From: Karel Zak <kzak@redhat.com>
Date: Thu, 12 Oct 2023 20:12:58 +0000 (+0200)
Subject: lib/mbsalign: calculate size of decoded string
X-Git-Tag: v2.40-rc1~195
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6b7247411d9ddfcfeb0933b3ab44bf295c071f7b;p=thirdparty%2Futil-linux.git

lib/mbsalign: calculate size of decoded string

The "safe" encoding replaces each unsafe byte with \x<hex>, the new
function mbs_safe_decoded_size() calculates the original size of the
string.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/mbsalign.h b/include/mbsalign.h
index 6e56755829..c1426105c1 100644
--- a/include/mbsalign.h
+++ b/include/mbsalign.h
@@ -55,6 +55,7 @@ extern size_t mbs_width(const char *s);
 extern char *mbs_safe_encode(const char *s, size_t *width);
 extern char *mbs_safe_encode_to_buffer(const char *s, size_t *width, char *buf, const char *safechars);
 extern size_t mbs_safe_encode_size(size_t bytes);
+extern size_t mbs_safe_decode_size(const char *s);
 
 extern char *mbs_invalid_encode(const char *s, size_t *width);
 extern char *mbs_invalid_encode_to_buffer(const char *s, size_t *width, char *buf);
diff --git a/lib/mbsalign.c b/lib/mbsalign.c
index 7b8f5a665d..b4ab7becdd 100644
--- a/lib/mbsalign.c
+++ b/lib/mbsalign.c
@@ -310,11 +310,32 @@ char *mbs_invalid_encode_to_buffer(const char *s, size_t *width, char *buf)
 	return buf;
 }
 
+/*
+ * Guess size
+ */
 size_t mbs_safe_encode_size(size_t bytes)
 {
 	return (bytes * 4) + 1;
 }
 
+/*
+ * Count size of the original string in bytes (count \x?? as one byte)
+ */
+size_t mbs_safe_decode_size(const char *p)
+{
+	size_t bytes = 0;
+
+	while (p && *p) {
+		if (*p == '\\' && *(p + 1) == 'x' &&
+		    isxdigit(*(p + 2)) && isxdigit(*(p + 3)))
+			p += 4;
+		else
+			p++;
+		bytes++;
+	}
+	return bytes;
+}
+
 /*
  * Returns allocated string where all control and non-printable chars are
  * replaced with \x?? hex sequence.