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std.uni: optimize simpleCaseTable

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Cuts size of simpleCaseTable entries in half (8 -> 4 bytes), reducing table size from 24 Kb to 12 Kb.
Still only 22 out of 32 bits per entry are actually used, so could be optimized further.
Using plain integers saves 10 ms semantic2 compile time.
This commit is contained in:
Dennis Korpel 2024-01-06 15:05:35 +01:00 • committed by The Dlang Bot
parent 733d335268
commit 135e9ad193
3 changed files with 436 additions and 790 deletions
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61
tools/unicode_table_generator.d
View file

@ -117,26 +117,37 @@ struct FullCaseEntry
}
}
enum mixedCCEntry = `
/// 8 byte easy SimpleCaseEntry, will be compressed to SCE which bit packs values to 4 bytes
struct SimpleCaseEntry
{
uint ch;
ubyte n, bucket;// n - number in bucket
ubyte n; // number in bucket
ubyte size;
bool isLower;
bool isUpper;
}
pure nothrow @nogc:
enum mixedCCEntry = `
/// Simple Case Entry, wrapper around uint to extract bit fields from simpleCaseTable()
struct SCE
{
uint x;
@property ubyte size() const
nothrow @nogc pure @safe:
this(uint x)
{
return bucket & 0x3F;
this.x = x;
}
@property auto isLower() const
this(uint ch, ubyte n, ubyte size)
{
return bucket & 0x40;
}
@property auto isUpper() const
{
return bucket & 0x80;
this.x = ch | n << 20 | size << 24;
}
int ch() const { return this.x & 0x1FFFF; }
int n() const { return (this.x >> 20) & 0xF; }
int size() const { return this.x >> 24; }
}
/// Bit backed FullCaseEntry
@ -432,10 +443,13 @@ void loadCaseFolding(string f)
sort(entry[0 .. size]);
foreach (i, value; entry[0 .. size])
{
auto withFlags = cast(ubyte) size | (value in lowerCaseSet ? 0x40 : 0)
| (value in upperCaseSet ? 0x80 : 0);
simpleTable ~= SimpleCaseEntry(value, cast(ubyte) i,
cast(ubyte) withFlags);
simpleTable ~= SimpleCaseEntry(
value,
cast(ubyte) i,
cast(ubyte) size,
cast(bool) (value in lowerCaseSet),
cast(bool) (value in upperCaseSet)
);
}
}
@ -882,17 +896,22 @@ void writeCaseFolding(File sink)
{
write(mixedCCEntry);
writeln("@property immutable(SimpleCaseEntry[]) simpleCaseTable()");
writeln("SCE simpleCaseTable(size_t i)");
writeln("{");
writeln("alias SCE = SimpleCaseEntry;");
writeln("static immutable SCE[] t = [");
writef("static immutable uint[%d] t = [", simpleTable.length);
foreach (i, v; simpleTable)
{
writef("SCE(0x%04x, %s, 0x%0x),", v.ch, v.n, v.bucket);
if (i % 4 == 0) writeln();
if (i % 8 == 0) writeln();
writef("0x%08X,", SCE(v.ch, v.n, v.size).x);
}
// Inspect max integer size, so efficient bit packing can be found:
stderr.writefln("max n: %X", simpleTable.maxElement!(x => x.n).n); // n: 2-bit
stderr.writefln("max ch: %X", simpleTable.maxElement!(x => x.ch).ch); // ch: 17-bit
stderr.writefln("max size: %X", simpleTable.maxElement!(x => x.size).size); // size: 3-bit
writeln("];");
writeln("return t;");
writeln("return SCE(t[i]);");
writeln("}");
writeln("@property FCE fullCaseTable(size_t index) nothrow @nogc @safe pure");
writeln("{");