src/liblzma/simple/simple_private.h

   1 // SPDX-License-Identifier: 0BSD
   2
   3 ///////////////////////////////////////////////////////////////////////////////
   4 //
   5 /// \file       simple_private.h
   6 /// \brief      Private definitions for so called simple filters
   7 //
   8 //  Author:     Lasse Collin
   9 //
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef LZMA_SIMPLE_PRIVATE_H
  13 #define LZMA_SIMPLE_PRIVATE_H
  14
  15 #include "simple_coder.h"
  16
  17
  18 typedef struct {
  19         /// Next filter in the chain
  20         lzma_next_coder next;
  21
  22         /// True if the next coder in the chain has returned LZMA_STREAM_END.
  23         bool end_was_reached;
  24
  25         /// True if filter() should encode the data; false to decode.
  26         /// Currently all simple filters use the same function for encoding
  27         /// and decoding, because the difference between encoders and decoders
  28         /// is very small.
  29         bool is_encoder;
  30
  31         /// Pointer to filter-specific function, which does
  32         /// the actual filtering.
  33         size_t (*filter)(void *simple, uint32_t now_pos,
  34                         bool is_encoder, uint8_t *buffer, size_t size);
  35
  36         /// Pointer to filter-specific data, or NULL if filter doesn't need
  37         /// any extra data.
  38         void *simple;
  39
  40         /// The lowest 32 bits of the current position in the data. Most
  41         /// filters need this to do conversions between absolute and relative
  42         /// addresses.
  43         uint32_t now_pos;
  44
  45         /// Size of the memory allocated for the buffer.
  46         size_t allocated;
  47
  48         /// Flushing position in the temporary buffer. buffer[pos] is the
  49         /// next byte to be copied to out[].
  50         size_t pos;
  51
  52         /// buffer[filtered] is the first unfiltered byte. When pos is smaller
  53         /// than filtered, there is unflushed filtered data in the buffer.
  54         size_t filtered;
  55
  56         /// Total number of bytes (both filtered and unfiltered) currently
  57         /// in the temporary buffer.
  58         size_t size;
  59
  60         /// Temporary buffer
  61         uint8_t buffer[];
  62 } lzma_simple_coder;
  63
  64
  65 extern lzma_ret lzma_simple_coder_init(lzma_next_coder *next,
  66                 const lzma_allocator *allocator,
  67                 const lzma_filter_info *filters,
  68                 size_t (*filter)(void *simple, uint32_t now_pos,
  69                         bool is_encoder, uint8_t *buffer, size_t size),
  70                 size_t simple_size, size_t unfiltered_max,
  71                 uint32_t alignment, bool is_encoder);
  72
  73 #endif