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// SPDX-License-Identifier: LGPL-3.0-or-later
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/**
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* \file cpr/bzip2.h
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*
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* Burrows–Wheeler bzip2 compression streaming support library.
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*
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* \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
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* \author Lorenzo Cogotti
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*/
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#ifndef DF_CPR_BZIP2_H_
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#define DF_CPR_BZIP2_H_
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#include "stm.h"
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/// Bzip2 stream handle.
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typedef struct Bzip2StmObj *Bzip2StmHn;
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/**
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* \brief BZip2 Compression options.
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*
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* \see `Bz2_InitCompress()`
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*/
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typedef struct {
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/**
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* \brief Compression level, from 1 to 9 inclusive.
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*
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* Higher values imply better compression, at the price of speed loss
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* and memory consumption.
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* Out of range values are silently clamped to allowed range.
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*/
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int compression;
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/// Compressor load factor.
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int factor;
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/// Compressor buffer size in bytes, 0 to use suggested value.
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size_t bufsiz;
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/**
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* \brief Debugging message verbosity.
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*
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* Values higher than 0 make the stream log debug messages to standard
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* error, debugging level goes from 0 to 4 inclusive.
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* Larger values are silently truncated to the maximum allowed.
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*/
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unsigned verbose;
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} Bzip2CprOpts;
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/**
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* \brief Decompression options.
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*
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* \see `Bz2_InitDecompress()`
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*/
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typedef struct {
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/// Decompressor buffer size in bytes, 0 to use suggested value.
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size_t bufsiz;
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/// Conserve memory during decompression, in spite of speed.
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Boolean low_mem;
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/**
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* \brief Debugging message verbosity.
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*
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* Values higher than 0 make the stream log debug messages to standard
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* error, debugging level goes from 0 to 4 inclusive.
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* Larger values are implicitly truncated to the maximum allowed.
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*/
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unsigned verbose;
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} Bzip2DecOpts;
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/// BZip2 result status, returned by `Bzip2_GetErrStat()`.
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typedef int Bzip2Ret; // 0 == OK
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/// Implementation of `StmOps` for BZip2 compression/decompression.
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extern const StmOps *const Bzip2_StmOps;
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/// Non-closing variant of `Bzip2_StmOps`.
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extern const StmOps *const Bzip2_NcStmOps;
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/// Return last BZip2 operation result.
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Bzip2Ret Bzip2_GetErrStat(void);
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/// Convert `Bzip2Ret` value to human readable string.
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const char *Bzip2_ErrorString(Bzip2Ret ret);
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/**
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* \brief Open stream for compression.
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*
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* \param [in,out] streamp Output stream for compressed data
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* \param [in] ops Write operations interface for `streamp`, must not be `NULL` and provide `Write()`
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* \param [in] opts Compression options, may be `NULL` for defaults
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*
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* \return The BZip2 compressor handle on success, `NULL` on failure.
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*/
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Bzip2StmHn Bzip2_OpenCompress(void *streamp, const StmOps *ops, const Bzip2CprOpts *opts);
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/**
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* \brief Open a stream for decompressing.
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*
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* \param [in,out] streamp Input stream for BZip2 compressed data
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* \param [in] ops Read operations interface for `streamp`, must not be `NULL` and provide `Read()`
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* \param [in] opts Decompression options, may be `NULL` for defaults
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*
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* \return The BZip2 decompressor handle on success, `NULL` on failure.
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*/
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Bzip2StmHn Bzip2_OpenDecompress(void *streamp, const StmOps *ops, const Bzip2DecOpts *opts);
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/**
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* \brief Decompress `nbytes` bytes from `hn` to `buf`.
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*
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* \return Number of actual bytes written to `buf`, 0 on end of stream,
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* -1 on error.
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*/
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Sint64 Bzip2_Read(Bzip2StmHn hn, void *buf, size_t nbytes);
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/**
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* \brief Compress `nbytes` bytes from `buf` to `hn`.
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*
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* \return Number of bytes actually written to `hn`, which may be less
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* than `nbytes`, -1 on error.
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*
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* \note Compression should be finalized with `Bzip2_Finish()` once all
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* data is written.
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*/
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Sint64 Bzip2_Write(Bzip2StmHn hn, const void *buf, size_t nbytes);
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/**
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* \brief Flush Bzip2 encoder.
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*
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* Should be called before closing a BZip2 encoder.
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*
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* \param [in,out] hn Stream to be finalized, must not be `NULL`
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*
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* \return `OK` on success, `NG` on failure.
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*/
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Judgement Bzip2_Finish(Bzip2StmHn hn);
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/// Close a Bzip2 stream.
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void Bzip2_Close(Bzip2StmHn hn);
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#endif
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