hunt.sql.visitor.functions.Char source code

1 /*
2  * Copyright 2015-2018 HuntLabs.cn
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 module hunt.sql.visitor.functions.Char;
17 
18 // import hunt.sql.visitor.SQLEvalVisitor.EVAL_VALUE;
19 
20 
21 import hunt.sql.ast.SQLExpr;
22 import hunt.sql.ast.expr.SQLMethodInvokeExpr;
23 import hunt.sql.visitor.SQLEvalVisitor;
24 import hunt.sql.visitor.functions.Function;
25 import hunt.Number;
26 import hunt.String;
27 import hunt.String;
28 import hunt.collection;
29 import hunt.math;
30 import hunt.text;
31 import std.concurrency : initOnce;
32 
33 public class Char : Function {
34 
35     static Char instance() {
36         __gshared Char inst;
37         return initOnce!inst(new Char());
38     }    
39     // public  static Char instance;
40 
41     // static this()
42     // {
43     //     instance = new Char();
44     // }
45 
46     public Object eval(SQLEvalVisitor visitor, SQLMethodInvokeExpr x) {
47         if (x.getParameters().size() == 0) {
48             return cast(Object)(SQLEvalVisitor.EVAL_ERROR);
49         }
50 
51         StringBuilder buf = new StringBuilder(x.getParameters().size());
52         foreach(SQLExpr param ; x.getParameters()) {
53             param.accept(visitor);
54 
55             Object paramValue = param.getAttributes().get(SQLEvalVisitor.EVAL_VALUE);
56 
57             if (cast(Number)(paramValue) !is null) {
58                 int charCode = (cast(Number) paramValue).intValue();
59                 buf.append(cast(char) charCode);
60             } else if (cast(String)(paramValue) !is null) {
61                 try {
62                     int charCode = new BigDecimal((cast(String) paramValue).value()).intValue();
63                     buf.append(cast(char) charCode);
64                 } catch (Exception e) {
65                 }
66             } else {
67                 return cast(Object)(SQLEvalVisitor.EVAL_ERROR);
68             }
69         }
70 
71         return new String(buf.toString());
72     }
73 }