From a783b26ce6009d5a329a1a81e11012b774850f2e Mon Sep 17 00:00:00 2001
From: cheney <cbed@163.com>
Date: Fri, 2 Sep 2022 14:27:08 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AD=97=E8=8A=82=E9=98=9F=E5=88=97=E7=B1=BB?=
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---
 .../com/sunyard/sge/bytes/BytesQueue.java     | 116 ++++++++++++++++++
 .../com/sunyard/sge/log/SydLogFactory.java    |   4 +
 src/test/java/test/ByteQueueTest.java         |  35 ++++++
 3 files changed, 155 insertions(+)
 create mode 100644 src/main/java/com/sunyard/sge/bytes/BytesQueue.java
 create mode 100644 src/main/java/com/sunyard/sge/log/SydLogFactory.java
 create mode 100644 src/test/java/test/ByteQueueTest.java

diff --git a/src/main/java/com/sunyard/sge/bytes/BytesQueue.java b/src/main/java/com/sunyard/sge/bytes/BytesQueue.java
new file mode 100644
index 0000000..17e9f87
--- /dev/null
+++ b/src/main/java/com/sunyard/sge/bytes/BytesQueue.java
@@ -0,0 +1,116 @@
+package com.sunyard.sge.bytes;
+
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * 字节流先入先出队列
+ * **非线程安全**
+ */
+public class BytesQueue {
+
+    // 字节队列
+    private List<byte[]>queue = new LinkedList<>();
+    // 有效字节起始位置指针
+    private int index = 0;
+    // 维护实时长度
+    private int length = 0;
+
+    /**
+     * 尾部添加
+     * @param datas
+     */
+    public void push(byte[] datas){
+        if ( null == datas ) {
+            return;
+        }
+        if ( datas.length == 0 ) {
+            return;
+        }
+
+        if ( datas.length > Integer.MAX_VALUE - length ){
+            throw new IllegalArgumentException("too big");
+        }
+
+        queue.add( datas );
+
+        length += datas.length;
+    }
+
+    /**
+     * 获取字节
+     * @param multiple 整倍数
+     * @param reserve 保留
+     * @return 所有字节
+     */
+    public byte[] pop(int multiple, int reserve){
+
+        if ( length <= reserve ) {
+            return new byte[0];
+        }
+
+        int len = length - reserve;
+        int raminder = len % multiple;
+        len -= raminder;
+
+        if ( 0 == len ) {
+            return new byte[0];
+        }
+
+        byte[] data = null;
+        int dataIndex = 0;
+        int needLen = len;
+        boolean isFirst = true;
+        Iterator<byte[]>it = queue.iterator();
+        while ( it.hasNext() ){
+            byte[] q = it.next();
+            // 首轮加速
+            if ( isFirst ) {
+                isFirst = false;
+
+                if ( 0 == index && q.length == needLen ) {
+                    queue.remove(0);
+                    index = 0;
+                    length -= needLen;
+                    return q;
+                }
+                data = new byte[  needLen ];
+            }
+
+            int hasLen = q.length - index;
+            System.out.println(String.format("-> %d %d %d", dataIndex, needLen, hasLen));
+            if ( hasLen == needLen ) {
+                System.arraycopy( q, index , data, dataIndex, needLen );
+                it.remove();
+                index = 0;
+                length -= needLen;
+                return data;
+            } else if ( hasLen > needLen ) {
+                System.arraycopy( q, index , data, dataIndex, needLen );
+                index += needLen;
+                length -= needLen;
+                return data;
+            } else {
+                System.arraycopy( q, index , data, dataIndex, hasLen );
+                it.remove();
+                index = 0;
+                length -= hasLen;
+                dataIndex += hasLen;
+                needLen = len - dataIndex;
+                if ( 0 == needLen ) {
+                    return data;
+                }
+            }
+        }
+        throw new RuntimeException("pop error");
+    }
+
+    public byte[] pop(int reserve){
+        return pop( 1, reserve );
+    }
+    public byte[] pop(){
+        return pop( 1, 0 );
+    }
+}
diff --git a/src/main/java/com/sunyard/sge/log/SydLogFactory.java b/src/main/java/com/sunyard/sge/log/SydLogFactory.java
new file mode 100644
index 0000000..6aab66e
--- /dev/null
+++ b/src/main/java/com/sunyard/sge/log/SydLogFactory.java
@@ -0,0 +1,4 @@
+package com.sunyard.sge.log;
+
+public class SydLogFactory {
+}
diff --git a/src/test/java/test/ByteQueueTest.java b/src/test/java/test/ByteQueueTest.java
new file mode 100644
index 0000000..16718aa
--- /dev/null
+++ b/src/test/java/test/ByteQueueTest.java
@@ -0,0 +1,35 @@
+package test;
+
+import com.sunyard.sge.bytes.BytesQueue;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Random;
+
+public class ByteQueueTest {
+
+    @Test
+    public void case1() {
+        BytesQueue queue = new BytesQueue();
+        int max = 1000;
+
+        for (int i = 0; i < max; i++) {
+            int r = new Random().nextInt(4096);
+            queue.push(new byte[r]);
+        }
+
+
+        while (true) {
+            byte[] data = queue.pop(16, 16);
+            Assert.assertEquals(data.length % 16, 0);
+            if (0 == data.length) {
+                data = queue.pop();
+                Assert.assertTrue( data.length >= 16 );
+                data = queue.pop();
+                Assert.assertEquals(0, data.length);
+                return;
+            }
+        }
+    }
+
+}