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Fix Issue 8516 - std.string.representation works incorrect for shared(const(T)) types #742

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merged 1 commit into from Aug 13, 2012
Merged

Fix Issue 8516 - std.string.representation works incorrect for shared(const(T)) types #742

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72 changes: 34 additions & 38 deletions std/string.d
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Expand Up @@ -774,66 +774,62 @@ unittest


/**
* Returns the representation type of a string, which is the same type
* Returns the representation of a string, which has the same type
* as the string except the character type is replaced by $(D ubyte),
* $(D ushort), or $(D uint) depending on the character width.
*
* Example:
----
string s = "hello";
static assert(is(typeof(representation(s)) == immutable(ubyte)[]));
assert(representation(s) is cast(immutable(ubyte)[]) s);
----
*/
auto representation(Char)(Char[] s) pure nothrow
if(isSomeChar!Char)
{
// Get representation type
static if (Char.sizeof == 1) enum t = "ubyte";
else static if (Char.sizeof == 2) enum t = "ushort";
else static if (Char.sizeof == 4) enum t = "uint";
else static assert(false); // can't happen due to isSomeChar!Char

// Get representation qualifier
static if (is(Char == immutable)) enum q = "immutable";
else static if (is(Char == const)) enum q = "const";
else static if (is(Char == shared)) enum q = "shared";
else enum q = "";

// Result type is qualifier(RepType)[]
static if (q.length)
return mixin("cast(" ~ q ~ "(" ~ t ~ ")[]) s");
else
return mixin("cast(" ~ t ~ "[]) s");
}
alias TypeTuple!(ubyte, ushort, uint)[Char.sizeof / 2] U;
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ingenious


unittest
{
auto c = to!(char[])("hello");
static assert(is(typeof(representation(c)) == ubyte[]));
// const and immutable storage classes
static if (is(Char == immutable)) alias immutable(U) T;
else static if (is(Char == const)) alias const(U) T;
else alias U T;

auto w = to!(wchar[])("hello");
static assert(is(typeof(representation(w)) == ushort[]));
// shared storage class (because shared(const(T)) is possible)
static if (is(Char == shared)) alias shared(T) ST;
else alias T ST;

auto d = to!(dchar[])("hello");
static assert(is(typeof(representation(d)) == uint[]));
return cast(ST[]) s;
}

const(char[]) cc = "hello";
static assert(is(typeof(representation(cc)) == const(ubyte)[]));
unittest
{
void test(Char, T)(Char[] str)
{
static assert(is(typeof(representation(str)) == T[]));
assert(representation(str) is cast(T[]) str);
}

const(wchar[]) cw = "hello"w;
static assert(is(typeof(representation(cw)) == const(ushort)[]));
test!(immutable(char) , immutable(ubyte) )("hello" );
test!(immutable(wchar), immutable(ushort))("hello"w);
test!(immutable(dchar), immutable(uint) )("hello"d);

const(dchar[]) cd = "hello"d;
static assert(is(typeof(representation(cd)) == const(uint)[]));
test!(const(char) , const(ubyte) )("hello" );
test!(const(wchar), const(ushort))("hello"w);
test!(const(dchar), const(uint) )("hello"d);

string s = "hello";
static assert(is(typeof(representation(s)) == immutable(ubyte)[]));
test!(char , ubyte )("hello" .dup);
test!(wchar, ushort)("hello"w.dup);
test!(dchar, uint )("hello"d.dup);

wstring iw = "hello"w;
static assert(is(typeof(representation(iw)) == immutable(ushort)[]));
test!(shared(char) , shared(ubyte) )(cast(shared) "hello" .dup);
test!(shared(wchar), shared(ushort))(cast(shared) "hello"w.dup);
test!(shared(dchar), shared(uint) )(cast(shared) "hello"d.dup);

dstring id = "hello"d;
static assert(is(typeof(representation(id)) == immutable(uint)[]));
test!(const(shared(char)) , const(shared(ubyte)) )("hello" );
test!(const(shared(wchar)), const(shared(ushort)))("hello"w);
test!(const(shared(dchar)), const(shared(uint)) )("hello"d);
}


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