%%	options

copyright owner	=	Dirk Krause
copyright year	=	2011-2014
license		=	bsd



%%	module

#include "dk3all.h"



$(trace-include)


/**	Low-level stream function to deal with gzip compression.
	Closing the stream also closes the gzip-file.
	@param	api	API structure.
*/
static
void
dk3stream_gz_fct(dk3_stream_api_t *api)
{
#if DK3_HAVE_ZLIB_H
  int		res = 0;	/* Operation result. */
  gzFile	g = NULL;	/* Low-level I/O object. */
#endif
  api->suc = 0;
  (api->res).sz = 0;
  (api->res).ec = DK3_ERROR_NOT_SUPPORTED;
#if DK3_HAVE_ZLIB_H
  (api->res).ec = 0;
  g = (gzFile)((api->arg).d);
  switch(api->cmd) {
    case DK3_STREAM_API_READ: {
      if(((api->arg).b) && ((api->arg).sz) && ((api->arg).d)) {
        res = gzread(g, (api->arg).b, (int)((api->arg).sz));
	if(res > 0) {
	  api->suc = 1; (api->res).ec = 0; (api->res).sz = (size_t)res;
	}
      }
    } break;
    case DK3_STREAM_API_WRITE: {
      if(((api->arg).b) && ((api->arg).sz) && ((api->arg).d)) {
        res = gzwrite(g, (api->arg).b, (int)((api->arg).sz));
	(api->res).sz = (size_t)res;
	if((size_t)res == (api->arg).sz) {
	  api->suc = 1; (api->res).ec = 0;
	}
      }
    } break;
    case DK3_STREAM_API_FLUSH: {
      if((api->arg).d) {
        if(gzflush(g, Z_FULL_FLUSH) == Z_OK) {
	  api->suc = 1; (api->res).ec = 0;
	}
      }
    } break;
    case DK3_STREAM_API_AT_END: {
      if((api->arg).d) {
        if(gzeof(g) == 1) {
	  api->suc = 1;
	}
      }
    } break;
    case DK3_STREAM_API_CLOSE: {
      if((api->arg).d) {
        if(gzclose(g) == Z_OK) {
	  api->suc = 1;
	}
      }
    } break;
    case DK3_STREAM_API_ZERO_IS_END: {
      api->suc = 0;
    } break;
    case DK3_STREAM_API_ERROR: {
      api->suc = 0;
    } break;
  }
#endif
}



/**	Low-level stream function to deal with gzip compression.
	Closing the stream does not close the gzip-file.
	@param	api	API structure.
*/
static
void
dk3stream_gz_fct_no_close(dk3_stream_api_t *api)
{
  if(api->cmd != DK3_STREAM_API_CLOSE) {
    dk3stream_gz_fct(api);
  } else {
    api->suc = 1; (api->res).ec = 0;
  }
}


#if DK3_HAVE_ZLIB_H

/**	Open stream for existing gzFile.
	@param	g	gzFile already opened.
	@param	fl	Read/write flags.
	@param	app	Application structure for diagnostics, may be NULL.
	@return	Pointer to new stream on success, NULL on error.
*/
dk3_stream_t *
dk3stream_open_gz_app(gzFile g, int fl, dk3_app_t *app)
{
  dk3_stream_t *back = NULL;
  if(g) {
    back = dk3stream_open_app((void *)g, dk3stream_gz_fct_no_close, fl, app);
  }
  return back;
}

#endif



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