl... |
786 787 |
if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) { free(l); |
1da177e4c Linux-2.6.12-rc2 |
788 |
return i; |
35c742264 [PATCH] x86: defl... |
789 |
} |
1da177e4c Linux-2.6.12-rc2 |
790 791 792 793 794 795 796 797 |
/* 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); |
35c742264 [PATCH] x86: defl... |
798 |
free(l); |
1da177e4c Linux-2.6.12-rc2 |
799 800 801 802 803 804 805 |
DEBG(">"); return i; } /* decompress until an end-of-block code */ |
35c742264 [PATCH] x86: defl... |
806 807 |
if (inflate_codes(tl, td, bl, bd)) { free(l); |
1da177e4c Linux-2.6.12-rc2 |
808 |
return 1; |
35c742264 [PATCH] x86: defl... |
809 |
} |
1da177e4c Linux-2.6.12-rc2 |
810 811 |
/* free the decoding tables, return */ |
35c742264 [PATCH] x86: defl... |
812 |
free(l); |
1da177e4c Linux-2.6.12-rc2 |
813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 |
huft_free(tl); huft_free(td); return 0; } /* * We use `noinline' here to prevent gcc-3.5 from using too much stack space */ STATIC int noinline INIT inflate_dynamic(void) /* 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 */ |
39b7ee068 [PATCH] x86-64: d... |
837 |
unsigned *ll; /* literal/length and distance code lengths */ |
1da177e4c Linux-2.6.12-rc2 |
838 839 |
register ulg b; /* bit buffer */ register unsigned k; /* number of bits in bit buffer */ |
39b7ee068 [PATCH] x86-64: d... |
840 |
int ret; |
1da177e4c Linux-2.6.12-rc2 |
841 842 |
DEBG("<dyn"); |
39b7ee068 [PATCH] x86-64: d... |
843 844 845 846 847 |
#ifdef PKZIP_BUG_WORKAROUND ll = malloc(sizeof(*ll) * (288+32)); /* literal/length and distance code lengths */ #else ll = malloc(sizeof(*ll) * (286+30)); /* literal/length and distance code lengths */ #endif |
22caa0417 lib/inflate.c: ha... |
848 849 |
if (ll == NULL) return 1; |
1da177e4c Linux-2.6.12-rc2 |
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 |
/* 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 |
39b7ee068 [PATCH] x86-64: d... |
870 871 872 873 |
{ ret = 1; /* bad lengths */ goto out; } |
1da177e4c Linux-2.6.12-rc2 |
874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 |
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); |
39b7ee068 [PATCH] x86-64: d... |
895 896 |
ret = i; /* incomplete code set */ goto out; |
1da177e4c Linux-2.6.12-rc2 |
897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 |
} 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) |
39b7ee068 [PATCH] x86-64: d... |
918 919 920 921 |
if ((unsigned)i + j > n) { ret = 1; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
922 923 924 925 926 927 928 929 |
while (j--) ll[i++] = l; } else if (j == 17) /* 3 to 10 zero length codes */ { NEEDBITS(3) j = 3 + ((unsigned)b & 7); DUMPBITS(3) |
39b7ee068 [PATCH] x86-64: d... |
930 931 932 933 |
if ((unsigned)i + j > n) { ret = 1; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
934 935 936 937 938 939 940 941 942 |
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) |
39b7ee068 [PATCH] x86-64: d... |
943 944 945 946 |
if ((unsigned)i + j > n) { ret = 1; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 |
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) { error("incomplete literal tree"); huft_free(tl); } |
39b7ee068 [PATCH] x86-64: d... |
975 976 |
ret = i; /* incomplete code set */ goto out; |
1da177e4c Linux-2.6.12-rc2 |
977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 |
} DEBG("dyn5c "); bd = dbits; if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) { DEBG("dyn5d "); if (i == 1) { error("incomplete distance tree"); #ifdef PKZIP_BUG_WORKAROUND i = 0; } #else huft_free(td); } huft_free(tl); |
39b7ee068 [PATCH] x86-64: d... |
992 993 |
ret = i; /* incomplete code set */ goto out; |
1da177e4c Linux-2.6.12-rc2 |
994 995 996 997 998 999 |
#endif } DEBG("dyn6 "); /* decompress until an end-of-block code */ |
39b7ee068 [PATCH] x86-64: d... |
1000 1001 1002 1003 |
if (inflate_codes(tl, td, bl, bd)) { ret = 1; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
1004 1005 1006 1007 1008 1009 1010 1011 |
DEBG("dyn7 "); /* free the decoding tables, return */ huft_free(tl); huft_free(td); DEBG(">"); |
39b7ee068 [PATCH] x86-64: d... |
1012 1013 1014 1015 |
ret = 0; out: free(ll); return ret; |
1da177e4c Linux-2.6.12-rc2 |
1016 |
|
39b7ee068 [PATCH] x86-64: d... |
1017 1018 1019 |
underrun: ret = 4; /* Input underrun */ goto out; |
1da177e4c Linux-2.6.12-rc2 |
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 |
