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authorDarkvater <darkvater@openttd.org>2007-03-04 00:49:40 +0000
committerDarkvater <darkvater@openttd.org>2007-03-04 00:49:40 +0000
commit0d643c624b0195c6c24fceb4ae4019956a6579ac (patch)
tree95ff058757206f56039f036e53389e09510090b5 /src
parentead8c82ab69799f2e0c2f91905b3b71f1c9dc7ef (diff)
downloadopenttd-0d643c624b0195c6c24fceb4ae4019956a6579ac.tar.xz
(svn r9003) -Codechange: Introduce a function Utf8PrevCharLen that finds the starting character of an UTF-8 sequence from a given position and returns the length to the first UTF-8 encoding byte of that sequence.
Diffstat (limited to 'src')
-rw-r--r--src/misc_gui.cpp11
-rw-r--r--src/string.h22
2 files changed, 24 insertions, 9 deletions
diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
index b736de9c4..306289eab 100644
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -805,11 +805,7 @@ static void DelChar(Textbuf *tb, bool backspace)
uint width;
size_t len;
- if (backspace) {
- do {
- tb->caretpos--;
- } while (IsUtf8Part(*(tb->buf + tb->caretpos)));
- }
+ if (backspace) tb->caretpos -= Utf8PrevCharLen(tb->buf + tb->caretpos);
len = Utf8Decode(&c, tb->buf + tb->caretpos);
width = GetCharacterWidth(FS_NORMAL, c);
@@ -892,10 +888,7 @@ bool MoveTextBufferPos(Textbuf *tb, int navmode)
if (tb->caretpos != 0) {
WChar c;
- do {
- tb->caretpos--;
- } while (IsUtf8Part(*(tb->buf + tb->caretpos)));
-
+ tb->caretpos -= Utf8PrevCharLen(tb->buf + tb->caretpos);
Utf8Decode(&c, tb->buf + tb->caretpos);
tb->caretxoffs -= GetCharacterWidth(FS_NORMAL, c);
diff --git a/src/string.h b/src/string.h
index 6b9924d63..da07f08d5 100644
--- a/src/string.h
+++ b/src/string.h
@@ -106,6 +106,28 @@ static inline bool IsUtf8Part(char c)
return GB(c, 6, 2) == 2;
}
+/**
+ * Retrieve the (partial) length of the previous UNICODE character
+ * in an UTF-8 encoded string.
+ * @param s char pointer pointing to the first char of the next character
+ * @returns the decoded length in bytes (size) of the UNICODE character
+ * that was just before the one where 's' is pointing to
+ * @note If 's' is not pointing to the first byte of the next UNICODE character
+ * only a partial length of the sequence will be returned.
+ * For example given this sequence: 0xE3 0x85 0x80, 0xE3 0x81 0x9E
+ * 1. 's' is pointing to the second 0xE3, return value is 3
+ * 2. 's' is pointing to 0x80, return value is 2.
+ * So take care with the return values of this function. To get the real length
+ * for an (invalid) sequence, pass the string offset of this function's return
+ * value to Utf8EncodedCharLen() or Utf8Decode()
+ */
+static inline size_t Utf8PrevCharLen(const char *s)
+{
+ size_t len = 1;
+ while (IsUtf8Part(*--s)) len++;
+ return len;
+}
+
static inline bool IsPrintable(WChar c)
{