tile38/controller/collection/collection.go

453 lines
12 KiB
Go

package collection
import (
"github.com/tidwall/btree"
"github.com/tidwall/tile38/geojson"
"github.com/tidwall/tile38/index"
)
// ScanType is the classification of objects that are returned from Scan()
type ScanType int
const (
// TypeAll means to return all type during a Scan()
TypeAll = ScanType(0)
// TypeGeometry means to return only geometries
TypeGeometry = ScanType(1)
// TypeNonGeometry means to return non-geometries
TypeNonGeometry = ScanType(2)
)
const (
idOrdered = 0
valueOrdered = 1
)
type itemT struct {
id string
object geojson.Object
fields []float64
}
func (i *itemT) Less(item btree.Item, ctx int) bool {
switch ctx {
default:
return false
case idOrdered:
return i.id < item.(*itemT).id
case valueOrdered:
i1, i2 := i.object.String(), item.(*itemT).object.String()
if i1 < i2 {
return true
}
if i1 > i2 {
return false
}
// the values match so we will compare the ids, which are always unique.
return i.id < item.(*itemT).id
}
}
func (i *itemT) Rect() (minX, minY, maxX, maxY float64) {
bbox := i.object.CalculatedBBox()
return bbox.Min.X, bbox.Min.Y, bbox.Max.X, bbox.Max.Y
}
func (i *itemT) Point() (x, y float64) {
x, y, _, _ = i.Rect()
return
}
// Collection represents a collection of geojson objects.
type Collection struct {
items *btree.BTree // items sorted by keys
values *btree.BTree // items sorted by value+key
index *index.Index // items geospatially indexed
fieldMap map[string]int
weight int
points int
objects int // geometry count
nobjects int // non-geometry count
}
var counter uint64
// New creates an empty collection
func New() *Collection {
col := &Collection{
index: index.New(),
items: btree.New(16, idOrdered),
values: btree.New(16, valueOrdered),
fieldMap: make(map[string]int),
}
return col
}
// Count returns the number of objects in collection.
func (c *Collection) Count(stype ScanType) int {
switch stype {
default:
return c.objects + c.nobjects
case TypeGeometry:
return c.objects
case TypeNonGeometry:
return c.nobjects
}
}
// PointCount returns the number of points (lat/lon coordinates) in collection.
func (c *Collection) PointCount() int {
return c.points
}
// TotalWeight calculates the in-memory cost of the collection in bytes.
func (c *Collection) TotalWeight() int {
return c.weight
}
// ReplaceOrInsert adds or replaces an object in the collection and returns the fields array.
// If an item with the same id is already in the collection then the new item will adopt the old item's fields.
// The fields argument is optional.
// The return values are the old object, the old fields, and the new fields
func (c *Collection) ReplaceOrInsert(id string, obj geojson.Object, fields []string, values []float64) (oldObject geojson.Object, oldFields []float64, newFields []float64) {
oldItem, ok := c.remove(id)
nitem := c.insert(id, obj)
if ok {
oldObject = oldItem.object
oldFields = oldItem.fields
nitem.fields = oldFields
c.weight += len(nitem.fields) * 8
}
if fields == nil && len(values) > 0 {
// directly set the field values, update weight
c.weight -= len(nitem.fields) * 8
nitem.fields = values
c.weight += len(nitem.fields) * 8
} else {
// map field name to value
for i, field := range fields {
c.setField(nitem, field, values[i])
}
}
return oldObject, oldFields, nitem.fields
}
func (c *Collection) remove(id string) (item *itemT, ok bool) {
i := c.items.Delete(&itemT{id: id})
if i == nil {
return nil, false
}
item = i.(*itemT)
if item.object.IsGeometry() {
c.index.Remove(item)
c.objects--
} else {
c.values.Delete(item)
c.nobjects--
}
c.weight -= len(item.fields) * 8
c.weight -= item.object.Weight() + len(item.id)
c.points -= item.object.PositionCount()
return item, true
}
func (c *Collection) insert(id string, obj geojson.Object) (item *itemT) {
item = &itemT{id: id, object: obj}
if obj.IsGeometry() {
c.index.Insert(item)
c.objects++
} else {
c.values.ReplaceOrInsert(item)
c.nobjects++
}
c.items.ReplaceOrInsert(item)
c.weight += obj.Weight() + len(id)
c.points += obj.PositionCount()
return item
}
// Remove removes an object and returns it.
