libglusterfs: Add checksum functions.

gf_rsync_weak_checksum:   Calculates a simple 32-bit checksum.
gf_rsync_strong_checksum: Calculates the MD5 checksum.

The strong checksum function makes use of Christophe Devine's
MD5 implementation (adapted from the rsync source code,
version 3.0.6. <http://www.samba.org/ftp/rsync/>).

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/libglusterfs/src/md5.h b/libglusterfs/src/md5.h
new file mode 100644
index 00000000000..ba8f08dbcfa
--- /dev/null
+++ b/libglusterfs/src/md5.h
@@ -0,0 +1,78 @@
+/* rsync-3.0.6/byteorder.h */
+
+/*
+ * Simple byteorder handling.
+ *
+ * Copyright (C) 1992-1995 Andrew Tridgell
+ * Copyright (C) 2007-2008 Wayne Davison
+ *
+ * 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 3 of the License, 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, visit the http://fsf.org website.
+ */
+
+#undef CAREFUL_ALIGNMENT
+
+/* We know that the x86 can handle misalignment and has the same
+ * byte order (LSB-first) as the 32-bit numbers we transmit. */
+
+#ifdef __i386__
+#define CAREFUL_ALIGNMENT 0
+#endif
+
+#ifndef CAREFUL_ALIGNMENT
+#define CAREFUL_ALIGNMENT 1
+#endif
+
+#define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
+#define UVAL(buf,pos) ((uint32_t)CVAL(buf,pos))
+#define SCVAL(buf,pos,val) (CVAL(buf,pos) = (val))
+
+#if CAREFUL_ALIGNMENT
+#define PVAL(buf,pos) (UVAL(buf,pos)|UVAL(buf,(pos)+1)<<8)
+#define IVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+2)<<16)
+#define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
+#define SIVALX(buf,pos,val) (SSVALX(buf,pos,val&0xFFFF),SSVALX(buf,pos+2,val>>16))
+#define SIVAL(buf,pos,val) SIVALX((buf),(pos),((uint32_t)(val)))
+#else
+
+/* this handles things for architectures like the 386 that can handle
+   alignment errors */
+
+/*
+   WARNING: This section is dependent on the length of int32
+   being correct. set CAREFUL_ALIGNMENT if it is not.
+*/
+
+#define IVAL(buf,pos) (*(uint32_t *)((char *)(buf) + (pos)))
+#define SIVAL(buf,pos,val) IVAL(buf,pos)=((uint32_t)(val))
+#endif
+
+/* The include file for both the MD4 and MD5 routines. */
+
+#define MD5_DIGEST_LEN 16
+#define MAX_DIGEST_LEN MD5_DIGEST_LEN
+
+#define CSUM_CHUNK 64
+
+typedef struct {
+	uint32_t A, B, C, D;
+	uint32_t totalN;          /* bit count, lower 32 bits */
+	uint32_t totalN2;         /* bit count, upper 32 bits */
+	uint8_t buffer[CSUM_CHUNK];
+} md_context;
+
+void md5_begin(md_context *ctx);
+void md5_update(md_context *ctx, const uint8_t *input, uint32_t length);
+void md5_result(md_context *ctx, uint8_t digest[MD5_DIGEST_LEN]);
+
+void get_md5(uint8_t digest[MD5_DIGEST_LEN], const uint8_t *input, int n);