[ZLIB] Add support for windowBits, memLevel, raw

sdk/lib/io/data_transformer.dart

Index: sdk/lib/io/data_transformer.dart
diff --git a/sdk/lib/io/data_transformer.dart b/sdk/lib/io/data_transformer.dart
index 79df03cc140dfac3b857a07f297157d3dd0f219d..95ae03f0e4fb66414c70f3ef30d966aa202c110a 100644
--- a/sdk/lib/io/data_transformer.dart
+++ b/sdk/lib/io/data_transformer.dart
@@ -22,23 +22,51 @@ class ZLibCodec extends Codec<List<int>, List<int>> {
   final int level;
 
   /**
+  * The windowBits parameter is the base two logarithm of the window size (the
+  * size of the history buffer). It should be in the range 8..15. Larger values
+  * of this parameter result in better compression at the expense of memory
+  * usage. The default value is 15
+  */
+  final int windowBits;
+
+  /**
+  * The [memLevel] parameter specifies how much memory should be allocated for
+  * the internal compression state. [memLevel]=1 uses minimum memory but is slow
+  * and reduces compression ratio; [memLevel]=9 uses maximum memory for optimal
+  * speed. The default value is 8
+  * The memory requirements for deflate are (in bytes):
+  *         (1 << (windowBits + 2)) +  (1 << (memLevel + 9))
+  * that is: 128K for windowBits = 15 + 128K for memLevel = 8  (default values)
+  */
+  final int memLevel;
+
+  /**
+  * When [raw] is true, deflate generates raw data with no zlib header or
+  * trailer, and will not compute an adler32 check value
+  */
+  final bool raw;
+
+  /**
    * Get a [Converter] for encoding to `ZLib` compressed data.
    */
   Converter<List<int>, List<int>> get encoder =>
-      new ZLibEncoder(gzip: false, level: level);
+      new ZLibEncoder(gzip: false, level: level, windowBits: windowBits,
+                      raw: raw, memLevel: memLevel);
 
   /**
    * Get a [Converter] for decoding `ZLib` compressed data.
    */
-  Converter<List<int>, List<int>> get decoder => const ZLibDecoder();
+  Converter<List<int>, List<int>> get decoder => new ZLibDecoder(
+      windowBits: windowBits, raw: raw);
 
   /**
-   * The compression-[level] can be set in the range of `1..10`, with `6` being
+   * The compression-[level] can be set in the range of `-1..9`, with `6` being
    * the default compression level. Levels above 6 will have higher compression
    * rates at the cost of more CPU and memory usage. Levels below 6 will use
    * less CPU and memory, but at the cost of lower compression rates.
    */
-  const ZLibCodec({this.level: 6});
+  const ZLibCodec({this.level: 6, this.windowBits: 15, this.raw: false,

[Anders Johnsen, 2014/01/15 10:52:08]

Please add some constants to ZLibCodec, ZLIB_LEVEL_DEFAULT, ZLIB_LEVEL_MIN, etc.

[Anders Johnsen, 2014/01/15 10:52:08]

Make raw the last argument.

[vicb, 2014/01/15 11:08:04]

That's in the pipe

[vicb, 2014/01/15 11:08:04]

Could I ask why ? (is order important for named params)

[Anders Johnsen, 2014/01/15 11:34:17]

Matter of taste I suppose :) `raw` is kind of different than the other flags, so
I think it should be in the front or back. And given that level is the most
common one, I suggested in the back. It's purely a suggestion, and you are free
to leave it as it, if you prefer.

[vicb, 2014/01/23 09:14:04]

I've moved raw to be the last parameter everywhere

+                  this.memLevel: 8});
 }
 
 
@@ -62,23 +90,52 @@ class GZipCodec extends Codec<List<int>, List<int>> {
   final int level;
 
   /**
+  * The windowBits parameter is the base two logarithm of the window size (the
+  * size of the history buffer). It should be in the range 8..15. Larger values
+  * of this parameter result in better compression at the expense of memory
+  * usage. The default value is 15
+  */
+  final int windowBits;
+
+  /**
+  * The [memLevel] parameter specifies how much memory should be allocated for
+  * the internal compression state. [memLevel]=1 uses minimum memory but is slow
+  * and reduces compression ratio; [memLevel]=9 uses maximum memory for optimal
+  * speed. The default value is 8
+  * The memory requirements for deflate are (in bytes):
+  *         (1 << (windowBits + 2)) +  (1 << (memLevel + 9))
+  * that is: 128K for windowBits = 15 + 128K for memLevel = 8  (default values)
+  */
+  final int memLevel;
+
+  /**
+  * When [raw] is true, deflate generates raw data with no zlib header or
+  * trailer, and will not compute an adler32 check value
+  */
+  final bool raw;
+
+  /**
    * Get a [Converter] for encoding to `GZip` compressed data.
    */
   Converter<List<int>, List<int>> get encoder =>
-      new ZLibEncoder(gzip: true, level: level);
+      new ZLibEncoder(gzip: true, level: level, windowBits: windowBits,
+                      raw: raw, memLevel: memLevel);
 
   /**
    * Get a [Converter] for decoding `GZip` compressed data.
    */
-  Converter<List<int>, List<int>> get decoder => const ZLibDecoder();
+  Converter<List<int>, List<int>> get decoder => new ZLibDecoder(
+      windowBits: windowBits, raw: raw);
 
