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Fix issue - sort should move elements instead of copy...

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... because it's reordering elements instead. Calling `opAssign` on
unitialized members might also  cause errors if the implementation
requires a valid instance (see `TimSortImpl`)
This commit is contained in:
MoonlightSentinel 2020-06-10 12:49:09 +02:00
parent 95e8303068
commit 574f1f594f
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GPG key ID: 1A1A60AECDC956AB
1 changed files with 103 additions and 25 deletions
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128
std/algorithm/sorting.d
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@ -1698,17 +1698,30 @@ private void shortSort(alias less, Range)(Range r)
auto t = r[0]; if (pred(t, r[0])) r[0] = r[0]; auto t = r[0]; if (pred(t, r[0])) r[0] = r[0];
}))) // Can we afford to temporarily invalidate the array? }))) // Can we afford to temporarily invalidate the array?
{ {
import core.lifetime : move;
size_t j = i + 1; size_t j = i + 1;
auto temp = r[i]; static if (hasLvalueElements!Range)
auto temp = move(r[i]);
else
auto temp = r[i];
if (pred(r[j], temp)) if (pred(r[j], temp))
{ {
do do
{ {
r[j - 1] = r[j]; static if (hasLvalueElements!Range)
trustedMoveEmplace(r[j], r[j - 1]);
else
r[j - 1] = r[j];
++j; ++j;
} }
while (j < r.length && pred(r[j], temp)); while (j < r.length && pred(r[j], temp));
r[j - 1] = temp;
static if (hasLvalueElements!Range)
trustedMoveEmplace(temp, r[j - 1]);
else
r[j - 1] = move(temp);
} }
} }
else else
@ -1725,6 +1738,13 @@ private void shortSort(alias less, Range)(Range r)
} }
} }
/// @trusted wrapper for moveEmplace
private void trustedMoveEmplace(T)(ref T source, ref T target) @trusted
{
import core.lifetime : moveEmplace;
moveEmplace(source, target);
}
@safe unittest @safe unittest
{ {
import std.random : Random = Xorshift, uniform; import std.random : Random = Xorshift, uniform;
@ -2274,9 +2294,9 @@ private template TimSortImpl(alias pred, R)
alias T = ElementType!R; alias T = ElementType!R;
alias less = binaryFun!pred; alias less = binaryFun!pred;
alias greater = (a, b) => less(b, a); bool greater()(auto ref T a, auto ref T b) { return less(b, a); }
alias greaterEqual = (a, b) => !less(a, b); bool greaterEqual()(auto ref T a, auto ref T b) { return !less(a, b); }
alias lessEqual = (a, b) => !less(b, a); bool lessEqual()(auto ref T a, auto ref T b) { return !less(b, a); }
enum minimalMerge = 128; enum minimalMerge = 128;
enum minimalGallop = 7; enum minimalGallop = 7;
@ -2448,8 +2468,17 @@ private template TimSortImpl(alias pred, R)
//moveAll(retro(range[lower .. sortedLen]), //moveAll(retro(range[lower .. sortedLen]),
// retro(range[lower+1 .. sortedLen+1])); // retro(range[lower+1 .. sortedLen+1]));
for (upper=sortedLen; upper > lower; upper--) for (upper=sortedLen; upper > lower; upper--)
range[upper] = range.moveAt(upper - 1); {
range[lower] = move(item); static if (hasLvalueElements!R)
move(range[upper -1], range[upper]);
else
range[upper] = range.moveAt(upper - 1);
}
static if (hasLvalueElements!R)
move(item, range[lower]);
else
range[lower] = move(item);
} }
} }
@ -2555,7 +2584,7 @@ private template TimSortImpl(alias pred, R)
copy(range[0 .. mid], temp); copy(range[0 .. mid], temp);
