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Diffstat (limited to 'manuals_and_examples/examples/c++/query2.cc')
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1 files changed, 181 insertions, 0 deletions
diff --git a/manuals_and_examples/examples/c++/query2.cc b/manuals_and_examples/examples/c++/query2.cc new file mode 100644 index 0000000..6388e78 --- /dev/null +++ b/manuals_and_examples/examples/c++/query2.cc @@ -0,0 +1,181 @@ +/* +* This file is part of rasdaman community. +* +* Rasdaman community is free software: you can redistribute it and/or modify +* it under the terms of the GNU General Public License as published by +* the Free Software Foundation, either version 3 of the License, or +* (at your option) any later version. +* +* Rasdaman community is distributed in the hope that it will be useful, +* but WITHOUT ANY WARRANTY; without even the implied warranty of +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +* GNU General Public License for more details. +* +* You should have received a copy of the GNU General Public License +* along with rasdaman community. If not, see <http://www.gnu.org/licenses/>. +* +* Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Peter Baumann / +rasdaman GmbH. +* +* For more information please see <http://www.rasdaman.org> +* or contact Peter Baumann via <baumann@rasdaman.com>. +*/ +/************************************************************* + * + * + * PURPOSE: + * Example program for rasql query invocation from C++, showing a + * typical mapping scenario. + * + * + * BUGS: + * - needs this link cmd line + * query2: query2.o + * $(CXX) $(LDFLAGS) -o $@ $^ \ + * -L$(RMANHOME)/lib -lrasodmg -lclientcomm -lcompression -lconversion -lraslib -lnetwork -ljpeg -lpng -ltiff -lmfhdf -ldf -lcrypt o -lclientcomm -lm -lz + * + ************************************************************/ + +#include <iostream> + +// Linux needs this for template instantiation +#ifdef EARLY_TEMPLATE +#define __EXECUTABLE__ +#ifdef __GNUG__ +#include "raslib/template_inst.hh" +#endif +#endif + +// this file is generated by the rasdl processor +#include "basictypes.hh" + +// connectivity constants +char *host = "localhost"; +int port = 7001; +char *db = "RASBASE"; +char *userName = "rasguest"; +char *userPass = "rasguest"; + +// demo program settings +// - collection ("map") name +char *collection = "rgb"; +// - coordinates of map bbox to be retrieved +unsigned int xImageLo = 100; +unsigned int xImageHi = 200; +unsigned int yImageLo = 100; +unsigned int yImageHi = 200; +// - target window size +unsigned int xSize = 10; +unsigned int ySize = 10; + +// global connection objects +r_Database database; +r_Transaction transaction; + +// sample image accessing function, typical for mapping applications +// input: collection ("map") name, source image coordinates, target window size +// output: ptr to image array +// precondition: we're accessing an RGB image, so that we can select the "green" channel of it +// note: the most important parts contain markups at the beginning of the line +unsigned char *readImage( const char *collection, int xImageLo, int xImageHi, int yImageLo, int yImageHi, int xSize, int ySize ) throw (r_Error) +{ + r_Set< r_Ref< r_GMarray > > imageSet; // result set + r_Ref< r_GMarray > image; + r_Iterator< r_Ref< r_GMarray > > iter; + + // function result + unsigned char *result = NULL; + + try + { + cout << "creating query..." << flush; + // parameters: + // $1 map bbox coordinate, lower x + // $2 map bbox coordinate, upper x + // $3 map bbox coordinate, lower y + // $4 map bbox coordinate, upper y + // $5 result window x size + // $6 result window y size + // $7 collection (i.e., map) name +/* 1 */ r_OQL_Query query("select scale(img.green[$1:$2,$3:$4],[1:$5,1:$6]) from $7 as img"); + + cout << "substituting parameters ..." << flush; +/* 2 */ query << xImageLo << xImageHi << yImageLo << yImageHi << xSize << ySize << collection; + cout << "[query: " << query.get_query() << "]..."; + + cout << "executing query..." << flush; +/* 3 */ r_oql_execute( query, imageSet ); + + // now we assume a result has come back + iter = imageSet.create_iterator(); + iter.reset(); +/* 4 */ result = (unsigned char*) (*iter)->get_array(); + + } + catch(r_Error& e) + { + cout << "Error: query failed: " << e.what() << flush; + throw; + } + + return result; +} + +// simple wrapper, handling db connectivity and demo output +int main() +{ + try + { + database.set_servername( host, port ); + database.set_useridentification( userName, userPass ); + + cout << "Opening database " << db << " on " << host << "..." << flush; + database.open( db ); + + cout << "starting read-only transaction..." << flush; + transaction.begin( r_Transaction::read_only ); + + // the real workhorse: fetch image data + unsigned char *imgPtr = readImage( collection, xImageLo, xImageHi, yImageLo, yImageHi, xSize, ySize ); + + cout << "result image:" << endl << hex; + for (int i = 0; i < xSize; i++) + { + for (int j = 0; j < ySize; j++) + { + register unsigned char c = *imgPtr; + cout << " " << setw(2) << (unsigned short) (c & 0xFF); + imgPtr++; + } + cout << endl; + } + cout << dec; + } + catch(r_Error& e) + { + cout << "Error: cannot access database: " << e.what() << endl << flush; + } + + + // ignore any (previous) errors for connection close + try + { + cout << "aborting transaction..." << flush; + transaction.abort(); + + cout << "closing database..." << flush; + database.close(); + + cout << "done." << endl; + } + catch(r_Error &e) + { + cout << "Error closing connection: " << e.what() << endl << flush; + } + + return 0; +} + +/* + * end of query2.cc + */ |