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/++
Enum utilities.
License: $(HTTP www.apache.org/licenses/LICENSE-2.0, Apache-2.0)
Authors: Ilia Ki
Macros:
+/
module mir.enums;
private bool hasSeqGrow(T)(T[] elems)
if (__traits(isIntegral, T))
{
assert(elems.length);
auto min = elems[0];
foreach (i, e; elems)
if (i != e - min)
return false;
return true;
}
/++
Enum index that corresponds of the list returned by `std.traits.EnumMembers`.
Returns:
enum member position index in the enum definition that corresponds the `value`.
+/
bool getEnumIndex(T)(const T value, ref uint index)
@safe pure nothrow @nogc
if (is(T == enum))
{
import std.traits: EnumMembers, isSomeString;
import mir.utility: _expect;
static if (__traits(isFloating, T))
{
// TODO: index based binary searach
foreach (i, member; enumMembers!T)
{
if (value == member)
{
index = cast(uint) i;
return true;
}
}
return false;
}
else
static if (!__traits(isIntegral, T)) //strings
{
enum string[1] stringEnumValue(alias symbol) = [symbol];
return getEnumIndexFromKey!(T, false, stringEnumValue)(value, index);
}
else
static if (hasSeqGrow(enumMembers!T))
{
import std.traits: Unsigned;
const shifted = cast(Unsigned!(typeof(value - T.min)))(value - T.min);
if (_expect(shifted < enumMembers!T.length, true))
{
index = cast(uint) shifted;
return true;
}
return false;
}
else
static if (is(T : bool))
{
index = !value;
return true;
}
else
{
import std.traits: Unsigned;
alias U = Unsigned!(typeof(T.max - T.min + 1));
enum length = cast(size_t)cast(U)(T.max - T.min + 1);
const shifted = cast(size_t)cast(U)(value - T.min);
static if (length <= 255)
{
static immutable ubyte[length] table = (){
ubyte[length] ret;
foreach (i, member; enumMembers!T)
{
ret[member - T.min] = cast(ubyte)(i + 1);
}
return ret;
}();
if (_expect(shifted < length, true))
{
int id = table[shifted] - 1;
if (_expect(id >= 0, true))
{
index = id;
return true;
}
}
return false;
}
else
{
switch (value)
{
foreach (i, member; EnumMembers!T)
{
case member:
index = i;
return true;
}
default: return false;
}
}
}
}
///
@safe pure nothrow @nogc
version(mir_core_test) unittest
{
import std.meta: AliasSeq;
enum Common { a, b, c }
enum Reversed { a = 1, b = 0, c = -1 }
enum Shifted { a = -4, b, c }
enum Small { a = -4, b, c = 10 }
enum Big { a = -4, b, c = 1000 }
enum InverseBool { True = true, False = false }
enum FP : float { a = -4, b, c }
enum S : string { a = "а", b = "б", c = "ц" }
uint index = -1;
foreach (E; AliasSeq!(Common, Reversed, Shifted, Small, Big, FP, S))
{
assert(getEnumIndex(E.a, index) && index == 0);
assert(getEnumIndex(E.b, index) && index == 1);
assert(getEnumIndex(E.c, index) && index == 2);
}
assert(getEnumIndex(InverseBool.True, index) && index == 0);
assert(getEnumIndex(InverseBool.False, index) && index == 1);
}
/++
Static immutable instance of `[std.traits.EnumMembers!T]`.
+/
template enumMembers(T)
if (is(T == enum))
{
import std.traits: EnumMembers;
///
static immutable T[EnumMembers!T.length] enumMembers = [EnumMembers!T];
}
///
version(mir_core_test) unittest
{
enum E {a = 1, b = -1, c}
static assert(enumMembers!E == [E.a, E.b, E.c]);
}
/++
Static immutable instance of Enum Identifiers.
+/
template enumIdentifiers(T)
if (is(T == enum))
{
import std.traits: EnumMembers;
static immutable string[EnumMembers!T.length] enumIdentifiers = () {
string[EnumMembers!T.length] identifiers;
static foreach(i, member; EnumMembers!T)
identifiers[i] = __traits(identifier, EnumMembers!T[i]);
return identifiers;
} ();
}
///
version(mir_core_test) unittest
{
enum E {z = 1, b = -1, c}
static assert(enumIdentifiers!E == ["z", "b", "c"]);
}
/++
Aliases itself to $(LREF enumMembers) for string enums and
$(LREF enumIdentifiers) for integral and floating point enums.
+/
template enumStrings(T)
if (is(T == enum))
{
static if (is(T : C[], C))
alias enumStrings = enumMembers!T;
else
alias enumStrings = enumIdentifiers!T;
}
///
version(mir_core_test) unittest
{
enum E {z = 1, b = -1, c}
static assert(enumStrings!E == ["z", "b", "c"]);
enum S {a = "A", b = "B", c = ""}
static assert(enumStrings!S == [S.a, S.b, S.c]);
}
/++
Params:
index = enum index `std.traits.EnumMembers!T`
Returns:
A enum value that corresponds to the index.
Note:
The function doesn't check that index is less then `EnumMembers!T.length`.
