projects / mirror_edk2.git / blame
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|---|---|---|
| 7eb75bcc DM |
1 | /* inftrees.h -- header to use inftrees.c\r |
| 2 | * Copyright (C) 1995-2005, 2010 Mark Adler\r | |
| 3 | * For conditions of distribution and use, see copyright notice in zlib.h\r | |
| 4 | */\r | |
| 5 | \r | |
| 6 | /* WARNING: this file should *not* be used by applications. It is\r | |
| 7 | part of the implementation of the compression library and is\r | |
| 8 | subject to change. Applications should only use zlib.h.\r | |
| 9 | */\r | |
| 10 | \r | |
| 11 | /* Structure for decoding tables. Each entry provides either the\r | |
| 12 | information needed to do the operation requested by the code that\r | |
| 13 | indexed that table entry, or it provides a pointer to another\r | |
| 14 | table that indexes more bits of the code. op indicates whether\r | |
| 15 | the entry is a pointer to another table, a literal, a length or\r | |
| 16 | distance, an end-of-block, or an invalid code. For a table\r | |
| 17 | pointer, the low four bits of op is the number of index bits of\r | |
| 18 | that table. For a length or distance, the low four bits of op\r | |
| 19 | is the number of extra bits to get after the code. bits is\r | |
| 20 | the number of bits in this code or part of the code to drop off\r | |
| 21 | of the bit buffer. val is the actual byte to output in the case\r | |
| 22 | of a literal, the base length or distance, or the offset from\r | |
| 23 | the current table to the next table. Each entry is four bytes. */\r | |
| 24 | typedef struct {\r | |
| 25 | unsigned char op; /* operation, extra bits, table bits */\r | |
| 26 | unsigned char bits; /* bits in this part of the code */\r | |
| 27 | unsigned short val; /* offset in table or code value */\r | |
| 28 | } code;\r | |
| 29 | \r | |
| 30 | /* op values as set by inflate_table():\r | |
| 31 | 00000000 - literal\r | |
| 32 | 0000tttt - table link, tttt != 0 is the number of table index bits\r | |
| 33 | 0001eeee - length or distance, eeee is the number of extra bits\r | |
| 34 | 01100000 - end of block\r | |
| 35 | 01000000 - invalid code\r | |
| 36 | */\r | |
| 37 | \r | |
| 38 | /* Maximum size of the dynamic table. The maximum number of code structures is\r | |
| 39 | 1444, which is the sum of 852 for literal/length codes and 592 for distance\r | |
| 40 | codes. These values were found by exhaustive searches using the program\r | |
| 41 | examples/enough.c found in the zlib distribtution. The arguments to that\r | |
| 42 | program are the number of symbols, the initial root table size, and the\r | |
| 43 | maximum bit length of a code. "enough 286 9 15" for literal/length codes\r | |
| 44 | returns returns 852, and "enough 30 6 15" for distance codes returns 592.\r | |
| 45 | The initial root table size (9 or 6) is found in the fifth argument of the\r | |
| 46 | inflate_table() calls in inflate.c and infback.c. If the root table size is\r | |
| 47 | changed, then these maximum sizes would be need to be recalculated and\r | |
| 48 | updated. */\r | |
| 49 | #define ENOUGH_LENS 852\r | |
| 50 | #define ENOUGH_DISTS 592\r | |
| 51 | #define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS)\r | |
| 52 | \r | |
| 53 | /* Type of code to build for inflate_table() */\r | |
| 54 | typedef enum {\r | |
| 55 | CODES,\r | |
| 56 | LENS,\r | |
| 57 | DISTS\r | |
| 58 | } codetype;\r | |
| 59 | \r | |
| 60 | int ZLIB_INTERNAL inflate_table OF((codetype type, unsigned short FAR *lens,\r | |
| 61 | unsigned codes, code FAR * FAR *table,\r | |
| 62 | unsigned FAR *bits, unsigned short FAR *work));\r |