Refactor: Remove all sync generators

Author: dipu-bd

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 2.4.1
+
+- Refactor: Remove all sync generator to improve runtime.
+
 # 2.4.0
 
 - **Breaking Changes**: Uses string for salt and hash in `CryptData`

lib/src/codecs/base16.dart

@@ -1,6 +1,8 @@
 // Copyright (c) 2023, Sudipto Chandra
 // All rights reserved. Check LICENSE file for details.
 
+import 'dart:typed_data';
+
 import 'package:hashlib_codecs/src/core/byte.dart';
 import 'package:hashlib_codecs/src/core/codec.dart';
 
@@ -21,28 +23,33 @@ class _Base16Encoder extends ByteEncoder {
   static const lower = _Base16Encoder._(_smallA - 10);
 
   @override
-  Iterable<int> convert(Iterable<int> input) sync* {
-    int a, b;
-    for (int x in input) {
+  Iterable<int> convert(Iterable<int> input) {
+    int i, p, x, a, b;
+    List<int> list = input is List<int> ? input : input.toList();
+    var result = Uint8List(list.length << 1);
+    for (i = p = 0; p < list.length; p++, i += 2) {
+      x = list[p];
       a = (x >>> 4) & 0xF;
       b = x & 0xF;
       a += a < 10 ? _zero : startCode;
       b += b < 10 ? _zero : startCode;
-      yield a;
-      yield b;
+      result[i] = a;
+      result[i + 1] = b;
     }
+    return result;
   }
 }
 
 class _Base16Decoder extends ByteDecoder {
   const _Base16Decoder() : super(bits: 4);
 
   @override
-  Iterable<int> convert(Iterable<int> input) sync* {
+  Iterable<int> convert(Iterable<int> input) {
     bool t;
     int p, x, y;
     p = 0;
     t = false;
+    List<int> out = <int>[];
     for (y in input) {
       if (y >= _smallA) {
         x = y - _smallA + 10;
@@ -57,7 +64,7 @@ class _Base16Decoder extends ByteDecoder {
         throw FormatException('Invalid character $y');
       }
       if (t) {
-        yield ((p << 4) | x);
+        out.add((p << 4) | x);
         p = 0;
         t = false;
       } else {
@@ -66,8 +73,9 @@ class _Base16Decoder extends ByteDecoder {
       }
     }
     if (t) {
-      yield p;
+      out.add(p);
     }
+    return out;
   }
 }
 

lib/src/codecs/base2.dart

@@ -1,6 +1,8 @@
 // Copyright (c) 2023, Sudipto Chandra
 // All rights reserved. Check LICENSE file for details.
 
+import 'dart:typed_data';
+
 import 'package:hashlib_codecs/src/core/byte.dart';
 import 'package:hashlib_codecs/src/core/codec.dart';
 
@@ -14,25 +16,31 @@ class _Base2Encoder extends ByteEncoder {
   const _Base2Encoder() : super(bits: 2);
 
   @override
-  Iterable<int> convert(Iterable<int> input) sync* {
-    for (int x in input) {
-      yield _zero + ((x >>> 7) & 1);
-      yield _zero + ((x >>> 6) & 1);
-      yield _zero + ((x >>> 5) & 1);
-      yield _zero + ((x >>> 4) & 1);
-      yield _zero + ((x >>> 3) & 1);
-      yield _zero + ((x >>> 2) & 1);
-      yield _zero + ((x >>> 1) & 1);
-      yield _zero + ((x) & 1);
+  Iterable<int> convert(Iterable<int> input) {
+    int i, p, x;
+    List<int> list = input is List<int> ? input : input.toList();
+    var result = Uint8List(list.length << 3);
+    for (i = p = 0; p < list.length; p++, i += 8) {
+      x = list[p];
+      result[i] = _zero + ((x >>> 7) & 1);
+      result[i + 1] = _zero + ((x >>> 6) & 1);
+      result[i + 2] = _zero + ((x >>> 5) & 1);
+      result[i + 3] = _zero + ((x >>> 4) & 1);
+      result[i + 4] = _zero + ((x >>> 3) & 1);
+      result[i + 5] = _zero + ((x >>> 2) & 1);
+      result[i + 6] = _zero + ((x >>> 1) & 1);
+      result[i + 7] = _zero + ((x) & 1);
     }
+    return result;
   }
 }
 
 class _Base2Decoder extends ByteDecoder {
   const _Base2Decoder() : super(bits: 2);
 
