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std.bitmanip

Bit-level manipulation facilities.


Category	Functions
Bit constructs	BitArray bitfields bitsSet
Endianness conversion	bigEndianToNative littleEndianToNative nativeToBigEndian nativeToLittleEndian swapEndian
Integral ranges	append peek read write
Floating-Point manipulation	DoubleRep FloatRep
Tagging	taggedClassRef taggedPointer

License:

Boost License 1.0.

Authors:

Walter Bright, Andrei Alexandrescu, Jonathan M Davis, Alex Rønne Petersen, Damian Ziemba, Amaury SECHET

Source std/bitmanip.d

template bitfields(T...)

Allows creating bit fields inside structs and classes.

The type of a bit field can be any integral type or enumerated type. The most efficient type to store in bitfields is bool, followed by unsigned types, followed by signed types.

See Also:

std.typecons.BitFlags

Examples:

Create a bitfield pack of eight bits, which fit in one ubyte. The bitfields are allocated starting from the least significant bit, i.e. x occupies the two least significant bits of the bitfields storage.

struct A
{
    int a;
    mixin(bitfields!(
        uint, "x",    2,
        int,  "y",    3,
        uint, "z",    2,
        bool, "flag", 1));
}

A obj;
obj.x = 2;
obj.z = obj.x;

writeln(obj.x); // 2
writeln(obj.y); // 0
writeln(obj.z); // 2
writeln(obj.flag); // false

Examples:

The sum of all bit lengths in one bitfield instantiation must be exactly 8, 16, 32, or 64. If padding is needed, just allocate one bitfield with an empty name.

struct A
{
    mixin(bitfields!(
        bool, "flag1",    1,
        bool, "flag2",    1,
        uint, "",         6));
}

A a;
writeln(a.flag1); // 0
a.flag1 = 1;
writeln(a.flag1); // 1
a.flag1 = 0;
writeln(a.flag1); // 0

Examples:

enums can be used too

enum ABC { A, B, C }
struct EnumTest
{
    mixin(bitfields!(
              ABC, "x", 2,
              bool, "y", 1,
              ubyte, "z", 5));
}

enum auto taggedPointer(T : T*, string name, Ts...);

This string mixin generator allows one to create tagged pointers inside structs and classes.

A tagged pointer uses the bits known to be zero in a normal pointer or class reference to store extra information. For example, a pointer to an integer must be 4-byte aligned, so there are 2 bits that are always known to be zero. One can store a 2-bit integer there.

The example above creates a tagged pointer in the struct A. The pointer is of type uint* as specified by the first argument, and is named x, as specified by the second argument.

Following arguments works the same way as bitfield's. The bitfield must fit into the bits known to be zero because of the pointer alignment.

Examples:

struct A
{
    int a;
    mixin(taggedPointer!(
        uint*, "x",
        bool, "b1", 1,
        bool, "b2", 1));
}
A obj;
obj.x = new uint;
obj.b1 = true;
obj.b2 = false;

template taggedClassRef(T, string name, Ts...) if (is(T == class))

This string mixin generator allows one to create tagged class reference inside structs and classes.

A tagged class reference uses the bits known to be zero in a normal class reference to store extra information. For example, a pointer to an integer must be 4-byte aligned, so there are 2 bits that are always known to be zero. One can store a 2-bit integer there.

The example above creates a tagged reference to an Object in the struct A. This expects the same parameters as taggedPointer, except the first argument which must be a class type instead of a pointer type.

Examples:

struct A
{
    int a;
    mixin(taggedClassRef!(
        Object, "o",
        uint, "i", 2));
}
A obj;
obj.o = new Object();
obj.i = 3;

struct FloatRep;

Allows manipulating the fraction, exponent, and sign parts of a float separately. The definition is:

struct FloatRep
{
    union
    {
        float value;
        mixin(bitfields!(
                  uint,  "fraction", 23,
                  ubyte, "exponent",  8,
                  bool,  "sign",      1));
    }
    enum uint bias = 127, fractionBits = 23, exponentBits = 8, signBits = 1;
}

Examples:

FloatRep rep = {value: 0};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 0
assert(!rep.sign);

rep.value = 42;
writeln(rep.fraction); // 2621440
writeln(rep.exponent); // 132
assert(!rep.sign);

rep.value = 10;
writeln(rep.fraction); // 2097152
writeln(rep.exponent); // 130

Examples:

FloatRep rep = {value: 1};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 127
assert(!rep.sign);

rep.exponent = 126;
writeln(rep.value); // 0.5

rep.exponent = 130;
writeln(rep.value); // 8

Examples:

FloatRep rep = {value: 1};
rep.value = -0.5;
writeln(rep.fraction); // 0
writeln(rep.exponent); // 126
assert(rep.sign);

rep.value = -1. / 3;
writeln(rep.fraction); // 2796203
writeln(rep.exponent); // 125
assert(rep.sign);

struct DoubleRep;

Allows manipulating the fraction, exponent, and sign parts of a double separately. The definition is:

struct DoubleRep
{
    union
    {
        double value;
        mixin(bitfields!(
                  ulong,   "fraction", 52,
                  ushort,  "exponent", 11,
                  bool,    "sign",      1));
    }
    enum uint bias = 1023, signBits = 1, fractionBits = 52, exponentBits = 11;
}

Examples:

DoubleRep rep = {value: 0};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 0
assert(!rep.sign);

rep.value = 42;
writeln(rep.fraction); // 1407374883553280
writeln(rep.exponent); // 1028
assert(!rep.sign);

rep.value = 10;
writeln(rep.fraction); // 1125899906842624
writeln(rep.exponent); // 1026

Examples:

DoubleRep rep = {value: 1};
writeln(rep.fraction); // 0
writeln(rep.exponent); // 1023
assert(!rep.sign);

rep.exponent = 1022;
writeln(rep.value); // 0.5

rep.exponent = 1026;
writeln(rep.value); // 8

Examples:

