Commit e4c89f93 authored by Maximilian Luz's avatar Maximilian Luz Committed by Bjorn Andersson
Browse files

lib/ucs2_string: Add UCS-2 strscpy function 



Add a ucs2_strscpy() function for UCS-2 strings. The behavior is
equivalent to the standard strscpy() function, just for 16-bit character
UCS-2 strings.

Signed-off-by: default avatarMaximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: default avatarBjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230827211408.689076-2-luzmaximilian@gmail.com


Signed-off-by: default avatarBjorn Andersson <andersson@kernel.org>
parent 0bb80ecc

include/linux/ucs2_string.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ typedef u16 ucs2_char_t; 
unsigned long ucs2_strnlen(const ucs2_char_t *s, size_t maxlength);

unsigned long ucs2_strlen(const ucs2_char_t *s);

unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);

ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count);

int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);



unsigned long ucs2_utf8size(const ucs2_char_t *src);

lib/ucs2_string.c

+52 −0
Original line number Diff line number Diff line
@@ -32,6 +32,58 @@ ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength) 
}

EXPORT_SYMBOL(ucs2_strsize);



/**

 * ucs2_strscpy() - Copy a UCS2 string into a sized buffer.

 *

 * @dst: Pointer to the destination buffer where to copy the string to.

 * @src: Pointer to the source buffer where to copy the string from.

 * @count: Size of the destination buffer, in UCS2 (16-bit) characters.

 *

 * Like strscpy(), only for UCS2 strings.

 *

 * Copy the source string @src, or as much of it as fits, into the destination

 * buffer @dst. The behavior is undefined if the string buffers overlap. The

 * destination buffer @dst is always NUL-terminated, unless it's zero-sized.

 *

 * Return: The number of characters copied into @dst (excluding the trailing

 * %NUL terminator) or -E2BIG if @count is 0 or @src was truncated due to the

 * destination buffer being too small.

 */

ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count)

{

	long res;



	/*

	 * Ensure that we have a valid amount of space. We need to store at

	 * least one NUL-character.

	 */

	if (count == 0 || WARN_ON_ONCE(count > INT_MAX / sizeof(*dst)))

		return -E2BIG;



	/*

	 * Copy at most 'count' characters, return early if we find a

	 * NUL-terminator.

	 */

	for (res = 0; res < count; res++) {

		ucs2_char_t c;



		c = src[res];

		dst[res] = c;



		if (!c)

			return res;

	}



	/*

	 * The loop above terminated without finding a NUL-terminator,

	 * exceeding the 'count': Enforce proper NUL-termination and return

	 * error.

	 */

	dst[count - 1] = 0;

	return -E2BIG;

}

EXPORT_SYMBOL(ucs2_strscpy);



int

ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)

{