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31 lines
726 B
Go
31 lines
726 B
Go
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// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information.
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package encryption
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// incrementBytes takes a byte slice buf and treats it like a little-endian
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// encoded unsigned integer. it adds amount to it (which must be nonnegative)
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// in place. if rollover happens (the most significant bytes don't fit
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// anymore), truncated is true.
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func incrementBytes(buf []byte, amount int64) (truncated bool, err error) {
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if amount < 0 {
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return false, Error.New("amount was negative")
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}
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idx := 0
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for amount > 0 && idx < len(buf) {
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var inc, prev byte
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inc, amount = byte(amount), amount>>8
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prev = buf[idx]
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buf[idx] += inc
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if buf[idx] < prev {
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amount++
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}
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idx++
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}
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return amount != 0, nil
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}
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