mem: add av_strndup() for duplicating substrings

1 files changed, 20 insertions, 0 deletions

diff --git a/libavutil/mem.c b/libavutil/mem.c
index be42342de2..b7bb65c139 100644
--- a/libavutil/mem.c
+++ b/libavutil/mem.c
@@ -222,6 +222,26 @@ char *av_strdup(const char *s)
     return ptr;
 }
 
+char *av_strndup(const char *s, size_t len)
+{
+    char *ret = NULL, *end;
+
+    if (!s)
+        return NULL;
+
+    end = memchr(s, 0, len);
+    if (end)
+        len = end - s;
+
+    ret = av_realloc(NULL, len + 1);
+    if (!ret)
+        return NULL;
+
+    memcpy(ret, s, len);
+    ret[len] = 0;
+    return ret;
+}
+
 static void fill16(uint8_t *dst, int len)
 {
     uint32_t v = AV_RN16(dst - 2);