Add support for opaque hash values.

src/OpaqueVal.h

@@ -0,0 +1,84 @@
+#ifndef OPAQUEVAL_H
+#define OPAQUEVAL_H
+
+#include "Val.h"
+#include "digest.h"
+
+class HashVal : public OpaqueVal {
+public:
+  virtual bool IsValid() const;
+  virtual bool Init();
+  virtual bool Feed(const void* data, size_t size);
+  virtual StringVal* Get();
+
+protected:
+  HashVal() { };
+  HashVal(OpaqueType* t);
+  virtual bool Update(const void* data, size_t size);
+  virtual StringVal* Finish();
+
+  DECLARE_SERIAL(HashVal);
+
+private:
+  // This flag exists because Get() can only be called once.
+  bool valid;
+};
+
+class MD5Val : public HashVal {
+public:
+  static void digest(val_list& vlist, u_char result[MD5_DIGEST_LENGTH]);
+
+  static void hmac(val_list& vlist,
+                   u_char key[MD5_DIGEST_LENGTH],
+                   u_char result[MD5_DIGEST_LENGTH]);
+
+  MD5Val() : HashVal(new OpaqueType("md5")) { }
+
+protected:
+  friend class Val;
+
+  virtual bool Init() /* override */;
+  virtual bool Update(const void* data, size_t size) /* override */;
+  virtual StringVal* Finish() /* override */;
+
+  DECLARE_SERIAL(MD5Val);
+
+private:
+  MD5_CTX ctx;
+};
+
+class SHA1Val : public HashVal {
+public:
+  SHA1Val() : HashVal(new OpaqueType("sha1")) { }
+
+protected:
+  friend class Val;
+
+  virtual bool Init() /* override */;
+  virtual bool Update(const void* data, size_t size) /* override */;
+  virtual StringVal* Finish() /* override */;
+
+  DECLARE_SERIAL(SHA1Val);
+
+private:
+  SHA_CTX ctx;
+};
+
+class SHA256Val : public HashVal {
+public:
+  SHA256Val() : HashVal(new OpaqueType("sha256")) { }
+
+protected:
+  friend class Val;
+
+  virtual bool Init() /* override */;
+  virtual bool Update(const void* data, size_t size) /* override */;
+  virtual StringVal* Finish() /* override */;
+
+  DECLARE_SERIAL(SHA256Val);
+
+private:
+  SHA256_CTX ctx;
+};
+
+#endif