   /**
-   * The compression-[level] can be set in the range of `1..10`, with `6` being
-   * the default compression level. Levels above 6 will have higher compression
-   * rates at the cost of more CPU and memory usage. Levels below 6 will use
-   * less CPU and memory, but at the cost of lower compression rates.
+   * The compression-[level] can be set in the range of `-1..9`, with `6` being
+   * the default compression level. Levels above `6` will have higher
+   * compression rates at the cost of more CPU and memory usage. Levels below
+   * `6` will use less CPU and memory, but at the cost of lower compression
+   * rates.
    */
-  const GZipCodec({this.level: 6});
+  const GZipCodec({this.level: 6, this.windowBits: 15, this.raw: false,
+                  this.memLevel: 8});
 }
 
 
@@ -98,11 +155,36 @@ class ZLibEncoder extends Converter<List<int>, List<int>> {
   final int level;
 
   /**
+  * The windowBits parameter is the base two logarithm of the window size (the
+  * size of the history buffer). It should be in the range 8..15. Larger values
+  * of this parameter result in better compression at the expense of memory
+  * usage. The default value is 15
+  */
+  final int windowBits;
+
+  /**
+  * The [memLevel] parameter specifies how much memory should be allocated for
+  * the internal compression state. [memLevel]=1 uses minimum memory but is slow
+  * and reduces compression ratio; [memLevel]=9 uses maximum memory for optimal
+  * speed. The default value is 8
+  * The memory requirements for deflate are (in bytes):
+  *         (1 << (windowBits + 2)) +  (1 << (memLevel + 9))
+  * that is: 128K for windowBits = 15 + 128K for memLevel = 8  (default values)
+  */
+  final int memLevel;
+
+  /**
+  * When [raw] is true, deflate generates raw data with no zlib header or
+  * trailer, and will not compute an adler32 check value
+  */
+  final bool raw;
+
+  /**
    * Create a new [ZLibEncoder] converter. If the [gzip] flag is set, the
    * encoder will wrap the encoded ZLib data in GZip frames.
    */
-  const ZLibEncoder({this.gzip: false, this.level: 6});
-
+  const ZLibEncoder({this.gzip: false, this.level: 6, this.windowBits: 15,
+                    this.raw: false, this.memLevel: 8});
 
   /**
    * Convert a list of bytes using the options given to the [ZLibEncoder]
@@ -127,7 +209,7 @@ class ZLibEncoder extends Converter<List<int>, List<int>> {
     if (sink is! ByteConversionSink) {
       sink = new ByteConversionSink.from(sink);
     }
-    return new _ZLibEncoderSink(sink, gzip, level);
+    return new _ZLibEncoderSink(sink, gzip, level, windowBits, raw, memLevel);
   }
 }
 
@@ -137,11 +219,24 @@ class ZLibEncoder extends Converter<List<int>, List<int>> {
  * decompress data.
  */
 class ZLibDecoder extends Converter<List<int>, List<int>> {
+  /**
+  * The windowBits parameter is the base two logarithm of the window size (the
+  * size of the history buffer). It should be in the range 8..15. Larger values
+  * of this parameter result in better compression at the expense of memory
+  * usage. The default value is 15
+  */
+  final int windowBits;
+
+  /**
+  * When [raw] is true, deflate generates raw data with no zlib header or
+  * trailer, and will not compute an adler32 check value
+  */
+  final bool raw;
 
   /**
-   * Create a new [ZLibEncoder] converter.
+   * Create a new [ZLibDecoder] converter.
    */
-  const ZLibDecoder();
+  const ZLibDecoder({this.windowBits: 15, this.raw: false});
 
   /**
    * Convert a list of bytes using the options given to the [ZLibDecoder]
@@ -165,7 +260,7 @@ class ZLibDecoder extends Converter<List<int>, List<int>> {
     if (sink is! ByteConversionSink) {
       sink = new ByteConversionSink.from(sink);
     }
-    return new _ZLibDecoderSink(sink);
+    return new _ZLibDecoderSink(sink, windowBits, raw);
   }
 }
 
@@ -191,14 +286,16 @@ class _BufferSink extends ByteConversionSink {
 
 
 class _ZLibEncoderSink extends _FilterSink {
-  _ZLibEncoderSink(ByteConversionSink sink, bool gzip, int level)
-      : super(sink, _Filter.newZLibDeflateFilter(gzip, level));
+  _ZLibEncoderSink(ByteConversionSink sink, bool gzip, int level,
+                   int windowBits, bool raw, int memLevel)
+      : super(sink, _Filter.newZLibDeflateFilter(gzip, level, windowBits, raw,
+                                                 memLevel));
 }
 
 
 class _ZLibDecoderSink extends _FilterSink {
-  _ZLibDecoderSink(ByteConversionSink sink)
-      : super(sink, _Filter.newZLibInflateFilter());
+  _ZLibDecoderSink(ByteConversionSink sink, int windowBits, bool raw)
+      : super(sink, _Filter.newZLibInflateFilter(windowBits, raw));
 }
 
 
@@ -208,7 +305,7 @@ class _FilterSink extends ByteConversionSink {
   bool _closed = false;
   bool _empty = true;
 
-  _FilterSink(ByteConversionSink this._sink, _Filter this._filter);
+  _FilterSink(this._sink, this._filter);
 
   void add(List<int> data) {
     addSlice(data, 0, data.length, false);
@@ -286,6 +383,8 @@ abstract class _Filter {
    */
   void end();
 
-  external static _Filter newZLibDeflateFilter(bool gzip, int level);
-  external static _Filter newZLibInflateFilter();
+  external static _Filter newZLibDeflateFilter(bool gzip, int level,
+                                               int windowBits, bool raw,
+                                               int memLevel);
+  external static _Filter newZLibInflateFilter(int windowBits, bool raw);
 }