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One more pass through __cmp #1787
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| Original file line number | Diff line number | Diff line change |
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@@ -3241,181 +3241,125 @@ template RTInfo(T) | |
| enum RTInfo = null; | ||
| } | ||
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| // Compare class and interface objects for ordering. | ||
| private int __cmp(Obj)(Obj lhs, Obj rhs) | ||
| if (is(Obj : Object)) | ||
| { | ||
| if (lhs is rhs) | ||
| return 0; | ||
| // Regard null references as always being "less than" | ||
| if (!lhs) | ||
| return -1; | ||
| if (!rhs) | ||
| return 1; | ||
| return lhs.opCmp(rhs); | ||
| } | ||
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| int __cmp(T)(const T[] lhs, const T[] rhs) @trusted | ||
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Author
There was a problem hiding this comment. @CyberShadow ok, so this overload should generate only one copy per scalar type. There are still a couple of opportunities:
I've let these be because they're relatively rare.
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Are you sure? This doesn't even compile: int __cmp(T)(const T[] lhs, const T[] rhs) @trusted {}
int[] a;
immutable(int)[] b;
__cmp(a, b);
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Author
There was a problem hiding this comment. @CyberShadow take that back, I decided to implement the whole shebang anyway, it doesn't take much code.
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Author
There was a problem hiding this comment. worksforme: void main()
{
int __cmp(T)(const T[] lhs, const T[] rhs) @trusted { return 0; }
int[] a;
immutable(int)[] b;
__cmp(a, b);
}
Member
There was a problem hiding this comment. Nice but constness issue remains, I think that would be good as a test BTW. |
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| if (__traits(isScalar, T)) | ||
| { | ||
| // Compute U as the implementation type for T | ||
| static if (is(T == ubyte) || is(T == void) || is(T == bool)) | ||
| alias U = char; | ||
| else static if (is(T == wchar)) | ||
| alias U = ushort; | ||
| else static if (is(T == dchar)) | ||
| alias U = uint; | ||
| else static if (is(T == ifloat)) | ||
| alias U = float; | ||
| else static if (is(T == idouble)) | ||
| alias U = double; | ||
| else static if (is(T == ireal)) | ||
| alias U = real; | ||
| else | ||
| alias U = T; | ||
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| static if (is(U == char)) | ||
| { | ||
| import core.internal.string : dstrcmp; | ||
| return dstrcmp(cast(char[]) lhs, cast(char[]) rhs); | ||
| } | ||
| else static if (!is(U == T)) | ||
| { | ||
| // Reuse another implementation | ||
| return __cmp(cast(U[]) lhs, cast(U[]) rhs); | ||
| } | ||
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| else | ||
| { | ||
| immutable len = lhs.length <= rhs.length ? lhs.length : rhs.length; | ||
| foreach (const u; 0 .. len) | ||
| { | ||
| static if (__traits(isFloating, T)) | ||
| { | ||
| immutable a = lhs.ptr[u], b = rhs.ptr[u]; | ||
| static if (is(T == cfloat) || is(T == cdouble) | ||
| || is(T == creal)) | ||
| { | ||
| // Use rt.cmath2._Ccmp instead ? | ||
| auto r = (a.re > b.re) - (a.re < b.re); | ||
| if (!r) r = (a.im > b.im) - (a.im < b.im); | ||
| } | ||
| else | ||
| { | ||
| const r = (a > b) - (a < b); | ||
| } | ||
| if (r) return r; | ||
| } | ||
| else if (lhs.ptr[u] != rhs.ptr[u]) | ||
| return lhs.ptr[u] < rhs.ptr[u] ? -1 : 1; | ||
| } | ||
| return lhs.length < rhs.length ? -1 : (lhs.length > rhs.length); | ||
| } | ||
| } | ||
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| // This function is called by the compiler when dealing with array | ||
| // comparisons in the semantic analysis phase of CmpExp. The ordering | ||
