diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/MetaData.java b/jetty-http/src/main/java/org/eclipse/jetty/http/MetaData.java
index bc7cc82998d..2bd270829e2 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/MetaData.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/MetaData.java
@@ -15,6 +15,7 @@ package org.eclipse.jetty.http;
 
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.Objects;
 import java.util.function.Supplier;
 
 public class MetaData implements Iterable<HttpField>
@@ -100,6 +101,28 @@ public class MetaData implements Iterable<HttpField>
         return _fields.iterator();
     }
 
+    @Override
+    public int hashCode()
+    {
+        return Objects.hash(_httpVersion, _contentLength, _fields, _trailerSupplier);
+    }
+
+    @Override
+    public boolean equals(Object obj)
+    {
+        if (!(obj instanceof MetaData))
+            return false;
+
+        MetaData other = (MetaData)obj;
+        if (!Objects.equals(_httpVersion, other._httpVersion))
+            return false;
+        if (!Objects.equals(_contentLength, other._contentLength))
+            return false;
+        if (!Objects.equals(_fields, other._fields))
+            return false;
+        return _trailerSupplier == null && other._trailerSupplier == null;
+    }
+
     @Override
     public String toString()
     {
diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/Huffman.java b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/Huffman.java
index 6a1ad3d6789..354885b9b9e 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/Huffman.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/Huffman.java
@@ -346,4 +346,47 @@ public class Huffman
             }
         }
     }
+
+    public static boolean isIllegalCharacter(char c)
+    {
+        return (c >= 256 || c < ' ');
+    }
+
+    public static char getReplacementCharacter(char c)
+    {
+        switch (c)
+        {
+            // A recipient of CR, LF, or NUL within a field value MUST either reject the message
+            // or replace each of those characters with SP before further processing
+            case '\r':
+            case '\n':
+            case 0x00:
+                return ' ';
+
+            default:
+                if (c >= 256 || c < ' ')
+                    return '?';
+        }
+
+        return c;
+    }
+
+    public static int getReplacementCharacter(int i)
+    {
+        switch (i)
+        {
+            // A recipient of CR, LF, or NUL within a field value MUST either reject the message
+            // or replace each of those characters with SP before further processing
+            case '\r':
+            case '\n':
+            case 0x00:
+                return ' ';
+
+            default:
+                if (i >= 256 || i < ' ')
+                    return '?';
+        }
+
+        return i;
+    }
 }
diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanDecoder.java b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanDecoder.java
index a043357946f..c0f19dc0851 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanDecoder.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanDecoder.java
@@ -15,7 +15,7 @@ package org.eclipse.jetty.http.compression;
 
 import java.nio.ByteBuffer;
 
-import org.eclipse.jetty.util.Utf8StringBuilder;
+import org.eclipse.jetty.util.CharsetStringBuilder;
 
 import static org.eclipse.jetty.http.compression.Huffman.rowbits;
 import static org.eclipse.jetty.http.compression.Huffman.rowsym;
@@ -34,7 +34,7 @@ public class HuffmanDecoder
         return decoded;
     }
 
-    private final Utf8StringBuilder _utf8 = new Utf8StringBuilder();
+    private final CharsetStringBuilder.Iso8859StringBuilder _builder = new CharsetStringBuilder.Iso8859StringBuilder();
     private int _length = 0;
     private int _count = 0;
     private int _node = 0;
@@ -71,7 +71,9 @@ public class HuffmanDecoder
                     }
 
                     // terminal node
-                    _utf8.append((byte)(0xFF & rowsym[_node]));
+                    int i = 0xFF & rowsym[_node];
+                    i = Huffman.getReplacementCharacter(i);
+                    _builder.append((byte)i);
                     _bits -= rowbits[_node];
                     _node = 0;
                 }
@@ -104,7 +106,9 @@ public class HuffmanDecoder
                 break;
             }
 
-            _utf8.append((byte)(0xFF & rowsym[_node]));
+            int i = 0xFF & rowsym[_node];
+            i = Huffman.getReplacementCharacter(i);
+            _builder.append((byte)i);
             _bits -= rowbits[_node];
             _node = 0;
         }
@@ -115,14 +119,14 @@ public class HuffmanDecoder
             throw new EncodingException("bad_termination");
         }
 
-        String value = _utf8.toString();
+        String value = _builder.build();
         reset();
         return value;
     }
 
     public void reset()
     {
-        _utf8.reset();
+        _builder.reset();
         _count = 0;
         _current = 0;
         _node = 0;
diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanEncoder.java b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanEncoder.java
index 15360d88e55..b6f05b5fc6b 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanEncoder.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/HuffmanEncoder.java
@@ -50,12 +50,12 @@ public class HuffmanEncoder
         encode(CODES, buffer, b);
     }
 
-    public static int octetsNeededLC(String s)
+    public static int octetsNeededLowercase(String s)
     {
         return octetsNeeded(LCCODES, s);
     }
 
-    public static void encodeLC(ByteBuffer buffer, String s)
+    public static void encodeLowercase(ByteBuffer buffer, String s)
     {
         encode(LCCODES, buffer, s);
     }
@@ -67,7 +67,7 @@ public class HuffmanEncoder
         for (int i = 0; i < len; i++)
         {
             char c = s.charAt(i);
-            if (c >= 128 || c < ' ')
+            if (Huffman.isIllegalCharacter(c))
                 return -1;
             needed += table[c][1];
         }
@@ -88,8 +88,8 @@ public class HuffmanEncoder
         for (int i = 0; i < len; i++)
         {
             char c = s.charAt(i);
-            if (c >= 128 || c < ' ')
-                throw new IllegalArgumentException();
+            if (Huffman.isIllegalCharacter(c))
+                 throw new IllegalArgumentException();
             int code = table[c][0];
             int bits = table[c][1];
 
