61 lines
1.7 KiB
D
61 lines
1.7 KiB
D
module bitmanip;
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private import std.traits : isUnsigned;
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private import std.bitmanip : nativeToLittleEndian, littleEndianToNative;
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UIntType rotateLeft(UIntType)(in UIntType val, in size_t len) nothrow @nogc pure @safe
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if (isUnsigned!UIntType)
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{
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auto reducedLen = len % (8 * UIntType.sizeof);
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// TODO: ensure the compiler does not create different code paths here
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return cast(UIntType)((val << reducedLen) | (val >> (8 * UIntType.sizeof - reducedLen)));
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}
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unittest
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{
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ubyte[] test = [0, 1, 128];
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assert(test[0].rotateLeft(1) == 0);
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assert(test[1].rotateLeft(1) == 2);
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assert(test[2].rotateLeft(1) == 1);
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assert(test[1].rotateLeft(7) == 128);
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}
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UIntType rotateRight(UIntType)(in UIntType val, in size_t len) nothrow @nogc pure @safe
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if (isUnsigned!UIntType)
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{
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auto reducedLen = len % (8 * UIntType.sizeof);
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// TODO: ensure the compiler does not create different code paths here
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return cast(UIntType)((val >> reducedLen) | (val << (8 * UIntType.sizeof - reducedLen)));
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}
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unittest
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{
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ubyte[] test = [0, 1, 128];
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assert(test[0].rotateRight(1) == 0);
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assert(test[1].rotateRight(1) == 128);
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assert(test[2].rotateRight(1) == 64);
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assert(test[2].rotateRight(7) == 1);
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}
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alias littleEndianInv = nativeToLittleEndian;
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uint littleEndian(in ubyte[] input) @safe pure nothrow @nogc
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in
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{
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assert(input.length == uint.sizeof);
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}
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body
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{
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ubyte[uint.sizeof] buf = input;
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return littleEndianToNative!uint(buf);
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}
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unittest
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{
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ubyte[] test0 = [0, 0, 0, 0];
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ubyte[] test1 = [86, 75, 30, 9];
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ubyte[] test2 = [255, 255, 255, 250];
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assert(littleEndian(test0) == 0x00000000);
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assert(littleEndian(test1) == 0x091e4b56);
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assert(littleEndian(test2) == 0xfaffffff);
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}
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