add sha2.h file for sha256 support

Author: tessus

sha2.h

@@ -0,0 +1,66 @@
+/*
+  +----------------------------------------------------------------------+
+  | sha2.h: APR sha256 include file                                      |
+  +----------------------------------------------------------------------+
+  | 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.                       |
+  +----------------------------------------------------------------------+
+  | Author: Aaron D. Gifford <[email protected]>                       |
+  +----------------------------------------------------------------------+
+  | A licence was granted to the ASF by Aaron on 4 November 2003.        |
+  +----------------------------------------------------------------------+
+*/
+
+#ifndef __SHA2_H__
+#define __SHA2_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "apr.h"
+
+/*** SHA-256 Various Length Definitions ***********************/
+#define SHA256_BLOCK_LENGTH             64
+#define SHA256_DIGEST_LENGTH            32
+#define SHA256_DIGEST_STRING_LENGTH     (SHA256_DIGEST_LENGTH * 2 + 1)
+
+
+/*** SHA-256/384/512 Context Structures *******************************/
+typedef struct _SHA256_CTX {
+        apr_uint32_t    state[8];
+        apr_uint64_t    bitcount;
+        apr_byte_t      buffer[SHA256_BLOCK_LENGTH];
+} SHA256_CTX;
+
+
+/*** SHA-256/384/512 Function Prototypes ******************************/
+void apr__SHA256_Init(SHA256_CTX *);
+void apr__SHA256_Update(SHA256_CTX *, const apr_byte_t *, size_t);
+void apr__SHA256_Final(apr_byte_t [SHA256_DIGEST_LENGTH], SHA256_CTX *);
+char* apr__SHA256_End(SHA256_CTX *, char [SHA256_DIGEST_STRING_LENGTH]);
+char* apr__SHA256_Data(const apr_byte_t *, size_t,
+                  char [SHA256_DIGEST_STRING_LENGTH]);
+
+#ifdef  __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __SHA2_H__ */
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: noet sw=4 ts=4 fdm=marker
+ * vim<600: noet sw=4 ts=4
+ */