lib: charset: upper/lower case conversion

Provide functions for upper and lower case conversion.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

include/charset.h

@@ -143,6 +143,22 @@ int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count);
 #define utf16_utf8_strcpy(d, s) utf16_utf8_strncpy((d), (s), SIZE_MAX)
 
 /**
+ * utf_to_lower() - convert a Unicode letter to lower case
+ *
+ * @code:		letter to convert
+ * Return:		lower case letter or unchanged letter
+ */
+s32 utf_to_lower(const s32 code);
+
+/**
+ * utf_to_upper() - convert a Unicode letter to upper case
+ *
+ * @code:		letter to convert
+ * Return:		upper case letter or unchanged letter
+ */
+s32 utf_to_upper(const s32 code);
+
+/**
  * u16_strlen - count non-zero words
  *
  * This function matches wsclen() if the -fshort-wchar compiler flag is set.

lib/charset.c

@@ -6,8 +6,18 @@
  */
 
 #include <charset.h>
+#include <capitalization.h>
 #include <malloc.h>
 
+static struct capitalization_table capitalization_table[] =
+#ifdef CONFIG_EFI_UNICODE_CAPITALIZATION
+	UNICODE_CAPITALIZATION_TABLE;
+#elif CONFIG_FAT_DEFAULT_CODEPAGE == 1250
+	CP1250_CAPITALIZATION_TABLE;
+#else
+	CP437_CAPITALIZATION_TABLE;
+#endif
+
 s32 utf8_get(const char **src)
 {
 	s32 code = 0;
@@ -241,6 +251,43 @@ int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count)
 	return 0;
 }
 
+s32 utf_to_lower(const s32 code)
+{
+	struct capitalization_table *pos = capitalization_table;
+	s32 ret = code;
+
+	if (code <= 0x7f) {
+		if (code >= 'A' && code <= 'Z')
+			ret += 0x20;
+		return ret;
+	}
+	for (; pos->upper; ++pos) {
+		if (pos->upper == code) {
+			ret = pos->lower;
+			break;
+		}
+	}
+	return ret;
+}
+
+s32 utf_to_upper(const s32 code)
+{
+	struct capitalization_table *pos = capitalization_table;
+	s32 ret = code;
+
+	if (code <= 0x7f) {
+		if (code >= 'a' && code <= 'z')
+			ret -= 0x20;
+		return ret;
+	}
+	for (; pos->lower; ++pos) {
+		if (pos->lower == code) {
+			ret = pos->upper;
+			break;
+		}
+	}
+	return ret;
+}
 
 size_t u16_strlen(const u16 *in)
 {

lib/efi_loader/Kconfig

@@ -15,6 +15,16 @@ config EFI_LOADER
 	  interfaces to a loaded EFI application, enabling it to reuse U-Boot's
 	  device drivers.
 
+config EFI_UNICODE_CAPITALIZATION
+	bool "Support Unicode capitalization"
+	depends on EFI_LOADER
+	default y
+	help
+	  Select this option to enable correct handling of the capitalization of
+	  Unicode codepoints in the range 0x0000-0xffff. If this option is not
+	  set, only the the correct handling of the letters of the codepage
+	  used by the FAT file system is ensured.
+
 config EFI_LOADER_BOUNCE_BUFFER
 	bool "EFI Applications use bounce buffers for DMA operations"
 	depends on EFI_LOADER && ARM64