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build/extraResources/mysql/include/my_compress.h

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+/* Copyright (c) 2019, 2025, Oracle and/or its affiliates.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License, version 2.0,
+   as published by the Free Software Foundation.
+
+   This program is designed to work with certain software (including
+   but not limited to OpenSSL) that is licensed under separate terms,
+   as designated in a particular file or component or in included license
+   documentation.  The authors of MySQL hereby grant you an additional
+   permission to link the program and your derivative works with the
+   separately licensed software that they have either included with
+   the program or referenced in the documentation.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License, version 2.0, for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+#ifndef MY_COMPRESS_INCLUDED
+#define MY_COMPRESS_INCLUDED
+
+/* List of valid values for compression_algorithm */
+enum enum_compression_algorithm {
+  MYSQL_UNCOMPRESSED = 1,
+  MYSQL_ZLIB,
+  MYSQL_ZSTD,
+  MYSQL_INVALID
+};
+
+/**
+  Compress context information. relating to zlib compression.
+*/
+
+typedef struct mysql_zlib_compress_context {
+  /**
+    Compression level to use in zlib compression.
+  */
+  unsigned int compression_level;
+} mysql_zlib_compress_context;
+
+typedef struct ZSTD_CCtx_s ZSTD_CCtx;
+typedef struct ZSTD_DCtx_s ZSTD_DCtx;
+
+/**
+  Compress context information relating to zstd compression.
+*/
+
+typedef struct mysql_zstd_compress_context {
+  /**
+    Pointer to compressor context.
+  */
+  ZSTD_CCtx *cctx;
+  /**
+    Pointer to decompressor context.
+  */
+  ZSTD_DCtx *dctx;
+  /**
+    Compression level to use in zstd compression.
+  */
+  unsigned int compression_level;
+} mysql_zstd_compress_context;
+
+/**
+  Compression context information.
+  It encapsulate the context information based on compression method and
+  presents a generic struct.
+*/
+
+typedef struct mysql_compress_context {
+  enum enum_compression_algorithm algorithm;  ///< Compression algorithm name.
+  union {
+    mysql_zlib_compress_context zlib_ctx;  ///< Context information of zlib.
+    mysql_zstd_compress_context zstd_ctx;  ///< Context information of zstd.
+  } u;
+} mysql_compress_context;
+
+/**
+  Get default compression level corresponding to a given compression method.
+
+  @param algorithm Compression Method. Possible values are zlib or zstd.
+
+  @return an unsigned int representing default compression level.
+  6 is the default compression level for zlib and 3 is the
+  default compression level for zstd.
+*/
+
+unsigned int mysql_default_compression_level(
+    enum enum_compression_algorithm algorithm);
+
+/**
+  Initialize a compress context object to be associated with a NET object.
+
+  @param cmp_ctx Pointer to compression context.
+  @param algorithm Compression algorithm.
+  @param compression_level Compression level corresponding to the compression
+  algorithm.
+*/
+
+void mysql_compress_context_init(mysql_compress_context *cmp_ctx,
+                                 enum enum_compression_algorithm algorithm,
+                                 unsigned int compression_level);
+/**
+  Deinitialize the compression context allocated.
+
+  @param mysql_compress_ctx Pointer to Compression context.
+*/
+
+void mysql_compress_context_deinit(mysql_compress_context *mysql_compress_ctx);
+
+#endif  // MY_COMPRESS_INCLUDED