[tracker] tracker-extract: Add code comment explaining strange FF D8 FF check

[Philip Van Hoof <pvanhoof src gnome org>]

commit b53bdf72241bc607081ded2f121368c85178fbd2
Author: Philip Van Hoof <philip codeminded be>
Date:   Thu Jul 28 14:41:33 2011 +0200

    tracker-extract: Add code comment explaining strange FF D8 FF check

 src/tracker-extract/tracker-albumart-pixbuf.c |    1 +
 src/tracker-extract/tracker-albumart-qt.cpp   |    1 +
 2 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/tracker-extract/tracker-albumart-pixbuf.c b/src/tracker-extract/tracker-albumart-pixbuf.c
index 4557b1c..cd943a6 100644
--- a/src/tracker-extract/tracker-albumart-pixbuf.c
+++ b/src/tracker-extract/tracker-albumart-pixbuf.c
@@ -67,6 +67,7 @@ tracker_albumart_buffer_to_jpeg (const unsigned char *buffer,
                                  const gchar         *buffer_mime,
                                  const gchar         *target)
 {
+	/* FF D8 FF are the three first bytes of JPeg images */
 	if ((g_strcmp0 (buffer_mime, "image/jpeg") == 0 ||
 	    g_strcmp0 (buffer_mime, "JPG") == 0) &&
 	    (buffer && len > 2 && buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff)) {
diff --git a/src/tracker-extract/tracker-albumart-qt.cpp b/src/tracker-extract/tracker-albumart-qt.cpp
index 95cb3de..00597d9 100644
--- a/src/tracker-extract/tracker-albumart-qt.cpp
+++ b/src/tracker-extract/tracker-albumart-qt.cpp
@@ -91,6 +91,7 @@ tracker_albumart_buffer_to_jpeg (const unsigned char *buffer,
                                  const gchar         *buffer_mime,
                                  const gchar         *target)
 {
+	/* FF D8 FF are the three first bytes of JPeg images */
 	if ((g_strcmp0 (buffer_mime, "image/jpeg") == 0 ||
 	    g_strcmp0 (buffer_mime, "JPG") == 0) &&
 	    (buffer && len > 2 && buffer[0] == 0xff && buffer[1] == 0xd8 && buffer[2] == 0xff)) {