+/
T unsafeEnumFromIndex(T)(size_t index)
@trusted pure nothrow @nogc
if (is(T == enum))
{
static if (__traits(isIntegral, T))
enum bool fastConv = hasSeqGrow(enumMembers!T);
else
enum bool fastConv = false;
assert(index < enumMembers!T.length);
static if (fastConv)
{
return cast(T) (index + enumMembers!T[0]);
}
else
{
return enumMembers!T[index];
}
}
///
version(mir_core_test)
unittest
{
enum Linear
{
one = 1,
two = 2
}
static assert(is(typeof(unsafeEnumFromIndex!Linear(0)) == Linear));
assert(unsafeEnumFromIndex!Linear(0) == Linear.one);
assert(unsafeEnumFromIndex!Linear(1) == Linear.two);
enum Mixed
{
one = 1,
oneAgain = 1,
two = 2
}
assert(unsafeEnumFromIndex!Mixed(0) == Mixed.one);
assert(unsafeEnumFromIndex!Mixed(1) == Mixed.one);
assert(unsafeEnumFromIndex!Mixed(2) == Mixed.two);
}
/++
Params:
T = enum type to introspect
key = some string that corresponds to some key name of the given enum
index = resulting enum index if this method returns true.
Returns:
boolean whether the key was found in the enum keys and if so, index is set.
+/
template getEnumIndexFromKey(T, bool caseInsensitive = true, getKeysTemplate...)
if (is(T == enum) && getKeysTemplate.length <= 1)
{
///
bool getEnumIndexFromKey(C)(scope const(C)[] key, ref uint index)
@safe pure nothrow @nogc
if (is(C == char) || is(C == wchar) || is(C == dchar))
{
import mir.string_table;
import mir.utility: simpleSort, _expect;
import std.traits: EnumMembers;
import std.meta: staticIndexOf;
alias String = immutable(C)[];
static if (getKeysTemplate.length)
{
alias keysOfImpl = getKeysTemplate[0];
enum String[] keysOf(alias symbol) = keysOfImpl!symbol;
}
else
static if (is(T : W[], W))
enum String[1] keysOf(alias symbol) = [cast(String)symbol];
else
enum String[1] keysOf(alias symbol) = [__traits(identifier, symbol)];
enum keys = () {
String[] keys;
foreach(i, member; EnumMembers!T)
keys ~= keysOf!(EnumMembers!T[i]);
return keys;
} ();
static if (keys.length == 0)
{
return false;
}
else
{
enum indexLength = keys.length + 1;
alias ct = createTable!C;
static immutable table = ct!(keys, caseInsensitive);
static immutable indices = ()
{
minimalSignedIndexType!indexLength[indexLength] indices;
foreach (i, member; EnumMembers!T)
foreach (key; keysOf!(EnumMembers!T[i]))
{
static if (caseInsensitive)
{
key = key.dup.fastToUpperInPlace;
}
indices[table[key]] = i;
}
return indices;
} ();
uint stringId = void;
if (_expect(table.get(key, stringId), true))
{
index = indices[stringId];
return true;
}
return false;
}
}
}
///
unittest
{
enum Short
{
hello,
world
}
enum Long
{
This,
Is,
An,
Enum,
With,
Lots,
Of,
Very,
Long,
EntriesThatArePartiallyAlsoVeryLongInStringLengthAsWeNeedToTestALotOfDifferentCasesThatCouldHappenInRealWorldCode_tm
}
uint i;
assert(getEnumIndexFromKey!Short("hello", i));
assert(i == 0);
assert(getEnumIndexFromKey!Short("world", i));
assert(i == 1);
assert(!getEnumIndexFromKey!Short("foo", i));
assert(getEnumIndexFromKey!Short("HeLlO", i));
assert(i == 0);
assert(getEnumIndexFromKey!Short("WoRLd", i));
assert(i == 1);
assert(!getEnumIndexFromKey!(Short, false)("HeLlO", i));
assert(!getEnumIndexFromKey!(Short, false)("WoRLd", i));
assert(getEnumIndexFromKey!Long("Is", i));
assert(i == 1);
assert(getEnumIndexFromKey!Long("Long", i));
assert(i == 8);
assert(getEnumIndexFromKey!Long("EntriesThatArePartiallyAlsoVeryLongInStringLengthAsWeNeedToTestALotOfDifferentCasesThatCouldHappenInRealWorldCode_tm", i));
assert(i == 9);
assert(!getEnumIndexFromKey!Long("EntriesThatArePartiallyAlsoVeryLongInStringLengthAsWeNeedToTestALotOfDifferentCasesThatCouldHappenInRealWorldCodeatm", i));
assert(!getEnumIndexFromKey!(Long, false)("EntriesThatArePartiallyAlsoVeryLongInStringLengthAsWeNeedToTestALotOfDifferentCasesThatCouldHappenInRealWorldCode_tM", i));
assert(!getEnumIndexFromKey!(Long, false)("entriesThatArePartiallyAlsoVeryLongInStringLengthAsWeNeedToTestALotOfDifferentCasesThatCouldHappenInRealWorldCode_tm", i));
}
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