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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* xfrm.h
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#ifndef IO_XFRM_H
#define IO_XFRM_H
#include "io/istream.h"
#include "io/ostream.h"
enum {
/**
* @brief Deflate compressor with gzip headers.
*
* This actually creates a gzip compatible file, including a
* gzip header and trailer.
*/
IO_COMPRESSOR_GZIP = 1,
IO_COMPRESSOR_XZ = 2,
IO_COMPRESSOR_ZSTD = 3,
IO_COMPRESSOR_BZIP2 = 4,
IO_COMPRESSOR_MIN = 1,
IO_COMPRESSOR_MAX = 4,
};
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Create an input stream that transparently uncompresses data.
*
* @memberof istream_t
*
* This function creates an input stream that wraps an underlying input stream
* that is compressed and transparently uncompresses the data when reading
* from it.
*
* The new stream takes ownership of the wrapped stream and destroys it when
* the compressor stream is destroyed. If this function fails, the wrapped
* stream is also destroyed.
*
* @param strm A pointer to another stream that should be wrapped.
* @param comp_id An identifier describing the compressor to use.
*
* @return A pointer to an input stream on success, NULL on failure.
*/
SQFS_INTERNAL istream_t *istream_compressor_create(istream_t *strm,
int comp_id);
/**
* @brief Create an output stream that transparently compresses data.
*
* @memberof ostream_t
*
* This function creates an output stream that transparently compresses all
* data appended to it and writes the compressed data to an underlying, wrapped
* output stream.
*
* The new stream takes ownership of the wrapped stream and destroys it when
* the compressor stream is destroyed. If this function fails, the wrapped
* stream is also destroyed.
*
* @param strm A pointer to another stream that should be wrapped.
* @param comp_id An identifier describing the compressor to use.
*
* @return A pointer to an output stream on success, NULL on failure.
*/
SQFS_INTERNAL ostream_t *ostream_compressor_create(ostream_t *strm,
int comp_id);
/**
* @brief Probe the buffered data in an istream to check if it is compressed.
*
* @memberof istream_t
*
* This function peeks into the internal buffer of an input stream to check
* for magic signatures of various compressors.
*
* @param strm A pointer to an input stream to check
* @param probe A callback used to check if raw/decoded data matches an
* expected format. Returns 0 if not, -1 on failure and +1
* on success.
*
* @return A compressor ID on success, 0 if no match was found, -1 on failure.
*/
SQFS_INTERNAL int istream_detect_compressor(istream_t *strm,
int (*probe)(const sqfs_u8 *data,
size_t size));
/**
* @brief Resolve a compressor name to an ID.
*
* @param name A compressor name.
*
* @return A compressor ID on success, -1 on failure.
*/
SQFS_INTERNAL int io_compressor_id_from_name(const char *name);
/**
* @brief Resolve a id to a compressor name.
*
* @param id A compressor ID.
*
* @return A compressor name on success, NULL on failure.
*/
SQFS_INTERNAL const char *io_compressor_name_from_id(int id);
/**
* @brief Check if support for a given compressor has been built in.
*
* @param id A compressor ID.
*
* @return True if the compressor is supported, false if not.
*/
SQFS_INTERNAL bool io_compressor_exists(int id);
#ifdef __cplusplus
}
#endif
#endif /* IO_XFRM_H */
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