@@ -119,9 +119,9 @@ public class HuffmanEncoder
 
         for (byte value : b)
         {
-            int c = 0xFF & value;
-            int code = table[c][0];
-            int bits = table[c][1];
+            int i = 0xFF & value;
+            int code = table[i][0];
+            int bits = table[i][1];
 
             current <<= bits;
             current |= code;
diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/NBitStringParser.java b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/NBitStringParser.java
index 5c2456d0383..b3091317f10 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/compression/NBitStringParser.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/compression/NBitStringParser.java
@@ -15,11 +15,13 @@ package org.eclipse.jetty.http.compression;
 
 import java.nio.ByteBuffer;
 
+import org.eclipse.jetty.util.CharsetStringBuilder;
+
 public class NBitStringParser
 {
     private final NBitIntegerParser _integerParser;
     private final HuffmanDecoder _huffmanBuilder;
-    private final StringBuilder _stringBuilder;
+    private final CharsetStringBuilder.Iso8859StringBuilder _builder;
     private boolean _huffman;
     private int _count;
     private int _length;
@@ -38,7 +40,7 @@ public class NBitStringParser
     {
         _integerParser = new NBitIntegerParser();
         _huffmanBuilder = new HuffmanDecoder();
-        _stringBuilder = new StringBuilder();
+        _builder = new CharsetStringBuilder.Iso8859StringBuilder();
     }
 
     public void setPrefix(int prefix)
@@ -70,7 +72,7 @@ public class NBitStringParser
                     continue;
 
                 case VALUE:
-                    String value = _huffman ? _huffmanBuilder.decode(buffer) : asciiStringDecode(buffer);
+                    String value = _huffman ? _huffmanBuilder.decode(buffer) : stringDecode(buffer);
                     if (value != null)
                         reset();
                     return value;
@@ -81,15 +83,16 @@ public class NBitStringParser
         }
     }
 
-    private String asciiStringDecode(ByteBuffer buffer)
+    private String stringDecode(ByteBuffer buffer)
     {
         for (; _count < _length; _count++)
         {
             if (!buffer.hasRemaining())
                 return null;
-            _stringBuilder.append((char)(0x7F & buffer.get()));
+            _builder.append(buffer.get());
         }
-        return _stringBuilder.toString();
+
+        return _builder.build();
     }
 
     public void reset()
@@ -97,7 +100,7 @@ public class NBitStringParser
         _state = State.PARSING;
         _integerParser.reset();
         _huffmanBuilder.reset();
-        _stringBuilder.setLength(0);
+        _builder.reset();
         _prefix = 0;
         _count = 0;
         _length = 0;
diff --git a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/HuffmanTest.java b/jetty-http/src/test/java/org/eclipse/jetty/http/HuffmanTest.java
similarity index 50%
rename from jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/HuffmanTest.java
rename to jetty-http/src/test/java/org/eclipse/jetty/http/HuffmanTest.java
index 48ce235f8b2..5007877094e 100644
--- a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/HuffmanTest.java
+++ b/jetty-http/src/test/java/org/eclipse/jetty/http/HuffmanTest.java
@@ -11,9 +11,8 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.http3.qpack;
+package org.eclipse.jetty.http;
 
-import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;
 import java.util.Locale;
 import java.util.stream.Stream;
@@ -21,14 +20,15 @@ import java.util.stream.Stream;
 import org.eclipse.jetty.http.compression.HuffmanDecoder;
 import org.eclipse.jetty.http.compression.HuffmanEncoder;
 import org.eclipse.jetty.util.BufferUtil;
+import org.eclipse.jetty.util.StringUtil;
 import org.eclipse.jetty.util.TypeUtil;
-import org.hamcrest.Matchers;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
-import org.junit.jupiter.params.provider.ValueSource;
 
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
@@ -72,15 +72,80 @@ public class HuffmanTest
         assertEquals(hex.length() / 2, HuffmanEncoder.octetsNeeded(expected));
     }
 
-    @ParameterizedTest(name = "[{index}]") // don't include unprintable character in test display-name
-    @ValueSource(chars = {(char)128, (char)0, (char)-1, ' ' - 1})
-    public void testEncode8859Only(char bad)
+    public static Stream<Arguments> testDecode8859OnlyArguments()
     {
-        String s = "bad '" + bad + "'";
+        return Stream.of(
+            // These are valid characters for ISO-8859-1.
+            Arguments.of("FfFe6f", (char)128),
+            Arguments.of("FfFfFbBf", (char)255),
 
-        assertThat(HuffmanEncoder.octetsNeeded(s), Matchers.is(-1));
+            // RFC9110 specifies these to be replaced as ' ' during decoding.
+            Arguments.of("FfC7", ' '), // (char)0
+            Arguments.of("FfFfFfF7", ' '), // '\r'
+            Arguments.of("FfFfFfF3", ' '), // '\n'
 
