wkb.h

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#ifndef SQL_GIS_WKB_H_INCLUDED
#define SQL_GIS_WKB_H_INCLUDED
 
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//
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/// @file
///
/// This file declares the interface of the WKB parser for geometries and the
/// parser for the internal geometry representation.
 
#include <memory>  // std::unique_ptr
 
#include "sql/gis/geometries.h"
#include "sql/gis/srid.h"
 
class THD;
class String;
namespace dd {
class Spatial_reference_system;
}
 
namespace gis {
 
/// Parses an SRID from a little-endian string.
///
/// @param[in] str The string.
/// @param[in] length Length of the string.
/// @param[out] srid The SRID read from the string.
///
/// @retval false Success.
/// @retval true Error. my_error() has not been called.
bool parse_srid(const char *str, std::size_t length, srid_t *srid);
 
///
/// Parses a geometry WKB string and constructs a geometry object.
///
/// The geometry is allocated on the heap and ownership is transferred to the
/// caller.
///
/// If ignore_axis_order is true, the string is assumed to be on the geometry
/// storage format, not general WKB. The storage format differs from ordinary
/// WKB by having a fixed x=longitude, y=latitude mapping.
///
/// @warning This function checks if there are so many nested levels of geometry
/// collections that the stack will be exhausted. If that happens, my_error is
/// called and the function exits with no geometry value. However, if thd is
/// nullptr, this check is disabled, and the caller is responsible for checking
/// that there is enough stack to parse the WKB string.
///
/// @param[in] thd Thread handle.
/// @param srs The SRS of the geometry.
/// @param wkb The WKB string.
/// @param length Length of the WKB string.
/// @param ignore_axis_order Ignore SRS axis order and assume it's always
/// long-lat.
///
/// @return The geometry. If an error occurred, the return value is a null
/// pointer. In case of stack overrun, my_error has been called.
std::unique_ptr<Geometry> parse_wkb(THD *thd,
                                    const dd::Spatial_reference_system *srs,
                                    const char *wkb, std::size_t length,
                                    bool ignore_axis_order = false);
 
/// Parses a little-endian geometry string (SRID + WKB).
///
/// The geometry is allocated on the heap and ownership is transferred to the
/// caller.
///
/// @param[in] thd Thread handle
/// @param[in] func_name The function name to use in error messages.
/// @param[in] str The geometry string.
/// @param[out] srs The spatial reference system of the geometry.
/// @param[out] geometry The geometry.
/// @param[in] treat_unknown_srid_as_cartesian Whether to treat unknown
/// SRIDs as Cartesian. If false, raise an error if the SRID is unknown.
///
/// @retval false Success.
/// @retval true Error. my_error() has been called.
bool parse_geometry(THD *thd, const char *func_name, const String *str,
                    const dd::Spatial_reference_system **srs,
                    std::unique_ptr<Geometry> *geometry,
                    bool treat_unknown_srid_as_cartesian = false);
 
/// Writes a little-endian geometry string (SRID + WKB).
///
/// @param[in] srs The SRS of the geometry.
/// @param[in] geometry The geometry.
/// @param[out] str The string to write the geometry to.
///
/// @retval false Success.
/// @retval true Error. my_error() has been called.
bool write_geometry(const dd::Spatial_reference_system *srs, Geometry &geometry,
                    String *str);
 
}  // namespace gis
 
#endif  // SQL_GIS_WKB_H_INCLUDED