| // comparison is lowered to a call to this template. | ||
| int __cmp(T1, T2)(T1[] s1, T2[] s2) | ||
| if (!__traits(isScalar, T1)) | ||
| { | ||
| import core.internal.traits : Unqual; | ||
| alias U1 = Unqual!T1; | ||
| alias U2 = Unqual!T2; | ||
| static assert(is(U1 == U2), "Internal error."); | ||
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| static @trusted ref R at(R)(R[] r, size_t i) { return r.ptr[i]; } | ||
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| // All unsigned byte-wide types = > dstrcmp | ||
| immutable len = s1.length <= s2.length ? s1.length : s2.length; | ||
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| foreach (const u; 0 .. len) | ||
| { | ||
| static if (__traits(compiles, __cmp(at(s1, u), at(s2, u)))) | ||
| { | ||
| auto c = __cmp(at(s1, u), at(s2, u)); | ||
| if (c != 0) | ||
| return c; | ||
| } | ||
| else static if (__traits(compiles, at(s1, u).opCmp(at(s2, u)))) | ||
| { | ||
| auto c = at(s1, u).opCmp(at(s2, u)); | ||
| if (c != 0) | ||
| return c; | ||
| } | ||
| else static if (__traits(compiles, at(s1, u) < at(s2, u))) | ||
| { | ||
| if (at(s1, u) != at(s2, u)) | ||
| return at(s1, u) < at(s2, u) ? -1 : 1; | ||
| } | ||
| else | ||
| { | ||
| // TODO: fix this legacy bad behavior, see | ||
| // https://issues.dlang.org/show_bug.cgi?id=17244 | ||
| import core.stdc.string : memcmp; | ||
| return (() @trusted => memcmp(&at(s1, u), &at(s2, u), U1.sizeof))(); | ||
| } | ||
| } | ||
| return s1.length < s2.length ? -1 : (s1.length > s2.length); | ||
| } | ||
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| // integral types | ||
| @safe unittest | ||
| { | ||
| void compareMinMax(T)() | ||
| { | ||
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@@ -3438,7 +3382,7 @@ unittest | |
| } | ||
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| // char types (dstrcmp) | ||
| @safe unittest | ||
| { | ||
| void compareMinMax(T)() | ||
| { | ||
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@@ -3461,7 +3405,7 @@ unittest | |
| } | ||
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| // fp types | ||
| @safe unittest | ||
| { | ||
| void compareMinMax(T)() | ||
| { | ||
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@@ -3487,27 +3431,47 @@ unittest | |
| compareMinMax!(immutable real); | ||
| } | ||
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| // objects | ||
| @safe unittest | ||
| { | ||
| class C | ||
| { | ||
| int i; | ||
| this(int i) { this.i = i; } | ||
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| override int opCmp(Object c) const @safe | ||
| { | ||
| return i - (cast(C)c).i; | ||
| } | ||
| } | ||
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| auto c1 = new C(1); | ||
| auto c2 = new C(2); | ||
| assert(__cmp(c1, null) > 0); | ||
| assert(__cmp(null, c1) < 0); | ||
| assert(__cmp(c1, c1) == 0); | ||
| assert(__cmp(c1, c2) < 0); | ||
| assert(__cmp(c2, c1) > 0); | ||
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| assert(__cmp([c1, c1][], [c2, c2][]) < 0); | ||
| assert(__cmp([c2, c2], [c1, c1]) > 0); | ||
| } | ||
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| // structs | ||
| @safe unittest | ||
| { | ||
| struct C | ||
| { | ||
| ubyte i; | ||
| this(ubyte i) { this.i = i; } | ||
| } | ||
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| auto c1 = C(1); | ||
| auto c2 = C(2); | ||
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| assert(__cmp([c1, c1][], [c2, c2][]) < 0); | ||
| assert(__cmp([c2, c2], [c1, c1]) > 0); | ||
| } | ||
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| // Helper functions | ||
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This (dstrcmp change) really ought to be in its own commit... currently there is no rationale. I see it's to add CTFE support?
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Affirmative.