65 lines
1.2 KiB
Go
65 lines
1.2 KiB
Go
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// Copyright 2017 The goimagehash Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package goimagehash
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import (
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"errors"
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)
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// hashKind describes the kinds of hash.
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type hashKind int
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type ImageHash struct {
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hash uint64
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kind hashKind
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}
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const (
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Unknown hashKind = iota
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AHash // Average Hash
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PHash // Perceptual Hash
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DHash // Difference Hash
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WHash // Wavlet Hash
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)
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// Create a new image hash.
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func NewImageHash(hash uint64, kind hashKind) *ImageHash {
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return &ImageHash{hash: hash, kind: kind}
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}
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// Return distance between hashes.
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func (h *ImageHash) Distance(other *ImageHash) (int, error) {
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if h.GetKind() != other.GetKind() {
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return -1, errors.New("Image hashes's kind should be identical.")
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}
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diff := 0
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lhash := h.GetHash()
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rhash := other.GetHash()
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hamming := lhash ^ rhash
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for hamming != 0 {
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diff += int(hamming & 1)
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hamming >>= 1
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}
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return diff, nil
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}
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// Return hash values.
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func (h *ImageHash) GetHash() uint64 {
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return h.hash
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}
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// Get kind of a hash.
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func (h *ImageHash) GetKind() hashKind {
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return h.kind
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}
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// Set index of bits.
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func (h *ImageHash) Set(idx int) {
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h.hash |= 1 << uint(idx)
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}
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