[gnome-games] mega-drive: Support more system strings

[Adrien Plazas <aplazas src gnome org>]

commit 0ea04bf237ab97b7518577360c6e5fcf30ebd268
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Fri Sep 16 09:26:32 2016 +0200

    mega-drive: Support more system strings
    
    Support games with the system strings starting by:
    - ' SEGA MEGA DRIV'
    - 'SEGA_MEGA_DRIVE'
    - 'SEGA are Regist'
    
    https://bugzilla.gnome.org/show_bug.cgi?id=771511

 plugins/mega-drive/src/mega-drive-header.vala |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/plugins/mega-drive/src/mega-drive-header.vala b/plugins/mega-drive/src/mega-drive-header.vala
index d823a59..e2a42ee 100644
--- a/plugins/mega-drive/src/mega-drive-header.vala
+++ b/plugins/mega-drive/src/mega-drive-header.vala
@@ -9,6 +9,8 @@ private class Games.MegaDriveHeader : Object {
        private const size_t CD_OFFSET = 0x0;
 
        private const size_t SYSTEM_OFFSET = 0x100;
+       // A game with a weird character at the 16th position was found so
+       // let's just use the 15 first chars.
        private const size_t SYSTEM_SIZE = 0xf;
 
        private const size_t DOMESTIC_NAME_OFFSET = 0x120;
@@ -69,12 +71,15 @@ private class Games.MegaDriveHeader : Object {
 
                var stream = new StringInputStream (file);
 
-               foreach (var possible_offset in POSSIBLE_HEADER_OFFSETS)
-                       if (stream.has_string (possible_offset + SYSTEM_OFFSET, "SEGA")) {
+               foreach (var possible_offset in POSSIBLE_HEADER_OFFSETS) {
+                       var system_string = stream.read_string_for_size (possible_offset + SYSTEM_OFFSET, 
SYSTEM_SIZE);
+                       system_string = system_string.strip ();
+                       if (system_string.has_prefix ("SEGA")) {
                                offset = possible_offset;
 
                                return offset;
                        }
+               }
 
                        throw new MegaDriveError.INVALID_HEADER (_("The file doesn't have a Genesis/Sega 
32X/Sega CD/Sega Pico header."));
        }
@@ -90,6 +95,9 @@ private class Games.MegaDriveHeader : Object {
                switch (system_string) {
                case "SEGA MEGA DRIVE":
                case "SEGA GENESIS":
+               case " SEGA MEGA DRIV":
+               case "SEGA_MEGA_DRIVE":
+               case "SEGA are Regist":
                        return is_cd ? MegaDriveSystem.MEGA_CD : MegaDriveSystem.MEGA_DRIVE;
                case "SEGA 32X":
                        return is_cd ? MegaDriveSystem.MEGA_CD_32X : MegaDriveSystem.32X;