string-util: add new memory_startswith() helper

We have code like this at various placer, let's make things shorter and
more readable with a helper for it.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/basic/string-util.h b/src/basic/string-util.h
index 56a64d7f5..52a1d7f2b 100644
--- a/src/basic/string-util.h
+++ b/src/basic/string-util.h
@@ -217,3 +217,21 @@ static inline size_t strlen_ptr(const char *s) {
 
         return strlen(s);
 }
+
+/* Like startswith(), but operates on arbitrary memory blocks */
+static inline void *memory_startswith(const void *p, size_t sz, const char *token) {
+        size_t n;
+
+        assert(token);
+
+        n = strlen(token);
+        if (sz < n)
+                return NULL;
+
+        assert(p);
+
+        if (memcmp(p, token, n) != 0)
+                return NULL;
+
+        return (uint8_t*) p + n;
+}