[Libguestfs] [PATCH 5/7] hivex: Move header checksum code into a function.

[Richard W.M. Jones]

This is just code motion.  We will reuse this function in a later
patch in the 'write' series.

Rich.

-- 
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>From 8b8885c16fba2c3aa51f5f2f8ea29f23d1a025c9 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones at redhat.com>
Date: Mon, 18 Jan 2010 17:56:13 +0000
Subject: [PATCH 5/7] hivex: Move header checksum code into a function.

This function can be reused later.
---
 hivex/hivex.c |   24 ++++++++++++++++--------
 1 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/hivex/hivex.c b/hivex/hivex.c
index cb6c772..cb6fc62 100644
--- a/hivex/hivex.c
+++ b/hivex/hivex.c
@@ -262,6 +262,21 @@ struct ntreg_vk_record {
   char name[1];                 /* key name follows here */
 } __attribute__((__packed__));
 
+static uint32_t
+header_checksum (hive_h *h)
+{
+  uint32_t *daddr = (uint32_t *) h->addr;
+  size_t i;
+  uint32_t sum = 0;
+
+  for (i = 0; i < 0x1fc / 4; ++i) {
+    sum ^= le32toh (*daddr);
+    daddr++;
+  }
+
+  return sum;
+}
+
 hive_h *
 hivex_open (const char *filename, int flags)
 {
@@ -340,14 +355,7 @@ hivex_open (const char *filename, int flags)
     goto error;
 
   /* Header checksum. */
-  uint32_t *daddr = (uint32_t *) h->addr;
-  size_t i;
-  uint32_t sum = 0;
-  for (i = 0; i < 0x1fc / 4; ++i) {
-    sum ^= le32toh (*daddr);
-    daddr++;
-  }
-
+  uint32_t sum = header_checksum (h);
   if (sum != le32toh (h->hdr->csum)) {
     fprintf (stderr, "hivex: %s: bad checksum in hive header\n", filename);
     errno = EINVAL;
-- 
1.6.5.2