pkg/analyzer/tool/blake3/generate.dart

// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// Generates the fixed-schedule, unrolled scalar BLAKE3 compression kernel.
library;

import 'dart:io';

void main() {
  const permutation = [2, 6, 3, 10, 7, 0, 4, 13, 1, 11, 12, 5, 9, 14, 15, 8];
  const groups = [
    (0, 4, 8, 12),
    (1, 5, 9, 13),
    (2, 6, 10, 14),
    (3, 7, 11, 15),
    (0, 5, 10, 15),
    (1, 6, 11, 12),
    (2, 7, 8, 13),
    (3, 4, 9, 14),
  ];
  var out = StringBuffer('''
// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// Generated by pkg/analyzer/tool/blake3/generate.dart. Do not edit.

part of 'blake3.dart';
''');

  out.write('''
/// Compresses one 64-byte block with four independent scalar chains.
final class _ScalarBlake3 extends _Blake3Base implements ScalarBlake3 {
@override
void _compress(Uint32List cv, Uint32List words, int offset,
    int counter, int blockLength, int flags) {
''');
  for (var i = 0; i < 8; i++) {
    out.writeln('var v$i = cv[$i];');
  }
  for (var i = 8; i < 12; i++) {
    out.writeln('var v$i = _blake3Iv[${i - 8}];');
  }
  out.write('''
var v12 = counter & 0xffffffff;
var v13 = counter >>> 32;
var v14 = blockLength;
var v15 = flags;
''');
  for (var i = 0; i < 16; i++) {
    out.writeln('var m$i = words[offset + $i];');
  }
  var schedule = List.generate(16, (i) => i);
  for (var round = 0; round < 7; round++) {
    out.writeln();
    out.writeln('// Round ${round + 1}.');
    for (var (j, (a, b, c, d)) in groups.indexed) {
      if (j > 0) {
        out.writeln();
      }
      out.writeln('// g($a, $b, $c, $d), permutation #$round');
      for (var (word, r1, r2) in [
        (schedule[2 * j], 16, 12),
        (schedule[2 * j + 1], 8, 7),
      ]) {
        out.write('''
v$a = (v$a + v$b + m$word) & 0xffffffff;
v$d ^= v$a;
v$d = ((v$d >>> $r1) | (v$d << ${32 - r1})) & 0xffffffff;
v$c = (v$c + v$d) & 0xffffffff;
v$b ^= v$c;
v$b = ((v$b >>> $r2) | (v$b << ${32 - r2})) & 0xffffffff;
''');
      }
    }
    schedule = [for (var i in permutation) schedule[i]];
  }
  for (var i = 0; i < 8; i++) {
    out.writeln('cv[$i] = v$i ^ v${i + 8};');
  }
  out.write('''
}
}
''');
  var output = File.fromUri(
    Platform.script.resolve(
      '../../lib/src/utilities/hash/blake3_scalar_compression.dart',
    ),
  );
  output.writeAsStringSync(out.toString());
}