DoubleRep rep = {value: 1};
rep.value = -0.5;
writeln(rep.fraction); // 0
writeln(rep.exponent); // 1022
assert(rep.sign);

rep.value = -1. / 3;
writeln(rep.fraction); // 1501199875790165
writeln(rep.exponent); // 1021
assert(rep.sign);

Examples:

Reading

DoubleRep x;
x.value = 1.0;
assert(x.fraction == 0 && x.exponent == 1023 && !x.sign);
x.value = -0.5;
assert(x.fraction == 0 && x.exponent == 1022 && x.sign);
x.value = 0.5;
assert(x.fraction == 0 && x.exponent == 1022 && !x.sign);

Examples:

Writing

DoubleRep x;
x.fraction = 1125899906842624;
x.exponent = 1025;
x.sign = true;
writeln(x.value); // -5.0

struct BitArray;

A dynamic array of bits. Each bit in a BitArray can be manipulated individually or by the standard bitwise operators &, |, ^, ~, >>, << and also by other effective member functions; most of them work relative to the BitArray's dimension (see dim), instead of its length.

Examples:

Slicing & bitsSet

import std.algorithm.comparison : equal;
import std.range : iota;

bool[] buf = new bool[64 * 3];
buf[0 .. 64] = true;
BitArray b = BitArray(buf);
assert(b.bitsSet.equal(iota(0, 64)));
b <<= 64;
assert(b.bitsSet.equal(iota(64, 128)));

Examples:

Concatenation and appending

import std.algorithm.comparison : equal;

auto b = BitArray([1, 0]);
b ~= true;
writeln(b[2]); // 1
b ~= BitArray([0, 1]);
auto c = BitArray([1, 0, 1, 0, 1]);
writeln(b); // c
assert(b.bitsSet.equal([0, 2, 4]));

Examples:

Bit flipping

import std.algorithm.comparison : equal;

auto b = BitArray([1, 1, 0, 1]);
b &= BitArray([0, 1, 1, 0]);
assert(b.bitsSet.equal([1]));
b.flip;
assert(b.bitsSet.equal([0, 2, 3]));

Examples:

String format of bitarrays

import std.format : format;
auto b = BitArray([1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]);
writeln(format("%b", b)); // "1_00001111_00001111"

Examples:

import std.format : format;

BitArray b;

b = BitArray([]);
writeln(format("%s", b)); // "[]"
assert(format("%b", b) is null);

b = BitArray([1]);
writeln(format("%s", b)); // "[1]"
writeln(format("%b", b)); // "1"

b = BitArray([0, 0, 0, 0]);
writeln(format("%b", b)); // "0000"

b = BitArray([0, 0, 0, 0, 1, 1, 1, 1]);
writeln(format("%s", b)); // "[0, 0, 0, 0, 1, 1, 1, 1]"
writeln(format("%b", b)); // "00001111"

b = BitArray([0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]);
writeln(format("%s", b)); // "[0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]"
writeln(format("%b", b)); // "00001111_00001111"

b = BitArray([1, 0, 0, 0, 0, 1, 1, 1, 1]);
writeln(format("%b", b)); // "1_00001111"

b = BitArray([1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]);
writeln(format("%b", b)); // "1_00001111_00001111"

pure nothrow this(in bool[] ba);

Creates a BitArray from a bool array, such that bool values read from left to right correspond to subsequent bits in the BitArray.

Parameters:

bool[] ba Source array of bool values.

Examples:

import std.algorithm.comparison : equal;

bool[] input = [true, false, false, true, true];
auto a = BitArray(input);
writeln(a.length); // 5
assert(a.bitsSet.equal([0, 3, 4]));

// This also works because an implicit cast to bool[] occurs for this array.
auto b = BitArray([0, 0, 1]);
writeln(b.length); // 3
assert(b.bitsSet.equal([2]));

Examples:

import std.algorithm.comparison : equal;
import std.array : array;
import std.range : iota, repeat;

BitArray a = true.repeat(70).array;
writeln(a.length); // 70
assert(a.bitsSet.equal(iota(0, 70)));

pure nothrow @nogc this(void[] v, size_t numbits);

Creates a BitArray from the raw contents of the source array. The source array is not copied but simply acts as the underlying array of bits, which stores data as size_t units.

That means a particular care should be taken when passing an array of a type different than size_t, firstly because its length should be a multiple of size_t.sizeof, and secondly because how the bits are mapped:

size_t[] source = [1, 2, 3, 3424234, 724398, 230947, 389492];
enum sbits = size_t.sizeof * 8;
auto ba = BitArray(source, source.length * sbits);
foreach (n; 0 .. source.length * sbits)
{
    auto nth_bit = cast(bool) (source[n / sbits] & (1L << (n % sbits)));
    assert(ba[n] == nth_bit);
}

The least significant bit in any size_t unit is the starting bit of this unit, and the most significant bit is the last bit of this unit. Therefore, passing e.g. an array of ints may result in a different BitArray depending on the processor's endianness.

This constructor is the inverse of opCast.

Parameters:

void[] `v`	Source array. `v`.length must be a multple of size_t.sizeof.
size_t `numbits`	Number of bits to be mapped from the source array, i.e. length of the created BitArray.

Examples:

import std.algorithm.comparison : equal;

auto a = BitArray([1, 0, 0, 1, 1]);

// Inverse of the cast.
auto v = cast(void[]) a;
auto b = BitArray(v, a.length);

writeln(b.length); // 5
assert(b.bitsSet.equal([0, 3, 4]));

// a and b share the underlying data.
a[0] = 0;
writeln(b[0]); // 0
writeln(a); // b

Examples:

import std.algorithm.comparison : equal;

size_t[] source = [0b1100, 0b0011];
enum sbits = size_t.sizeof * 8;
auto ba = BitArray(source, source.length * sbits);
// The least significant bit in each unit is this unit's starting bit.
assert(ba.bitsSet.equal([2, 3, sbits, sbits + 1]));

Examples:

// Example from the doc for this constructor.
static immutable size_t[] sourceData = [1, 0b101, 3, 3424234, 724398, 230947, 389492];
size_t[] source = sourceData.dup;
enum sbits = size_t.sizeof * 8;
auto ba = BitArray(source, source.length * sbits);
foreach (n; 0 .. source.length * sbits)
{
    auto nth_bit = cast(bool) (source[n / sbits] & (1L << (n % sbits)));
    writeln(ba[n]); // nth_bit
}

// Example of mapping only part of the array.
import std.algorithm.comparison : equal;

auto bc = BitArray(source, sbits + 1);
assert(bc.bitsSet.equal([0, sbits]));
// Source array has not been modified.
writeln(source); // sourceData

const pure nothrow @nogc @property @safe size_t dim();

Returns:

Dimension i.e. the number of native words backing this BitArray.

