Disable legacy codepage handling in bootloaders

Turn off legacy codepage handling in the filesystem code for
bootloaders, and support ISO-8859-1 (Latin-1) only.

This only affects DOS 8.3 filename parsing when FAT32 long
names are unavailable; long names are Unicode and can always
be decoded properly regardless of this setting.

In reality, bootloaders never supported codepages other than
Latin-1 in the first place. They did contain the code to load
codepages from disk, but had no way to actually change the
codepage away from Latin-1.

Compiling out this useless codepage handling code frees up
precious space for very size-constrained bootloaders like the
Sansa e200v2.

Change-Id: I26b049dd648fed4a0cc61fa938faa84e9816ab7d

2 files changed, 18 insertions, 0 deletions

diff --git a/firmware/common/file_internal.c b/firmware/common/file_internal.c
index a73d9beaa2..e4554670af 100644
--- a/firmware/common/file_internal.c
+++ b/firmware/common/file_internal.c
@@ -223,6 +223,7 @@ int test_dir_empty_internal(struct filestr_base *stream)
 /* iso decode the name to UTF-8 */
 void iso_decode_d_name(char *d_name)
 {
+#ifdef HAVE_FILESYSTEM_CODEPAGE
     if (is_dotdir_name(d_name))
         return;
 
@@ -232,6 +233,9 @@ void iso_decode_d_name(char *d_name)
     /* This MUST be the default codepage thus not something that could be
        loaded on call */
     iso_decode(shortname, d_name, -1, len + 1);
+#else
+    (void)d_name;
+#endif
 }
 
 #ifdef HAVE_DIRCACHE
diff --git a/firmware/export/config.h b/firmware/export/config.h
index 26ed7395ff..80d59ea836 100644
--- a/firmware/export/config.h
+++ b/firmware/export/config.h
@@ -1343,6 +1343,20 @@ Lyre prototype 1 */
 # define HAVE_PERCEPTUAL_VOLUME
 #endif
 
+/*
+ * Turn off legacy codepage handling in the filesystem code for bootloaders,
+ * and support ISO-8859-1 (Latin-1) only. This only affects DOS 8.3 filename
+ * parsing when FAT32 long names are unavailable; long names are Unicode and
+ * can always be decoded properly regardless of this setting.
+ *
+ * In reality, bootloaders never supported codepages other than Latin-1 in
+ * the first place. They did contain the code to load codepages from disk,
+ * but had no way to actually change the codepage away from Latin-1.
+ */
+#if !defined(BOOTLOADER)
+# define HAVE_FILESYSTEM_CODEPAGE
+#endif
+
 /* null audiohw setting macro for when codec header is included for reasons
    other than audio support */
 #define AUDIOHW_SETTING(name, us, nd, st, minv, maxv, defv, expr...)