Compute SHA-1 checksums of regular files to be stored with index data.

[cumulus.git] / sha1.h

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+/* Declarations of functions and data types used for SHA1 sum
+   library functions.
+   Copyright (C) 2000, 2001, 2003, 2005 Free Software Foundation, Inc.
+   Copyright (C) 2006 Michael Vrable
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef SHA1_H
+# define SHA1_H 1
+
+# include <stdio.h>
+# include <stdint.h>
+
+typedef uint32_t md5_uint32;
+
+/* Structure to save state of computation between the single steps.  */
+struct sha1_ctx
+{
+  md5_uint32 A;
+  md5_uint32 B;
+  md5_uint32 C;
+  md5_uint32 D;
+  md5_uint32 E;
+
+  md5_uint32 total[2];
+  md5_uint32 buflen;
+  char buffer[128] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
+};
+
+
+/* Initialize structure containing state of computation. */
+extern void sha1_init_ctx (struct sha1_ctx *ctx);
+
+/* Starting with the result of former calls of this function (or the
+   initialization function update the context for the next LEN bytes
+   starting at BUFFER.
+   It is necessary that LEN is a multiple of 64!!! */
+extern void sha1_process_block (const void *buffer, size_t len,
+                               struct sha1_ctx *ctx);
+
+/* Starting with the result of former calls of this function (or the
+   initialization function update the context for the next LEN bytes
+   starting at BUFFER.
+   It is NOT required that LEN is a multiple of 64.  */
+extern void sha1_process_bytes (const void *buffer, size_t len,
+                               struct sha1_ctx *ctx);
+
+/* Process the remaining bytes in the buffer and put result from CTX
+   in first 20 bytes following RESBUF.  The result is always in little
+   endian byte order, so that a byte-wise output yields to the wanted
+   ASCII representation of the message digest.
+
+   IMPORTANT: On some systems it is required that RESBUF be correctly
+   aligned for a 32 bits value.  */
+extern void *sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf);
+
+
+/* Put result from CTX in first 20 bytes following RESBUF.  The result is
+   always in little endian byte order, so that a byte-wise output yields
+   to the wanted ASCII representation of the message digest.
+
+   IMPORTANT: On some systems it is required that RESBUF is correctly
+   aligned for a 32 bits value.  */
+extern void *sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf);
+
+/* An object-oriented wrapper around checksumming functionality. */
+class SHA1Checksum {
+private:
+    struct sha1_ctx ctx;
+    char resbuf[20] __attribute__ ((__aligned__ (__alignof__ (md5_uint32))));
+
+public:
+    SHA1Checksum();
+    ~SHA1Checksum();
+
+    void process(void *data, size_t len);
+    const uint8_t *checksum();
+    size_t checksum_size() const { return 20; }
+};
+
+#endif