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geo_write.c

/**********************************************************************
 *
 *  geo_write.c  -- Public routines for GEOTIFF GeoKey access.
 *
 *    Written By: Niles D. Ritter.
 *
 *  copyright (c) 1995   Niles D. Ritter
 *
 *  Permission granted to use this software, so long as this copyright
 *  notice accompanies any source code derived therefrom.
 *
 **********************************************************************/

#include "geotiffio.h"   /* public interface        */
#include "geo_tiffp.h" /* external TIFF interface */
#include "geo_keyp.h"  /* private interface       */

static int WriteKey(GTIF* gt, KeyEntry* entptr,GeoKey* keyptr);
static int SortKeys(GTIF* gt,int *sortkeys);

int GTIFWriteKeys(GTIF *gt)
{
        int i;
        GeoKey *keyptr;
        KeyEntry *entptr;
        KeyHeader *header;
        int sortkeys[MAX_KEYS];
        
        if (!(gt->gt_flags & FLAG_FILE_MODIFIED)) return 1;
        
        /*  Sort the Keys into numerical order */
        if (!SortKeys(gt,sortkeys))
        {
                /* XXX error: a key was not recognized */
        }
        
        /* Set up header of ProjectionInfo tag */
        header = (KeyHeader *)gt->gt_short;
        header->hdr_num_keys = gt->gt_num_keys;
        header->hdr_version  = GvCurrentVersion;
        header->hdr_rev_major  = GvCurrentRevision;
        header->hdr_rev_minor  = GvCurrentMinorRev;
        
        /* Set up the rest of SHORT array properly */
        keyptr = gt->gt_keys;
        entptr = (KeyEntry*)(gt->gt_short + 4);
        for (i=0; i< gt->gt_num_keys; i++,entptr++)
        {
                if (!WriteKey(gt,entptr,keyptr+sortkeys[i])) return 0;
        }       
        
        /* Write out the Key Directory */
        (gt->gt_methods.set)(gt->gt_tif, GTIFF_GEOKEYDIRECTORY, gt->gt_nshorts, gt->gt_short ); 
        
        /* Write out the params directories */
        if (gt->gt_ndoubles)
          (gt->gt_methods.set)(gt->gt_tif, GTIFF_DOUBLEPARAMS, gt->gt_ndoubles, gt->gt_double );
        if (gt->gt_nascii)
        {
          gt->gt_ascii[gt->gt_nascii] = '\0'; /* just to be safe */
          (gt->gt_methods.set)(gt->gt_tif, GTIFF_ASCIIPARAMS, 0, gt->gt_ascii );
        }
        
        gt->gt_flags &= ~FLAG_FILE_MODIFIED;
        return 1;
}

/**********************************************************************
 *
 *                        Private Routines
 *
 **********************************************************************/
 
/*
 * Given GeoKey, write out the KeyEntry entries, returning 0 if failure.
 *  This is the exact complement of ReadKey().
 */

static int WriteKey(GTIF* gt, KeyEntry* entptr,GeoKey* keyptr)
{
        int count;
        
        entptr->ent_key = keyptr->gk_key;
        entptr->ent_count = keyptr->gk_count;
        count = entptr->ent_count;
        
        if (count==1 && keyptr->gk_type==TYPE_SHORT)
        {
                entptr->ent_location = GTIFF_LOCAL;
                entptr->ent_val_offset = *(pinfo_t*)&keyptr->gk_data;
                return 1;
        }
                  
        switch (keyptr->gk_type)
        {
                case TYPE_SHORT:
                        entptr->ent_location = GTIFF_GEOKEYDIRECTORY;
                        entptr->ent_val_offset = 
                           (pinfo_t*)keyptr->gk_data - gt->gt_short;
                        break;
                case TYPE_DOUBLE:
                        entptr->ent_location = GTIFF_DOUBLEPARAMS;
                        entptr->ent_val_offset = 
                           (double*)keyptr->gk_data - gt->gt_double;
                        break;
                case TYPE_ASCII:
                        entptr->ent_location = GTIFF_ASCIIPARAMS;
                        entptr->ent_val_offset = 
                           (char*)keyptr->gk_data - gt->gt_ascii;
                        break;
                default:
                        return 0; /* failure */
        }
        
        return 1; /* success */
}


/* 
 * Numerically sort the GeoKeys.
 * We just do a linear search through
 * the list and pull out the keys that were set.
 */

static int SortKeys(GTIF* gt,int *sortkeys)
{
    int loc;
    int nkeys=0;
    geokey_t key,kmin,kmax;
    int *index = gt->gt_keyindex;
        
    kmin = (geokey_t) gt->gt_keymin;
    kmax = (geokey_t) gt->gt_keymax;
    for (key=kmin; key<=kmax; key++)
    {
        if ( (loc=index[key]) != 0 )
        {
            sortkeys[nkeys] = loc;
            nkeys++;
        }
    }
        
    return nkeys==gt->gt_num_keys;
}

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