The R Project SVN R

///////////////////////////////////////////////////////////////////////////////
//
/// \file       simple_private.h
/// \brief      Private definitions for so called simple filters
//
//  Author:     Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef LZMA_SIMPLE_PRIVATE_H
#define LZMA_SIMPLE_PRIVATE_H

#include "simple_coder.h"


typedef struct lzma_simple_s lzma_simple;

struct lzma_coder_s {
    /// Next filter in the chain
    lzma_next_coder next;

    /// True if the next coder in the chain has returned LZMA_STREAM_END.
    bool end_was_reached;

    /// True if filter() should encode the data; false to decode.
    /// Currently all simple filters use the same function for encoding
    /// and decoding, because the difference between encoders and decoders
    /// is very small.
    bool is_encoder;

    /// Pointer to filter-specific function, which does
    /// the actual filtering.
    size_t (*filter)(lzma_simple *simple, uint32_t now_pos,
            bool is_encoder, uint8_t *buffer, size_t size);

    /// Pointer to filter-specific data, or NULL if filter doesn't need
    /// any extra data.
    lzma_simple *simple;

    /// The lowest 32 bits of the current position in the data. Most
    /// filters need this to do conversions between absolute and relative
    /// addresses.
    uint32_t now_pos;

    /// Size of the memory allocated for the buffer.
    size_t allocated;

    /// Flushing position in the temporary buffer. buffer[pos] is the
    /// next byte to be copied to out[].
    size_t pos;

    /// buffer[filtered] is the first unfiltered byte. When pos is smaller
    /// than filtered, there is unflushed filtered data in the buffer.
    size_t filtered;

    /// Total number of bytes (both filtered and unfiltered) currently
    /// in the temporary buffer.
    size_t size;

    /// Temporary buffer
    uint8_t buffer[];
};


extern lzma_ret lzma_simple_coder_init(lzma_next_coder *next,
        lzma_allocator *allocator, const lzma_filter_info *filters,
        size_t (*filter)(lzma_simple *simple, uint32_t now_pos,
            bool is_encoder, uint8_t *buffer, size_t size),
        size_t simple_size, size_t unfiltered_max,
        uint32_t alignment, bool is_encoder);

#endif