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//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftCrypto open source project
//
// Copyright (c) 2019-2020 Apple Inc. and the SwiftCrypto project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.md for the list of SwiftCrypto project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
#if CRYPTO_IN_SWIFTPM && !CRYPTO_IN_SWIFTPM_FORCE_BUILD_API
@_exported import CryptoKit
#else
import Foundation
internal func I2OSP(value: Int, outputByteCount: Int) -> Data {
precondition(outputByteCount > 0, "Cannot I2OSP with no output length.")
precondition(value >= 0, "I2OSP requires a non-null value.")
let requiredBytes = Int(ceil(log2(Double(max(value, 1) + 1)) / 8))
precondition(outputByteCount >= requiredBytes)
var data = Data(repeating: 0, count: outputByteCount)
for i in (outputByteCount - requiredBytes)...(outputByteCount - 1) {
data[i] = UInt8(truncatingIfNeeded: (value >> (8 * (outputByteCount - 1 - i))))
}
return data
}
#endif // Linux or !SwiftPM
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