-        assertThrows(BufferOverflowException.class,
-            () -> HuffmanEncoder.encode(BufferUtil.allocate(32), s));
+            // We replace control chars with the default replacement character of '?'.
+            Arguments.of("FfFfFfBf", '?') // (char)(' ' - 1)
+        );
+    }
+
+    @ParameterizedTest(name = "[{index}]") // don't include unprintable character in test display-name
+    @MethodSource("testDecode8859OnlyArguments")
+    public void testDecode8859Only(String hexString, char expected) throws Exception
+    {
+        ByteBuffer buffer = ByteBuffer.wrap(StringUtil.fromHexString(hexString));
+        String decoded = HuffmanDecoder.decode(buffer, buffer.remaining());
+        assertThat(decoded, equalTo("" + expected));
+    }
+
+    public static Stream<Arguments> testEncode8859OnlyArguments()
+    {
+        return Stream.of(
+            Arguments.of((char)128, (char)128),
+            Arguments.of((char)255, (char)255),
+            Arguments.of((char)0, null),
+            Arguments.of('\r', null),
+            Arguments.of('\n', null),
+            Arguments.of((char)456, null),
+            Arguments.of((char)256, null),
+            Arguments.of((char)-1, null),
+            Arguments.of((char)(' ' - 1), null)
+        );
+    }
+
+    @ParameterizedTest(name = "[{index}]") // don't include unprintable character in test display-name
+    @MethodSource("testEncode8859OnlyArguments")
+    public void testEncode8859Only(char value, Character expectedValue) throws Exception
+    {
+        String s = "value = '" + value + "'";
+
+        // If expected is null we should not be able to encode.
+        if (expectedValue == null)
+        {
+            assertThat(HuffmanEncoder.octetsNeeded(s), equalTo(-1));
+            assertThrows(Throwable.class, () -> encode(s));
+            return;
+        }
+
+        String expected = "value = '" + expectedValue + "'";
+        assertThat(HuffmanEncoder.octetsNeeded(s), greaterThan(0));
+        ByteBuffer buffer = encode(s);
+        String decode = decode(buffer);
+        System.err.println("decoded: " + decode);
+        assertThat(decode, equalTo(expected));
+    }
+
+    private ByteBuffer encode(String s)
+    {
+        ByteBuffer buffer = BufferUtil.allocate(32);
+        BufferUtil.clearToFill(buffer);
+        HuffmanEncoder.encode(buffer, s);
+        BufferUtil.flipToFlush(buffer, 0);
+        return buffer;
+    }
+
+    private String decode(ByteBuffer buffer) throws Exception
+    {
+        return HuffmanDecoder.decode(buffer, buffer.remaining());
     }
 }
diff --git a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerParserTest.java b/jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerParserTest.java
similarity index 97%
rename from jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerParserTest.java
rename to jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerParserTest.java
index 2c0647bc6c4..e0673a64705 100644
--- a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerParserTest.java
+++ b/jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerParserTest.java
@@ -11,7 +11,7 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.http3.qpack;
+package org.eclipse.jetty.http;
 
 import java.nio.ByteBuffer;
 
diff --git a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerTest.java b/jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerTest.java
similarity index 99%
rename from jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerTest.java
rename to jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerTest.java
index 695e87791e7..8559b65cfe0 100644
--- a/jetty-http3/http3-qpack/src/test/java/org/eclipse/jetty/http3/qpack/NBitIntegerTest.java
+++ b/jetty-http/src/test/java/org/eclipse/jetty/http/NBitIntegerTest.java
@@ -11,7 +11,7 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.http3.qpack;
+package org.eclipse.jetty.http;
 
 import java.nio.ByteBuffer;
 
diff --git a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackDecoder.java b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackDecoder.java
index aa5fadeb19b..77e4d05c61b 100644
--- a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackDecoder.java
+++ b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackDecoder.java
@@ -24,6 +24,7 @@ import org.eclipse.jetty.http.compression.HuffmanDecoder;
 import org.eclipse.jetty.http.compression.NBitIntegerParser;
 import org.eclipse.jetty.http2.hpack.HpackContext.Entry;
 import org.eclipse.jetty.util.BufferUtil;
+import org.eclipse.jetty.util.CharsetStringBuilder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -39,6 +40,7 @@ public class HpackDecoder
 
     private final HpackContext _context;
     private final MetaDataBuilder _builder;
+    private final HuffmanDecoder _huffmanDecoder;
     private int _localMaxDynamicTableSize;
 
     /**
@@ -50,6 +52,7 @@ public class HpackDecoder
         _context = new HpackContext(localMaxDynamicTableSize);
         _localMaxDynamicTableSize = localMaxDynamicTableSize;
         _builder = new MetaDataBuilder(maxHeaderSize);
+        _huffmanDecoder = new HuffmanDecoder();
     }
 
     public HpackContext getHpackContext()
@@ -168,7 +171,7 @@ public class HpackDecoder
                     if (huffmanName)
                         name = huffmanDecode(buffer, length);
                     else
-                        name = toASCIIString(buffer, length);
+                        name = toISO8859String(buffer, length);
                     check:
                     for (int i = name.length(); i-- > 0; )
                     {
@@ -209,7 +212,7 @@ public class HpackDecoder
                 if (huffmanValue)
                     value = huffmanDecode(buffer, length);
                 else
-                    value = toASCIIString(buffer, length);
+                    value = toISO8859String(buffer, length);
 
                 // Make the new field
                 HttpField field;
@@ -288,7 +291,11 @@ public class HpackDecoder
     {
         try
         {
-            return HuffmanDecoder.decode(buffer, length);
+            _huffmanDecoder.setLength(length);
+            String decoded = _huffmanDecoder.decode(buffer);
+            if (decoded == null)
+                throw new HpackException.CompressionException("invalid string encoding");
+            return decoded;
         }
         catch (EncodingException e)
         {
@@ -296,16 +303,20 @@ public class HpackDecoder
             compressionException.initCause(e);
             throw compressionException;
         }
+        finally
+        {
+            _huffmanDecoder.reset();
+        }
     }
 
-    public static String toASCIIString(ByteBuffer buffer, int length)
+    public static String toISO8859String(ByteBuffer buffer, int length)
     {
-        StringBuilder builder = new StringBuilder(length);
+        CharsetStringBuilder.Iso8859StringBuilder builder = new CharsetStringBuilder.Iso8859StringBuilder();
         for (int i = 0; i < length; ++i)
         {
             builder.append((char)(0x7F & buffer.get()));
         }
-        return builder.toString();
+        return builder.build();
     }
 
