39 lines
1 KiB
C
39 lines
1 KiB
C
#include <my_global.h>
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#include <my_sys.h>
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#include <m_string.h>
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#include <mysql.h>
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my_bool maptile_for_point_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
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{
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if ( args->arg_count != 3 ||
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args->arg_type[0] != INT_RESULT ||
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args->arg_type[1] != INT_RESULT ||
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args->arg_type[2] != INT_RESULT )
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{
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strcpy( message, "Your maptile_for_point arguments are bogus!" );
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return 1;
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}
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return 0;
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}
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void maptile_for_point_deinit(UDF_INIT *initid)
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{
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return;
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}
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long long maptile_for_point(UDF_INIT *initid, UDF_ARGS *args, char *is_null, char *error)
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{
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double lat = *(long long *)args->args[0] / 10000000.0;
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double lon = *(long long *)args->args[1] / 10000000.0;
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long long zoom = *(long long *)args->args[2];
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double scale = pow(2, zoom);
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double r_per_d = M_PI / 180;
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unsigned int x;
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unsigned int y;
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x = floor((lon + 180.0) * scale / 360.0);
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y = floor((1 - log(tan(lat * r_per_d) + 1.0 / cos(lat * r_per_d)) / M_PI) * scale / 2.0);
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return (x << zoom) | y;
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}
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