text: 
  #ifndef HEADER_COMP_H
  #define HEADER_COMP_H
  
  #include <openssl/crypto.h>
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
  
  typedef struct comp_ctx_st COMP_CTX;
  
  typedef struct comp_method_st
  	{
  	int type;		/* NID for compression library */
  	const char *name;	/* A text string to identify the library */
  	int (*init)(COMP_CTX *ctx);
  	void (*finish)(COMP_CTX *ctx);
  	int (*compress)(COMP_CTX *ctx,
  			unsigned char *out, unsigned int olen,
  			unsigned char *in, unsigned int ilen);
  	int (*expand)(COMP_CTX *ctx,
  		      unsigned char *out, unsigned int olen,
  		      unsigned char *in, unsigned int ilen);
  	/* The following two do NOTHING, but are kept for backward compatibility */
  	long (*ctrl)(void);
  	long (*callback_ctrl)(void);
  	} COMP_METHOD;
  
  struct comp_ctx_st
  	{
  	COMP_METHOD *meth;
  	unsigned long compress_in;
  	unsigned long compress_out;
  	unsigned long expand_in;
  	unsigned long expand_out;
  
  	CRYPTO_EX_DATA	ex_data;
  	};
  
  
  COMP_CTX *COMP_CTX_new(COMP_METHOD *meth);
  void COMP_CTX_free(COMP_CTX *ctx);
  int COMP_compress_block(COMP_CTX *ctx, unsigned char *out, int olen,
  	unsigned char *in, int ilen);
  int COMP_expand_block(COMP_CTX *ctx, unsigned char *out, int olen,
  	unsigned char *in, int ilen);
  COMP_METHOD *COMP_rle(void );
  COMP_METHOD *COMP_zlib(void );
  void COMP_zlib_cleanup(void);
  
  #ifdef HEADER_BIO_H
  #ifdef ZLIB
  BIO_METHOD *BIO_f_zlib(void);
  #endif
  #endif
  
  /* BEGIN ERROR CODES */
  /* The following lines are auto generated by the script mkerr.pl. Any changes
   * made after this point may be overwritten when the script is next run.
   */
  void ERR_load_COMP_strings(void);
  
  /* Error codes for the COMP functions. */
  
  /* Function codes. */
  #define COMP_F_BIO_ZLIB_FLUSH				 99
  #define COMP_F_BIO_ZLIB_NEW				 100
  #define COMP_F_BIO_ZLIB_READ				 101
  #define COMP_F_BIO_ZLIB_WRITE				 102
  
  /* Reason codes. */
  #define COMP_R_ZLIB_DEFLATE_ERROR			 99
  #define COMP_R_ZLIB_INFLATE_ERROR			 100
  #define COMP_R_ZLIB_NOT_SUPPORTED			 101
  
  #ifdef  __cplusplus
  }
  #endif
  #endif
  