     @Override
diff --git a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackEncoder.java b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackEncoder.java
index 0117e992136..e665c839f35 100644
--- a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackEncoder.java
+++ b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackEncoder.java
@@ -14,7 +14,6 @@
 package org.eclipse.jetty.http2.hpack;
 
 import java.nio.ByteBuffer;
-import java.nio.charset.StandardCharsets;
 import java.util.EnumMap;
 import java.util.EnumSet;
 import java.util.HashSet;
@@ -29,6 +28,7 @@ import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.http.MetaData;
 import org.eclipse.jetty.http.PreEncodedHttpField;
+import org.eclipse.jetty.http.compression.Huffman;
 import org.eclipse.jetty.http.compression.HuffmanEncoder;
 import org.eclipse.jetty.http.compression.NBitIntegerEncoder;
 import org.eclipse.jetty.http2.hpack.HpackContext.Entry;
@@ -441,8 +441,8 @@ public class HpackEncoder
             // leave name index bits as 0
             // Encode the name always with lowercase huffman
             buffer.put((byte)0x80);
-            NBitIntegerEncoder.encode(buffer, 7, HuffmanEncoder.octetsNeededLC(name));
-            HuffmanEncoder.encodeLC(buffer, name);
+            NBitIntegerEncoder.encode(buffer, 7, HuffmanEncoder.octetsNeededLowercase(name));
+            HuffmanEncoder.encodeLowercase(buffer, name);
         }
         else
         {
@@ -456,20 +456,9 @@ public class HpackEncoder
         {
             // huffman literal value
             buffer.put((byte)0x80);
-
             int needed = HuffmanEncoder.octetsNeeded(value);
-            if (needed >= 0)
-            {
-                NBitIntegerEncoder.encode(buffer, 7, needed);
-                HuffmanEncoder.encode(buffer, value);
-            }
-            else
-            {
-                // Not iso_8859_1
-                byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
-                NBitIntegerEncoder.encode(buffer, 7, HuffmanEncoder.octetsNeeded(bytes));
-                HuffmanEncoder.encode(buffer, bytes);
-            }
+            NBitIntegerEncoder.encode(buffer, 7, needed);
+            HuffmanEncoder.encode(buffer, value);
         }
         else
         {
@@ -479,15 +468,7 @@ public class HpackEncoder
             for (int i = 0; i < value.length(); i++)
             {
                 char c = value.charAt(i);
-                if (c < ' ' || c > 127)
-                {
-                    // Not iso_8859_1, so re-encode as UTF-8
-                    buffer.reset();
-                    byte[] bytes = value.getBytes(StandardCharsets.UTF_8);
-                    NBitIntegerEncoder.encode(buffer, 7, bytes.length);
-                    buffer.put(bytes, 0, bytes.length);
-                    return;
-                }
+                c = Huffman.getReplacementCharacter(c);
                 buffer.put((byte)c);
             }
         }
diff --git a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackFieldPreEncoder.java b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackFieldPreEncoder.java
index 7d60108e105..3b924f0368b 100644
--- a/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackFieldPreEncoder.java
+++ b/jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackFieldPreEncoder.java
@@ -73,8 +73,8 @@ public class HpackFieldPreEncoder implements HttpFieldPreEncoder
         else
         {
             buffer.put((byte)0x80);
-            NBitIntegerEncoder.encode(buffer, 7, HuffmanEncoder.octetsNeededLC(name));
-            HuffmanEncoder.encodeLC(buffer, name);
+            NBitIntegerEncoder.encode(buffer, 7, HuffmanEncoder.octetsNeededLowercase(name));
+            HuffmanEncoder.encodeLowercase(buffer, name);
         }
 
         HpackEncoder.encodeValue(buffer, huffman, value);
diff --git a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HpackTest.java b/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HpackTest.java
index 576d310937d..c1fb03ab666 100644
--- a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HpackTest.java
+++ b/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HpackTest.java
@@ -134,26 +134,27 @@ public class HpackTest
     }
 
     @Test
-    public void encodeDecodeNonAscii() throws Exception
+    public void encodeNonAscii() throws Exception
     {
         HpackEncoder encoder = new HpackEncoder();
-        HpackDecoder decoder = new HpackDecoder(4096, 8192);
         ByteBuffer buffer = BufferUtil.allocate(16 * 1024);
 
         HttpFields fields0 = HttpFields.build()
-        // @checkstyle-disable-check : AvoidEscapedUnicodeCharactersCheck
+            // @checkstyle-disable-check : AvoidEscapedUnicodeCharactersCheck
             .add("Cookie", "[\uD842\uDF9F]")
             .add("custom-key", "[\uD842\uDF9F]");
         Response original0 = new MetaData.Response(HttpVersion.HTTP_2, 200, fields0);
 
-        BufferUtil.clearToFill(buffer);
-        encoder.encode(buffer, original0);
-        BufferUtil.flipToFlush(buffer, 0);
-        Response decoded0 = (Response)decoder.decode(buffer);
+        HpackException.SessionException throwable = assertThrows(HpackException.SessionException.class, () ->
+        {
+            BufferUtil.clearToFill(buffer);
+            encoder.encode(buffer, original0);
+            BufferUtil.flipToFlush(buffer, 0);
+        });
 
