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29 lines
670 B
Go
29 lines
670 B
Go
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// Copyright 2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
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//
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// This Source Code Form is subject to the terms of the MIT License.
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// If a copy of the MIT was not distributed with this file,
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// You can obtain one at https://github.com/gogf/gf.
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package gvalid
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// checkLuHn checks value with LUHN algorithm.
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// It's usually used for bank card number validation.
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func checkLuHn(value string) bool {
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var (
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sum = 0
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nDigits = len(value)
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parity = nDigits % 2
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)
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for i := 0; i < nDigits; i++ {
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var digit = int(value[i] - 48)
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if i%2 == parity {
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digit *= 2
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if digit > 9 {
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digit -= 9
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}
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}
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sum += digit
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}
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return sum%10 == 0
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}
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