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comparison pkg/common/delta.go @ 5710:37c8feeecb4d

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Merged branch sr-v2 into default.
author Sascha L. Teichmann <sascha.teichmann@intevation.de>
date Tue, 20 Feb 2024 21:28:56 +0100
parents 3bc15e38c7e8
children
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5672:b1a10654bf0f 5710:37c8feeecb4d
1 // This is Free Software under GNU Affero General Public License v >= 3.0
2 // without warranty, see README.md and license for details.
3 //
4 // SPDX-License-Identifier: AGPL-3.0-or-later
5 // License-Filename: LICENSES/AGPL-3.0.txt
6 //
7 // Copyright (C) 2024 by via donau
8 // – Österreichische Wasserstraßen-Gesellschaft mbH
9 // Software engineering by Intevation GmbH
10 //
11 // Author(s):
12 // * Sascha L. Teichmann <sascha.teichmann@intevation.de>
13
14 package common
15
16 // Delta returns a function which returns its argument when called
17 // the first time and the delta to the last call afterwards.
18 func Delta() func(int64) int64 {
19 var last int64
20 return func(x int64) (y int64) {
21 y = x - last
22 last = x
23 return
24 }
25 }
26
27 // InvDelta is the inverse function to Delta. A sequence of numbers
28 // fed into the function generated by InvDelta restores
29 // the values fed into the function generated by Delta.
30 func InvDelta() func(int64) int64 {
31 var last int64
32 return func(x int64) (y int64) {
33 y = x + last
34 last = y
35 return
36 }
37 }