forked from hardcoresushi/DroidFS
48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
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// Copyright 2012 Aaron Jacobs. All Rights Reserved.
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// Author: aaronjjacobs@gmail.com (Aaron Jacobs)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build 386 arm,!arm64 mips mipsle
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package cmac
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import (
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"log"
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"unsafe"
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)
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// XOR the blockSize bytes starting at a and b, writing the result over dst.
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func xorBlock(
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dstPtr unsafe.Pointer,
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aPtr unsafe.Pointer,
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bPtr unsafe.Pointer) {
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// Check assumptions. (These are compile-time constants, so this should
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// compile out.)
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const wordSize = unsafe.Sizeof(uintptr(0))
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if blockSize != 4*wordSize {
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log.Panicf("%d %d", blockSize, wordSize)
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}
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// Convert.
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a := (*[4]uintptr)(aPtr)
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b := (*[4]uintptr)(bPtr)
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dst := (*[4]uintptr)(dstPtr)
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// Compute.
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dst[0] = a[0] ^ b[0]
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dst[1] = a[1] ^ b[1]
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dst[2] = a[2] ^ b[2]
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dst[3] = a[3] ^ b[3]
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}
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