finish Component: SignatureInfo

src/main/java/component/SignatureInfo.java

@@ -0,0 +1,182 @@
+package component;
+
+import encoding.*;
+/*
+ * @Author: Wang Feng
+ * @Description: 表示签名的元数据，包含：签名类型、用于签名的证书或公钥的位置
+//	1. 格式如下：
+//		SignatureInfo = 201 TLV-LENGTH
+//                <SignatureType>
+//                [KeyLocator]
+//	2. 详情参见：http://gitea.qjm253.cn/PKUSZ-future-network-lab/minlib/src/branch/master/docs/PacketFormat.md#4-signature
+ * @Version: 1.0.0
+ * @Date: 20:26 2021/3/15
+ * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
+ */
+public class SignatureInfo implements TlvComponentBase, IEncodingAble {
+    private SignatureType signatureType;
+    private KeyLocator keyLocator;
+
+    /**
+     * 根据签名值类型创建一个 SignatureInfo
+     * @param value
+     */
+    public SignatureInfo(SignatureAlgorithm value){
+        this.buildSignatureInfoBySignatureTypeValue(value);
+    }
+
+    /**
+     * 根据签名值类型和 KeyLocator 创建一个 SignatureInfo
+     * @param value
+     * @param locator
+     */
+    public SignatureInfo(SignatureAlgorithm value,KeyLocator locator){
+        this.buildSignatureInfoBySignatureTypeValueAndKeyLocator(value,locator);
+    }
+
+    /**
+     * 根据 TLV Block 创建一个 SignatureInfo
+     * @param block
+     */
+    public SignatureInfo(Block block){
+        this.buildSignatureInfoByBlock(block);
+    }
+
+    /**
+     * 根据签名类型值初始化当前 SignatureInfo
+     * @param signatureTypeValue
+     * @return
+     */
+    public boolean buildSignatureInfoBySignatureTypeValue(SignatureAlgorithm signatureTypeValue){
+        return this.signatureType.buildSignatureTypeByValue(signatureTypeValue);
+    }
+
+    /**
+     * 根据签名类型值和 KeyLocator 初始化当前 SignatureInfo
+     * @param value
+     * @param locator
+     * @return
+     */
+    public boolean buildSignatureInfoBySignatureTypeValueAndKeyLocator(SignatureAlgorithm value,KeyLocator locator){
+        if(!this.signatureType.buildSignatureTypeByValue(value)){
+            return false;
+        }
+
+        if(!this.keyLocator.buildKeyLocatorByIdentifier(keyLocator.getIdentifier())){
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * 根据 TLV Block 初始化当前 SignatureInfo
+     * @param block
+     * @return
+     */
+    public boolean buildSignatureInfoByBlock(Block block){
+        return this.wireDecode(block);
+    }
+
+    /**
+     * 获得签名类型
+     * @return
+     */
+    public SignatureType getSignatureType() {
+        return signatureType;
+    }
+
+    /**
+     * 获得 KeyLocator
+     * @return
+     */
+    public KeyLocator getKeyLocator() {
+        return keyLocator;
+    }
+
+    /**
+     * 将 SignatureInfo 线速编码为 TLV
+     * @param encoder
+     * @return
+     */
+    @Override
+    public int wireEncode(Encoder encoder) {
+        int totalLength=0;
+        // 编码 TLV-VALUE
+        if(!this.keyLocator.isValid()){
+            // KeyLocator 是可选的，如果当前 SignatureInfo 对象有一个有效的 KeyLocator，则对其进行编码
+            int tmplen=this.keyLocator.wireEncode(encoder);
+            if(tmplen<=0){
+                return 0;
+            }
+            totalLength+=tmplen;
+        }
+        int tmplen=this.signatureType.wireEncode(encoder);
+        if(tmplen<=0){
+            return 0;
+        }
+        totalLength+=tmplen;
+
+        // 编码 TLV-LENGTH
+        tmplen=encoder.prependVarNumber(new VlInt(totalLength));
+        if(tmplen<=0){
+            return 0;
+        }
+        totalLength+=tmplen;
+
+        // 编码 TLV-TYPE
+        tmplen=encoder.prependVarNumber(new VlInt(TLV.TlvSignatureInfo));
+        if(tmplen<=0){
+            return 0;
+        }
+        totalLength+=tmplen;
+
+        return totalLength;
+    }
+
+    /**
+     * 从 TLV Block 中解码出一个 SignatureInfo
+     * @param block
+     * @return
+     */
+    @Override
+    public boolean wireDecode(Block block) {
+        // 检查 Type 是否正确
+        if(!TLV.expectType(block.getType(),new VlInt(TLV.TlvSignatureInfo))){
+            return false;
+        }
+
+        // 解析子 TLV
+        if(!block.parseSubElements()){
+            return false;
+        }
+
+        boolean findSignatureType=false;
+        int elementSize=block.getSubElements().length();
+        for (int i=0;i<elementSize;i++) {
+            Block cacheBlock=block.getSubElements().getBlock(i);
+            switch (cacheBlock.getType().getVlIntValue2Int()){
+                case TLV.TlvSignatureType:
+                    if(!this.signatureType.wireDecode(cacheBlock)){
+                        return false;
+                    }
+                    findSignatureType=true;
+                case TLV.TlvKeyLocator:
+                    if(!this.keyLocator.wireDecode(cacheBlock)){
+                        return false;
+                    }
+                default:
+                    throw new Error("SignatureInfo.wireDecode: SignatureInfo sub element type error");
+//                    return false;
+
+            }
+        }
+
+        // 缺失必要的 SignatureType 子TLV
+        if(!findSignatureType){
+            throw new Error("SignatureInfo.wireDecode: Parse SignatureInfo error, require SignatureType sub-element");
+        }
+
+        return true;
+    }
+}