From 984f251feeb932cfe551cbd62c5f7f5e073b6cc3 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Mon, 9 Oct 2017 21:09:05 +0200 Subject: [PATCH] efi_loader: MAX_UTF8_PER_UTF16 = 3 The constant MAX_UTF8_PER_UTF16 is used to calculate required memory when converting from UTF-16 to UTF-8. If this constant is too big we waste memory. A code point encoded by one UTF-16 symbol is converted to a maximum of three UTF-8 symbols, e.g. 0xffff could be encoded as 0xef 0xbf 0xbf. The first byte carries four bits, the second and third byte carry six bits each. A code point encoded by two UTF-16 symbols is converted to four UTF-8 symbols. So in this case we need a maximum of two UTF-8 symbols per UTF-16 symbol. As the overall maximum is three UTF-8 symobls per UTF-16 symbol we need MAX_UTF8_PER_UTF16 = 3. Fixes: 78178bb0c9d lib: add some utf16 handling helpers Signed-off-by: Heinrich Schuchardt Signed-off-by: Alexander Graf --- include/charset.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/charset.h b/include/charset.h index 39279f7..37a3278 100644 --- a/include/charset.h +++ b/include/charset.h @@ -9,7 +9,7 @@ #ifndef __CHARSET_H_ #define __CHARSET_H_ -#define MAX_UTF8_PER_UTF16 4 +#define MAX_UTF8_PER_UTF16 3 /** * utf16_strlen() - Get the length of an utf16 string @@ -52,7 +52,7 @@ uint16_t *utf16_strdup(const uint16_t *s); * Converts 'size' characters of the utf16 string 'src' to utf8 * written to the 'dest' buffer. * - * NOTE that a single utf16 character can generate up to 4 utf8 + * NOTE that a single utf16 character can generate up to 3 utf8 * characters. See MAX_UTF8_PER_UTF16. * * @dest the destination buffer to write the utf8 characters