mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
1210 lines
37 KiB
C
1210 lines
37 KiB
C
#define DEBG(x)
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#define DEBG1(x)
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/* inflate.c -- Not copyrighted 1992 by Mark Adler
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version c10p1, 10 January 1993 */
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/*
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* Adapted for booting Linux by Hannu Savolainen 1993
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* based on gzip-1.0.3
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*
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* Nicolas Pitre <nico@cam.org>, 1999/04/14 :
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* Little mods for all variable to reside either into rodata or bss segments
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* by marking constant variables with 'const' and initializing all the others
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* at run-time only. This allows for the kernel uncompressor to run
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* directly from Flash or ROM memory on embedded systems.
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*/
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/*
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Inflate deflated (PKZIP's method 8 compressed) data. The compression
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method searches for as much of the current string of bytes (up to a
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length of 258) in the previous 32 K bytes. If it doesn't find any
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matches (of at least length 3), it codes the next byte. Otherwise, it
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codes the length of the matched string and its distance backwards from
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the current position. There is a single Huffman code that codes both
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single bytes (called "literals") and match lengths. A second Huffman
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code codes the distance information, which follows a length code. Each
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length or distance code actually represents a base value and a number
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of "extra" (sometimes zero) bits to get to add to the base value. At
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the end of each deflated block is a special end-of-block (EOB) literal/
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length code. The decoding process is basically: get a literal/length
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code; if EOB then done; if a literal, emit the decoded byte; if a
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length then get the distance and emit the referred-to bytes from the
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sliding window of previously emitted data.
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There are (currently) three kinds of inflate blocks: stored, fixed, and
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dynamic. The compressor deals with some chunk of data at a time, and
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decides which method to use on a chunk-by-chunk basis. A chunk might
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typically be 32 K or 64 K. If the chunk is incompressible, then the
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"stored" method is used. In this case, the bytes are simply stored as
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is, eight bits per byte, with none of the above coding. The bytes are
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preceded by a count, since there is no longer an EOB code.
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If the data is compressible, then either the fixed or dynamic methods
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are used. In the dynamic method, the compressed data is preceded by
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an encoding of the literal/length and distance Huffman codes that are
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to be used to decode this block. The representation is itself Huffman
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coded, and so is preceded by a description of that code. These code
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descriptions take up a little space, and so for small blocks, there is
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a predefined set of codes, called the fixed codes. The fixed method is
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used if the block codes up smaller that way (usually for quite small
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chunks), otherwise the dynamic method is used. In the latter case, the
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codes are customized to the probabilities in the current block, and so
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can code it much better than the pre-determined fixed codes.
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The Huffman codes themselves are decoded using a multi-level table
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lookup, in order to maximize the speed of decoding plus the speed of
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building the decoding tables. See the comments below that precede the
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lbits and dbits tuning parameters.
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*/
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/*
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Notes beyond the 1.93a appnote.txt:
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1. Distance pointers never point before the beginning of the output
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stream.
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2. Distance pointers can point back across blocks, up to 32k away.
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3. There is an implied maximum of 7 bits for the bit length table and
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15 bits for the actual data.
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4. If only one code exists, then it is encoded using one bit. (Zero
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would be more efficient, but perhaps a little confusing.) If two
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codes exist, they are coded using one bit each (0 and 1).
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5. There is no way of sending zero distance codes--a dummy must be
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sent if there are none. (History: a pre 2.0 version of PKZIP would
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store blocks with no distance codes, but this was discovered to be
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too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
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zero distance codes, which is sent as one code of zero bits in
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length.
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6. There are up to 286 literal/length codes. Code 256 represents the
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end-of-block. Note however that the static length tree defines
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288 codes just to fill out the Huffman codes. Codes 286 and 287
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cannot be used though, since there is no length base or extra bits
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defined for them. Similarly, there are up to 30 distance codes.
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However, static trees define 32 codes (all 5 bits) to fill out the
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Huffman codes, but the last two had better not show up in the data.
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7. Unzip can check dynamic Huffman blocks for complete code sets.
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The exception is that a single code would not be complete (see #4).
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8. The five bits following the block type is really the number of
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literal codes sent minus 257.