Technically, this is the length of the underlying array storing bits, which is equal to ceil(length / (size_t.sizeof * 8)), as bits are packed into size_t units.

const pure nothrow @nogc @property @safe size_t length();

Returns:

Number of bits in the BitArray.

pure nothrow @property @system size_t length(size_t newlen);

Sets the amount of bits in the BitArray. Warning: increasing length may overwrite bits in the final word of the current underlying data regardless of whether it is shared between BitArray objects. i.e. D dynamic array extension semantics are not followed.

const pure nothrow @nogc bool opIndex(size_t i);

Gets the i'th bit in the BitArray.

Examples:

static void fun(const BitArray arr)
{
    auto x = arr[0];
    writeln(x); // 1
}
BitArray a;
a.length = 3;
a[0] = 1;
fun(a);

pure nothrow @nogc bool opIndexAssign(bool b, size_t i);

Sets the i'th bit in the BitArray.

void opSliceAssign(bool val);

Sets all the values in the BitArray to the value specified by val.

Examples:

import std.algorithm.comparison : equal;

auto b = BitArray([1, 0, 1, 0, 1, 1]);

b[] = true;
// all bits are set
assert(b.bitsSet.equal([0, 1, 2, 3, 4, 5]));

b[] = false;
// none of the bits are set
assert(b.bitsSet.empty);

pure nothrow void opSliceAssign(bool val, size_t start, size_t end);

Sets the bits of a slice of BitArray starting at index start and ends at index ($D end - 1) with the values specified by val.

Examples:

import std.algorithm.comparison : equal;
import std.range : iota;
import std.stdio;

auto b = BitArray([1, 0, 0, 0, 1, 1, 0]);
b[1 .. 3] = true;
assert(b.bitsSet.equal([0, 1, 2, 4, 5]));

bool[72] bitArray;
auto b1 = BitArray(bitArray);
b1[63 .. 67] = true;
assert(b1.bitsSet.equal([63, 64, 65, 66]));
b1[63 .. 67] = false;
assert(b1.bitsSet.empty);
b1[0 .. 64] = true;
assert(b1.bitsSet.equal(iota(0, 64)));
b1[0 .. 64] = false;
assert(b1.bitsSet.empty);

bool[256] bitArray2;
auto b2 = BitArray(bitArray2);
b2[3 .. 245] = true;
assert(b2.bitsSet.equal(iota(3, 245)));
b2[3 .. 245] = false;
assert(b2.bitsSet.empty);

void flip();

Flips all the bits in the BitArray

Examples:

import std.algorithm.comparison : equal;
import std.range : iota;

// positions 0, 2, 4 are set
auto b = BitArray([1, 0, 1, 0, 1, 0]);
b.flip();
// after flipping, positions 1, 3, 5 are set
assert(b.bitsSet.equal([1, 3, 5]));

bool[270] bits;
auto b1 = BitArray(bits);
b1.flip();
assert(b1.bitsSet.equal(iota(0, 270)));

void flip(size_t i);

Flips a single bit, specified by pos

Examples:

auto ax = BitArray([1, 0, 0, 1]);
ax.flip(0);
writeln(ax[0]); // 0

bool[200] y;
y[90 .. 130] = true;
auto ay = BitArray(y);
ay.flip(100);
writeln(ay[100]); // 0

size_t count();

Counts all the set bits in the BitArray

Examples:

auto a = BitArray([0, 1, 1, 0, 0, 1, 1]);
writeln(a.count); // 4

BitArray b;
writeln(b.count); // 0

bool[200] boolArray;
boolArray[45 .. 130] = true;
auto c = BitArray(boolArray);
writeln(c.count); // 85

const pure nothrow @property BitArray dup();

Duplicates the BitArray and its contents.

Examples:

BitArray a;
BitArray b;

a.length = 3;
a[0] = 1; a[1] = 0; a[2] = 1;
b = a.dup;
writeln(b.length); // 3
foreach (i; 0 .. 3)
    writeln(b[i]); // (((i ^ 1) & 1) ? true : false)

int opApply(scope int delegate(ref bool) dg); const int opApply(scope int delegate(bool) dg); int opApply(scope int delegate(size_t, ref bool) dg); const int opApply(scope int delegate(size_t, bool) dg);

Support for foreach loops for BitArray.

Examples:

bool[] ba = [1,0,1];

auto a = BitArray(ba);

int i;
foreach (b;a)
{
    switch (i)
    {
        case 0: assert(b == true); break;
        case 1: assert(b == false); break;
        case 2: assert(b == true); break;
        default: assert(0);
    }
    i++;
}

foreach (j,b;a)
{
    switch (j)
    {
        case 0: assert(b == true); break;
        case 1: assert(b == false); break;
        case 2: assert(b == true); break;
        default: assert(0);
    }
}

pure nothrow @nogc @property BitArray reverse();

Reverses the bits of the BitArray.

Examples:

BitArray b;
bool[5] data = [1,0,1,1,0];

b = BitArray(data);
b.reverse;
foreach (i; 0 .. data.length)
    writeln(b[i]); // data[4 - i]

pure nothrow @nogc @property BitArray sort();

Sorts the BitArray's elements.