-        assertMetaDataSame(original0, decoded0);
+        assertThat(throwable.getMessage(), containsString("Could not hpack encode"));
     }
-    
+
     @Test
     public void evictReferencedFieldTest() throws Exception
     {
diff --git a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HuffmanTest.java b/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HuffmanTest.java
deleted file mode 100644
index a2daea5ba2e..00000000000
--- a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/HuffmanTest.java
+++ /dev/null
@@ -1,84 +0,0 @@
-//
-// ========================================================================
-// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
-//
-// This program and the accompanying materials are made available under the
-// terms of the Eclipse Public License v. 2.0 which is available at
-// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
-// which is available at https://www.apache.org/licenses/LICENSE-2.0.
-//
-// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
-// ========================================================================
-//
-
-package org.eclipse.jetty.http2.hpack;
-
-import java.nio.BufferOverflowException;
-import java.nio.ByteBuffer;
-import java.util.Locale;
-import java.util.stream.Stream;
-
-import org.eclipse.jetty.http.compression.HuffmanDecoder;
-import org.eclipse.jetty.http.compression.HuffmanEncoder;
-import org.eclipse.jetty.util.BufferUtil;
-import org.eclipse.jetty.util.StringUtil;
-import org.hamcrest.Matchers;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.MethodSource;
-import org.junit.jupiter.params.provider.ValueSource;
-
-import static org.hamcrest.MatcherAssert.assertThat;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-public class HuffmanTest
-{
-    public static Stream<Arguments> data()
-    {
-        return Stream.of(
-            new String[][]{
-                {"D.4.1", "f1e3c2e5f23a6ba0ab90f4ff", "www.example.com"},
-                {"D.4.2", "a8eb10649cbf", "no-cache"},
-                {"D.6.1k", "6402", "302"},
-                {"D.6.1v", "aec3771a4b", "private"},
-                {"D.6.1d", "d07abe941054d444a8200595040b8166e082a62d1bff", "Mon, 21 Oct 2013 20:13:21 GMT"},
-                {"D.6.1l", "9d29ad171863c78f0b97c8e9ae82ae43d3", "https://www.example.com"},
-                {"D.6.2te", "640cff", "303"},
-                }).map(Arguments::of);
-    }
-
-    @ParameterizedTest(name = "[{index}] spec={0}")
-    @MethodSource("data")
-    public void testDecode(String specSection, String hex, String expected) throws Exception
-    {
-        byte[] encoded = StringUtil.fromHexString(hex);
-        String decoded = HuffmanDecoder.decode(ByteBuffer.wrap(encoded), encoded.length);
-        assertEquals(expected, decoded, specSection);
-    }
-
-    @ParameterizedTest(name = "[{index}] spec={0}")
-    @MethodSource("data")
-    public void testEncode(String specSection, String hex, String expected)
-    {
-        ByteBuffer buf = BufferUtil.allocate(1024);
-        int pos = BufferUtil.flipToFill(buf);
-        HuffmanEncoder.encode(buf, expected);
-        BufferUtil.flipToFlush(buf, pos);
-        String encoded = StringUtil.toHexString(BufferUtil.toArray(buf)).toLowerCase(Locale.ENGLISH);
-        assertEquals(hex, encoded, specSection);
-        assertEquals(hex.length() / 2, HuffmanEncoder.octetsNeeded(expected));
-    }
-
-    @ParameterizedTest(name = "[{index}]") // don't include unprintable character in test display-name
-    @ValueSource(chars = {(char)128, (char)0, (char)-1, ' ' - 1})
-    public void testEncode8859Only(char bad)
-    {
-        String s = "bad '" + bad + "'";
-
-        assertThat(HuffmanEncoder.octetsNeeded(s), Matchers.is(-1));
-
-        assertThrows(BufferOverflowException.class,
-            () -> HuffmanEncoder.encode(BufferUtil.allocate(32), s));
-    }
-}
diff --git a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/NBitIntegerTest.java b/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/NBitIntegerTest.java
deleted file mode 100644
index 29615a5b514..00000000000
--- a/jetty-http2/http2-hpack/src/test/java/org/eclipse/jetty/http2/hpack/NBitIntegerTest.java
+++ /dev/null
@@ -1,201 +0,0 @@
-//
-// ========================================================================
-// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
-//
-// This program and the accompanying materials are made available under the
-// terms of the Eclipse Public License v. 2.0 which is available at
-// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
-// which is available at https://www.apache.org/licenses/LICENSE-2.0.
-//
-// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
-// ========================================================================
-//
-
-package org.eclipse.jetty.http2.hpack;
-
-import java.nio.ByteBuffer;
-
-import org.eclipse.jetty.http.compression.NBitIntegerEncoder;
-import org.eclipse.jetty.http.compression.NBitIntegerParser;
-import org.eclipse.jetty.util.BufferUtil;
-import org.eclipse.jetty.util.StringUtil;
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-public class NBitIntegerTest
-{
-
-    @Test
-    public void testOctetsNeeded()
-    {
-        assertEquals(0, NBitIntegerEncoder.octetsNeeded(5, 10));
-        assertEquals(2, NBitIntegerEncoder.octetsNeeded(5, 1337));
-        assertEquals(1, NBitIntegerEncoder.octetsNeeded(8, 42));
-        assertEquals(3, NBitIntegerEncoder.octetsNeeded(8, 1337));
-
-        assertEquals(0, NBitIntegerEncoder.octetsNeeded(6, 62));
-        assertEquals(1, NBitIntegerEncoder.octetsNeeded(6, 63));
-        assertEquals(1, NBitIntegerEncoder.octetsNeeded(6, 64));
-        assertEquals(2, NBitIntegerEncoder.octetsNeeded(6, 63 + 0x00 + 0x80 * 0x01));
-        assertEquals(3, NBitIntegerEncoder.octetsNeeded(6, 63 + 0x00 + 0x80 * 0x80));
