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    1 /**********************************************************************
    2  *
    3  *  geo_get.c  -- Public routines for GEOTIFF GeoKey access.
    4  *
    5  *    Written By: Niles D. Ritter.
    6  *
    7  *  copyright (c) 1995   Niles D. Ritter
    8  *
    9  *  Permission granted to use this software, so long as this copyright
   10  *  notice accompanies any products derived therefrom.
   11  *
   12  *  Revision History;
   13  *
   14  *    20 June, 1995      Niles D. Ritter         New
   15  *    3 July,  1995      Greg Martin             Fix strings and index
   16  *    6 July,  1995      Niles D. Ritter         Unfix indexing.
   17  *
   18  **********************************************************************/
   19 
   20 #include "geotiff.h"   /* public interface        */
   21 #include "geo_tiffp.h" /* external TIFF interface */
   22 #include "geo_keyp.h"  /* private interface       */
   23 
   24 /* return the Header info of this geotiff file */
   25 
   26 void GTIFDirectoryInfo(GTIF *gtif, int version[3], int *keycount)
   27 {
   28         if (version)
   29         {
   30                 version[0]  = gtif->gt_version;
   31                 version[1]  = gtif->gt_rev_major;
   32                 version[2]  = gtif->gt_rev_minor;
   33         }
   34         if (keycount) *keycount = gtif->gt_num_keys;
   35 }
   36 
   37 
   38 int GTIFKeyInfo(GTIF *gtif, geokey_t key, int *size, tagtype_t* type)
   39 {
   40         int nIndex = gtif->gt_keyindex[ key ];
   41         GeoKey *keyptr;
   42 
   43         if (!nIndex) return 0;
   44 
   45         keyptr = gtif->gt_keys + nIndex;
   46         if (size) *size = (int) keyptr->gk_size;
   47         if (type) *type = keyptr->gk_type;
   48 
   49         return (int)keyptr->gk_count;
   50 }
   51 
   52 /**
   53 
   54 This function reads the value of a single GeoKey from a GeoTIFF file.
   55 
   56 @param gtif The geotiff information handle from GTIFNew().
   57 
   58 @param thekey The geokey_t name (such as ProjectedCSTypeGeoKey).
   59 This must come from the list of legal geokey_t values
   60 (an enumeration) listed below.
   61 
   62 @param val The <b>val</b> argument is a pointer to the
   63 variable into which the value should be read.  The type of the variable
   64 varies depending on the geokey_t given.  While there is no ready mapping
   65 of geokey_t values onto types, in general code values are of type <i>short</i>,
   66 citations are strings, and everything else is of type <i>double</i>.  Note
   67 that pointer's to <i>int</i> should never be passed to GTIFKeyGet() for
   68 integer values as they will be shorts, and the int's may not be properly
   69 initialized (and will be grossly wrong on MSB systems).
   70 
   71 @param nIndex Indicates how far into the list of values
   72 for this geokey to offset. Should normally be zero.
   73 
   74 @param count Indicates how many values
   75 to read.  At this time all keys except for strings have only one value,
   76 so <b>nIndex</b> should be zero, and <b>count</b> should be one.
   77 
   78 @return The GTIFKeyGet() function returns the number of values read.  Normally
   79 this would be one if successful or zero if the key doesn't exist for this
   80 file.