Examples:

size_t x = 0b1100011000;
auto ba = BitArray(10, &x);
ba.sort;
foreach (i; 0 .. 6)
    writeln(ba[i]); // false
foreach (i; 6 .. 10)
    writeln(ba[i]); // true

const pure nothrow @nogc bool opEquals(ref const BitArray a2);

Support for operators == and != for BitArray.

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1];
bool[] bc = [1,0,1,0,1,0,1];
bool[] bd = [1,0,1,1,1];
bool[] be = [1,0,1,0,1];
bool[] bf = [1,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
bool[] bg = [1,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1];

auto a = BitArray(ba);
auto b = BitArray(bb);
auto c = BitArray(bc);
auto d = BitArray(bd);
auto e = BitArray(be);
auto f = BitArray(bf);
auto g = BitArray(bg);

assert(a != b);
assert(a != c);
assert(a != d);
writeln(a); // e
assert(f != g);

const pure nothrow @nogc int opCmp(BitArray a2);

Supports comparison operators for BitArray.

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1];
bool[] bc = [1,0,1,0,1,0,1];
bool[] bd = [1,0,1,1,1];
bool[] be = [1,0,1,0,1];
bool[] bf = [1,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1];
bool[] bg = [1,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);
auto c = BitArray(bc);
auto d = BitArray(bd);
auto e = BitArray(be);
auto f = BitArray(bf);
auto g = BitArray(bg);

assert(a >  b);
assert(a >= b);
assert(a <  c);
assert(a <= c);
assert(a <  d);
assert(a <= d);
writeln(a); // e
assert(a <= e);
assert(a >= e);
assert(f <  g);
assert(g <= g);

const pure nothrow @nogc size_t toHash();

Support for hashing for BitArray.

pure nothrow @nogc void[] opCast(T : void[])();

Convert to void[].

pure nothrow @nogc size_t[] opCast(T : size_t[])();

Convert to size_t[].

Examples:

import std.array : array;
import std.range : repeat, take;

// bit array with 300 elements
auto a = BitArray(true.repeat.take(300).array);
size_t[] v = cast(size_t[]) a;
const blockSize = size_t.sizeof * 8;
writeln(v.length); // (a.length + blockSize - 1) / blockSize

const pure nothrow BitArray opUnary(string op)() if (op == "~");

Support for unary operator ~ for BitArray.

Examples:

bool[] ba = [1,0,1,0,1];

auto a = BitArray(ba);
BitArray b = ~a;

writeln(b[0]); // 0
writeln(b[1]); // 1
writeln(b[2]); // 0
writeln(b[3]); // 1
writeln(b[4]); // 0

const pure nothrow BitArray opBinary(string op)(const BitArray e2) if (op == "-" || op == "&" || op == "|" || op == "^");

Support for binary bitwise operators for BitArray.

Examples:

static bool[] ba = [1,0,1,0,1];
static bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

BitArray c = a & b;

writeln(c[0]); // 1
writeln(c[1]); // 0
writeln(c[2]); // 1
writeln(c[3]); // 0
writeln(c[4]); // 0

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

BitArray c = a | b;

writeln(c[0]); // 1
writeln(c[1]); // 0
writeln(c[2]); // 1
writeln(c[3]); // 1
writeln(c[4]); // 1

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

BitArray c = a ^ b;

writeln(c[0]); // 0
writeln(c[1]); // 0
writeln(c[2]); // 0
writeln(c[3]); // 1
writeln(c[4]); // 1

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

BitArray c = a - b;

writeln(c[0]); // 0
writeln(c[1]); // 0
writeln(c[2]); // 0
writeln(c[3]); // 0
writeln(c[4]); // 1

pure nothrow @nogc BitArray opOpAssign(string op)(const BitArray e2) if (op == "-" || op == "&" || op == "|" || op == "^");

Support for operator op= for BitArray.

Examples:

bool[] ba = [1,0,1,0,1,1,0,1,0,1];
bool[] bb = [1,0,1,1,0];
auto a = BitArray(ba);
auto b = BitArray(bb);
BitArray c = a;
c.length = 5;
c &= b;
writeln(a[5]); // 1
writeln(a[6]); // 0
writeln(a[7]); // 1
writeln(a[8]); // 0
writeln(a[9]); // 1

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

a &= b;
writeln(a[0]); // 1
writeln(a[1]); // 0
writeln(a[2]); // 1
writeln(a[3]); // 0
writeln(a[4]); // 0

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

a |= b;
writeln(a[0]); // 1
writeln(a[1]); // 0
writeln(a[2]); // 1
writeln(a[3]); // 1
writeln(a[4]); // 1

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

a ^= b;
writeln(a[0]); // 0
writeln(a[1]); // 0
writeln(a[2]); // 0
writeln(a[3]); // 1
writeln(a[4]); // 1

Examples:

bool[] ba = [1,0,1,0,1];
bool[] bb = [1,0,1,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);

a -= b;
writeln(a[0]); // 0
writeln(a[1]); // 0
writeln(a[2]); // 0
writeln(a[3]); // 0
writeln(a[4]); // 1

pure nothrow BitArray opOpAssign(string op)(bool b) if (op == "~"); pure nothrow BitArray opOpAssign(string op)(BitArray b) if (op == "~");

Support for operator ~= for BitArray. Warning: This will overwrite a bit in the final word of the current underlying data regardless of whether it is shared between BitArray objects. i.e. D dynamic array concatenation semantics are not followed

Examples:

bool[] ba = [1,0,1,0,1];

auto a = BitArray(ba);
BitArray b;

b = (a ~= true);
writeln(a[0]); // 1
writeln(a[1]); // 0
writeln(a[2]); // 1
writeln(a[3]); // 0
writeln(a[4]); // 1
writeln(a[5]); // 1

writeln(b); // a

Examples:

bool[] ba = [1,0];
bool[] bb = [0,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);
BitArray c;

c = (a ~= b);
writeln(a.length); // 5
writeln(a[0]); // 1
writeln(a[1]); // 0
writeln(a[2]); // 0
writeln(a[3]); // 1
writeln(a[4]); // 0

writeln(c); // a

const pure nothrow BitArray opBinary(string op)(bool b) if (op == "~"); const pure nothrow BitArray opBinaryRight(string op)(bool b) if (op == "~"); const pure nothrow BitArray opBinary(string op)(BitArray b) if (op == "~");

Support for binary operator ~ for BitArray.

