mirror of https://github.com/tidwall/grect.git
first commit
This commit is contained in:
Josh Baker
commit
ba9a043346
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@ -0,0 +1,20 @@
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The MIT License (MIT)
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Copyright (c) 2016 Josh Baker
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Permission is hereby granted, free of charge, to any person obtaining a copy of
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this software and associated documentation files (the "Software"), to deal in
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the Software without restriction, including without limitation the rights to
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use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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the Software, and to permit persons to whom the Software is furnished to do so,
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subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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@ -0,0 +1,25 @@
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GRECT
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====
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Quickly get the outer rectangle for GeoJSON, WKT, WKB.
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```go
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r := grect.Get(`{
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"type": "Polygon",
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"coordinates": [
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[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0],
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[100.0, 1.0], [100.0, 0.0] ]
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]
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}`)
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fmt.Printf("%v %v\n", r.Min, r.Max)
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// Output:
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// [100 0] [101 1]
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```
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## Contact
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Josh Baker [@tidwall](http://twitter.com/tidwall)
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## License
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GRECT source code is available under the MIT [License](/LICENSE).
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@ -0,0 +1,337 @@
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package grect
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import (
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"strconv"
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"strings"
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"github.com/tidwall/gjson"
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)
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type Rect struct {
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Min, Max []float64
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}
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func (r Rect) String() string {
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diff := len(r.Min) != len(r.Max)
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if !diff {
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for i := 0; i < len(r.Min); i++ {
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if r.Min[i] != r.Max[i] {
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diff = true
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break
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}
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}
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}
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var buf []byte
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buf = append(buf, '[')
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for i, v := range r.Min {
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if i > 0 {
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buf = append(buf, ' ')
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}
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buf = append(buf, strconv.FormatFloat(v, 'f', -1, 64)...)
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}
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if diff {
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buf = append(buf, ']', ',', '[')
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for i, v := range r.Max {
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if i > 0 {
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buf = append(buf, ' ')
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}
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buf = append(buf, strconv.FormatFloat(v, 'f', -1, 64)...)
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}
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}
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buf = append(buf, ']')
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return string(buf)
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}
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func normalize(min, max []float64) (nmin, nmax []float64) {
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if len(max) == 0 {
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return min, min
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} else if len(max) != len(min) {
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if len(max) < len(min) {
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max = append(max, min[len(max):]...)
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} else if len(min) < len(max) {
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min = append(min, max[len(min):]...)
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}
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}
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match := true
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for i := 0; i < len(min); i++ {
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if min[i] != max[i] {
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if match {
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match = false
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}
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if min[i] > max[i] {
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min[i], max[i] = max[i], min[i]
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}
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}
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}
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if match {
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return min, min
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}
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return min, max
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}
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func Get(s string) Rect {
