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QgsDataProvider base class. git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@3971 c8812cc2-4d05-0410-92ff-de0c093fc19c
336 lines
9.6 KiB
C++
336 lines
9.6 KiB
C++
/***************************************************************************
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qgsdelimitedtextprovider.h - Data provider for delimted text
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-------------------
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begin : 2004-02-27
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copyright : (C) 2004 by Gary E.Sherman
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email : sherman at mrcc.com
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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/* $Id$ */
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#include "../../src/qgsvectordataprovider.h"
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#include <map>
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class QgsFeature;
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class QgsField;
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class QFile;
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/**
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\class QgsDelimitedTextProvider
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\brief Data provider for delimited text files.
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*
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* The provider needs to know both the path to the text file and
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* the delimiter to use. Since the means to add a layer is farily
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* rigid, we must provide this information encoded in a form that
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* the provider can decipher and use.
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* The uri must contain the path and delimiter in this format:
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* /full/path/too/delimited.txt?delimiter=<delimiter>
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*
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* Example uri = "/home/foo/delim.txt?delimiter=|"
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*/
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class QgsDelimitedTextProvider : public QgsVectorDataProvider
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{
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public:
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QgsDelimitedTextProvider(QString const & uri = "");
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virtual ~ QgsDelimitedTextProvider();
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/**
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* Returns the permanent storage type for this layer as a friendly name.
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*/
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QString storageType();
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/** get the first feature
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mFile should be open with the file pointer at the record of the next
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feature, or EOF. The feature found on the current line is parsed.
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@param feature the feature object to be populated with next feature
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@param fetchAttributes is true if you want to get the feature attributes, too
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The search will be limited to the search region if one is active.
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@return found QgsFeature, or null if not found
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*/
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QgsFeature *getFirstFeature(bool fetchAttributes = false);
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/** Get the next feature, if any
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mFile should be open with the file pointer at the record of the next
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feature, or EOF. The feature found on the current line is parsed.
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@param feature the feature object to be populated with next feature
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@param fetchAttributes is true if you want to get the feature attributes, too
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The search will be limited to the search region if one is active.
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* @return found QgsFeature, or null if not found
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*/
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QgsFeature *getNextFeature(bool fetchAttributes = false);
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/** get the next feature, if any
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mFile should be open with the file pointer at the record of the next
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feature, or EOF. The feature found on the current line is parsed.
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@param feature the feature object to be populated with next feature
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@param fetchAttributes is true if you want to get the feature attributes, too
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@return false if unable to get the next feature
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@note that feature will also be set invalid if unable to locate the next
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feature
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The search will be limited to the search region if one is active.
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/** Used to ask the layer for its projection as a WKT string. Implements
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virtual method of same name in QgsDataProvider. */
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QString getProjectionWKT() {return QString("Not implemented yet");} ;
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/**
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* Get the first feature resulting from a select operation
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* @return QgsFeature
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*/
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bool getNextFeature(QgsFeature & feature, bool fetchAttributes = false);
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/** get the next feature, if any
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mFile should be open with the file pointer at the record of the next
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feature, or EOF. The feature found on the current line is parsed.
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@param feature the feature object to be populated with next feature @param
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attlist is list of attributes by their field positions to fetch
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with object
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@return false if unable to get the next feature
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@note That feature will also be set invalid if unable to locate the next
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feature.
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The search will be limited to the search region if one is active.
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*/
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QgsFeature *getNextFeature(std::list<int> const & desiredAttributes, int featureQueueSize = 1);
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/** Get the feature type. This corresponds to
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WKBPoint,
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WKBLineString,
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WKBPolygon,
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WKBMultiPoint,
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WKBMultiLineString or
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WKBMultiPolygon
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* as defined in qgis.h
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* This provider will always return WKBPoint
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*/
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int geometryType() const;
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/** return the number of layers for the current data source
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@note
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Should this be subLayerCount() instead?
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*/
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size_t layerCount() const;
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/**
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* Get the number of features in the layer
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*/
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long featureCount() const;
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/**
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* Get the number of fields in the layer
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*/
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int fieldCount() const;
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/**
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* Select features based on a bounding rectangle. Features can be retrieved
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* with calls to getFirstFeature and getNextFeature.