Examples:

bool[] ba = [1,0];
bool[] bb = [0,1,0];

auto a = BitArray(ba);
auto b = BitArray(bb);
BitArray c;

c = (a ~ b);
writeln(c.length); // 5
writeln(c[0]); // 1
writeln(c[1]); // 0
writeln(c[2]); // 0
writeln(c[3]); // 1
writeln(c[4]); // 0

c = (a ~ true);
writeln(c.length); // 3
writeln(c[0]); // 1
writeln(c[1]); // 0
writeln(c[2]); // 1

c = (false ~ a);
writeln(c.length); // 3
writeln(c[0]); // 0
writeln(c[1]); // 1
writeln(c[2]); // 0

pure nothrow @nogc void opOpAssign(string op)(size_t nbits) if (op == "<<");

Operator <<= support.

Shifts all the bits in the array to the left by the given number of bits. The leftmost bits are dropped, and 0's are appended to the end to fill up the vacant bits.

Warning: unused bits in the final word up to the next word boundary may be overwritten by this operation. It does not attempt to preserve bits past the end of the array.

pure nothrow @nogc void opOpAssign(string op)(size_t nbits) if (op == ">>");

Operator >>= support.

Shifts all the bits in the array to the right by the given number of bits. The rightmost bits are dropped, and 0's are inserted at the back to fill up the vacant bits.

Warning: unused bits in the final word up to the next word boundary may be overwritten by this operation. It does not attempt to preserve bits past the end of the array.

Examples:

import std.format : format;

auto b = BitArray([1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1]);

b <<= 1;
writeln(format("%b", b)); // "01100_10101101"

b >>= 1;
writeln(format("%b", b)); // "11001_01011010"

b <<= 4;
writeln(format("%b", b)); // "00001_10010101"

b >>= 5;
writeln(format("%b", b)); // "10010_10100000"

b <<= 13;
writeln(format("%b", b)); // "00000_00000000"

b = BitArray([1, 0, 1, 1, 0, 1, 1, 1]);
b >>= 8;
writeln(format("%b", b)); // "00000000"

const void toString(W)(ref W sink, ref scope const FormatSpec!char fmt) if (isOutputRange!(W, char));

Return a string representation of this BitArray.

Two format specifiers are supported:

%s which prints the bits as an array, and

%b which prints the bits as 8-bit byte packets

separated with an underscore.

Parameters:

W `sink`	A char accepting output range.
FormatSpec!char `fmt`	A std.format.FormatSpec which controls how the data is displayed.

Examples:

import std.format : format;

auto b = BitArray([0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]);

auto s1 = format("%s", b);
writeln(s1); // "[0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]"

auto s2 = format("%b", b);
writeln(s2); // "00001111_00001111"

const nothrow @property auto bitsSet();

Return a lazy range of the indices of set bits.

Examples:

import std.algorithm.comparison : equal;

auto b1 = BitArray([0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]);
assert(b1.bitsSet.equal([4, 5, 6, 7, 12, 13, 14, 15]));

BitArray b2;
b2.length = 1000;
b2[333] = true;
b2[666] = true;
b2[999] = true;
assert(b2.bitsSet.equal([333, 666, 999]));

pure nothrow @nogc @safe T swapEndian(T)(const T val) if (isIntegral!T || isSomeChar!T || isBoolean!T);

Swaps the endianness of the given integral value or character.

Examples:

writeln(42.swapEndian); // 704643072
assert(42.swapEndian.swapEndian == 42); // reflexive
writeln(1.swapEndian); // 16777216

writeln(true.swapEndian); // true
writeln(byte(10).swapEndian); // 10
writeln(char(10).swapEndian); // 10

writeln(ushort(10).swapEndian); // 2560
writeln(long(10).swapEndian); // 720575940379279360
writeln(ulong(10).swapEndian); // 720575940379279360

pure nothrow @nogc @safe auto nativeToBigEndian(T)(const T val) if (canSwapEndianness!T);

Converts the given value from the native endianness to big endian and returns it as a ubyte[n] where n is the size of the given type.

Returning a ubyte[n] helps prevent accidentally using a swapped value as a regular one (and in the case of floating point values, it's necessary, because the FPU will mess up any swapped floating point values. So, you can't actually have swapped floating point values as floating point values).

real is not supported, because its size is implementation-dependent and therefore could vary from machine to machine (which could make it unusable if you tried to transfer it to another machine).

Examples:

int i = 12345;
ubyte[4] swappedI = nativeToBigEndian(i);
writeln(i); // bigEndianToNative!int(swappedI)

float f = 123.45f;
ubyte[4] swappedF = nativeToBigEndian(f);
writeln(f); // bigEndianToNative!float(swappedF)

const float cf = 123.45f;
ubyte[4] swappedCF = nativeToBigEndian(cf);
writeln(cf); // bigEndianToNative!float(swappedCF)

double d = 123.45;
ubyte[8] swappedD = nativeToBigEndian(d);
writeln(d); // bigEndianToNative!double(swappedD)

const double cd = 123.45;
ubyte[8] swappedCD = nativeToBigEndian(cd);
writeln(cd); // bigEndianToNative!double(swappedCD)

pure nothrow @nogc @safe T bigEndianToNative(T, size_t n)(ubyte[n] val) if (canSwapEndianness!T && (n == T.sizeof));

Converts the given value from big endian to the native endianness and returns it. The value is given as a ubyte[n] where n is the size of the target type. You must give the target type as a template argument, because there are multiple types with the same size and so the type of the argument is not enough to determine the return type.