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var i int
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var ws bool
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var min, max []float64
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for ; i < len(s); i++ {
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switch s[i] {
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default:
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continue
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case ' ', '\t', '\r', '\n':
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ws = true
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continue
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case '[':
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min, max, i = getRect(s, i)
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case '{':
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min, max, i = getGeoJSON(s, i)
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case 0x00, 0x01:
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if !ws {
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// return parseWKB(s, i)
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}
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case 'p', 'P', 'l', 'L', 'm', 'M', 'g', 'G':
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min, max, i = getWKT(s, i)
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}
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break
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}
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min, max = normalize(min, max)
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return Rect{Min: min, Max: max}
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}
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func getRect(s string, i int) (min, max []float64, ri int) {
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a := s[i:]
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parts := strings.Split(a, ",")
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for i := 0; i < len(parts) && i < 2; i++ {
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part := parts[i]
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if len(part) > 0 && (part[0] <= ' ' || part[len(part)-1] <= ' ') {
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part = strings.TrimSpace(part)
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}
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if len(part) >= 2 && part[0] == '[' && part[len(part)-1] == ']' {
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pieces := strings.Split(part[1:len(part)-1], " ")
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if i == 0 {
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min = make([]float64, 0, len(pieces))
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} else {
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max = make([]float64, 0, len(pieces))
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}
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for j := 0; j < len(pieces); j++ {
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piece := pieces[j]
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if piece != "" {
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n, _ := strconv.ParseFloat(piece, 64)
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if i == 0 {
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min = append(min, n)
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} else {
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max = append(max, n)
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}
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}
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}
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}
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}
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// normalize
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if len(parts) == 1 {
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max = min
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} else {
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min, max = normalize(min, max)
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}
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return min, max, len(s)
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}
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func union(min1, max1, min2, max2 []float64) (umin, umax []float64) {
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for i := 0; i < len(min1) || i < len(min2); i++ {
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if i >= len(min1) {
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// just copy min2
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umin = append(umin, min2[i])
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umax = append(umax, max2[i])
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} else if i >= len(min2) {
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// just copy min1
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umin = append(umin, min1[i])
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umax = append(umax, max1[i])
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} else {
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if min1[i] < min2[i] {
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umin = append(umin, min1[i])
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} else {
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umin = append(umin, min2[i])
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}
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if max1[i] > max2[i] {
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umax = append(umax, max1[i])
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} else {
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umax = append(umax, max2[i])
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}
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}
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}
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return umin, umax
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}
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func getWKT(s string, i int) (min, max []float64, ri int) {
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switch s[i] {
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default:
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for ; i < len(s); i++ {
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if s[i] == ',' {
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return nil, nil, i
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}
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if s[i] == '(' {
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return getWKTAny(s, i)
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}
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}
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return nil, nil, i
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case 'g', 'G':