// Move first element into place // Move first element into place
range[0] = range[mid]; moveEntry(range, mid, range, 0);
size_t i = 1, lef = 0, rig = mid + 1; size_t i = 1, lef = 0, rig = mid + 1;
size_t count_lef, count_rig; size_t count_lef, count_rig;
@ -2572,14 +2601,14 @@ private template TimSortImpl(alias pred, R)
{ {
if (lessEqual(temp[lef], range[rig])) if (lessEqual(temp[lef], range[rig]))
{ {
range[i++] = temp[lef++]; moveEntry(temp, lef++, range, i++);
if (lef >= lef_end) break outer; if (lef >= lef_end) break outer;
++count_lef; ++count_lef;
count_rig = 0; count_rig = 0;
} }
else else
{ {
range[i++] = range[rig++]; moveEntry(range, rig++, range, i++);
if (rig >= range.length) break outer; if (rig >= range.length) break outer;
count_lef = 0; count_lef = 0;
++count_rig; ++count_rig;
@ -2590,14 +2619,14 @@ private template TimSortImpl(alias pred, R)
do do
{ {
count_lef = gallopForwardUpper(temp[lef .. $], range[rig]); count_lef = gallopForwardUpper(temp[lef .. $], range[rig]);
foreach (j; 0 .. count_lef) range[i++] = temp[lef++]; foreach (j; 0 .. count_lef) moveEntry(temp, lef++, range, i++);
if (lef >= temp.length) break outer; if (lef >= temp.length) break outer;
count_rig = gallopForwardLower(range[rig .. range.length], temp[lef]); count_rig = gallopForwardLower(range[rig .. range.length], temp[lef]);
foreach (j; 0 .. count_rig) range[i++] = range[rig++]; foreach (j; 0 .. count_rig) moveEntry(range, rig++, range, i++);
if (rig >= range.length) while (true) if (rig >= range.length) while (true)
{ {
range[i++] = temp[lef++]; moveEntry(temp, lef++, range, i++);
if (lef >= temp.length) break outer; if (lef >= temp.length) break outer;
} }
@ -2610,11 +2639,11 @@ private template TimSortImpl(alias pred, R)
// Move remaining elements from right // Move remaining elements from right
while (rig < range.length) while (rig < range.length)
range[i++] = range[rig++]; moveEntry(range, rig++, range, i++);
// Move remaining elements from left // Move remaining elements from left
while (lef < temp.length) while (lef < temp.length)
range[i++] = temp[lef++]; moveEntry(temp, lef++, range, i++);
return minGallop > 0 ? minGallop : 1; return minGallop > 0 ? minGallop : 1;
} }
@ -2641,7 +2670,7 @@ private template TimSortImpl(alias pred, R)
copy(range[mid .. range.length], temp); copy(range[mid .. range.length], temp);
// Move first element into place // Move first element into place
range[range.length - 1] = range[mid - 1]; moveEntry(range, mid - 1, range, range.length - 1);
size_t i = range.length - 2, lef = mid - 2, rig = temp.length - 1; size_t i = range.length - 2, lef = mid - 2, rig = temp.length - 1;
size_t count_lef, count_rig; size_t count_lef, count_rig;
@ -2657,19 +2686,19 @@ private template TimSortImpl(alias pred, R)
{ {
if (greaterEqual(temp[rig], range[lef])) if (greaterEqual(temp[rig], range[lef]))
{ {
range[i--] = temp[rig]; moveEntry(temp, rig, range, i--);
if (rig == 1) if (rig == 1)
{ {
// Move remaining elements from left // Move remaining elements from left
while (true) while (true)
{ {
range[i--] = range[lef]; moveEntry(range, lef, range, i--);
if (lef == 0) break; if (lef == 0) break;
--lef; --lef;
} }
// Move last element into place // Move last element into place
range[i] = temp[0]; moveEntry(temp, 0, range, i);
break outer; break outer;