Taking a ubyte[n] helps prevent accidentally using a swapped value as a regular one (and in the case of floating point values, it's necessary, because the FPU will mess up any swapped floating point values. So, you can't actually have swapped floating point values as floating point values).

Examples:

ushort i = 12345;
ubyte[2] swappedI = nativeToBigEndian(i);
writeln(i); // bigEndianToNative!ushort(swappedI)

dchar c = 'D';
ubyte[4] swappedC = nativeToBigEndian(c);
writeln(c); // bigEndianToNative!dchar(swappedC)

pure nothrow @nogc @safe auto nativeToLittleEndian(T)(const T val) if (canSwapEndianness!T);

Converts the given value from the native endianness to little endian and returns it as a ubyte[n] where n is the size of the given type.

Examples:

int i = 12345;
ubyte[4] swappedI = nativeToLittleEndian(i);
writeln(i); // littleEndianToNative!int(swappedI)

double d = 123.45;
ubyte[8] swappedD = nativeToLittleEndian(d);
writeln(d); // littleEndianToNative!double(swappedD)

pure nothrow @nogc @safe T littleEndianToNative(T, size_t n)(ubyte[n] val) if (canSwapEndianness!T && (n == T.sizeof));

Converts the given value from little endian to the native endianness and returns it. The value is given as a ubyte[n] where n is the size of the target type. You must give the target type as a template argument, because there are multiple types with the same size and so the type of the argument is not enough to determine the return type.

real is not supported, because its size is implementation-dependent and therefore could vary from machine to machine (which could make it unusable if you tried to transfer it to another machine).

Examples:

ushort i = 12345;
ubyte[2] swappedI = nativeToLittleEndian(i);
writeln(i); // littleEndianToNative!ushort(swappedI)

dchar c = 'D';
ubyte[4] swappedC = nativeToLittleEndian(c);
writeln(c); // littleEndianToNative!dchar(swappedC)

T peek(T, Endian endianness = Endian.bigEndian, R)(R range) if (canSwapEndianness!T && isForwardRange!R && is(ElementType!R : const(ubyte))); T peek(T, Endian endianness = Endian.bigEndian, R)(R range, size_t index) if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : const(ubyte))); T peek(T, Endian endianness = Endian.bigEndian, R)(R range, size_t* index) if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : const(ubyte)));

Takes a range of ubytes and converts the first T.sizeof bytes to T. The value returned is converted from the given endianness to the native endianness. The range is not consumed.

Parameters:

T	The integral type to convert the first T.sizeof bytes to.
endianness	The endianness that the bytes are assumed to be in.
R `range`	The range to read from.
size_t `index`	The index to start reading from (instead of starting at the front). If index is a pointer, then it is updated to the index after the bytes read. The overloads with index are only available if hasSlicing!R is true.

Examples:

ubyte[] buffer = [1, 5, 22, 9, 44, 255, 8];
writeln(buffer.peek!uint()); // 17110537
writeln(buffer.peek!ushort()); // 261
writeln(buffer.peek!ubyte()); // 1

writeln(buffer.peek!uint(2)); // 369700095
writeln(buffer.peek!ushort(2)); // 5641
writeln(buffer.peek!ubyte(2)); // 22

size_t index = 0;
writeln(buffer.peek!ushort(&index)); // 261
writeln(index); // 2

writeln(buffer.peek!uint(&index)); // 369700095
writeln(index); // 6

writeln(buffer.peek!ubyte(&index)); // 8
writeln(index); // 7

Examples:

import std.algorithm.iteration : filter;
ubyte[] buffer = [1, 5, 22, 9, 44, 255, 7];
auto range = filter!"true"(buffer);
writeln(range.peek!uint()); // 17110537
writeln(range.peek!ushort()); // 261
writeln(range.peek!ubyte()); // 1

T read(T, Endian endianness = Endian.bigEndian, R)(ref R range) if (canSwapEndianness!T && isInputRange!R && is(ElementType!R : const(ubyte)));

Takes a range of ubytes and converts the first T.sizeof bytes to T. The value returned is converted from the given endianness to the native endianness. The T.sizeof bytes which are read are consumed from the range.

Parameters:

T	The integral type to convert the first T.sizeof bytes to.
endianness	The endianness that the bytes are assumed to be in.
R `range`	The range to read from.

Examples:

import std.range.primitives : empty;
ubyte[] buffer = [1, 5, 22, 9, 44, 255, 8];
writeln(buffer.length); // 7

writeln(buffer.read!ushort()); // 261
writeln(buffer.length); // 5

writeln(buffer.read!uint()); // 369700095
writeln(buffer.length); // 1

writeln(buffer.read!ubyte()); // 8
assert(buffer.empty);

void write(T, Endian endianness = Endian.bigEndian, R)(R range, const T value, size_t index) if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : ubyte)); void write(T, Endian endianness = Endian.bigEndian, R)(R range, const T value, size_t* index) if (canSwapEndianness!T && isForwardRange!R && hasSlicing!R && is(ElementType!R : ubyte));

Takes an integral value, converts it to the given endianness, and writes it to the given range of ubytes as a sequence of T.sizeof ubytes starting at index. hasSlicing!R must be true.

Parameters:

T	The integral type to convert the first T.sizeof bytes to.
endianness	The endianness to write the bytes in.
R `range`	The range to write to.
T `value`	The value to write.
size_t `index`	The index to start writing to. If index is a pointer, then it is updated to the index after the bytes read.

