text: /*------------------------------------------------------------------------------
   *
   * Copyright (c) 2011-2021, EURid vzw. All rights reserved.
   * The YADIFA TM software product is provided under the BSD 3-clause license:
   *
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   * modification, are permitted provided that the following conditions
   * are met:
   *
   *        * Redistributions of source code must retain the above copyright
   *          notice, this list of conditions and the following disclaimer.
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   *          notice, this list of conditions and the following disclaimer in the
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   *        * Neither the name of EURid nor the names of its contributors may be
   *          used to endorse or promote products derived from this software
   *          without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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   *------------------------------------------------------------------------------
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   */
  
  /** @defgroup digest Cryptographic digest functions.
   *  @ingroup dnscore
   *  @brief Cryptographic digest functions.
   *  
   * Cryptographic digest functions: SHA0, SHA1, SHA256, SHA384 SHA512
   * 
   * They are very simple and self-explanatory wrappers around the cryptographic
   * library (currently : openssl)
   * Hence the small specific C-files are not documented.
   * 
   * Adding more would be trivial but these are the only ones needed for DNS at
   * this point.
   * 
   * @{
   */
  #ifndef _DIGEST_H
  #define	_DIGEST_H
  
  #include <openssl/engine.h>
  #include <openssl/sha.h>
  #include <dnscore/sys_types.h>
  #include <dnscore/bytearray_output_stream.h>
  
  #define DIGEST_BUFFER_SIZE 128
  
  struct digest_s;
  
  typedef s32 digest_update_method(struct digest_s*,const void*, u32);
  typedef s32 digest_final_method(struct digest_s*);
  typedef s32 digest_sha1_final_copy_bytes_method(struct digest_s*, void*, u32);
  typedef s32 digest_get_size_method(struct digest_s*);
  typedef s32 digest_get_digest_method(struct digest_s*, void**);
  
  struct digest_vtbl
  {
      digest_update_method* update;
      digest_final_method* final;
      digest_sha1_final_copy_bytes_method* final_copy_bytes;
      digest_get_size_method* get_size;
      digest_get_digest_method* get_digest;
      const char * __class__;
  };
  
  struct digest_rawdata_ctx
  {
      bytearray_output_stream_context baos_ctx;
      output_stream baos; // accumulates bytes (EDDSA)    // total: about 11 pointers
      u8 data[sizeof(SHA512_CTX) - sizeof(output_stream) - sizeof(bytearray_output_stream_context)];
  };
  
  struct digest_s
  {
      const struct digest_vtbl *vtbl;
      union
      {
          SHA_CTX sha0;
          SHA_CTX sha1;
          SHA256_CTX sha256;
          SHA512_CTX sha384; /// @note 20160202 edf -- there is no SHA384_CTX, SHA512_CTX must be used
          SHA512_CTX sha512;
          struct digest_rawdata_ctx rawdata;
      } ctx;
  
      u8 digest[DIGEST_BUFFER_SIZE];  // used so the caller does not need to keep a copy of the digest.
  };
  
  typedef struct digest_s digest_s;
  
  #define digest_class(is_) ((is_)->vtbl)
  #define digest_class_name(is_) ((is_)->vtbl->__class__)
  #define digest_update(ctx_,buffer_,len_) (ctx_)->vtbl->update(ctx_,buffer_,len_)
  #define digest_final(ctx_) (ctx_)->vtbl->final(ctx_)
  #define digest_final_copy_bytes(ctx_,buffer_,buffer_size_) (ctx_)->vtbl->final_copy_bytes((ctx_),(buffer_),(buffer_size_))
  #define digest_get_size(ctx_) (ctx_)->vtbl->get_size(ctx_)
  #define digest_get_digest(ctx_,ptr_) (ctx_)->vtbl->get_digest((ctx_),(ptr_))
  
  static inline void digest_copy_bytes(digest_s *ctx, void *buffer)
  {
      void *digest_bytes;
      s32 size = digest_get_digest(ctx, &digest_bytes);
      memcpy(buffer, digest_bytes, size);
  }
  
  static inline void* digest_get_digest_ptr(digest_s *ctx)
  {
      void *digest_bytes;
      digest_get_digest(ctx, &digest_bytes);
      return digest_bytes;
  }
  
  #ifndef OPENSSL_NO_SHA1
  void digest_sha1_init(digest_s *ctx);
  #endif
  
  #ifndef OPENSSL_NO_SHA256
  void digest_sha256_init(digest_s *ctx);
  #endif
  
  #ifndef OPENSSL_NO_SHA512
  void digest_sha384_init(digest_s *ctx);
  void digest_sha512_init(digest_s *ctx);
  #endif
  
  void digest_rawdata_init(digest_s *ctx);
  
  #ifndef OPENSSL_NO_SHA0
  void digest_sha0_init(digest_s *ctx);
  #endif
  
  #endif // _DIGEST_H
  