   81 
   82 From geokeys.inc we see the following geokey_t values are possible:<p>
   83 
   84 <pre>
   85 -- 6.2.1 GeoTIFF Configuration Keys --
   86 
   87 ValuePair(  GTModelTypeGeoKey,  1024) -- Section 6.3.1.1 Codes       --
   88 ValuePair(  GTRasterTypeGeoKey, 1025) -- Section 6.3.1.2 Codes       --
   89 ValuePair(  GTCitationGeoKey,   1026) -- documentation --
   90 
   91 -- 6.2.2 Geographic CS Parameter Keys --
   92 
   93 ValuePair(  GeographicTypeGeoKey,   2048) -- Section 6.3.2.1 Codes     --
   94 ValuePair(  GeogCitationGeoKey, 2049) -- documentation             --
   95 ValuePair(  GeogGeodeticDatumGeoKey,    2050) -- Section 6.3.2.2 Codes     --
   96 ValuePair(  GeogPrimeMeridianGeoKey,    2051) -- Section 6.3.2.4 codes     --
   97 ValuePair(  GeogLinearUnitsGeoKey,  2052) -- Section 6.3.1.3 Codes     --
   98 ValuePair(  GeogLinearUnitSizeGeoKey,   2053) -- meters                    --
   99 ValuePair(  GeogAngularUnitsGeoKey, 2054) -- Section 6.3.1.4 Codes     --
  100 ValuePair(  GeogAngularUnitSizeGeoKey,  2055) -- radians                   --
  101 ValuePair(  GeogEllipsoidGeoKey,    2056) -- Section 6.3.2.3 Codes     --
  102 ValuePair(  GeogSemiMajorAxisGeoKey,    2057) -- GeogLinearUnits           --
  103 ValuePair(  GeogSemiMinorAxisGeoKey,    2058) -- GeogLinearUnits           --
  104 ValuePair(  GeogInvFlatteningGeoKey,    2059) -- ratio                     --
  105 ValuePair(  GeogAzimuthUnitsGeoKey, 2060) -- Section 6.3.1.4 Codes     --
  106 ValuePair(  GeogPrimeMeridianLongGeoKey,    2061) -- GeoAngularUnit            --
  107 
  108 -- 6.2.3 Projected CS Parameter Keys --
  109 --    Several keys have been renamed,--
  110 --    and the deprecated names aliased for backward compatibility --
  111 
  112 ValuePair(  ProjectedCSTypeGeoKey,  3072)     -- Section 6.3.3.1 codes   --
  113 ValuePair(  PCSCitationGeoKey,  3073)     -- documentation           --
  114 ValuePair(  ProjectionGeoKey,   3074)     -- Section 6.3.3.2 codes   --
  115 ValuePair(  ProjCoordTransGeoKey,   3075)     -- Section 6.3.3.3 codes   --
  116 ValuePair(  ProjLinearUnitsGeoKey,  3076)     -- Section 6.3.1.3 codes   --
  117 ValuePair(  ProjLinearUnitSizeGeoKey,   3077)     -- meters                  --
  118 ValuePair(  ProjStdParallel1GeoKey, 3078)     -- GeogAngularUnit --
  119 ValuePair(  ProjStdParallelGeoKey,ProjStdParallel1GeoKey) -- ** alias **   --
  120 ValuePair(  ProjStdParallel2GeoKey, 3079)     -- GeogAngularUnit --
  121 ValuePair(  ProjNatOriginLongGeoKey,    3080)     -- GeogAngularUnit --
  122 ValuePair(  ProjOriginLongGeoKey,ProjNatOriginLongGeoKey) -- ** alias **     --
  123 ValuePair(  ProjNatOriginLatGeoKey, 3081)     -- GeogAngularUnit --
  124 ValuePair(  ProjOriginLatGeoKey,ProjNatOriginLatGeoKey)   -- ** alias **     --
  125 ValuePair(  ProjFalseEastingGeoKey, 3082)     -- ProjLinearUnits --
  126 ValuePair(  ProjFalseNorthingGeoKey,    3083)     -- ProjLinearUnits --
  127 ValuePair(  ProjFalseOriginLongGeoKey,  3084)     -- GeogAngularUnit --
  128 ValuePair(  ProjFalseOriginLatGeoKey,   3085)     -- GeogAngularUnit --
  129 ValuePair(  ProjFalseOriginEastingGeoKey,   3086)     -- ProjLinearUnits --
  130 ValuePair(  ProjFalseOriginNorthingGeoKey,  3087)     -- ProjLinearUnits --
  131 ValuePair(  ProjCenterLongGeoKey,   3088)     -- GeogAngularUnit --
  132 ValuePair(  ProjCenterLatGeoKey,    3089)     -- GeogAngularUnit --
  133 ValuePair(  ProjCenterEastingGeoKey,    3090)     -- ProjLinearUnits --
  134 ValuePair(  ProjCenterNorthingGeoKey,   3091)     -- ProjLinearUnits --
  135 ValuePair(  ProjScaleAtNatOriginGeoKey, 3092)     -- ratio   --
  136 ValuePair(  ProjScaleAtOriginGeoKey,ProjScaleAtNatOriginGeoKey)  -- ** alias **   --
  137 ValuePair(  ProjScaleAtCenterGeoKey,    3093)     -- ratio   --
  138 ValuePair(  ProjAzimuthAngleGeoKey, 3094)     -- GeogAzimuthUnit --
  139 ValuePair(  ProjStraightVertPoleLongGeoKey, 3095)     -- GeogAngularUnit --
  140 
  141  6.2.4 Vertical CS Keys
  142 
  143 ValuePair(  VerticalCSTypeGeoKey,   4096)  -- Section 6.3.4.1 codes   --
  144 ValuePair(  VerticalCitationGeoKey, 4097)  -- documentation --
  145 ValuePair(  VerticalDatumGeoKey,    4098)  -- Section 6.3.4.2 codes   --
  146 ValuePair(  VerticalUnitsGeoKey,    4099)  -- Section 6.3.1 (.x) codes   --