-        assertEquals(4, NBitIntegerEncoder.octetsNeeded(6, 63 + 0x00 + 0x80 * 0x80 * 0x80));
-    }
-
-    @Test
-    public void testEncode()
-    {
-        testEncode(6, 0, "00");
-        testEncode(6, 1, "01");
-        testEncode(6, 62, "3e");
-        testEncode(6, 63, "3f00");
-        testEncode(6, 63 + 1, "3f01");
-        testEncode(6, 63 + 0x7e, "3f7e");
-        testEncode(6, 63 + 0x7f, "3f7f");
-        testEncode(6, 63 + 0x00 + 0x80 * 0x01, "3f8001");
-        testEncode(6, 63 + 0x01 + 0x80 * 0x01, "3f8101");
-        testEncode(6, 63 + 0x7f + 0x80 * 0x01, "3fFf01");
-        testEncode(6, 63 + 0x00 + 0x80 * 0x02, "3f8002");
-        testEncode(6, 63 + 0x01 + 0x80 * 0x02, "3f8102");
-        testEncode(6, 63 + 0x7f + 0x80 * 0x7f, "3fFf7f");
-        testEncode(6, 63 + 0x00 + 0x80 * 0x80, "3f808001");
-        testEncode(6, 63 + 0x7f + 0x80 * 0x80 * 0x7f, "3fFf807f");
-        testEncode(6, 63 + 0x00 + 0x80 * 0x80 * 0x80, "3f80808001");
-
-        testEncode(8, 0, "00");
-        testEncode(8, 1, "01");
-        testEncode(8, 128, "80");
-        testEncode(8, 254, "Fe");
-        testEncode(8, 255, "Ff00");
-        testEncode(8, 255 + 1, "Ff01");
-        testEncode(8, 255 + 0x7e, "Ff7e");
-        testEncode(8, 255 + 0x7f, "Ff7f");
-        testEncode(8, 255 + 0x80, "Ff8001");
-        testEncode(8, 255 + 0x00 + 0x80 * 0x80, "Ff808001");
-    }
-
-    public void testEncode(int n, int i, String expected)
-    {
-        ByteBuffer buf = BufferUtil.allocate(16);
-        int p = BufferUtil.flipToFill(buf);
-        if (n < 8)
-            buf.put((byte)0x00);
-        NBitIntegerEncoder.encode(buf, n, i);
-        BufferUtil.flipToFlush(buf, p);
-        String r = StringUtil.toHexString(BufferUtil.toArray(buf));
-        assertEquals(expected, r);
-
-        assertEquals(expected.length() / 2, (n < 8 ? 1 : 0) + NBitIntegerEncoder.octetsNeeded(n, i));
-    }
-
-    @Test
-    public void testDecode() throws Exception
-    {
-        testDecode(6, 0, "00");
-        testDecode(6, 1, "01");
-        testDecode(6, 62, "3e");
-        testDecode(6, 63, "3f00");
-        testDecode(6, 63 + 1, "3f01");
-        testDecode(6, 63 + 0x7e, "3f7e");
-        testDecode(6, 63 + 0x7f, "3f7f");
-        testDecode(6, 63 + 0x80, "3f8001");
-        testDecode(6, 63 + 0x81, "3f8101");
-        testDecode(6, 63 + 0x7f + 0x80 * 0x01, "3fFf01");
-        testDecode(6, 63 + 0x00 + 0x80 * 0x02, "3f8002");
-        testDecode(6, 63 + 0x01 + 0x80 * 0x02, "3f8102");
-        testDecode(6, 63 + 0x7f + 0x80 * 0x7f, "3fFf7f");
-        testDecode(6, 63 + 0x00 + 0x80 * 0x80, "3f808001");
-        testDecode(6, 63 + 0x7f + 0x80 * 0x80 * 0x7f, "3fFf807f");
-        testDecode(6, 63 + 0x00 + 0x80 * 0x80 * 0x80, "3f80808001");
-
-        testDecode(8, 0, "00");
-        testDecode(8, 1, "01");
-        testDecode(8, 128, "80");
-        testDecode(8, 254, "Fe");
-        testDecode(8, 255, "Ff00");
-        testDecode(8, 255 + 1, "Ff01");
-        testDecode(8, 255 + 0x7e, "Ff7e");
-        testDecode(8, 255 + 0x7f, "Ff7f");
-        testDecode(8, 255 + 0x80, "Ff8001");
-        testDecode(8, 255 + 0x00 + 0x80 * 0x80, "Ff808001");
-    }
-
-    public void testDecode(int n, int expected, String encoded) throws Exception
-    {
-        ByteBuffer buf = ByteBuffer.wrap(StringUtil.fromHexString(encoded));
-        buf.position(n == 8 ? 0 : 1);
-        assertEquals(expected, NBitIntegerParser.decode(buf, n));
-    }
-
-    @Test
-    public void testEncodeExampleD11()
-    {
-        ByteBuffer buf = BufferUtil.allocate(16);
-        int p = BufferUtil.flipToFill(buf);
-        buf.put((byte)0x77);
-        buf.put((byte)0xFF);
-        NBitIntegerEncoder.encode(buf, 5, 10);
-        BufferUtil.flipToFlush(buf, p);
-
-        String r = StringUtil.toHexString(BufferUtil.toArray(buf));
-
-        assertEquals("77Ea", r);
-    }
-
-    @Test
-    public void testDecodeExampleD11() throws Exception
-    {
-        ByteBuffer buf = ByteBuffer.wrap(StringUtil.fromHexString("77EaFF"));
-        buf.position(2);
-
-        assertEquals(10, NBitIntegerParser.decode(buf, 5));
-    }
-
-    @Test
-    public void testEncodeExampleD12()
-    {
-        ByteBuffer buf = BufferUtil.allocate(16);
-        int p = BufferUtil.flipToFill(buf);
-        buf.put((byte)0x88);
-        buf.put((byte)0x00);
-        NBitIntegerEncoder.encode(buf, 5, 1337);
-        BufferUtil.flipToFlush(buf, p);
-
-        String r = StringUtil.toHexString(BufferUtil.toArray(buf));
-
-        assertEquals("881f9a0a", r);
-    }
-
-    @Test
-    public void testDecodeExampleD12() throws Exception
-    {
-        ByteBuffer buf = ByteBuffer.wrap(StringUtil.fromHexString("881f9a0aff"));
-        buf.position(2);
-
-        assertEquals(1337, NBitIntegerParser.decode(buf, 5));
-    }
-
-    @Test
-    public void testEncodeExampleD13()
-    {
-        ByteBuffer buf = BufferUtil.allocate(16);
-        int p = BufferUtil.flipToFill(buf);
-        buf.put((byte)0x88);
-        buf.put((byte)0xFF);
-        NBitIntegerEncoder.encode(buf, 8, 42);
-        BufferUtil.flipToFlush(buf, p);
-
-        String r = StringUtil.toHexString(BufferUtil.toArray(buf));
-
-        assertEquals("88Ff2a", r);
-    }
-
-    @Test
-    public void testDecodeExampleD13() throws Exception
-    {
-        ByteBuffer buf = ByteBuffer.wrap(StringUtil.fromHexString("882aFf"));
-        buf.position(1);
-
-        assertEquals(42, NBitIntegerParser.decode(buf, 8));
-    }
-}
diff --git a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/EncodableEntry.java b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/EncodableEntry.java
index bc202e09807..542232dca9c 100644
--- a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/EncodableEntry.java
+++ b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/EncodableEntry.java
@@ -14,6 +14,7 @@
 package org.eclipse.jetty.http3.qpack.internal;
 
