Быстрый write/read int8, патч выдачи reserved байт при getBuffer

src/main/java/io/orprotocol/Stream.java

@@ -3,17 +3,17 @@ package io.orprotocol;
 import java.util.Arrays;
 
 public class Stream {
-    
+
     private byte[] stream;
-    private int readPointer = 0;
-    private int writePointer = 0;
+    private int readPointer = 0;   // bits
+    private int writePointer = 0;  // bits
 
     public Stream() {
         this.stream = new byte[0];
     }
 
     public Stream(byte[] stream) {
-        this.stream = stream;
+        this.stream = (stream == null) ? new byte[0] : stream;
         this.readPointer = 0;
         this.writePointer = this.stream.length << 3;
     }
@@ -23,51 +23,72 @@ public class Stream {
     }
 
     public void setStream(byte[] stream) {
-        this.stream = stream;
+        this.stream = (stream == null) ? new byte[0] : stream;
         this.readPointer = 0;
         this.writePointer = this.stream.length << 3;
     }
 
+    // Fast path: write 9 bits (sign + value) in <= 2 byte writes
     public void writeInt8(int value) {
         int negationBit = value < 0 ? 1 : 0;
         int int8Value = Math.abs(value) & 0xFF;
-        /**
-         * 1 sign
-         * 8 bits for value
-         */
+        int packed9 = (negationBit << 8) | int8Value; // 9 bits total
+
         reserveBits(9);
-        stream[writePointer >> 3] |= (byte) (negationBit << (7 - (writePointer & 7)));
-        writePointer++;
-        
-        for (int i = 0; i < 8; i++) {
-            int bit = (int8Value >> (7 - i)) & 1;
-            stream[writePointer >> 3] |= (byte) (bit << (7 - (writePointer & 7)));
-            writePointer++;
-        }
+
+        int wp = writePointer;
+        int byteIndex = wp >> 3;
+        int bitOffset = wp & 7; // 0..7
+
+        int firstCount = 8 - bitOffset;   // bits into current byte
+        int secondCount = 9 - firstCount; // bits into next byte (1..8)
+
+        int firstPart = packed9 >> secondCount; // fits firstCount bits
+        stream[byteIndex] |= (byte) firstPart;
+
+        int secondMask = (1 << secondCount) - 1;
+        int secondPart = (packed9 & secondMask) << (8 - secondCount);
+        stream[byteIndex + 1] |= (byte) secondPart;
+
+        writePointer = wp + 9;
     }
 
+    // Fast path: read 9 bits (sign + value) from <= 2 bytes
     public int readInt8() {
-        int value = 0;
-        int negationBit = (stream[readPointer >> 3] >> (7 - (readPointer & 7))) & 1;
-        readPointer++;
-        
-        for (int i = 0; i < 8; i++) {
-            int bit = (stream[readPointer >> 3] >> (7 - (readPointer & 7))) & 1;
-            value |= bit << (7 - i);
-            readPointer++;
+        if (remainingBits() < 9L) {
+            throw new IllegalStateException("Not enough bits to read Int8");
         }
-        
-        return negationBit == 1 ? -value : value;
+
+        int rp = readPointer;
+        int byteIndex = rp >> 3;
+        int bitOffset = rp & 7;
+
+        int firstCount = 8 - bitOffset;
+        int secondCount = 9 - firstCount;
+
+        int firstMask = (1 << firstCount) - 1;
+        int firstPart = stream[byteIndex] & firstMask;
+        int secondPart = ((stream[byteIndex + 1] & 0xFF) >> (8 - secondCount));
+
+        int packed9 = (firstPart << secondCount) | secondPart;
+        readPointer = rp + 9;
+
+        int negationBit = (packed9 >> 8) & 1;
+        int int8Value = packed9 & 0xFF;
+        return negationBit == 1 ? -int8Value : int8Value;
     }
 
     public void writeBit(int value) {
+        reserveBits(1);
         int bit = value & 1;
-        ensureCapacity(writePointer >> 3);
         stream[writePointer >> 3] |= (byte) (bit << (7 - (writePointer & 7)));
         writePointer++;
     }
 
     public int readBit() {
+        if (remainingBits() < 1L) {
+            throw new IllegalStateException("Not enough bits to read bit");
+        }
         int bit = (stream[readPointer >> 3] >> (7 - (readPointer & 7))) & 1;
         readPointer++;
         return bit;
@@ -125,6 +146,10 @@ public class Stream {
     }
 
     public void writeString(String value) {
+        if (value == null) {
+            value = "";
+        }
+
         int length = value.length();
         writeInt32(length);
 
@@ -132,7 +157,7 @@ public class Stream {
             return;
         }
 
-        // writeInt16 -> 2 * writeInt8 -> 18 бит на символ
+        // writeInt16 -> 2 * writeInt8 -> 18 bits per char
         reserveBits((long) length * 18L);
 
         for (int i = 0; i < length; i++) {
@@ -147,10 +172,8 @@ public class Stream {
             return "";
         }
 
-        // На один символ тратится 18 бит (через writeInt16/readInt16)
-        long remainingBits = ((long) stream.length << 3) - readPointer;
         long requiredBits = (long) length * 18L;
-        if (requiredBits > remainingBits) {
+        if (requiredBits > remainingBits()) {
             return "";
         }
 
@@ -162,23 +185,34 @@ public class Stream {
     }
 
     public void writeBytes(byte[] value) {
+        if (value == null) {
+            value = new byte[0];
+        }
+
         writeInt32(value.length);
 
         if (value.length > 0) {
+            // writeInt8 = 9 bits per byte
             reserveBits((long) value.length * 9L);
         }
 
-        for (int i = 0; i < value.length; i++) {
-            writeInt8(value[i]);
+        for (byte b : value) {
+            writeInt8(b);
         }
     }
 
     public byte[] readBytes() {
         int length = readInt32();
+
         if (length < 0) {
             return new byte[0];
         }
 
+        long requiredBits = (long) length * 9L;
+        if (requiredBits > remainingBits()) {
+            return new byte[0];
+        }
+
         byte[] value = new byte[length];
         for (int i = 0; i < length; i++) {
             value[i] = (byte) readInt8();
@@ -187,15 +221,20 @@ public class Stream {
     }
 
     public boolean isEmpty() {
-        return this.stream.length == 0;
+        return writePointer == 0;
     }
 
+    // useful bytes without reserved tail
     public int length() {
         return (writePointer + 7) >> 3;
     }
 
     public byte[] getBuffer() {
-        return this.stream;
+        return getStream();
+    }
+
+    private long remainingBits() {
+        return (long) writePointer - readPointer;
     }
 
     private void reserveBits(long bitsToWrite) {