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* @param mbr QgsRect containing the extent to use in selecting features
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*/
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void select(QgsRect * mbr, bool useIntersect = false);
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/**
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* Identify features within the search radius specified by rect
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* @param rect Bounding rectangle of search radius
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* @return std::vector containing QgsFeature objects that intersect rect
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*/
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virtual std::vector < QgsFeature > &identify(QgsRect * rect);
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/** Return the extent for this data layer
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*/
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virtual QgsRect *extent();
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/**
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* Get the attributes associated with a feature
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*/
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void getFeatureAttributes(int key, QgsFeature * f);
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/**
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* Get the field information for the layer
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*/
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std::vector<QgsField> const & fields() const;
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/* Reset the layer (ie move the file pointer to the head
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of the file.
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*/
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void reset();
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/**Returns the minimum value of an attribute
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@param position the number of the attribute*/
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QString minValue(int position);
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/**Returns the maximum value of an attribute
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@param position the number of the attribute*/
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QString maxValue(int position);
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/**Returns true if this is a valid delimited file
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*/
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bool isValid();
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/**
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* Check to see if the point is withn the selection
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* rectangle
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* @param x X value of point
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* @param y Y value of point
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* @return True if point is within the rectangle
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*/
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bool boundsCheck(double x, double y);
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int capabilities() const;
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//! Save the layer as a shapefile
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bool saveAsShapefile();
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QgsDataSourceURI *getURI()
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{
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return 0;
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};
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/** The delimited text provider does not do its own transforms so we return
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* false for the following three functions to indicate that transforms
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* should be handled by the QgsCoordinateTransform object. See the
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* documentation on QgsVectorDataProvider for details on these functions.
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*/
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bool supportsNativeTransform(){return false;}
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bool usesSrid(){return false;}
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bool usesWKT(){return false;}
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/** return a provider name
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Essentially just returns the provider key. Should be used to build file
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dialogs so that providers can be shown with their supported types. Thus
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if more than one provider supports a given format, the user is able to
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select a specific provider to open that file.
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@note
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Instead of being pure virtual, might be better to generalize this
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behavior and presume that none of the sub-classes are going to do
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anything strange with regards to their name or description?
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*/
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QString name() const;
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/** return description
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Return a terse string describing what the provider is.
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@note
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Instead of being pure virtual, might be better to generalize this
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behavior and presume that none of the sub-classes are going to do
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anything strange with regards to their name or description?
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*/
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QString description() const;
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private:
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/** get the next feature, if any
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mFile should be open with the file pointer at the record of the next
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feature, or EOF. The feature found on the current line is parsed.
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@param feature the feature object to be populated with next feature
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@param getAttributes is true if you want to get the feature attributes, too
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@param desiredAttributes attributes fields to be collected for the feature
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as denoted by their position
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@return false if unable to get the next feature
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*/
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bool getNextFeature_( QgsFeature & feature,
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bool getAttributes,
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std::list<int> const * desiredAttributes = 0 );
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void fillMinMaxCash();
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int *getFieldLengths();
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//! Fields
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std::vector < QgsField > attributeFields;
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//! Map to store field position by name
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std::map < QString, int >fieldPositions;
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QString mFileName;
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QString mDelimiter;
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QString mXField;
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QString mYField;
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//! Layer extent
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QgsRect *mExtent;
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//! Current selection rectangle
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QgsRect *mSelectionRectangle;
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//! Text file
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QFile *mFile;
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bool mValid;
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int mGeomType;
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long mNumberFeatures;
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//! Feature id
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long mFid;
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/**Flag indicating, if the minmaxcache should be renewed (true) or not (false)*/
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bool mMinMaxCacheDirty;
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/**Matrix storing the minimum and maximum values*/
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double **mMinMaxCache;
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/**Fills the cash and sets minmaxcachedirty to false*/
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void mFillMinMaxCash();
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struct wkbPoint
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{
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unsigned char byteOrder;
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Q_UINT32 wkbType;
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double x;
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double y;
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};
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wkbPoint mWKBpt;
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};
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