Examples:

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0];
buffer.write!uint(29110231u, 0);
writeln(buffer); // [1, 188, 47, 215, 0, 0, 0, 0]

buffer.write!ushort(927, 0);
writeln(buffer); // [3, 159, 47, 215, 0, 0, 0, 0]

buffer.write!ubyte(42, 0);
writeln(buffer); // [42, 159, 47, 215, 0, 0, 0, 0]

Examples:

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0, 0];
buffer.write!uint(142700095u, 2);
writeln(buffer); // [0, 0, 8, 129, 110, 63, 0, 0, 0]

buffer.write!ushort(19839, 2);
writeln(buffer); // [0, 0, 77, 127, 110, 63, 0, 0, 0]

buffer.write!ubyte(132, 2);
writeln(buffer); // [0, 0, 132, 127, 110, 63, 0, 0, 0]

Examples:

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0];
size_t index = 0;
buffer.write!ushort(261, &index);
writeln(buffer); // [1, 5, 0, 0, 0, 0, 0, 0]
writeln(index); // 2

buffer.write!uint(369700095u, &index);
writeln(buffer); // [1, 5, 22, 9, 44, 255, 0, 0]
writeln(index); // 6

buffer.write!ubyte(8, &index);
writeln(buffer); // [1, 5, 22, 9, 44, 255, 8, 0]
writeln(index); // 7

Examples:

bool

ubyte[] buffer = [0, 0];
buffer.write!bool(false, 0);
writeln(buffer); // [0, 0]

buffer.write!bool(true, 0);
writeln(buffer); // [1, 0]

buffer.write!bool(true, 1);
writeln(buffer); // [1, 1]

buffer.write!bool(false, 1);
writeln(buffer); // [1, 0]

size_t index = 0;
buffer.write!bool(false, &index);
writeln(buffer); // [0, 0]
writeln(index); // 1

buffer.write!bool(true, &index);
writeln(buffer); // [0, 1]
writeln(index); // 2

Examples:

char(8-bit)

ubyte[] buffer = [0, 0, 0];

buffer.write!char('a', 0);
writeln(buffer); // [97, 0, 0]

buffer.write!char('b', 1);
writeln(buffer); // [97, 98, 0]

size_t index = 0;
buffer.write!char('a', &index);
writeln(buffer); // [97, 98, 0]
writeln(index); // 1

buffer.write!char('b', &index);
writeln(buffer); // [97, 98, 0]
writeln(index); // 2

buffer.write!char('c', &index);
writeln(buffer); // [97, 98, 99]
writeln(index); // 3

Examples:

wchar (16bit - 2x ubyte)

ubyte[] buffer = [0, 0, 0, 0];

buffer.write!wchar('ą', 0);
writeln(buffer); // [1, 5, 0, 0]

buffer.write!wchar('”', 2);
writeln(buffer); // [1, 5, 32, 29]

size_t index = 0;
buffer.write!wchar('ć', &index);
writeln(buffer); // [1, 7, 32, 29]
writeln(index); // 2

buffer.write!wchar('ą', &index);
writeln(buffer); // [1, 7, 1, 5]
writeln(index); // 4

Examples:

dchar (32bit - 4x ubyte)

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0];

buffer.write!dchar('ą', 0);
writeln(buffer); // [0, 0, 1, 5, 0, 0, 0, 0]

buffer.write!dchar('”', 4);
writeln(buffer); // [0, 0, 1, 5, 0, 0, 32, 29]

size_t index = 0;
buffer.write!dchar('ć', &index);
writeln(buffer); // [0, 0, 1, 7, 0, 0, 32, 29]
writeln(index); // 4

buffer.write!dchar('ą', &index);
writeln(buffer); // [0, 0, 1, 7, 0, 0, 1, 5]
writeln(index); // 8

Examples:

float (32bit - 4x ubyte)

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0];

buffer.write!float(32.0f, 0);
writeln(buffer); // [66, 0, 0, 0, 0, 0, 0, 0]

buffer.write!float(25.0f, 4);
writeln(buffer); // [66, 0, 0, 0, 65, 200, 0, 0]

size_t index = 0;
buffer.write!float(25.0f, &index);
writeln(buffer); // [65, 200, 0, 0, 65, 200, 0, 0]
writeln(index); // 4

buffer.write!float(32.0f, &index);
writeln(buffer); // [65, 200, 0, 0, 66, 0, 0, 0]
writeln(index); // 8

Examples:

double (64bit - 8x ubyte)

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

buffer.write!double(32.0, 0);
writeln(buffer); // [64, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

buffer.write!double(25.0, 8);
writeln(buffer); // [64, 64, 0, 0, 0, 0, 0, 0, 64, 57, 0, 0, 0, 0, 0, 0]

size_t index = 0;
buffer.write!double(25.0, &index);
writeln(buffer); // [64, 57, 0, 0, 0, 0, 0, 0, 64, 57, 0, 0, 0, 0, 0, 0]
writeln(index); // 8

buffer.write!double(32.0, &index);
writeln(buffer); // [64, 57, 0, 0, 0, 0, 0, 0, 64, 64, 0, 0, 0, 0, 0, 0]
writeln(index); // 16

Examples:

enum

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

enum Foo
{
    one = 10,
    two = 20,
    three = 30
}

buffer.write!Foo(Foo.one, 0);
writeln(buffer); // [0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0]

buffer.write!Foo(Foo.two, 4);
writeln(buffer); // [0, 0, 0, 10, 0, 0, 0, 20, 0, 0, 0, 0]

buffer.write!Foo(Foo.three, 8);
writeln(buffer); // [0, 0, 0, 10, 0, 0, 0, 20, 0, 0, 0, 30]

size_t index = 0;
buffer.write!Foo(Foo.three, &index);
writeln(buffer); // [0, 0, 0, 30, 0, 0, 0, 20, 0, 0, 0, 30]
writeln(index); // 4

buffer.write!Foo(Foo.one, &index);
writeln(buffer); // [0, 0, 0, 30, 0, 0, 0, 10, 0, 0, 0, 30]
writeln(index); // 8

buffer.write!Foo(Foo.two, &index);
writeln(buffer); // [0, 0, 0, 30, 0, 0, 0, 10, 0, 0, 0, 20]
writeln(index); // 12