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9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
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(1+6+6). Therefore, to output three times the length, you output
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three codes (1+1+1), whereas to output four times the same length,
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you only need two codes (1+3). Hmm.
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10. In the tree reconstruction algorithm, Code = Code + Increment
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only if BitLength(i) is not zero. (Pretty obvious.)
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11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
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12. Note: length code 284 can represent 227-258, but length code 285
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really is 258. The last length deserves its own, short code
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since it gets used a lot in very redundant files. The length
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258 is special since 258 - 3 (the min match length) is 255.
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13. The literal/length and distance code bit lengths are read as a
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single stream of lengths. It is possible (and advantageous) for
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a repeat code (16, 17, or 18) to go across the boundary between
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the two sets of lengths.
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*/
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#include <linux/compiler.h>
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#ifdef RCSID
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static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #";
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#endif
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#ifndef STATIC
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#if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H)
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# include <sys/types.h>
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# include <stdlib.h>
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#endif
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#include "gzip.h"
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#define STATIC
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#endif /* !STATIC */
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#ifndef INIT
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#define INIT
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#endif
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#define slide window
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/* Huffman code lookup table entry--this entry is four bytes for machines
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that have 16-bit pointers (e.g. PC's in the small or medium model).
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Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
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means that v is a literal, 16 < e < 32 means that v is a pointer to
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the next table, which codes e - 16 bits, and lastly e == 99 indicates
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an unused code. If a code with e == 99 is looked up, this implies an
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error in the data. */
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struct huft {
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uch e; /* number of extra bits or operation */
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uch b; /* number of bits in this code or subcode */
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union {
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ush n; /* literal, length base, or distance base */
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struct huft *t; /* pointer to next level of table */
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} v;
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};
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/* Function prototypes */
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STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned,
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const ush *, const ush *, struct huft **, int *));
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STATIC int INIT huft_free OF((struct huft *));
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STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int));
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STATIC int INIT inflate_stored OF((void));
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STATIC int INIT inflate_fixed OF((void));
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STATIC int INIT inflate_dynamic OF((void));
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STATIC int INIT inflate_block OF((int *));
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STATIC int INIT inflate OF((void));
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/* The inflate algorithm uses a sliding 32 K byte window on the uncompressed
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stream to find repeated byte strings. This is implemented here as a
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circular buffer. The index is updated simply by incrementing and then
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ANDing with 0x7fff (32K-1). */
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/* It is left to other modules to supply the 32 K area. It is assumed
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to be usable as if it were declared "uch slide[32768];" or as just
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"uch *slide;" and then malloc'ed in the latter case. The definition
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must be in unzip.h, included above. */
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/* unsigned wp; current position in slide */
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#define wp outcnt
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#define flush_output(w) (wp=(w),flush_window())
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/* Tables for deflate from PKZIP's appnote.txt. */
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static const unsigned border[] = { /* Order of the bit length code lengths */
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
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static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */
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3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
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/* note: see note #13 above about the 258 in this list. */
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static const ush cplext[] = { /* Extra bits for literal codes 257..285 */
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0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */
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static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */
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1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
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8193, 12289, 16385, 24577};
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static const ush cpdext[] = { /* Extra bits for distance codes */
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
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12, 12, 13, 13};
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/* Macros for inflate() bit peeking and grabbing.
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The usage is:
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NEEDBITS(j)
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x = b & mask_bits[j];
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DUMPBITS(j)
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where NEEDBITS makes sure that b has at least j bits in it, and
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DUMPBITS removes the bits from b. The macros use the variable k
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for the number of bits in b. Normally, b and k are register
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variables for speed, and are initialized at the beginning of a
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routine that uses these macros from a global bit buffer and count.
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If we assume that EOB will be the longest code, then we will never
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ask for bits with NEEDBITS that are beyond the end of the stream.
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So, NEEDBITS should not read any more bytes than are needed to
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meet the request. Then no bytes need to be "returned" to the buffer
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at the end of the last block.
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However, this assumption is not true for fixed blocks--the EOB code
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is 7 bits, but the other literal/length codes can be 8 or 9 bits.
