/********************************************************************** * Project: CPL - Common Portability Library * Purpose: Registry of compression/decompression functions * Author: Even Rouault * ********************************************************************** * Copyright (c) 2021, Even Rouault * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. ****************************************************************************/ #include "cpl_port.h" #include /** * \file cpl_compressor.h * * API for compressors and decompressors of binary buffers. */ CPL_C_START /** Callback of a compressor/decompressor. * * For a compressor, input is uncompressed data, and output compressed data. * For a decompressor, input is compressed data, and output uncompressed data. * * Valid situations for output_data and output_size are: *
    *
  • output_data != NULL and *output_data != NULL and output_size != NULL and * *output_size != 0. The caller provides the output * buffer in *output_data and its size in *output_size. In case of successful * operation, *output_size will be updated to the actual size. * This mode is the one that is always guaranteed to be implemented efficiently. * In case of failure due to insufficient space, it will be updated to the size * needed (if known), or 0 (if unknown)
  • *
  • output_data == NULL and output_size != NULL. *output_size will be updated * with the minimum size the output buffer should be (if known), or 0 (if unknown).
  • *
  • output_data != NULL and *output_data == NULL and output_size != NULL. * *output_data will be allocated using VSIMalloc(), and should be freed by the * caller with VSIFree(). *output_size will be updated to the size of the output * buffer.
  • *
* * @param input_data Input data. Should not be NULL. * @param input_size Size of input data, in bytes. * @param output_data Pointer to output data. * @param output_size Pointer to output size. * @param options NULL terminated list of options. Or NULL. * @param compressor_user_data User data provided at registration time. * @return true in case of success. */ typedef bool (*CPLCompressionFunc)(const void* input_data, size_t input_size, void** output_data, size_t* output_size, CSLConstList options, void* compressor_user_data); /** Type of compressor */ typedef enum { /** Compressor */ CCT_COMPRESSOR, /** Filter */ CCT_FILTER } CPLCompressorType; /** Compressor/decompressor description */ typedef struct { /** Structure version. Should be set to 1 */ int nStructVersion; /** Id of the compressor/decompressor. Should NOT be NULL. */ const char* pszId; /** Compressor type */ CPLCompressorType eType; /** Metadata, as a NULL terminated list of strings. Or NULL. * The OPTIONS metadata key is reserved for compressors/decompressors to * provide the available options as a XML string of the form * <Options> * <Option name='' type='' description='' default=''/> * </Options> */ CSLConstList papszMetadata; /** Compressor/decompressor callback. Should NOT be NULL. */ CPLCompressionFunc pfnFunc; /** User data to provide to the callback. May be NULL. */ void* user_data; } CPLCompressor; bool CPL_DLL CPLRegisterCompressor(const CPLCompressor* compressor); bool CPL_DLL CPLRegisterDecompressor(const CPLCompressor* decompressor); char CPL_DLL ** CPLGetCompressors(void); char CPL_DLL ** CPLGetDecompressors(void); const CPLCompressor CPL_DLL *CPLGetCompressor(const char* pszId); const CPLCompressor CPL_DLL *CPLGetDecompressor(const char* pszId); /*! @cond Doxygen_Suppress */ void CPL_DLL CPLDestroyCompressorRegistry(void); /*! @endcond */ CPL_C_END