Examples:

enum - float

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0];

enum Float: float
{
    one = 32.0f,
    two = 25.0f
}

buffer.write!Float(Float.one, 0);
writeln(buffer); // [66, 0, 0, 0, 0, 0, 0, 0]

buffer.write!Float(Float.two, 4);
writeln(buffer); // [66, 0, 0, 0, 65, 200, 0, 0]

size_t index = 0;
buffer.write!Float(Float.two, &index);
writeln(buffer); // [65, 200, 0, 0, 65, 200, 0, 0]
writeln(index); // 4

buffer.write!Float(Float.one, &index);
writeln(buffer); // [65, 200, 0, 0, 66, 0, 0, 0]
writeln(index); // 8

Examples:

enum - double

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

enum Double: double
{
    one = 32.0,
    two = 25.0
}

buffer.write!Double(Double.one, 0);
writeln(buffer); // [64, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

buffer.write!Double(Double.two, 8);
writeln(buffer); // [64, 64, 0, 0, 0, 0, 0, 0, 64, 57, 0, 0, 0, 0, 0, 0]

size_t index = 0;
buffer.write!Double(Double.two, &index);
writeln(buffer); // [64, 57, 0, 0, 0, 0, 0, 0, 64, 57, 0, 0, 0, 0, 0, 0]
writeln(index); // 8

buffer.write!Double(Double.one, &index);
writeln(buffer); // [64, 57, 0, 0, 0, 0, 0, 0, 64, 64, 0, 0, 0, 0, 0, 0]
writeln(index); // 16

Examples:

enum - real

ubyte[] buffer = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

enum Real: real
{
    one = 32.0,
    two = 25.0
}

static assert(!__traits(compiles, buffer.write!Real(Real.one)));

void append(T, Endian endianness = Endian.bigEndian, R)(R range, const T value) if (canSwapEndianness!T && isOutputRange!(R, ubyte));

Takes an integral value, converts it to the given endianness, and appends it to the given range of ubytes (using put) as a sequence of T.sizeof ubytes starting at index. hasSlicing!R must be true.

Parameters:

T	The integral type to convert the first T.sizeof bytes to.
endianness	The endianness to write the bytes in.
R `range`	The range to append to.
T `value`	The value to append.

Examples:

import std.array;
auto buffer = appender!(const ubyte[])();
buffer.append!ushort(261);
writeln(buffer.data); // [1, 5]

buffer.append!uint(369700095u);
writeln(buffer.data); // [1, 5, 22, 9, 44, 255]

buffer.append!ubyte(8);
writeln(buffer.data); // [1, 5, 22, 9, 44, 255, 8]

Examples:

bool

import std.array : appender;
auto buffer = appender!(const ubyte[])();

buffer.append!bool(true);
writeln(buffer.data); // [1]

buffer.append!bool(false);
writeln(buffer.data); // [1, 0]

Examples:

char wchar dchar

import std.array : appender;
auto buffer = appender!(const ubyte[])();

buffer.append!char('a');
writeln(buffer.data); // [97]

buffer.append!char('b');
writeln(buffer.data); // [97, 98]

buffer.append!wchar('ą');
writeln(buffer.data); // [97, 98, 1, 5]

buffer.append!dchar('ą');
    writeln(buffer.data); // [97, 98, 1, 5, 0, 0, 1, 5]

Examples:

float double

import std.array : appender;
auto buffer = appender!(const ubyte[])();

buffer.append!float(32.0f);
writeln(buffer.data); // [66, 0, 0, 0]

buffer.append!double(32.0);
writeln(buffer.data); // [66, 0, 0, 0, 64, 64, 0, 0, 0, 0, 0, 0]

Examples:

enum

import std.array : appender;
auto buffer = appender!(const ubyte[])();

enum Foo
{
    one = 10,
    two = 20,
    three = 30
}

buffer.append!Foo(Foo.one);
writeln(buffer.data); // [0, 0, 0, 10]

buffer.append!Foo(Foo.two);
writeln(buffer.data); // [0, 0, 0, 10, 0, 0, 0, 20]

buffer.append!Foo(Foo.three);
writeln(buffer.data); // [0, 0, 0, 10, 0, 0, 0, 20, 0, 0, 0, 30]

Examples:

enum - bool

import std.array : appender;
auto buffer = appender!(const ubyte[])();

enum Bool: bool
{
    bfalse = false,
    btrue = true,
}

buffer.append!Bool(Bool.btrue);
writeln(buffer.data); // [1]

buffer.append!Bool(Bool.bfalse);
writeln(buffer.data); // [1, 0]

buffer.append!Bool(Bool.btrue);
writeln(buffer.data); // [1, 0, 1]

Examples:

enum - float

import std.array : appender;
auto buffer = appender!(const ubyte[])();

enum Float: float
{
    one = 32.0f,
    two = 25.0f
}

buffer.append!Float(Float.one);
writeln(buffer.data); // [66, 0, 0, 0]

buffer.append!Float(Float.two);
writeln(buffer.data); // [66, 0, 0, 0, 65, 200, 0, 0]

Examples:

enum - double

import std.array : appender;
auto buffer = appender!(const ubyte[])();

enum Double: double
{
    one = 32.0,
    two = 25.0
}

buffer.append!Double(Double.one);
writeln(buffer.data); // [64, 64, 0, 0, 0, 0, 0, 0]

buffer.append!Double(Double.two);
writeln(buffer.data); // [64, 64, 0, 0, 0, 0, 0, 0, 64, 57, 0, 0, 0, 0, 0, 0]

Examples:

enum - real

import std.array : appender;
auto buffer = appender!(const ubyte[])();

enum Real: real
{
    one = 32.0,
    two = 25.0
}

static assert(!__traits(compiles, buffer.append!Real(Real.one)));

pure nothrow @nogc auto bitsSet(T)(const T value) if (isIntegral!T);

Range that iterates the indices of the set bits in value. Index 0 corresponds to the least significant bit. For signed integers, the highest index corresponds to the sign bit.

Examples:

import std.algorithm.comparison : equal;
import std.range : iota;

assert(bitsSet(1).equal([0]));
assert(bitsSet(5).equal([0, 2]));
assert(bitsSet(-1).equal(iota(32)));
assert(bitsSet(int.min).equal([31]));

Library Reference

std.bitmanip