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.util.Objects;
 
 import org.eclipse.jetty.http.HttpField;
@@ -173,7 +174,7 @@ public abstract class EncodableEntry
             {
                 buffer.put((byte)0x00);
                 NBitIntegerEncoder.encode(buffer, 7, value.length());
-                buffer.put(value.getBytes());
+                buffer.put(value.getBytes(StandardCharsets.ISO_8859_1));
             }
         }
 
@@ -229,13 +230,12 @@ public abstract class EncodableEntry
             }
             else
             {
-                // TODO: What charset should we be using? (this applies to the instruction generators as well).
                 buffer.put((byte)(0x20 | allowIntermediary));
                 NBitIntegerEncoder.encode(buffer, 3, name.length());
-                buffer.put(name.getBytes());
+                buffer.put(name.getBytes(StandardCharsets.ISO_8859_1));
                 buffer.put((byte)0x00);
                 NBitIntegerEncoder.encode(buffer, 7, value.length());
-                buffer.put(value.getBytes());
+                buffer.put(value.getBytes(StandardCharsets.ISO_8859_1));
             }
         }
 
@@ -268,7 +268,6 @@ public abstract class EncodableEntry
         }
     }
 
-    // TODO: pass in the HTTP version to avoid hard coding HTTP3?
     private static class PreEncodedEntry extends EncodableEntry
     {
         private final PreEncodedHttpField _httpField;
diff --git a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/IndexedNameEntryInstruction.java b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/IndexedNameEntryInstruction.java
index 35c225fa9f1..555703192b1 100644
--- a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/IndexedNameEntryInstruction.java
+++ b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/IndexedNameEntryInstruction.java
@@ -14,6 +14,7 @@
 package org.eclipse.jetty.http3.qpack.internal.instruction;
 
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 
 import org.eclipse.jetty.http.compression.HuffmanEncoder;
 import org.eclipse.jetty.http.compression.NBitIntegerEncoder;
@@ -72,7 +73,7 @@ public class IndexedNameEntryInstruction implements Instruction
         {
             buffer.put((byte)(0x00));
             NBitIntegerEncoder.encode(buffer, 7, _value.length());
-            buffer.put(_value.getBytes());
+            buffer.put(_value.getBytes(StandardCharsets.ISO_8859_1));
         }
 
         BufferUtil.flipToFlush(buffer, 0);
diff --git a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/LiteralNameEntryInstruction.java b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/LiteralNameEntryInstruction.java
index 2caad6044b6..8ebed39a0c0 100644
--- a/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/LiteralNameEntryInstruction.java
+++ b/jetty-http3/http3-qpack/src/main/java/org/eclipse/jetty/http3/qpack/internal/instruction/LiteralNameEntryInstruction.java
@@ -14,6 +14,7 @@
 package org.eclipse.jetty.http3.qpack.internal.instruction;
 
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.compression.HuffmanEncoder;
@@ -69,7 +70,7 @@ public class LiteralNameEntryInstruction implements Instruction
         {
             buffer.put((byte)(0x40));
             NBitIntegerEncoder.encode(buffer, 5, _name.length());
-            buffer.put(_name.getBytes());
+            buffer.put(_name.getBytes(StandardCharsets.ISO_8859_1));
         }
 
         if (_huffmanValue)
@@ -82,7 +83,7 @@ public class LiteralNameEntryInstruction implements Instruction
         {
             buffer.put((byte)(0x00));
             NBitIntegerEncoder.encode(buffer, 5, _value.length());
-            buffer.put(_value.getBytes());
+            buffer.put(_value.getBytes(StandardCharsets.ISO_8859_1));
         }
 
