3.3.7

cores/esp32/HashBuilder.h

@@ -0,0 +1,63 @@
+// Copyright 2024 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef HashBuilder_h
+#define HashBuilder_h
+
+#include <WString.h>
+#include <Stream.h>
+
+#include "HEXBuilder.h"
+
+/* Try to prevent most compilers from optimizing out clearing of memory that
+ * becomes unaccessible after this function is called. This is mostly the case
+ * for clearing local stack variables at the end of a function. This is not
+ * exactly perfect, i.e., someone could come up with a compiler that figures out
+ * the pointer is pointing to memset and then end up optimizing the call out, so
+ * try go a bit further by storing the first octet (now zero) to make this even
+ * a bit more difficult to optimize out. Once memset_s() is available, that
+ * could be used here instead. */
+static void *(*const volatile memset_func)(void *, int, size_t) = memset;
+static uint8_t forced_memzero_val;
+
+static inline void forced_memzero(void *ptr, size_t len) {
+  memset_func(ptr, 0, len);
+  if (len) {
+    forced_memzero_val = ((uint8_t *)ptr)[0];
+  }
+}
+
+// Base class for hash builders
+
+class HashBuilder : public HEXBuilder {
+public:
+  virtual ~HashBuilder() {}
+  virtual void begin() = 0;
+
+  virtual void add(const uint8_t *data, size_t len) = 0;
+  void add(const char *data);
+  void add(String data);
+
+  void addHexString(const char *data);
+  void addHexString(String data);
+
+  virtual bool addStream(Stream &stream, const size_t maxLen) = 0;
+  virtual void calculate() = 0;
+  virtual void getBytes(uint8_t *output) = 0;
+  virtual void getChars(char *output) = 0;
+  virtual String toString() = 0;
+  virtual size_t getHashSize() const = 0;
+};
+
+#endif