[PATCH 02/13] xfs_scrub: hoist code that removes ignorable characters

Darrick J. Wong
2023-12-31T22:45:34Z

Hoist the loop that removes "ignorable" code points from the skeleton
string into a separate function and give the UChar cursors names that
are easier to understand. Convert the code to use the safe versions of
the U16_ accessor functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
scrub/unicrash.c | 39 ++++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/scrub/unicrash.c b/scrub/unicrash.c
index 02a1b94efb4..96e20114c48 100644
--- a/scrub/unicrash.c
+++ b/scrub/unicrash.c
@@ -145,6 +145,31 @@ is_utf8_locale(void)
return answer;
}

+/*
+ * Remove control/formatting characters from this string and return its new
+ * length. UChar32 is required for U16_NEXT, despite the name.
+ */
+static int32_t
+remove_ignorable(
+ UChar *ustr,
+ int32_t ustrlen)
+{
+ UChar32 uchr;
+ int32_t src, dest;
+
+ for (src = 0, dest = 0; src < ustrlen; dest = src) {
+ U16_NEXT(ustr, src, ustrlen, uchr);
+ if (!u_isIDIgnorable(uchr))
+ continue;
+ memmove(&ustr[dest], &ustr[src],
+ (ustrlen - src + 1) * sizeof(UChar));
+ ustrlen -= (src - dest);
+ src = dest;
+ }
+
+ return dest;
+}
+
/*
* Generate normalized form and skeleton of the name. If this fails, just
* forget everything and return false; this is an advisory checker.
@@ -160,9 +185,6 @@ name_entry_compute_checknames(
int32_t normstrlen;
int32_t unistrlen;
int32_t skelstrlen;
- UChar32 uchr;
- int32_t i, j;
-
UErrorCode uerr = U_ZERO_ERROR;

/* Convert bytestr to unistr for normalization */
@@ -206,16 +228,7 @@ name_entry_compute_checknames(
if (U_FAILURE(uerr))
goto out_skelstr;

- /* Remove control/formatting characters from skeleton. */
- for (i = 0, j = 0; i < skelstrlen; j = i) {
- U16_NEXT_UNSAFE(skelstr, i, uchr);
- if (!u_isIDIgnorable(uchr))
- continue;
- memmove(&skelstr[j], &skelstr[i],
- (skelstrlen - i + 1) * sizeof(UChar));
- skelstrlen -= (i - j);
- i = j;
- }
+ skelstrlen = remove_ignorable(skelstr, skelstrlen);

entry->skelstr = skelstr;
entry->skelstrlen = skelstrlen;