// If the object does not exist then the 'ok' return value will be false.
func (c *Collection) Remove(id string) (obj geojson.Object, fields []float64, ok bool) {
item, ok := c.remove(id)
if !ok {
return nil, nil, false
}
return item.object, item.fields, true
}
func (c *Collection) get(id string) (obj geojson.Object, fields []float64, ok bool) {
i := c.items.Get(&itemT{id: id})
if i == nil {
return nil, nil, false
}
item := i.(*itemT)
return item.object, item.fields, true
}
// Get returns an object.
// If the object does not exist then the 'ok' return value will be false.
func (c *Collection) Get(id string) (obj geojson.Object, fields []float64, ok bool) {
return c.get(id)
}
// SetField set a field value for an object and returns that object.
// If the object does not exist then the 'ok' return value will be false.
func (c *Collection) SetField(id, field string, value float64) (obj geojson.Object, fields []float64, updated bool, ok bool) {
i := c.items.Get(&itemT{id: id})
if i == nil {
ok = false
return
}
item := i.(*itemT)
updated = c.setField(item, field, value)
return item.object, item.fields, updated, true
}
func (c *Collection) setField(item *itemT, field string, value float64) (updated bool) {
idx, ok := c.fieldMap[field]
if !ok {
idx = len(c.fieldMap)
c.fieldMap[field] = idx
}
c.weight -= len(item.fields) * 8
for idx >= len(item.fields) {
item.fields = append(item.fields, 0)
}
c.weight += len(item.fields) * 8
ovalue := item.fields[idx]
item.fields[idx] = value
return ovalue != value
}
// FieldMap return a maps of the field names.
func (c *Collection) FieldMap() map[string]int {
return c.fieldMap
}
// FieldArr return an array representation of the field names.
func (c *Collection) FieldArr() []string {
arr := make([]string, len(c.fieldMap))
for field, i := range c.fieldMap {
arr[i] = field
}
return arr
}
// Scan iterates though the collection. A cursor can be used for paging.
func (c *Collection) Scan(cursor uint64, stype ScanType, desc bool,
iterator func(id string, obj geojson.Object, fields []float64) bool,
) (ncursor uint64) {
var i uint64
var active = true
iter := func(item btree.Item) bool {
if i >= cursor {
iitm := item.(*itemT)
active = iterator(iitm.id, iitm.object, iitm.fields)
}
i++
return active
}
if desc {
c.items.Descend(iter)
} else {
c.items.Ascend(iter)
}
return i
}
// ScanGreaterOrEqual iterates though the collection starting with specified id. A cursor can be used for paging.
func (c *Collection) ScanRange(cursor uint64, stype ScanType, start, end string, desc bool,
iterator func(id string, obj geojson.Object, fields []float64) bool,
) (ncursor uint64) {
var i uint64
var active = true
iter := func(item btree.Item) bool {
if i >= cursor {
iitm := item.(*itemT)
active = iterator(iitm.id, iitm.object, iitm.fields)
}
i++
return active
}
if desc {
c.items.DescendRange(&itemT{id: start}, &itemT{id: end}, iter)
} else {
c.items.AscendRange(&itemT{id: start}, &itemT{id: end}, iter)
}
return i
}
// ScanGreaterOrEqual iterates though the collection starting with specified id. A cursor can be used for paging.
func (c *Collection) ScanGreaterOrEqual(id string, cursor uint64, stype ScanType, desc bool,
iterator func(id string, obj geojson.Object, fields []float64) bool,
) (ncursor uint64) {
var i uint64
var active = true
iter := func(item btree.Item) bool {
if i >= cursor {
iitm := item.(*itemT)
active = iterator(iitm.id, iitm.object, iitm.fields)
}
i++
return active
}
if desc {
c.items.DescendLessOrEqual(&itemT{id: id}, iter)
} else {
c.items.AscendGreaterOrEqual(&itemT{id: id}, iter)
}
return i
}
func (c *Collection) geoSearch(cursor uint64, bbox geojson.BBox, iterator func(id string, obj geojson.Object, fields []float64) bool) (ncursor uint64) {
return c.index.Search(cursor, bbox.Min.Y, bbox.Min.X, bbox.Max.Y, bbox.Max.X, func(item index.Item) bool {
var iitm *itemT
iitm, ok := item.(*itemT)
if !ok {
return true // just ignore
}
if !iterator(iitm.id, iitm.object, iitm.fields) {
return false
}
return true
})
}
// Nearby returns all object that are nearby a point.
