/**********************************************************************

 *

 *  geo_tiffp.c  Private TIFF interface module for GEOTIFF

 *

 *    This module implements the interface between the GEOTIFF

 *    tag parser and the TIFF i/o module. The current setup

 *    relies on the "libtiff" code, but if you use your own

 *    TIFF reader software, you may replace the module implementations

 *    here with your own calls. No "libtiff" dependencies occur

 *    anywhere else in this code.

 *

 * copyright (c) 1995   Niles D. Ritter

 *

 * Permission granted to use this software, so long as this copyright

 * notice accompanies any products derived therefrom.

 *

 **********************************************************************/

#include "geotiff.h"    /* public GTIFF interface */

#include "geo_tiffp.h"  /* Private TIFF interface */

#include "geo_keyp.h"   /* Private GTIFF interface */

/* tiff size array global */

gsize_t _gtiff_size[] = { 0, 1, 2, 4, 8, 1, 4, 8, 1, 2, 4, 1 };

static int        _GTIFGetField (tiff_t *tif, pinfo_t tag, int *count, void *value );

static int        _GTIFSetField (tiff_t *tif, pinfo_t tag, int  count, void *value );

static tagtype_t  _GTIFTagType  (tiff_t *tif, pinfo_t tag);

/*

 * Set up default TIFF handlers.

 */

void _GTIFSetDefaultTIFF(TIFFMethod *method)

{

  if (!method) return;

  method->get = _GTIFGetField;

  method->set = _GTIFSetField;

  method->type = _GTIFTagType;

}

gdata_t _GTIFcalloc(gsize_t size)

{

    gdata_t data=(gdata_t)_TIFFmalloc((tsize_t)size);

  if (data) _TIFFmemset((tdata_t)data,0,(tsize_t)size);

  return data;

}

gdata_t _GTIFrealloc(gdata_t ptr, gsize_t size)

{

    return _TIFFrealloc((tdata_t)ptr, (tsize_t) size);

}

void _GTIFmemcpy(gdata_t out,gdata_t in,gsize_t size)

{

  _TIFFmemcpy((tdata_t)out,(tdata_t)in,(tsize_t)size);

}

void _GTIFFree(gdata_t data)

{

  if (data) _TIFFfree((tdata_t)data);

}

/* returns the value of TIFF tag <tag>, or if

 * the value is an array, returns an allocated buffer

 * containing the values. Allocate a copy of the actual

 * buffer, sized up for updating.

 */

static int _GTIFGetField (tiff_t *tif, pinfo_t tag, int *count, void *val )

{

  int status;

  unsigned short scount=0;

  char *tmp;

  const gsize_t size = _gtiff_size[_GTIFTagType (tif,tag)];

  if (_GTIFTagType(tif,  tag) == TYPE_ASCII)

  {

    status = TIFFGetField((TIFF *)tif,tag,&tmp);

    if (!status) return status;

    scount = (unsigned short) (strlen(tmp)+1);

  }

  else status = TIFFGetField((TIFF *)tif,tag,&scount,&tmp);

  if (!status) return status;

  *count = scount;

  char *value = (char *)_GTIFcalloc( (scount+MAX_VALUES)*size);

  if (!value) return 0;

  _TIFFmemcpy( value, tmp,  size * scount);

  *(char **)val = value;

  return status;

}

/*

 * Set a GeoTIFF TIFF field.

 */

static int _GTIFSetField (tiff_t *tif, pinfo_t tag, int count, void *value )

{

  const unsigned short scount = (unsigned short) count;

  int status;

  /* libtiff ASCII uses null-delimiter */

  if (_GTIFTagType(tif,  tag) == TYPE_ASCII)

    status = TIFFSetField((TIFF *)tif,tag,value);

  else

    status = TIFFSetField((TIFF *)tif,tag,scount,value);

  return status;

}

/*

 *  This routine is supposed to return the TagType of the <tag>

 *  TIFF tag. Unfortunately, "libtiff" does not provide this

 *  service by default, so we just have to "know" what type of tags

 *  we've got, and how many. We only define the ones Geotiff

 *  uses here, and others return UNKNOWN. The "tif" parameter

 *  is provided for those TIFF implementations that provide

 *  for tag-type queries.

 */

static tagtype_t  _GTIFTagType  (tiff_t *tif, pinfo_t tag)

{

  (void) tif; /* dummy reference */

  tagtype_t ttype;

  switch (tag)

  {

    case GTIFF_ASCIIPARAMS:    ttype=TYPE_ASCII; break;

    case GTIFF_PIXELSCALE:

    case GTIFF_TRANSMATRIX:

    case GTIFF_TIEPOINTS:

    case GTIFF_DOUBLEPARAMS:   ttype=TYPE_DOUBLE; break;

    case GTIFF_GEOKEYDIRECTORY: ttype=TYPE_SHORT; break;

    default: ttype = TYPE_UNKNOWN;

  }

  return ttype;

}