Add a fz_strnlen function (strnlen is not standard C).

3 files changed, 14 insertions, 1 deletions

diff --git a/include/mupdf/fitz/string-util.h b/include/mupdf/fitz/string-util.h
index fdf47c86..2bfc728f 100644
--- a/include/mupdf/fitz/string-util.h
+++ b/include/mupdf/fitz/string-util.h
@@ -11,6 +11,12 @@
 */
 
 /*
+	fz_strnlen: Return strlen(s), if that is less than maxlen, or maxlen if
+	there is no null byte ('\0') among the first maxlen bytes.
+*/
+size_t fz_strnlen(const char *s, size_t maxlen);
+
+/*
 	fz_strsep: Given a pointer to a C string (or a pointer to NULL) break
 	it at the first occurrence of a delimiter char (from a given set).
 
diff --git a/source/fitz/load-png.c b/source/fitz/load-png.c
index 39c4ea81..cf1ab536 100644
--- a/source/fitz/load-png.c
+++ b/source/fitz/load-png.c
@@ -347,7 +347,7 @@ png_read_icc(fz_context *ctx, struct info *info, const unsigned char *p, unsigne
 	fz_stream *mstm = NULL, *zstm = NULL;
 	fz_colorspace *cs = NULL;
 	size_t m = fz_mini(80, size);
-	size_t n = strnlen((const char *)p, m);
+	size_t n = fz_strnlen((const char *)p, m);
 	if (n + 2 > m)
 	{
 		fz_warn(ctx, "invalid ICC profile name");
diff --git a/source/fitz/string.c b/source/fitz/string.c
index dbcc2c22..a014ce89 100644
--- a/source/fitz/string.c
+++ b/source/fitz/string.c
@@ -14,6 +14,13 @@ fz_tolower(int c)
 	return c;
 }
 
+size_t
+fz_strnlen(const char *s, size_t n)
+{
+	const char *p = memchr(s, 0, n);
+	return p ? p - s : n;
+}
+
 int
 fz_strcasecmp(const char *a, const char *b)
 {