From 5c5f9e8e28dc7665051b10494a7133d331f673f5 Mon Sep 17 00:00:00 2001
From: Quincey Koziol <koziol@hdfgroup.org>
Date: Tue, 22 Aug 2006 12:50:25 -0500
Subject: [svn-r12612] Description:     Provide more abstract internal routine
 for computing checksums on metadata in a file.  This will allow a unified
 policy on which algorithm to choose and under what criteria (length probably)
 to be more easily maintained.

Tested On:
    Linux/32 2.6 (chicago)
    Linux/64 2.6 (chicago2)
---
 src/H5HFcache.c  | 12 ++++++------
 src/H5checksum.c | 35 +++++++++++++++++++++++++++++++++++
 src/H5private.h  |  1 +
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/src/H5HFcache.c b/src/H5HFcache.c
index ddf8e0c..5da8197 100644
--- a/src/H5HFcache.c
+++ b/src/H5HFcache.c
@@ -396,7 +396,7 @@ HDfprintf(stderr, "%s: Load heap header, addr = %a\n", FUNC, addr);
 
     /* Compute checksum on entire header */
     /* (including the filter information, if present) */
-    computed_chksum = H5_fletcher32(buf, (hdr->heap_size - H5HF_SIZEOF_CHKSUM));
+    computed_chksum = H5_checksum_metadata(buf, (hdr->heap_size - H5HF_SIZEOF_CHKSUM));
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -525,7 +525,7 @@ HDfprintf(stderr, "%s: Flushing heap header, addr = %a, destroy = %u\n", FUNC, a
         } /* end if */
 
         /* Compute metadata checksum */
-        metadata_chksum = H5_fletcher32(buf, hdr->heap_size - H5HF_SIZEOF_CHKSUM);
+        metadata_chksum = H5_checksum_metadata(buf, hdr->heap_size - H5HF_SIZEOF_CHKSUM);
 
         /* Metadata checksum */
         UINT32ENCODE(p, metadata_chksum);
@@ -826,7 +826,7 @@ HDfprintf(stderr, "%s: iblock->ents[%Zu] = {%a}\n", FUNC, u, iblock->ents[u].add
     HDassert((size_t)(p - buf) == iblock->size);
 
     /* Compute checksum on indirect block */
-    computed_chksum = H5_fletcher32(buf, (iblock->size - H5HF_SIZEOF_CHKSUM));
+    computed_chksum = H5_checksum_metadata(buf, (iblock->size - H5HF_SIZEOF_CHKSUM));
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -973,7 +973,7 @@ HDfprintf(stderr, "%s: iblock->filt_ents[%Zu] = {%Zu, %x}\n", FUNC, u, iblock->f
         } /* end for */
 
         /* Compute checksum */
-        metadata_chksum = H5_fletcher32(buf, iblock->size - H5HF_SIZEOF_CHKSUM);
+        metadata_chksum = H5_checksum_metadata(buf, iblock->size - H5HF_SIZEOF_CHKSUM);
 
         /* Metadata checksum */
         UINT32ENCODE(p, metadata_chksum);
@@ -1235,7 +1235,7 @@ HGOTO_ERROR(H5E_HEAP, H5E_UNSUPPORTED, NULL, "I/O filters not supported yet")
         HDmemset((uint8_t *)p - H5HF_SIZEOF_CHKSUM, 0, (size_t)H5HF_SIZEOF_CHKSUM);
 
         /* Compute checksum on entire direct block */
-        computed_chksum = H5_fletcher32(dblock->blk, dblock->size);
+        computed_chksum = H5_checksum_metadata(dblock->blk, dblock->size);
 
         /* Verify checksum */
         if(stored_chksum != computed_chksum)
@@ -1314,7 +1314,7 @@ H5HF_cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
             HDmemset(p, 0, (size_t)H5HF_SIZEOF_CHKSUM);
 
             /* Compute checksum on entire direct block */
-            metadata_chksum = H5_fletcher32(dblock->blk, dblock->size);
+            metadata_chksum = H5_checksum_metadata(dblock->blk, dblock->size);
 
             /* Metadata checksum */
             UINT32ENCODE(p, metadata_chksum);
diff --git a/src/H5checksum.c b/src/H5checksum.c
index 9ad575d..4a1e5de 100644
--- a/src/H5checksum.c
+++ b/src/H5checksum.c
@@ -136,3 +136,38 @@ H5_fletcher32(const void *_data, size_t _len)
     FUNC_LEAVE_NOAPI((sum2 << 16) | sum1)
 } /* end H5_fletcher32() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5_checksum_metadata
+ *
+ * Purpose:	Provide a more abstract routine for checksumming metadata
+ *              in a file, where the policy of which algorithm to choose
+ *              is centralized.
+ *
+ * Return:	checksum of input buffer (can't fail)
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, August 22, 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+uint32_t
+H5_checksum_metadata(const void *data, size_t len)
+{
+    uint32_t chksum;            /* Checksum value to return */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5_checksum_metadata)
+
+    /* Sanity check */
+    HDassert(data);
+    HDassert(len > 0);
+
+    /* Choose the appropriate checksum routine */
+    /* (use fletcher32 for everything right now, but will probably go
+     *  with a CRC algorithm for "shorter" pieces of metadata eventually)
+     */
+    chksum = H5_fletcher32(data, len);
+
+    FUNC_LEAVE_NOAPI(chksum)
+} /* end H5_checksum_metadata() */
+
diff --git a/src/H5private.h b/src/H5private.h
index f3bae08..28c72c8 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -1448,6 +1448,7 @@ H5_DLL int H5Z_term_interface(void);
 
 /* Checksum functions */
 H5_DLL uint32_t H5_fletcher32(const void *data, size_t len);
+H5_DLL uint32_t H5_checksum_metadata(const void *data, size_t len);
 
 /* Functions for debugging */
 H5_DLL herr_t H5_buffer_dump(FILE *stream, int indent, uint8_t *buf,
-- 
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