   @override
-  Iterable<int> convert(Iterable<int> input) sync* {
+  Iterable<int> convert(Iterable<int> input) {
+    List<int> out = <int>[];
     int p, n, x, y;
     p = n = 0;
     for (y in input) {
@@ -44,14 +52,15 @@ class _Base2Decoder extends ByteDecoder {
         p = (p << 1) | x;
         n++;
       } else {
-        yield p;
+        out.add(p);
         n = 1;
         p = x;
       }
     }
     if (n > 0) {
-      yield p;
+      out.add(p);
     }
+    return out;
   }
 }
 

lib/src/codecs/bigint.dart

@@ -19,7 +19,7 @@ class _BigIntLSBFirstEncoder extends BigIntEncoder {
   @override
   BigInt convert(Iterable<int> input) {
     int a, b, i, j;
-    var out = <int>[];
+    List<int> out = <int>[];
     for (int x in input) {
       a = (x >>> 4) & 0xF;
       b = x & 0xF;
@@ -48,28 +48,29 @@ class _BigIntLSBFirstDecoder extends BigIntDecoder {
   const _BigIntLSBFirstDecoder();
 
   @override
-  Iterable<int> convert(BigInt input) sync* {
+  Iterable<int> convert(BigInt input) {
     if (input.isNegative) {
       throw FormatException('Negative numbers are not supported');
     }
     if (input == BigInt.zero) {
-      yield 0;
-      return;
+      return [0];
     }
     int i, a, b;
+    List<int> out = <int>[];
     var bytes = input.toRadixString(16).codeUnits;
     for (i = bytes.length - 2; i >= 0; i -= 2) {
       a = bytes[i];
       b = bytes[i + 1];
       a -= a < _smallA ? _zero : _smallA - 10;
       b -= b < _smallA ? _zero : _smallA - 10;
-      yield (a << 4) | b;
+      out.add((a << 4) | b);
     }
     if (i == -1) {
       a = bytes[0];
       a -= a < _smallA ? _zero : _smallA - 10;
-      yield a;
+      out.add(a);
     }
+    return out;
   }
 }
 
@@ -83,7 +84,7 @@ class _BigIntMSBFirstEncoder extends BigIntEncoder {
   @override
   BigInt convert(Iterable<int> input) {
     int a, b;
-    var out = <int>[];
+    List<int> out = <int>[];
     for (int x in input) {
       a = (x >>> 4) & 0xF;
       b = x & 0xF;
@@ -103,31 +104,32 @@ class _BigIntMSBFirstDecoder extends BigIntDecoder {
   const _BigIntMSBFirstDecoder();
 
   @override
-  Iterable<int> convert(BigInt input) sync* {
+  Iterable<int> convert(BigInt input) {
     if (input.isNegative) {
       throw FormatException('Negative numbers are not supported');
     }
     if (input == BigInt.zero) {
-      yield 0;
-      return;
+      return [0];
     }
     int i, a, b, n;
+    List<int> out = <int>[];
     var bytes = input.toRadixString(16).codeUnits;
     n = bytes.length;
     i = 1;
     if (n & 1 == 1) {
       a = bytes[0];
       a -= a < _smallA ? _zero : _smallA - 10;
-      yield a;
+      out.add(a);
       i++;
     }
     for (; i < n; i += 2) {
       a = bytes[i - 1];
       b = bytes[i];
       a -= a < _smallA ? _zero : _smallA - 10;
       b -= b < _smallA ? _zero : _smallA - 10;
-      yield (a << 4) | b;
+      out.add((a << 4) | b);
     }
+    return out;
   }
 }
 

lib/src/core/alphabet.dart

@@ -34,17 +34,15 @@ class AlphabetEncoder extends BitEncoder {
   int get target => bits;
 
