[libgsf] OLE seek: refactor.

[Morten Welinder <mortenw src gnome org>]

commit 727473fe1b0afc335ce25b2e36a2c107f5cd7266
Author: Morten Welinder <terra gnome org>
Date:   Thu Dec 20 19:21:37 2012 -0500

    OLE seek: refactor.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=690524

 ChangeLog              |    5 +++++
 gsf/gsf-infile-msole.c |   27 +++++++++++++++++----------
 2 files changed, 22 insertions(+), 10 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 1a15aba..76048af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-12-20  =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre lureau gmail com>
+
+	* gsf/gsf-infile-msole.c (ole_seek_block): Factor out from
+	gsf_infile_msole_read.
+
 2012-12-05  Morten Welinder  <terra gnome org>
 
 	* gsf/gsf-infile-msole.c (gsf_infile_msole_child_by_index)
diff --git a/gsf/gsf-infile-msole.c b/gsf/gsf-infile-msole.c
index e445d38..b00fe6a 100644
--- a/gsf/gsf-infile-msole.c
+++ b/gsf/gsf-infile-msole.c
@@ -104,6 +104,21 @@ static GsfInput *gsf_infile_msole_new_child (GsfInfileMSOle *parent,
 					     MSOleDirent *dirent, GError **err);
 static void ole_info_unref (MSOleInfo *info);
 
+static gboolean
+ole_seek_block (GsfInfileMSOle const *ole, guint32 block, gsf_off_t offset)
+{
+	g_return_val_if_fail (block < ole->info->max_block, FALSE);
+
+	/* OLE_HEADER_SIZE is fixed at 512, but the sector containing the
+	 * header is padded out to bb.size (sector size) when bb.size > 512. */
+	if (gsf_input_seek (ole->input,
+		(gsf_off_t)(MAX (OLE_HEADER_SIZE, ole->info->bb.size) + (block << ole->info->bb.shift)) + offset,
+		G_SEEK_SET) < 0)
+		return FALSE;
+
+	return TRUE;
+}
+
 /**
  * ole_get_block :
  * @ole: the infile
@@ -119,13 +134,7 @@ static void ole_info_unref (MSOleInfo *info);
 static guint8 const *
 ole_get_block (GsfInfileMSOle const *ole, guint32 block, guint8 *buffer)
 {
-	g_return_val_if_fail (block < ole->info->max_block, NULL);
-
-	/* OLE_HEADER_SIZE is fixed at 512, but the sector containing the
-	 * header is padded out to bb.size (sector size) when bb.size > 512. */
-	if (gsf_input_seek (ole->input,
-		(gsf_off_t)(MAX (OLE_HEADER_SIZE, ole->info->bb.size) + (block << ole->info->bb.shift)),
-		G_SEEK_SET) < 0)
+	if (!ole_seek_block (ole, block, 0))
 		return NULL;
 
 	return gsf_input_read (ole->input, ole->info->bb.size, buffer);
@@ -677,9 +686,7 @@ gsf_infile_msole_read (GsfInput *input, size_t num_bytes, guint8 *buffer)
 	if (i > last_block) {
 		/* optimization don't seek if we don't need to */
 		if (ole->cur_block != first_block) {
-			if (gsf_input_seek (ole->input,
-				(gsf_off_t)(MAX (OLE_HEADER_SIZE, ole->info->bb.size) + (ole->bat.block [first_block] << ole->info->bb.shift) + offset),
-				G_SEEK_SET) < 0)
+			if (!ole_seek_block (ole, ole->bat.block [first_block], offset))
 				return NULL;
 		}
 		ole->cur_block = last_block;