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(The EOB code is shorter than other codes because fixed blocks are
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generally short. So, while a block always has an EOB, many other
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literal/length codes have a significantly lower probability of
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showing up at all.) However, by making the first table have a
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lookup of seven bits, the EOB code will be found in that first
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lookup, and so will not require that too many bits be pulled from
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the stream.
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*/
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STATIC ulg bb; /* bit buffer */
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STATIC unsigned bk; /* bits in bit buffer */
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STATIC const ush mask_bits[] = {
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0x0000,
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0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
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0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
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};
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#define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; })
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#define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
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#define DUMPBITS(n) {b>>=(n);k-=(n);}
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/*
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Huffman code decoding is performed using a multi-level table lookup.
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The fastest way to decode is to simply build a lookup table whose
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size is determined by the longest code. However, the time it takes
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to build this table can also be a factor if the data being decoded
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is not very long. The most common codes are necessarily the
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shortest codes, so those codes dominate the decoding time, and hence
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the speed. The idea is you can have a shorter table that decodes the
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shorter, more probable codes, and then point to subsidiary tables for
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the longer codes. The time it costs to decode the longer codes is
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then traded against the time it takes to make longer tables.
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This results of this trade are in the variables lbits and dbits
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below. lbits is the number of bits the first level table for literal/
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length codes can decode in one step, and dbits is the same thing for
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the distance codes. Subsequent tables are also less than or equal to
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those sizes. These values may be adjusted either when all of the
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codes are shorter than that, in which case the longest code length in
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bits is used, or when the shortest code is *longer* than the requested
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table size, in which case the length of the shortest code in bits is
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used.
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There are two different values for the two tables, since they code a
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different number of possibilities each. The literal/length table
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codes 286 possible values, or in a flat code, a little over eight
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bits. The distance table codes 30 possible values, or a little less
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than five bits, flat. The optimum values for speed end up being
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about one bit more than those, so lbits is 8+1 and dbits is 5+1.
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The optimum values may differ though from machine to machine, and
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possibly even between compilers. Your mileage may vary.
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*/
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STATIC const int lbits = 9; /* bits in base literal/length lookup table */
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STATIC const int dbits = 6; /* bits in base distance lookup table */
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/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
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#define BMAX 16 /* maximum bit length of any code (16 for explode) */
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#define N_MAX 288 /* maximum number of codes in any set */
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STATIC unsigned hufts; /* track memory usage */
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STATIC int INIT huft_build(
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unsigned *b, /* code lengths in bits (all assumed <= BMAX) */
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unsigned n, /* number of codes (assumed <= N_MAX) */
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unsigned s, /* number of simple-valued codes (0..s-1) */
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const ush *d, /* list of base values for non-simple codes */
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const ush *e, /* list of extra bits for non-simple codes */
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struct huft **t, /* result: starting table */
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int *m /* maximum lookup bits, returns actual */
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)
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/* Given a list of code lengths and a maximum table size, make a set of
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tables to decode that set of codes. Return zero on success, one if
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the given code set is incomplete (the tables are still built in this
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case), two if the input is invalid (all zero length codes or an
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oversubscribed set of lengths), and three if not enough memory. */
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{
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unsigned a; /* counter for codes of length k */
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unsigned c[BMAX+1]; /* bit length count table */
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unsigned f; /* i repeats in table every f entries */
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int g; /* maximum code length */
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int h; /* table level */
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register unsigned i; /* counter, current code */
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register unsigned j; /* counter */
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register int k; /* number of bits in current code */
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int l; /* bits per table (returned in m) */
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register unsigned *p; /* pointer into c[], b[], or v[] */
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register struct huft *q; /* points to current table */
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struct huft r; /* table entry for structure assignment */
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struct huft *u[BMAX]; /* table stack */
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unsigned v[N_MAX]; /* values in order of bit length */
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register int w; /* bits before this table == (l * h) */
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unsigned x[BMAX+1]; /* bit offsets, then code stack */
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unsigned *xp; /* pointer into x */
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int y; /* number of dummy codes added */
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unsigned z; /* number of entries in current table */
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DEBG("huft1 ");
