新增基于token hash的解析器，暂时只做了词法切割和hash，还没做分析

Author: ishotoli

src/main/java/io/mycat/NewSQLParser.java

@@ -0,0 +1,91 @@
+package io.mycat;
+
+import java.nio.charset.StandardCharsets;
+import java.util.stream.IntStream;
+
+/**
+ * Created by Kaiz on 2017/2/6.
+ */
+public class NewSQLParser {
+    SQLContext context;
+    SQLReader reader;
+
+    class HashArray {
+        long[] hashArray = new long[1024];
+        int pos = 0;
+
+        void init() {
+            while(pos>=0) {
+                hashArray[pos--] = 0;
+            }
+            pos = 0;
+        };
+        void set(long hash) { hashArray[pos++] = hash; }
+        long get(int idx) { return hashArray[idx]; }
+        int getCount() {return pos;}
+    }
+
+    final byte[] charType = new byte[128];
+    final short[] tokenPos = new short[1024];
+    HashArray hashArray = new HashArray();
+
+    void init() {
+        IntStream.range('A', 'Z').forEach(c -> charType[c] = 1);
+        IntStream.range('a', 'z').forEach(c -> charType[c] = 1);
+        charType['_'] = 1;
+    }
+
+    int parseToken(byte[] sql, int pos, int sqlLength) {
+        int tp = 0;
+        byte c = (byte)(sql[pos] & 0xDF);
+        long hash = c;
+        pos++;
+        while (pos < sqlLength && charType[c = sql[pos]] == 1) {
+            hash += (long)(c & 0xDF) << (tp & 0xFF);
+            pos++;
+            tp++;
+        }
+        hashArray.set(hash);
+        return pos;
+    }
+
+    void tokenize(byte[] sql) {
+        int sqlLength = sql.length;
+        int pos = 0;
+        hashArray.init();
+        while (pos < sqlLength) {
+            if (charType[sql[pos]]==1) {
+                pos = parseToken(sql, pos, sqlLength);
+            } else {
+                pos++;
+            }
+        }
+    }
+
+    static long RunBench(byte[] src, NewSQLParser parser) {
+        int count = 0;
+        long start = System.currentTimeMillis();
+        do {
+            parser.tokenize(src);
+        } while (count++ < 10_000_000);
+        return System.currentTimeMillis() - start;
+    }
+
+    public static void main(String[] args) {
+        NewSQLParser parser = new NewSQLParser();
+        parser.init();
+        long min = 0;
+        byte[] src = "SELECT a FROM ab             , ee.ff AS f,(SELECT a FROM `schema_bb`.`tbl_bb`,(SELECT a FROM ccc AS c, `dddd`));".getBytes(StandardCharsets.UTF_8);//20个token
+        for (int i = 0; i < 50; i++) {
+            System.out.print("Loop " + i + " : ");
+            long cur = RunBench(src, parser);//by kaiz : 不加分析应该可以进2.6秒
+            System.out.println(cur);
+            if (cur < min || min == 0) {
+                min = cur;
+            }
+        }
+        System.out.print("min time : " + min);
+//        parser.tokenize(src);
+//        System.out.print("token count : "+parser.hashArray.getCount());
+    }
+}