src/liblzma/simple/simple_private.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       simple_private.h
   4 /// \brief      Private definitions for so called simple filters
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef LZMA_SIMPLE_PRIVATE_H
  14 #define LZMA_SIMPLE_PRIVATE_H
  15
  16 #include "simple_coder.h"
  17
  18
  19 typedef struct {
  20         /// Next filter in the chain
  21         lzma_next_coder next;
  22
  23         /// True if the next coder in the chain has returned LZMA_STREAM_END.
  24         bool end_was_reached;
  25
  26         /// True if filter() should encode the data; false to decode.
  27         /// Currently all simple filters use the same function for encoding
  28         /// and decoding, because the difference between encoders and decoders
  29         /// is very small.
  30         bool is_encoder;
  31
  32         /// Pointer to filter-specific function, which does
  33         /// the actual filtering.
  34         size_t (*filter)(void *simple, uint32_t now_pos,
  35                         bool is_encoder, uint8_t *buffer, size_t size);
  36
  37         /// Pointer to filter-specific data, or NULL if filter doesn't need
  38         /// any extra data.
  39         void *simple;
  40
  41         /// The lowest 32 bits of the current position in the data. Most
  42         /// filters need this to do conversions between absolute and relative
  43         /// addresses.
  44         uint32_t now_pos;
  45
  46         /// Size of the memory allocated for the buffer.
  47         size_t allocated;
  48
  49         /// Flushing position in the temporary buffer. buffer[pos] is the
  50         /// next byte to be copied to out[].
  51         size_t pos;
  52
  53         /// buffer[filtered] is the first unfiltered byte. When pos is smaller
  54         /// than filtered, there is unflushed filtered data in the buffer.
  55         size_t filtered;
  56
  57         /// Total number of bytes (both filtered and unfiltered) currently
  58         /// in the temporary buffer.
  59         size_t size;
  60
  61         /// Temporary buffer
  62         uint8_t buffer[];
  63 } lzma_simple_coder;
  64
  65
  66 extern lzma_ret lzma_simple_coder_init(lzma_next_coder *next,
  67                 const lzma_allocator *allocator,
  68                 const lzma_filter_info *filters,
  69                 size_t (*filter)(void *simple, uint32_t now_pos,
  70                         bool is_encoder, uint8_t *buffer, size_t size),
  71                 size_t simple_size, size_t unfiltered_max,
  72                 uint32_t alignment, bool is_encoder);
  73
  74 #endif