[RESEND RFC PATCH v2 2/4] lib/charset: add u16_strlcat() function

[Simon Glass]

Hi Masahisa,

On Thu, 24 Feb 2022 at 18:31, Masahisa Kojima
<masahisa.kojima at linaro.org> wrote:
>
> Provide u16 string version of strlcat().
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> ---
> Changes in v2:
> - implement u16_strlcat(with the destination buffer size in argument)
>   instead of u16_strcat
>
>  include/charset.h | 15 +++++++++++++++
>  lib/charset.c     | 20 ++++++++++++++++++++
>  2 files changed, 35 insertions(+)

Reviewed-by: Simon Glass <sjg at chromium.org>

nits below

>
> diff --git a/include/charset.h b/include/charset.h
> index b93d023092..dc5fc275ec 100644
> --- a/include/charset.h
> +++ b/include/charset.h
> @@ -259,6 +259,21 @@ 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.

add

> + * It will append at most size - u16_strlen(dst) - 1 bytes, NUL-terminating the result.
> + *
> + * @dest:              destination buffer (null terminated)
> + * @src:               source buffer (null terminated)
> + * @size:              destination buffer size in bytes
> + * Return:             total size of the created string in bytes.
> + *                     If return value >= size, 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 f44c58d9d8..f15d5df19a 100644
> --- a/lib/charset.c
> +++ b/lib/charset.c
> @@ -428,6 +428,26 @@ u16 *u16_strdup(const void *src)
>         return new;
>  }
>
> +size_t u16_strlcat(u16 *dest, const u16 *src, size_t size)
> +{
> +       size_t dstrlen = u16_strnlen(dest, size >> 1);
> +       size_t dlen = dstrlen * sizeof(u16);
> +       size_t len = u16_strlen(src) * sizeof(u16);
> +       size_t ret = dlen + len;
> +
> +       if (dlen >= size)
> +               return ret;
> +
> +       dest += dstrlen;
> +       size -= dlen;
> +       if (len >= size)
> +               len = size - sizeof(u16);
> +
> +       memcpy(dest, src, len);
> +       dest[len >> 1] = u'\0';

blank line before final return

> +       return ret;
> +}
> +
>  /* Convert UTF-16 to UTF-8.  */
>  uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size)
>  {
> --
> 2.17.1
>

Regards,
Simon