[expr] Add coding of functions SUBSTR, MID.

Author: lasyard

coding/src/main/java/io/dingodb/expr/coding/ExprCoder.java

@@ -280,9 +280,22 @@ public CodingFlag visitBinaryOpExpr(@NonNull BinaryOpExpr expr, OutputStream obj
         return null;
     }
 
+    @SneakyThrows
     @Override
     public CodingFlag visitTertiaryOpExpr(@NonNull TertiaryOpExpr expr, @NonNull OutputStream obj) {
-        return super.visitTertiaryOpExpr(expr, obj);
+        if (visit(expr.getOperand0(), obj) == OK
+            && visit(expr.getOperand1(), obj) == OK
+            && visit(expr.getOperand2(), obj) == OK
+        ) {
+            boolean success = false;
+            if (expr.getOpType() == OpType.FUN) {
+                success = writeFun(obj, FunIndex.getTertiary(expr.getOp()));
+            }
+            if (success) {
+                return OK;
+            }
+        }
+        return null;
     }
 
     @SneakyThrows

coding/src/main/java/io/dingodb/expr/coding/FunIndex.java

@@ -17,6 +17,7 @@
 package io.dingodb.expr.coding;
 
 import io.dingodb.expr.runtime.op.BinaryOp;
+import io.dingodb.expr.runtime.op.TertiaryOp;
 import io.dingodb.expr.runtime.op.UnaryOp;
 import io.dingodb.expr.runtime.op.mathematical.AcosFunFactory;
 import io.dingodb.expr.runtime.op.mathematical.AsinFunFactory;
@@ -35,8 +36,12 @@
 import io.dingodb.expr.runtime.op.string.LTrimFunFactory;
 import io.dingodb.expr.runtime.op.string.LeftFunFactory;
 import io.dingodb.expr.runtime.op.string.LowerFunFactory;
+import io.dingodb.expr.runtime.op.string.Mid2FunFactory;
+import io.dingodb.expr.runtime.op.string.Mid3FunFactory;
 import io.dingodb.expr.runtime.op.string.RTrimFunFactory;
 import io.dingodb.expr.runtime.op.string.RightFunFactory;
+import io.dingodb.expr.runtime.op.string.Substr2FunFactory;
+import io.dingodb.expr.runtime.op.string.Substr3FunFactory;
 import io.dingodb.expr.runtime.op.string.TrimFunFactory;
 import io.dingodb.expr.runtime.op.string.UpperFunFactory;
 import io.dingodb.expr.runtime.type.Types;
@@ -133,6 +138,28 @@ static int getBinary(@NonNull BinaryOp op) {
             case RightFunFactory.NAME:
                 funIndex = 0x25;
                 break;
+            case Substr2FunFactory.NAME:
+                funIndex = 0x2D;
+                break;
+            case Mid2FunFactory.NAME:
+                funIndex = 0x2F;
+                break;
+            default:
+                break;
+        }
+        return funIndex;
+    }
+
+    static int getTertiary(@NonNull TertiaryOp op) {
+        String funName = op.getName();
+        int funIndex = -1;
+        switch (funName) {
+            case Substr3FunFactory.NAME:
+                funIndex = 0x2C;
+                break;
+            case Mid3FunFactory.NAME:
+                funIndex = 0x2E;
+                break;
             default:
                 break;
         }

libexpr

@@ -26,7 +26,10 @@ abstract class Substr2Fun extends BinaryStringIntFun {
     private static final long serialVersionUID = 992163045871277543L;
 
     static @NonNull String substr(@NonNull String value0, int start) {
-        return value0.substring(start);
+        if (start < 0) {
+            start = 0;
+        }
+        return (start == 0) ? value0 : value0.substring(start);
     }
 
     @Override

runtime/src/main/java/io/dingodb/expr/runtime/op/string/Substr2Fun.java

@@ -26,7 +26,13 @@ abstract class Substr3Fun extends TertiaryStringIntIntFun {
     private static final long serialVersionUID = -5730776211565201950L;
 
     static @NonNull String substr(@NonNull String value0, int start, int end) {
-        return value0.substring(start, end);
+        if (start < 0) {
+            start = 0;
+        }
+        if (start == 0) {
+            return end >= value0.length() ? value0 : value0.substring(start, end);
+        }
+        return end >= value0.length() ? value0.substring(start) : value0.substring(start, end);
     }
 
     @Override