} STATIC int INIT inflate_block( int *e /* last block flag */ ) /* decompress an inflated block */ { unsigned t; /* block type */ register ulg 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; underrun: return 4; /* Input underrun */ } STATIC int INIT inflate(void) /* decompress an inflated entry */ { int e; /* last block flag */ int r; /* result code */ unsigned h; /* maximum struct huft's malloc'ed */ |
1da177e4c Linux-2.6.12-rc2 |
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 |
/* initialize window, bit buffer */ wp = 0; bk = 0; bb = 0; /* decompress until the last block */ h = 0; do { hufts = 0; |
2d6ffcca6 inflate: refactor... |
1092 1093 1094 1095 1096 1097 |
#ifdef ARCH_HAS_DECOMP_WDOG arch_decomp_wdog(); #endif r = inflate_block(&e); if (r) return r; |
1da177e4c Linux-2.6.12-rc2 |
1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 |
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 */ #ifdef DEBUG fprintf(stderr, "<%u> ", h); #endif /* DEBUG */ return 0; } /********************************************************************** * * The following are support routines for inflate.c * **********************************************************************/ static ulg crc_32_tab[256]; static ulg crc; /* initialized in makecrc() so it'll reside in bss */ #define CRC_VALUE (crc ^ 0xffffffffUL) /* * Code to compute the CRC-32 table. Borrowed from * gzip-1.0.3/makecrc.c. */ static void INIT makecrc(void) { /* Not copyrighted 1990 Mark Adler */ unsigned long c; /* crc shift register */ unsigned long e; /* 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 const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; /* Make exclusive-or pattern from polynomial */ e = 0; for (i = 0; i < sizeof(p)/sizeof(int); i++) e |= 1L << (31 - p[i]); crc_32_tab[0] = 0; for (i = 1; i < 256; i++) { c = 0; for (k = i | 256; k != 1; k >>= 1) { c = c & 1 ? (c >> 1) ^ e : c >> 1; if (k & 1) c ^= e; } crc_32_tab[i] = c; } /* this is initialized here so this code could reside in ROM */ crc = (ulg)0xffffffffUL; /* shift register contents */ } /* 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 */ /* * Do the uncompression! */ static int INIT gunzip(void) { uch flags; unsigned char magic[2]; /* magic header */ char method; ulg orig_crc = 0; /* original crc */ ulg orig_len = 0; /* original uncompressed length */ int res; magic[0] = NEXTBYTE(); magic[1] = NEXTBYTE(); method = NEXTBYTE(); if (magic[0] != 037 || ((magic[1] != 0213) && (magic[1] != 0236))) { error("bad gzip magic numbers"); return -1; } /* We only support method #8, DEFLATED */ if (method != 8) { error("internal error, invalid method"); return -1; } flags = (uch)get_byte(); if ((flags & ENCRYPTED) != 0) { error("Input is encrypted"); return -1; } if ((flags & CONTINUATION) != 0) { error("Multi part input"); return -1; } if ((flags & RESERVED) != 0) { error("Input has invalid flags"); return -1; } NEXTBYTE(); /* Get timestamp */ NEXTBYTE(); NEXTBYTE(); NEXTBYTE(); (void)NEXTBYTE(); /* Ignore extra flags for the moment */ (void)NEXTBYTE(); /* Ignore OS type for the moment */ if ((flags & EXTRA_FIELD) != 0) { unsigned len = (unsigned)NEXTBYTE(); len |= ((unsigned)NEXTBYTE())<<8; while (len--) (void)NEXTBYTE(); } /* Get original file name if it was truncated */ if ((flags & ORIG_NAME) != 0) { /* Discard the old name */ while (NEXTBYTE() != 0) /* null */ ; } /* Discard file comment if any */ if ((flags & COMMENT) != 0) { while (NEXTBYTE() != 0) /* null */ ; } /* Decompress */ if ((res = inflate())) { switch (res) { case 0: break; case 1: error("invalid compressed format (err=1)"); break; case 2: error("invalid compressed format (err=2)"); break; case 3: error("out of memory"); break; case 4: error("out of input data"); break; default: error("invalid compressed format (other)"); } return -1; } /* Get the crc and original length */ /* crc32 (see algorithm.doc) * uncompressed input size modulo 2^32 */ orig_crc = (ulg) NEXTBYTE(); orig_crc |= (ulg) NEXTBYTE() << 8; orig_crc |= (ulg) NEXTBYTE() << 16; orig_crc |= (ulg) NEXTBYTE() << 24; orig_len = (ulg) NEXTBYTE(); orig_len |= (ulg) NEXTBYTE() << 8; orig_len |= (ulg) NEXTBYTE() << 16; orig_len |= (ulg) NEXTBYTE() << 24; /* Validate decompression */ if (orig_crc != CRC_VALUE) { error("crc error"); return -1; } if (orig_len != bytes_out) { error("length error"); return -1; } return 0; underrun: /* NEXTBYTE() goto's here if needed */ error("out of input data"); return -1; } |