} }
@ -2679,10 +2708,10 @@ private template TimSortImpl(alias pred, R)
} }
else else
{ {
range[i--] = range[lef]; moveEntry(range, lef, range, i--);
if (lef == 0) while (true) if (lef == 0) while (true)
{ {
range[i--] = temp[rig]; moveEntry(temp, rig, range, i--);
if (rig == 0) break outer; if (rig == 0) break outer;
--rig; --rig;
} }
@ -2698,7 +2727,7 @@ private template TimSortImpl(alias pred, R)
count_rig = rig - gallopReverseLower(temp[0 .. rig], range[lef]); count_rig = rig - gallopReverseLower(temp[0 .. rig], range[lef]);
foreach (j; 0 .. count_rig) foreach (j; 0 .. count_rig)
{ {
range[i--] = temp[rig]; moveEntry(temp, rig, range, i--);
if (rig == 0) break outer; if (rig == 0) break outer;
--rig; --rig;
} }
@ -2706,10 +2735,10 @@ private template TimSortImpl(alias pred, R)
count_lef = lef - gallopReverseUpper(range[0 .. lef], temp[rig]); count_lef = lef - gallopReverseUpper(range[0 .. lef], temp[rig]);
foreach (j; 0 .. count_lef) foreach (j; 0 .. count_lef)
{ {
range[i--] = range[lef]; moveEntry(range, lef, range, i--);
if (lef == 0) while (true) if (lef == 0) while (true)
{ {
range[i--] = temp[rig]; moveEntry(temp, rig, range, i--);
if (rig == 0) break outer; if (rig == 0) break outer;
--rig; --rig;
} }
@ -2806,6 +2835,21 @@ private template TimSortImpl(alias pred, R)
alias gallopForwardUpper = gallopSearch!(false, true); alias gallopForwardUpper = gallopSearch!(false, true);
alias gallopReverseLower = gallopSearch!( true, false); alias gallopReverseLower = gallopSearch!( true, false);
alias gallopReverseUpper = gallopSearch!( true, true); alias gallopReverseUpper = gallopSearch!( true, true);
/// Helper method that moves from[fIdx] into to[tIdx] if both are lvalues and
/// uses a plain assignment if not (necessary for backwards compatibility)
void moveEntry(X, Y)(ref X from, const size_t fIdx, ref Y to, const size_t tIdx)
{
// This template is instantiated with different combinations of range (R) and temp (T[]).
// T[] obviously has lvalue-elements, so checking R should be enough here
static if (hasLvalueElements!R)
{
import core.lifetime : move;
move(from[fIdx], to[tIdx]);
}
else
to[tIdx] = from[fIdx];
}
} }
@safe unittest @safe unittest
@ -2918,6 +2962,40 @@ private template TimSortImpl(alias pred, R)
sort!("a < b", SwapStrategy.stable)(arr); sort!("a < b", SwapStrategy.stable)(arr);
} }
@safe unittest
{
static struct NoCopy
{
pure nothrow @nogc @safe:
int key;
this(scope const ref NoCopy)
{
assert(false, "Tried to copy struct!");
}
ref opAssign()(scope const auto ref NoCopy other)
{
assert(false, "Tried to copy struct!");
}
this(this) {}
}
static NoCopy[] makeArray(const size_t size)
{
NoCopy[] array = new NoCopy[](size);
foreach (const i, ref t; array[0..$/2]) t.key = cast(int) (size - i);
foreach (const i, ref t; array[$/2..$]) t.key = cast(int) i;
return array;
}
alias cmp = (ref NoCopy a, ref NoCopy b) => a.key < b.key;
enum minMerge = TimSortImpl!(cmp, NoCopy[]).minimalMerge;
sort!(cmp, SwapStrategy.unstable)(makeArray(20));
sort!(cmp, SwapStrategy.stable)(makeArray(minMerge - 5));
sort!(cmp, SwapStrategy.stable)(makeArray(minMerge + 5));
}
// schwartzSort // schwartzSort
/** /**
Alternative sorting method that should be used when comparing keys involves an Alternative sorting method that should be used when comparing keys involves an