patch-2.4.14 linux/fs/cramfs/inflate/infblock.c
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- Lines: 361
- Date:
Wed Dec 31 16:00:00 1969
- Orig file:
v2.4.13/linux/fs/cramfs/inflate/infblock.c
- Orig date:
Wed Apr 12 09:47:29 2000
diff -u --recursive --new-file v2.4.13/linux/fs/cramfs/inflate/infblock.c linux/fs/cramfs/inflate/infblock.c
@@ -1,360 +0,0 @@
-/* infblock.c -- interpret and process block types to last block
- * Copyright (C) 1995-1998 Mark Adler
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
-
-#include "zutil.h"
-#include "infblock.h"
-#include "inftrees.h"
-#include "infcodes.h"
-#include "infutil.h"
-
-struct inflate_codes_state {int dummy;}; /* for buggy compilers */
-
-/* simplify the use of the inflate_huft type with some defines */
-#define exop word.what.Exop
-#define bits word.what.Bits
-
-/* Table for deflate from PKZIP's appnote.txt. */
-local const uInt 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};
-
-/*
- 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. Similarily, 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.
- */
-
-
-void cramfs_inflate_blocks_reset(s, z, c)
-inflate_blocks_statef *s;
-z_streamp z;
-uLongf *c;
-{
- if (c != Z_NULL)
- *c = s->check;
- if (s->mode == CODES)
- cramfs_inflate_codes_free(s->sub.decode.codes, z);
- s->mode = TYPE;
- s->bitk = 0;
- s->bitb = 0;
- s->read = s->write = s->window;
- if (s->checkfn != Z_NULL)
- z->adler = s->check = (*s->checkfn)(0L, (const Bytef *)Z_NULL, 0);
-}
-
-
-inflate_blocks_statef *cramfs_inflate_blocks_new(z, c, w)
-z_streamp z;
-check_func c;
-uInt w;
-{
- inflate_blocks_statef *s;
- static struct inflate_blocks_state working_blocks_state;
- static inflate_huft working_hufts[MANY];
- static unsigned char working_window[1 << MAX_WBITS];
-
- s = &working_blocks_state;
- s->hufts = working_hufts;
- s->window = working_window;
- s->end = s->window + w;
- s->checkfn = c;
- s->mode = TYPE;
- cramfs_inflate_blocks_reset(s, z, Z_NULL);
- return s;
-}
-
-
-int cramfs_inflate_blocks(s, z, r)
-inflate_blocks_statef *s;
-z_streamp z;
-int r;
-{
- uInt t; /* temporary storage */
- uLong b; /* bit buffer */
- uInt k; /* bits in bit buffer */
- Bytef *p; /* input data pointer */
- uInt n; /* bytes available there */
- Bytef *q; /* output window write pointer */
- uInt m; /* bytes to end of window or read pointer */
-
- /* copy input/output information to locals (UPDATE macro restores) */
- LOAD
-
- /* process input based on current state */
- while (1) switch (s->mode)
- {
- case TYPE:
- NEEDBITS(3)
- t = (uInt)b & 7;
- s->last = t & 1;
- switch (t >> 1)
- {
- case 0: /* stored */
- DUMPBITS(3)
- t = k & 7; /* go to byte boundary */
- DUMPBITS(t)
- s->mode = LENS; /* get length of stored block */
- break;
- case 1: /* fixed */
- {
- uInt bl, bd;
- inflate_huft *tl, *td;
-
- cramfs_inflate_trees_fixed(&bl, &bd, &tl, &td, z);
- s->sub.decode.codes = cramfs_inflate_codes_new(bl, bd, tl, td, z);
- if (s->sub.decode.codes == Z_NULL)
- {
- r = Z_MEM_ERROR;
- LEAVE
- }
- }
- DUMPBITS(3)
- s->mode = CODES;
- break;
- case 2: /* dynamic */
- DUMPBITS(3)
- s->mode = TABLE;
- break;
- case 3: /* illegal */
- DUMPBITS(3)
- s->mode = BAD;
- z->msg = (char*)"invalid block type";
- r = Z_DATA_ERROR;
- LEAVE
- }
- break;
- case LENS:
- NEEDBITS(32)
- if ((((~b) >> 16) & 0xffff) != (b & 0xffff))
- {
- s->mode = BAD;
- z->msg = (char*)"invalid stored block lengths";
- r = Z_DATA_ERROR;
- LEAVE
- }
- s->sub.left = (uInt)b & 0xffff;
- b = k = 0; /* dump bits */
- s->mode = s->sub.left ? STORED : (s->last ? DRY : TYPE);
- break;
- case STORED:
- if (n == 0)
- LEAVE
- NEEDOUT
- t = s->sub.left;
- if (t > n) t = n;
- if (t > m) t = m;