  147 </pre>
  148 */
  149 
  150 int GTIFKeyGet(GTIF *gtif, geokey_t thekey, void *val, int nIndex, int count)
  151 {
  152         int kindex = gtif->gt_keyindex[ thekey ];
  153         GeoKey *key;
  154         gsize_t size;
  155         char *data;
  156         tagtype_t type;
  157 
  158         if (!kindex) return 0;
  159 
  160         key = gtif->gt_keys+kindex;
  161         if (!count) count = (int) (key->gk_count - nIndex);
  162         if (count <=0) return 0;
  163         if (count > key->gk_count) count = (int) key->gk_count;
  164         size = key->gk_size;
  165         type = key->gk_type;
  166 
  167         if (count==1 && type==TYPE_SHORT) data = (char *)&key->gk_data;
  168         else data = key->gk_data;
  169 
  170         _GTIFmemcpy( val, data + nIndex*size, count*size );
  171 
  172         if (type==TYPE_ASCII)
  173            ((char *)val)[count-1] = '\0'; /* replace last char with NULL */
  174 
  175         return count;
  176 }
  177 
  178 /************************************************************************/
  179 /*                       GTIFKeyGetInternal()                           */
  180 /************************************************************************/
  181 
  182 static int GTIFKeyGetInternal( GTIF *psGTIF, geokey_t key,
  183                            void* pData,
  184                            int nIndex,
  185                            int nCount,
  186                            tagtype_t expected_tagtype )
  187 {
  188     tagtype_t tagtype;
  189     if( !GTIFKeyInfo(psGTIF, key, NULL, &tagtype) )
  190         return 0;
  191     if( tagtype != expected_tagtype )
  192     {
  193         if( psGTIF->gt_error_callback )
  194         {
  195             psGTIF->gt_error_callback(
  196                 psGTIF,
  197                 LIBGEOTIFF_WARNING,
  198                 "Expected key %s to be of type %s. Got %s",
  199                 GTIFKeyName(key), GTIFTypeName(expected_tagtype),
  200                 GTIFTypeName(tagtype));
  201         }
  202         return 0;
  203     }
  204     return GTIFKeyGet( psGTIF, key, pData, nIndex, nCount );
  205 }
  206 
  207 /************************************************************************/
  208 /*                          GTIFKeyGetASCII()                           */
  209 /************************************************************************/
  210 
  211 /**
  212  * This function reads the value of a single GeoKey of type ASCII from a GeoTIFF file.
  213  *
  214  * Same as GTIFGetKey() except that it adds checking that the key read is of the
  215  * expected type.
  216  */
  217 int GTIFKeyGetASCII( GTIF *gtif, geokey_t key, char* szStr, int szStrMaxLen )
  218 {
  219     return GTIFKeyGetInternal( gtif, key, szStr, 0, szStrMaxLen, TYPE_ASCII );
  220 }
  221 
  222 /************************************************************************/
  223 /*                          GTIFKeyGetSHORT()                           */
  224 /************************************************************************/
  225 
  226 /**
  227  * This function reads the value of a single GeoKey of type SHORT from a GeoTIFF file.
  228  *
  229  * Same as GTIFGetKey() except that it adds checking that the key read is of the
  230  * expected type.
  231  */
  232 int GTIFKeyGetSHORT( GTIF *gtif, geokey_t key, unsigned short* pnVal, int nIndex,
  233                      int nCount )
  234 {
  235     return GTIFKeyGetInternal(gtif, key, pnVal, nIndex, nCount, TYPE_SHORT);
  236 }
  237 
  238 /************************************************************************/
  239 /*                        GDALGTIFKeyGetDOUBLE()                        */
  240 /************************************************************************/
  241 
  242 /**
  243  * This function reads the value of a single GeoKey of type DOUBLE from a GeoTIFF file.
  244  *
  245  * Same as GTIFGetKey() except that it adds checking that the key read is of the
  246  * expected type.
  247  */
  248 int GTIFKeyGetDOUBLE( GTIF *gtif, geokey_t key, double* pdfVal, int nIndex,
  249                       int nCount )
  250 {
  251     return GTIFKeyGetInternal(gtif, key, pdfVal, nIndex, nCount, TYPE_DOUBLE);
  252 }