inftrees.h 2.3 KB

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  1. #ifndef INFTREES_H
  2. #define INFTREES_H
  3. /* inftrees.h -- header to use inftrees.c
  4. * Copyright (C) 1995-2005 Mark Adler
  5. * For conditions of distribution and use, see copyright notice in zlib.h
  6. */
  7. /* WARNING: this file should *not* be used by applications. It is
  8. part of the implementation of the compression library and is
  9. subject to change. Applications should only use zlib.h.
  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. /* op values as set by inflate_table():
  30. 00000000 - literal
  31. 0000tttt - table link, tttt != 0 is the number of table index bits
  32. 0001eeee - length or distance, eeee is the number of extra bits
  33. 01100000 - end of block
  34. 01000000 - invalid code
  35. */
  36. /* Maximum size of dynamic tree. The maximum found in a long but non-
  37. exhaustive search was 1444 code structures (852 for length/literals
  38. and 592 for distances, the latter actually the result of an
  39. exhaustive search). The true maximum is not known, but the value
  40. below is more than safe. */
  41. #define ENOUGH 2048
  42. #define MAXD 592
  43. /* Type of code to build for inftable() */
  44. typedef enum {
  45. CODES,
  46. LENS,
  47. DISTS
  48. } codetype;
  49. extern int zlib_inflate_table (codetype type, unsigned short *lens,
  50. unsigned codes, code **table,
  51. unsigned *bits, unsigned short *work);
  52. #endif