         BufferUtil.flipToFlush(buffer, 0);
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/CharsetStringBuilder.java b/jetty-util/src/main/java/org/eclipse/jetty/util/CharsetStringBuilder.java
new file mode 100644
index 00000000000..9aa2d783cd6
--- /dev/null
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/CharsetStringBuilder.java
@@ -0,0 +1,279 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.CharacterCodingException;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CodingErrorAction;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Objects;
+
+/**
+ * <p>Build a string from a sequence of bytes.</p>
+ * <p>Implementations of this interface are optimized for processing a mix of calls to already decoded
+ * character based appends (e.g. {@link #append(char)} and calls to undecoded byte methods (e.g. {@link #append(byte)}.
+ * This is particularly useful for decoding % encoded strings that are mostly already decoded but may contain
+ * escaped byte sequences that are not decoded.  The standard {@link CharsetDecoder} API is not well suited for this
+ * use-case.</p>
+ * <p>Any coding errors in the string will be reported by a {@link CharacterCodingException} thrown
+ * from the {@link #build()} method.</p>
+ * @see Utf8StringBuilder for UTF-8 decoding with replacement of coding errors and/or fast fail behaviour.
+ * @see CharsetDecoder for decoding arbitrary {@link Charset}s with control over {@link CodingErrorAction}.
+ */
+public interface CharsetStringBuilder
+{
+    void append(byte b);
+
+    void append(char c);
+
+    default void append(byte[] bytes)
+    {
+        append(bytes, 0, bytes.length);
+    }
+
+    default void append(byte[] b, int offset, int length)
+    {
+        int end = offset + length;
+        for (int i = offset; i < end; i++)
+            append(b[i]);
+    }
+
+    default void append(CharSequence chars, int offset, int length)
+    {
+        int end = offset + length;
+        for (int i = offset; i < end; i++)
+            append(chars.charAt(i));
+    }
+
+    default void append(ByteBuffer buf)
+    {
+        int end = buf.position() + buf.remaining();
+        while (buf.position() < end)
+            append(buf.get());
+    }
+
+    /**
+     * <p>Build the completed string and reset the buffer.</p>
+     * @return The decoded built string which must be complete in regard to any multibyte sequences.
+     * @throws CharacterCodingException If the bytes cannot be correctly decoded or a multibyte sequence is incomplete.
+     */
+    String build() throws CharacterCodingException;
+
+    void reset();
+
+    static CharsetStringBuilder forCharset(Charset charset)
+    {
+        Objects.requireNonNull(charset);
+        if (charset == StandardCharsets.ISO_8859_1)
+            return new Iso8859StringBuilder();
+        if (charset == StandardCharsets.US_ASCII)
+            return new UsAsciiStringBuilder();
+
+        // Use a CharsetDecoder that defaults to CodingErrorAction#REPORT
+        return new DecoderStringBuilder(charset.newDecoder());
+    }
+
+    class Iso8859StringBuilder implements CharsetStringBuilder
+    {
+        private final StringBuilder _builder = new StringBuilder();
+
+        @Override
+        public void append(byte b)
+        {
+            _builder.append((char)(0xff & b));
+        }
+
+        @Override
+        public void append(char c)
+        {
+            _builder.append(c);
+        }
+
+        @Override
+        public void append(CharSequence chars, int offset, int length)
+        {
+            _builder.append(chars, offset, length);
+        }
+
+        @Override
+        public String build()
+        {
+            String s = _builder.toString();
+            _builder.setLength(0);
+            return s;
+        }
+
+        @Override
+        public void reset()
+        {
+            _builder.setLength(0);
+        }
+    }
+    
+    class UsAsciiStringBuilder implements CharsetStringBuilder
+    {
+        private final StringBuilder _builder = new StringBuilder();
+
+        @Override
+        public void append(byte b)
+        {
+            if (b < 0)
+                throw new IllegalArgumentException();
+            _builder.append((char)b);
+        }
+
+        @Override
+        public void append(char c)
+        {
+            _builder.append(c);
+        }
+
+        @Override
+        public void append(CharSequence chars, int offset, int length)
+        {
+            _builder.append(chars, offset, length);
+        }
+
+        @Override
+        public String build()
+        {
+            String s = _builder.toString();
+            _builder.setLength(0);
+            return s;
+        }
+
+        @Override
+        public void reset()
+        {
+            _builder.setLength(0);
+        }
+    }
+
+    class DecoderStringBuilder implements CharsetStringBuilder
+    {
+        private final CharsetDecoder _decoder;
+        private final StringBuilder _stringBuilder = new StringBuilder(32);
+        private ByteBuffer _buffer = ByteBuffer.allocate(32);
+        
+        public DecoderStringBuilder(CharsetDecoder charsetDecoder)
+        {
+            _decoder = charsetDecoder;
+        }
+
+        private void ensureSpace(int needed)
+        {
+            int space = _buffer.remaining();
+            if (space < needed)
+            {
+                int position = _buffer.position();
+                _buffer = ByteBuffer.wrap(Arrays.copyOf(_buffer.array(), _buffer.capacity() + needed - space + 32)).position(position);
+            }
+        }
+
+        @Override
+        public void append(byte b)
+        {
+            ensureSpace(1);
+            _buffer.put(b);
+        }
+
+        @Override
+        public void append(char c)
+        {
+            if (_buffer.position() > 0)
+            {
+                try
+                {
+                    // Append any data already in the decoder
+                    _stringBuilder.append(_decoder.decode(_buffer.flip()));
+                    _buffer.clear();
+                }
+                catch (CharacterCodingException e)
+                {
+                    // This will be thrown only if the decoder is configured to REPORT,
+                    // otherwise errors will be ignored or replaced and we will not catch here.
+                    throw new RuntimeException(e);
+                }
+            }
+            _stringBuilder.append(c);
+        }
+
+        @Override
+        public void append(CharSequence chars, int offset, int length)
+        {
+            if (_buffer.position() > 0)
+            {
+                try
+                {
+                    // Append any data already in the decoder
+                    _stringBuilder.append(_decoder.decode(_buffer.flip()));
+                    _buffer.clear();
+                }
+                catch (CharacterCodingException e)
+                {
+                    // This will be thrown only if the decoder is configured to REPORT,
+                    // otherwise errors will be ignored or replaced and we will not catch here.
+                    throw new RuntimeException(e);
+                }
+            }
+            _stringBuilder.append(chars, offset, offset + length);
+        }
+
+        @Override
+        public void append(byte[] b, int offset, int length)
+        {
+            ensureSpace(length);
+            _buffer.put(b, offset, length);
+        }
+
+        @Override
+        public void append(ByteBuffer buf)
+        {
+            ensureSpace(buf.remaining());
+            _buffer.put(buf);
+        }
+
+        @Override
+        public String build() throws CharacterCodingException
+        {
+            try
+            {
+                if (_buffer.position() > 0)
+                {
+                    CharSequence decoded = _decoder.decode(_buffer.flip());
+                    _buffer.clear();
+                    if (_stringBuilder.length() == 0)
+                        return decoded.toString();
+                    _stringBuilder.append(decoded);
+                }
+                return _stringBuilder.toString();
+            }
+            finally
+            {
+                _stringBuilder.setLength(0);
+            }
+        }
+
+        @Override
+        public void reset()
+        {
+            _stringBuilder.setLength(0);
+        }
+    }
+}
+
+