mtsatellite/common/basetilehash.go

43 lines
767 B
Go
Raw Normal View History

// Copyright 2016 by Sascha L. Teichmann
// Use of this source code is governed by the MIT license
// that can be found in the LICENSE file.
package common
import (
"bytes"
"image"
"sync"
)
type btPos struct {
x int
y int
}
type BaseTileHash struct {
// XXX: Maybe use some kind of LRU cache instead?
hashes map[btPos][]byte
sync.Mutex
}
func NewBaseTileHash() *BaseTileHash {
return &BaseTileHash{hashes: map[btPos][]byte{}}
}
func (bth *BaseTileHash) Update(x, y int, img image.Image) bool {
hash := SHA1Image(img)
key := btPos{x, y}
bth.Lock()
defer bth.Unlock()
if old, found := bth.hashes[key]; found {
equals := bytes.Equal(old, hash)
if !equals {
bth.hashes[key] = hash
}
return !equals
}
bth.hashes[key] = hash
return true
}