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/* Generate counts for each bit length */
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memzero(c, sizeof(c));
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p = b; i = n;
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do {
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Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"),
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n-i, *p));
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c[*p]++; /* assume all entries <= BMAX */
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p++; /* Can't combine with above line (Solaris bug) */
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} while (--i);
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if (c[0] == n) /* null input--all zero length codes */
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{
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*t = (struct huft *)NULL;
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*m = 0;
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return 0;
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}
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DEBG("huft2 ");
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/* Find minimum and maximum length, bound *m by those */
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l = *m;
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for (j = 1; j <= BMAX; j++)
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if (c[j])
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break;
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k = j; /* minimum code length */
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if ((unsigned)l < j)
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l = j;
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for (i = BMAX; i; i--)
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if (c[i])
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break;
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g = i; /* maximum code length */
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if ((unsigned)l > i)
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l = i;
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*m = l;
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DEBG("huft3 ");
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/* Adjust last length count to fill out codes, if needed */
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for (y = 1 << j; j < i; j++, y <<= 1)
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if ((y -= c[j]) < 0)
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return 2; /* bad input: more codes than bits */
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if ((y -= c[i]) < 0)
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return 2;
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c[i] += y;
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DEBG("huft4 ");
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/* Generate starting offsets into the value table for each length */
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x[1] = j = 0;
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p = c + 1; xp = x + 2;
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while (--i) { /* note that i == g from above */
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*xp++ = (j += *p++);
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}
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DEBG("huft5 ");
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/* Make a table of values in order of bit lengths */
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p = b; i = 0;
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do {
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if ((j = *p++) != 0)
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v[x[j]++] = i;
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} while (++i < n);
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DEBG("h6 ");
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/* Generate the Huffman codes and for each, make the table entries */
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x[0] = i = 0; /* first Huffman code is zero */
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p = v; /* grab values in bit order */
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h = -1; /* no tables yet--level -1 */
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w = -l; /* bits decoded == (l * h) */
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u[0] = (struct huft *)NULL; /* just to keep compilers happy */
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q = (struct huft *)NULL; /* ditto */
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z = 0; /* ditto */
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DEBG("h6a ");
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/* go through the bit lengths (k already is bits in shortest code) */
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for (; k <= g; k++)
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{
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DEBG("h6b ");
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a = c[k];
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while (a--)
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{
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DEBG("h6b1 ");
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/* here i is the Huffman code of length k bits for value *p */
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/* make tables up to required level */
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while (k > w + l)
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{
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DEBG1("1 ");
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h++;
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w += l; /* previous table always l bits */
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/* compute minimum size table less than or equal to l bits */
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z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */
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if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */
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{ /* too few codes for k-w bit table */
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DEBG1("2 ");
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f -= a + 1; /* deduct codes from patterns left */
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xp = c + k;
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while (++j < z) /* try smaller tables up to z bits */
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{
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if ((f <<= 1) <= *++xp)
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break; /* enough codes to use up j bits */
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f -= *xp; /* else deduct codes from patterns */
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}
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}
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DEBG1("3 ");
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z = 1 << j; /* table entries for j-bit table */
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/* allocate and link in new table */
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if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) ==
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(struct huft *)NULL)
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{
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if (h)
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huft_free(u[0]);
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return 3; /* not enough memory */
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}
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DEBG1("4 ");
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hufts += z + 1; /* track memory usage */
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*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 */
|
|
return y != 0 && g != 1;
|
|
}
|
|
|
|
|
|
|
|
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 */
|
|
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;
|
|
}
|
|
|
|
|
|
/*
|
|
* 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 */
|
|
#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 ulg 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) {
|
|
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) {
|
|
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;
|
|
|
|
underrun:
|
|
return 4; /* Input underrun */
|
|
}
|
|
|
|
|
|
|
|
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 */
|
|
void *ptr;
|
|
|
|
/* initialize window, bit buffer */
|
|
wp = 0;
|
|
bk = 0;
|
|
bb = 0;
|
|
|
|
|
|
/* decompress until the last block */
|
|
h = 0;
|
|
do {
|
|
hufts = 0;
|
|
gzip_mark(&ptr);
|
|
if ((r = inflate_block(&e)) != 0) {
|
|
gzip_release(&ptr);
|
|
return r;
|
|
}
|
|
gzip_release(&ptr);
|
|
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;
|
|
}
|
|
|
|
|