On 4/28/22 10:09, Masahisa Kojima wrote:
Provide u16 string version of strlcat().
Signed-off-by: Masahisa Kojima <masahisa.koj...@linaro.org>
---
Changes in v5:
- change 3rd argument from size to count, it indicates
the maximum u16 string count that dest buffer can have.
Other u16_strXXX functions in U-Boot use string count, not the
buffer size. u16_strlcat() should follow.
- update function comment to clealy describe the behavior
- use strlen() instead of strnlen(), to correctly handle
the case if the count is smaller than or equal to initial dest count
Changes in v4:
- add blank line above the return statement
Changes in v2:
- implement u16_strlcat(with the destination buffer size in argument)
instead of u16_strcat
include/charset.h | 17 +++++++++++++++++
lib/charset.c | 22 ++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/include/charset.h b/include/charset.h
index 38908e08f0..ae356ad9a5 100644
--- a/include/charset.h
+++ b/include/charset.h
@@ -261,6 +261,23 @@ u16 *u16_strcpy(u16 *dest, const u16 *src);
*/
u16 *u16_strdup(const void *src);
+/**
+ * u16_strlcat() - Append a length-limited, %NUL-terminated string to another
+ *
+ * Append the src string to the dest string, overwriting the terminating
+ * null word at the end of dest, and then adds a terminating null word.
+ *
+ * @dest: destination buffer (must include the trailing 0x0000)
+ * @src: source buffer (must include the trailing 0x0000)
+ * @count: maximum number of code points that dest buffer can have,
+ * including the trailing 0x0000
+ * Return: total count of the created u16 string
+ * u16_strlen(src) + min(count, u16_strlen(initial dest)),
+ * does not include trailing 0x0000.
+ * If return value >= count, truncation occurred.
+ */
+size_t u16_strlcat(u16 *dest, const u16 *src, size_t size);
+
/**
* utf16_to_utf8() - Convert an utf16 string to utf8
*
diff --git a/lib/charset.c b/lib/charset.c
index de201cf3b9..f295dfc11a 100644
--- a/lib/charset.c
+++ b/lib/charset.c
@@ -416,6 +416,28 @@ u16 *u16_strdup(const void *src)
return new;
}
+size_t u16_strlcat(u16 *dest, const u16 *src, size_t count)
+{
+ size_t destlen, srclen, ret;
+
+ destlen = u16_strlen(dest);
+ srclen = u16_strlen(src);
+ ret = min(count, destlen) + srclen; /* does not include trailing 0x0000
*/
Why should count influence the return value?
Using a first call with count = 0 and src = NULL to retrieve the buffer
size to realloc() and a second call after re-allocation would be a
typical usage scenario.
Best regards
Heinrich
+
+ if (destlen >= count)
+ return ret;
+
+ dest += destlen;
+ count -= destlen;
+ if (srclen >= count)
+ srclen = count - 1 /* for trailing 0x0000 */;
+
+ memcpy(dest, src, srclen * sizeof(u16));
+ dest[srclen] = u'\0';
+
+ return ret;
+}
+
/* Convert UTF-16 to UTF-8. */
uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size)
{