- memcpy(q, p, t);
- p += t; n -= t;
- q += t; m -= t;
- if ((s->sub.left -= t) != 0)
- break;
- s->mode = s->last ? DRY : TYPE;
- break;
- case TABLE:
- NEEDBITS(14)
- s->sub.trees.table = t = (uInt)b & 0x3fff;
-#ifndef PKZIP_BUG_WORKAROUND
- if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
- {
- s->mode = BAD;
- z->msg = (char*)"too many length or distance symbols";
- r = Z_DATA_ERROR;
- LEAVE
- }
-#endif
- {
- static unsigned int working_blens [258 + 0x1f + 0x1f];
- s->sub.trees.blens = working_blens;
- }
- DUMPBITS(14)
- s->sub.trees.index = 0;
- s->mode = BTREE;
- case BTREE:
- while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
- {
- NEEDBITS(3)
- s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
- DUMPBITS(3)
- }
- while (s->sub.trees.index < 19)
- s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
- s->sub.trees.bb = 7;
- t = cramfs_inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
- &s->sub.trees.tb, s->hufts, z);
- if (t != Z_OK)
- {
- r = t;
- if (r == Z_DATA_ERROR)
- s->mode = BAD;
- LEAVE
- }
- s->sub.trees.index = 0;
- s->mode = DTREE;
- case DTREE:
- while (t = s->sub.trees.table,
- s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
- {
- inflate_huft *h;
- uInt i, j, c;
-
- t = s->sub.trees.bb;
- NEEDBITS(t)
- h = s->sub.trees.tb + ((uInt)b & cramfs_inflate_mask[t]);
- t = h->bits;
- c = h->base;
- if (c < 16)
- {
- DUMPBITS(t)
- s->sub.trees.blens[s->sub.trees.index++] = c;
- }
- else /* c == 16..18 */
- {
- i = c == 18 ? 7 : c - 14;
- j = c == 18 ? 11 : 3;
- NEEDBITS(t + i)
- DUMPBITS(t)
- j += (uInt)b & cramfs_inflate_mask[i];
- DUMPBITS(i)
- i = s->sub.trees.index;
- t = s->sub.trees.table;
- if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
- (c == 16 && i < 1))
- {
- s->mode = BAD;
- z->msg = (char*)"invalid bit length repeat";
- r = Z_DATA_ERROR;
- LEAVE
- }
- c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
- do {
- s->sub.trees.blens[i++] = c;
- } while (--j);
- s->sub.trees.index = i;
- }
- }
- s->sub.trees.tb = Z_NULL;
- {
- uInt bl, bd;
- inflate_huft *tl, *td;
- inflate_codes_statef *c;
-
- bl = 9; /* must be <= 9 for lookahead assumptions */
- bd = 6; /* must be <= 9 for lookahead assumptions */
- t = s->sub.trees.table;
- t = cramfs_inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
- s->sub.trees.blens, &bl, &bd, &tl, &td,
- s->hufts, z);
- if (t != Z_OK)
- {
- if (t == (uInt)Z_DATA_ERROR)
- s->mode = BAD;
- r = t;
- LEAVE
- }
- if ((c = cramfs_inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL)
- {
- r = Z_MEM_ERROR;
- LEAVE
- }
- s->sub.decode.codes = c;
- }
- s->mode = CODES;
- case CODES:
- UPDATE
- if ((r = cramfs_inflate_codes(s, z, r)) != Z_STREAM_END)
- return cramfs_inflate_flush(s, z, r);
- r = Z_OK;
- cramfs_inflate_codes_free(s->sub.decode.codes, z);
- LOAD
- if (!s->last)
- {
- s->mode = TYPE;
- break;
- }
- s->mode = DRY;
- case DRY:
- FLUSH
- if (s->read != s->write)
- LEAVE
- s->mode = DONE;
- case DONE:
- r = Z_STREAM_END;
- LEAVE
- case BAD:
- r = Z_DATA_ERROR;
- LEAVE
- default:
- r = Z_STREAM_ERROR;
- LEAVE
- }
-}
-
-
-int cramfs_inflate_blocks_free(s, z)
-inflate_blocks_statef *s;
-z_streamp z;
-{
- cramfs_inflate_blocks_reset(s, z, Z_NULL);
- return Z_OK;
-}
-
-
-void cramfs_inflate_set_dictionary(s, d, n)
-inflate_blocks_statef *s;
-const Bytef *d;
-uInt n;
-{
- memcpy(s->window, d, n);
- s->read = s->write = s->window + n;
-}
-
-
-/* Returns true if inflate is currently at the end of a block generated
- * by Z_SYNC_FLUSH or Z_FULL_FLUSH.
- * IN assertion: s != Z_NULL
- */
-int inflate_blocks_sync_point(s)
-inflate_blocks_statef *s;
-{
- return s->mode == LENS;
-}
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