   @override
-  Iterable<int> convert(Iterable<int> input) sync* {
-    int l = 0;
-    for (final x in super.convert(input)) {
-      yield alphabet[x];
-      l += target;
-    }
+  Iterable<int> convert(Iterable<int> input) {
+    var out = super.convert(input).map((x) => alphabet[x]).toList();
+    int l = out.length * target;
     if (padding != null) {
       for (; (l & 7) != 0; l += target) {
-        yield padding!;
+        out.add(padding!);
       }
     }
+    return out;
   }
 }
 

lib/src/core/byte.dart

@@ -7,9 +7,6 @@ import 'encoder.dart';
 class ByteEncoder extends BitEncoder {
   final int bits;
 
-  @override
-  final int source = 8;
-
   /// Creates a new [ByteEncoder] instance.
   ///
   /// Parameters:
@@ -18,16 +15,16 @@ class ByteEncoder extends BitEncoder {
     required this.bits,
   });
 
+  @override
+  final int source = 8;
+
   @override
   int get target => bits;
 }
 
 class ByteDecoder extends BitDecoder {
   final int bits;
 
-  @override
-  final int target = 8;
-
   /// Creates a new [ByteDecoder] instance.
   ///
   /// Parameters:
@@ -38,4 +35,7 @@ class ByteDecoder extends BitDecoder {
 
   @override
   int get source => bits;
+
+  @override
+  final int target = 8;
 }

lib/src/core/decoder.dart

@@ -1,6 +1,8 @@
 // Copyright (c) 2023, Sudipto Chandra
 // All rights reserved. Check LICENSE file for details.
 
+import 'dart:typed_data';
+
 import 'codec.dart';
 
 abstract class BitDecoder extends HashlibConverter {
@@ -16,30 +18,36 @@ abstract class BitDecoder extends HashlibConverter {
   ///
   /// After consuming all of input sequence, if there are some non-zero partial
   /// word remains, it will throw [FormatException].
+  // TODO: sync is slow. use typed list
   @override
-  Iterable<int> convert(Iterable<int> encoded) sync* {
-    if (source < 2 || source > 64) {
+  Iterable<int> convert(Iterable<int> encoded) {
+    int x, p, s, t, l, n, sb, tb;
+    sb = source;
+    tb = target;
+    if (sb < 2 || sb > 64) {
       throw ArgumentError('The source bit length should be between 2 to 64');
     }
-    if (target < 2 || target > 64) {
+    if (tb < 2 || tb > 64) {
       throw ArgumentError('The target bit length should be between 2 to 64');
     }
 
-    int x, p, n, s, t;
-    p = n = t = 0;
-    s = 1 << (source - 1);
-    s = s ^ (s - 1);
+    List<int> list = encoded is List<int> ? encoded : List<int>.of(encoded);
+    l = list.length * sb;
+    var out = Uint8List(l ~/ tb);
 
     // generate words from the input bits
-    for (x in encoded) {
+    p = n = t = l = 0;
+    s = 1 << (sb - 1);
+    s = s ^ (s - 1);
+    for (x in list) {
       if (x < 0 || x > s) break;
-      p = (p << source) ^ x;
-      t = (t << source) ^ s;
-      n += source;
-      while (n >= target) {
-        n -= target;
-        yield p >>> n;
-        t >>>= target;
+      p = (p << sb) ^ x;
+      t = (t << sb) ^ s;
+      n += sb;
+      while (n >= tb) {
+        n -= tb;
+        out[l++] = p >>> n;
+        t >>>= tb;
         p &= t;
       }
     }
@@ -48,5 +56,7 @@ abstract class BitDecoder extends HashlibConverter {
     if (p > 0) {
       throw FormatException('Invalid length');
     }
+
+    return Uint8List.view(out.buffer, 0, l);
   }
 }