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if len(s)-i < 18 {
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return nil, nil, i
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}
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return getWKTGeometryCollection(s, i+18)
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}
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}
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func getWKTAny(s string, i int) (min, max []float64, ri int) {
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min, max = make([]float64, 0, 4), make([]float64, 0, 4)
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var depth int
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var ni int
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var idx int
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loop:
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for ; i < len(s); i++ {
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switch s[i] {
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default:
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if ni == 0 {
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ni = i
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}
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case '(':
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depth++
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case ')', ' ', '\t', '\r', '\n', ',':
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if ni != 0 {
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n, _ := strconv.ParseFloat(s[ni:i], 64)
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if idx >= len(min) {
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min = append(min, n)
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max = append(max, n)
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} else {
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if n < min[idx] {
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min[idx] = n
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} else if n > max[idx] {
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max[idx] = n
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}
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}
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idx++
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ni = 0
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}
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switch s[i] {
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case ')':
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idx = 0
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depth--
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if depth == 0 {
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i++
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break loop
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}
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case ',':
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idx = 0
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}
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}
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}
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return min, max, i
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}
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func getWKTGeometryCollection(s string, i int) (min, max []float64, ri int) {
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var depth int
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for ; i < len(s); i++ {
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if s[i] == ',' || s[i] == ')' {
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// do not increment the index
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return nil, nil, i
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}
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if s[i] == '(' {
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depth++
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i++
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break
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}
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}
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next:
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for ; i < len(s); i++ {
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switch s[i] {
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case 'p', 'P', 'l', 'L', 'm', 'M', 'g', 'G':
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var min2, max2 []float64
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min2, max2, i = getWKT(s, i)
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min, max = union(min, max, min2, max2)
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for ; i < len(s); i++ {
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if s[i] == ',' {
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i++
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goto next
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}
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if s[i] == ')' {
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i++
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goto done
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}
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}
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case ' ', '\t', '\r', '\n':
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continue
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default:
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goto end_early
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}
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}
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end_early:
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// just balance the parens
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for ; i < len(s); i++ {
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if s[i] == '(' {
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depth++
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} else if s[i] == ')' {
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depth--
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if depth == 0 {
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i++
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break
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}
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}
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}
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done:
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return min, max, i
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}
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func getGeoJSON(s string, i int) (min, max []float64, ri int) {
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json := s[i:]
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switch gjson.Get(json, "type").String() {
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default:
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min, max = getMinMaxBrackets(gjson.Get(json, "coordinates").Raw)
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case "Feature":
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min, max, _ = getGeoJSON(gjson.Get(json, "geometry").String(), 0)
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case "FeatureCollection":
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for _, json := range gjson.Get(json, "features").Array() {
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nmin, nmax, _ := getGeoJSON(json.String(), 0)
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min, max = union(min, max, nmin, nmax)
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}
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case "GeometryCollection":
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for _, json := range gjson.Get(json, "geometries").Array() {
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nmin, nmax, _ := getGeoJSON(json.String(), 0)
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min, max = union(min, max, nmin, nmax)
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}
|
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}
|
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return min, max, len(json)
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}
|
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|
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func getMinMaxBrackets(s string) (min, max []float64) {
|
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var ni int
|
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var idx int
|
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for i := 0; i < len(s); i++ {
|
||||
switch s[i] {
|
||||
default:
|
||||
if ni == 0 {
|
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ni = i
|
||||
}
|
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case '[', ',', ']', ' ', '\t', '\r', '\n':
|
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if ni > 0 {
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n, _ := strconv.ParseFloat(s[ni:i], 64)
|
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if idx >= len(min) {
|
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min = append(min, n)
|
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max = append(max, n)
|
||||
} else {
|
||||
if n < min[idx] {
|
||||
min[idx] = n
|
||||
} else if n > max[idx] {
|
||||
max[idx] = n
|
||||
}
|
||||
}
|
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ni = 0
|
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idx++
|
||||
}
|
||||
if s[i] == ']' {
|
||||
idx = 0
|
||||
}
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
return
|
||||
}
|
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|
|
@ -0,0 +1,101 @@
|
|||
package grect
|
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|
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import (
|
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"fmt"
|
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"math/rand"
|
||||
"testing"
|
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"time"
|
||||
)
|
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|
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func testGet(t *testing.T, s, expect string) {
|
||||
if Get(s).String() != expect {
|
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t.Fatalf("for '%v': expected '%v', got '%v'", s, expect, Get(s).String())
|
||||
}
|
||||
}
|
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|
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func TestRect(t *testing.T) {
|
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testGet(t, "", "[]")
|
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testGet(t, "[]", "[]")
|
||||
testGet(t, "[],[]", "[]")
|
||||
testGet(t, "[],[],[]", "[]")
|
||||
testGet(t, "[10]", "[10]")
|
||||
testGet(t, "[10],[10]", "[10]")
|
||||
testGet(t, "[10 11],[10]", "[10 11]")
|
||||
testGet(t, "[10 11],[11 10]", "[10 10],[11 11]")
|
||||
testGet(t, ",[10]", "[10]")
|
||||
testGet(t, "[10 11]", "[10 11]")
|
||||
testGet(t, "[-3 -2 -1 0 1 2 3],[3 2 1 0 -1 -2 -3]", "[-3 -2 -1 0 -1 -2 -3],[3 2 1 0 1 2 3]")
|
||||
}
|
||||
|
||||
func TestWKT(t *testing.T) {
|
||||
testGet(t, "POINT(1 2)", "[1 2]")
|
||||
testGet(t, "LINESTRING(3 4, -1 -3, (-20 15 18 ))", "[-20 -3 18],[3 15 18]")
|
||||
testGet(t, "POLYGON (((1 2 0), 3 4 1, -1 -3 123))", "[-1 -3 0],[3 4 123]")
|
||||
testGet(t, "MULTIPOINT (1 2, 3 4, -1 0)", "[-1 0],[3 4]")
|
||||
testGet(t, " mUltiLineString ( (1 2, 3 4),(3 4, (5 6)), (-1 -2 -3)) ", "[-1 -2 -3],[5 6 -3]")
|
||||
testGet(t, ` MULTIPOLYGON (
|
||||
((1 2,2 3),(2 3,8 9)),
|
||||
((4 5,6 7))
|
||||
)`, "[1 2],[8 9]")
|
||||
testGet(t, `
|
||||
GEOMETRYCOLLECTION (
|
||||
POLYGON EMPTY,
|
||||
POINT EMPTY,
|
||||
POINT(1000 2),
|
||||
POINT EMPTY,
|
||||
LINESTRING(3 4, -1 -3, (-20 15 18)),
|
||||
GEOMETRYCOLLECTION EMPTY,
|
||||
GEOMETRYCOLLECTION(POINT(-1000),POLYGON((10 20,-50 1500))),
|
||||
)`, "[-1000 -3 18],[1000 1500 18]")
|
||||
}
|
||||
|
||||
func TestGeoJSON(t *testing.T) {
|
||||
testGet(t, `{"type":"Point","coordinates":[1,2]}`, "[1 2]")
|
||||
testGet(t, `{"type":"LineString","coordinates":[[3,4], [-1,-3], [-20,15,18]]}`, "[-20 -3 18],[3 15 18]")
|
||||
testGet(t, `{"type":"Polygon", "coordinates": [[[[1,2,0]],[ 3,4,1], [-1,-3,123]]]}`, "[-1 -3 0],[3 4 123]")
|
||||
testGet(t, `{"type":"MultiPoint", "coordinates":[[1,2], [3,4], [-1,0]]}`, "[-1 0],[3 4]")
|
||||
testGet(t, `{"type":"mUltiLineString","coordinates": [ [[1,2], [3,4]],[[3,4], [5,6]], [-1,-2,-3]]} `, "[-1 -2 -3],[5 6 -3]")
|
||||
testGet(t, `{"type":"MULTIPOLYGON","coordinates": [
|
||||
[[[1 2],[2 3]],[[2 3],[8 9]]],
|
||||
[[[4 5],[6 7]]]
|
||||
)`, "[1 2],[8 9]")
|
||||
testGet(t, `{"type":"GeometryCollection", "geometries":[
|
||||
{"type":"Feature","geometry":{"type":"Point","coordinates":[0 -10, 17]}},
|
||||
{"type":"FeatureCollection","features":[
|
||||
{"type":"Feature","geometry":{"type":"Point","coordinates":[0 -10]}},
|
||||
{"type":"Feature","geometry":{"type":"Point","coordinates":[0 -11]}}
|
||||
]},
|
||||
{"type":"POLYGON","coordinates":[]},
|
||||
{"type":"POINT","coordinates":[]},
|
||||
{"type":"POINT","coordinates":[1000,2]},
|
||||
{"type":"POINT","coordinates":[]},
|
||||
{"type":"LINESTRING","coordinates":[[3,4], [-1,-3], [[-20,15,18]]]},
|
||||
{"type":"GeometryCollection","geometries":[]},
|
||||
{"type":"GeometryCollection","geometries":[
|
||||
{"type":"Point","coordinates":[-1000]},
|
||||
{"type":"Polygon","coordinates":[[[10,20],[-50,1500]]]}
|
||||
],
|
||||
]}`, "[-1000 -11 17],[1000 1500 18]")
|
||||
}
|
||||
|
||||
func TestRandom(t *testing.T) {
|
||||
buf := make([]byte, 50)
|
||||
rand.Seed(time.Now().UnixNano())
|
||||
for i := 0; i < 10000000; i++ {
|
||||
rand.Read(buf)
|
||||
Get(string(buf))
|
||||
}
|
||||
}
|
||||
|
||||
func ExampleGet() {
|
||||
r := Get(`{
|
||||
"type": "Polygon",
|
||||
"coordinates": [
|
||||
[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0],
|
||||
[100.0, 1.0], [100.0, 0.0] ]
|
||||
]
|
||||
}`)
|
||||
fmt.Printf("%v %v\n", r.Min, r.Max)
|
||||
// Output:
|
||||
// [100 0] [101 1]
|
||||
}
|
||||
Loading…
Reference in New Issue