func (c *Collection) Nearby(cursor uint64, sparse uint8, lat, lon, meters float64, iterator func(id string, obj geojson.Object, fields []float64) bool) (ncursor uint64) {
center := geojson.Position{X: lon, Y: lat, Z: 0}
bbox := geojson.BBoxesFromCenter(lat, lon, meters)
bboxes := bbox.Sparse(sparse)
if sparse > 0 {
for _, bbox := range bboxes {
c.geoSearch(cursor, bbox, func(id string, obj geojson.Object, fields []float64) bool {
if obj.Nearby(center, meters) {
if iterator(id, obj, fields) {
return false
}
}
return true
})
}
return 0
}
return c.geoSearch(cursor, bbox, func(id string, obj geojson.Object, fields []float64) bool {
if obj.Nearby(center, meters) {
return iterator(id, obj, fields)
}
return true
})
}
// Within returns all object that are fully contained within an object or bounding box. Set obj to nil in order to use the bounding box.
func (c *Collection) Within(cursor uint64, sparse uint8, obj geojson.Object, minLat, minLon, maxLat, maxLon float64, iterator func(id string, obj geojson.Object, fields []float64) bool) (ncursor uint64) {
var bbox geojson.BBox
if obj != nil {
bbox = obj.CalculatedBBox()
} else {
bbox = geojson.BBox{Min: geojson.Position{X: minLon, Y: minLat, Z: 0}, Max: geojson.Position{X: maxLon, Y: maxLat, Z: 0}}
}
bboxes := bbox.Sparse(sparse)
if sparse > 0 {
for _, bbox := range bboxes {
if obj != nil {
c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.Within(obj) {
if iterator(id, o, fields) {
return false
}
}
return true
})
}
c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.WithinBBox(bbox) {
if iterator(id, o, fields) {
return false
}
}
return true
})
}
return 0
}
if obj != nil {
return c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.Within(obj) {
return iterator(id, o, fields)
}
return true
})
}
return c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.WithinBBox(bbox) {
return iterator(id, o, fields)
}
return true
})
}
// Intersects returns all object that are intersect an object or bounding box. Set obj to nil in order to use the bounding box.
func (c *Collection) Intersects(cursor uint64, sparse uint8, obj geojson.Object, minLat, minLon, maxLat, maxLon float64, iterator func(id string, obj geojson.Object, fields []float64) bool) (ncursor uint64) {
var bbox geojson.BBox
if obj != nil {
bbox = obj.CalculatedBBox()
} else {
bbox = geojson.BBox{Min: geojson.Position{X: minLon, Y: minLat, Z: 0}, Max: geojson.Position{X: maxLon, Y: maxLat, Z: 0}}
}
var bboxes []geojson.BBox
if sparse > 0 {
split := 1 << sparse
xpart := (bbox.Max.X - bbox.Min.X) / float64(split)
ypart := (bbox.Max.Y - bbox.Min.Y) / float64(split)
for y := bbox.Min.Y; y < bbox.Max.Y; y += ypart {
for x := bbox.Min.X; x < bbox.Max.X; x += xpart {
bboxes = append(bboxes, geojson.BBox{
Min: geojson.Position{X: x, Y: y, Z: 0},
Max: geojson.Position{X: x + xpart, Y: y + ypart, Z: 0},
})
}
}
for _, bbox := range bboxes {
if obj != nil {
c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.Intersects(obj) {
if iterator(id, o, fields) {
return false
}
}
return true
})
}
c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.IntersectsBBox(bbox) {
if iterator(id, o, fields) {
return false
}
}
return true
})
}
return 0
}
if obj != nil {
return c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.Intersects(obj) {
return iterator(id, o, fields)
}
return true
})
}
return c.geoSearch(cursor, bbox, func(id string, o geojson.Object, fields []float64) bool {
if o.IntersectsBBox(bbox) {
return iterator(id, o, fields)
}
return true
})
}
func (c *Collection) SearchValues(pivot string, desc bool, iterator func(id string, obj geojson.Object, fields []float64) bool) {
}