The Tor Browser / file comparison
comparison: modules/zlib/src/inftrees.h
modules/zlib/src/inftrees.h
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- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:25b223f8772d |
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| 1 /* inftrees.h -- header to use inftrees.c | |
| 2 * Copyright (C) 1995-2005, 2010 Mark Adler | |
| 3 * For conditions of distribution and use, see copyright notice in zlib.h | |
| 4 */ | |
| 5 | |
| 6 /* WARNING: this file should *not* be used by applications. It is | |
| 7 part of the implementation of the compression library and is | |
| 8 subject to change. Applications should only use zlib.h. | |
| 9 */ | |
| 10 | |
| 11 /* Structure for decoding tables. Each entry provides either the | |
| 12 information needed to do the operation requested by the code that | |
| 13 indexed that table entry, or it provides a pointer to another | |
| 14 table that indexes more bits of the code. op indicates whether | |
| 15 the entry is a pointer to another table, a literal, a length or | |
| 16 distance, an end-of-block, or an invalid code. For a table | |
| 17 pointer, the low four bits of op is the number of index bits of | |
| 18 that table. For a length or distance, the low four bits of op | |
| 19 is the number of extra bits to get after the code. bits is | |
| 20 the number of bits in this code or part of the code to drop off | |
| 21 of the bit buffer. val is the actual byte to output in the case | |
| 22 of a literal, the base length or distance, or the offset from | |
| 23 the current table to the next table. Each entry is four bytes. */ | |
| 24 typedef struct { | |
| 25 unsigned char op; /* operation, extra bits, table bits */ | |
| 26 unsigned char bits; /* bits in this part of the code */ | |
| 27 unsigned short val; /* offset in table or code value */ | |
| 28 } code; | |
| 29 | |
| 30 /* op values as set by inflate_table(): | |
| 31 00000000 - literal | |
| 32 0000tttt - table link, tttt != 0 is the number of table index bits | |
| 33 0001eeee - length or distance, eeee is the number of extra bits | |
| 34 01100000 - end of block | |
| 35 01000000 - invalid code | |
| 36 */ | |
| 37 | |
| 38 /* Maximum size of the dynamic table. The maximum number of code structures is | |
| 39 1444, which is the sum of 852 for literal/length codes and 592 for distance | |
| 40 codes. These values were found by exhaustive searches using the program | |
| 41 examples/enough.c found in the zlib distribtution. The arguments to that | |
| 42 program are the number of symbols, the initial root table size, and the | |
| 43 maximum bit length of a code. "enough 286 9 15" for literal/length codes | |
| 44 returns returns 852, and "enough 30 6 15" for distance codes returns 592. | |
| 45 The initial root table size (9 or 6) is found in the fifth argument of the | |
| 46 inflate_table() calls in inflate.c and infback.c. If the root table size is | |
| 47 changed, then these maximum sizes would be need to be recalculated and | |
| 48 updated. */ | |
| 49 #define ENOUGH_LENS 852 | |
| 50 #define ENOUGH_DISTS 592 | |
| 51 #define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS) | |
| 52 | |
| 53 /* Type of code to build for inflate_table() */ | |
| 54 typedef enum { | |
| 55 CODES, | |
| 56 LENS, | |
| 57 DISTS | |
| 58 } codetype; | |
| 59 | |
| 60 int ZLIB_INTERNAL inflate_table OF((codetype type, unsigned short FAR *lens, | |
| 61 unsigned codes, code FAR * FAR *table, | |
| 62 unsigned FAR *bits, unsigned short FAR *work)); |
