iovec-wrapper: introduce iovw_compare() and iovw_equal()

src/basic/iovec-wrapper.c

@@ -23,6 +23,28 @@ void iovw_done_free(struct iovec_wrapper *iovw) {
         iovw_done(iovw);
 }
 
+int iovw_compare(const struct iovec_wrapper *a, const struct iovec_wrapper *b) {
+        int r;
+
+        if (a == b)
+                return 0;
+
+        if (!a || !b)
+                return CMP(!!a, !!b);
+
+        /* Note, this performs structural (element-by-element) comparison, not content-based comparison.
+         * Two wrappers with identical concatenated content but different element boundaries
+         * (e.g., ["fo","o"] vs ["f","oo"]) will not compare as equal. */
+
+        for (size_t i = 0, n = MIN(a->count, b->count); i < n; i++) {
+                r = iovec_memcmp(a->iovec + i, b->iovec + i);
+                if (r != 0)
+                        return r;
+        }
+
+        return CMP(a->count, b->count);
+}
+
 int iovw_put(struct iovec_wrapper *iovw, void *data, size_t len) {
         assert(iovw);
 

src/basic/iovec-wrapper.h

@@ -11,6 +11,11 @@ struct iovec_wrapper {
 void iovw_done_free(struct iovec_wrapper *iovw);
 void iovw_done(struct iovec_wrapper *iovw);
 
+int iovw_compare(const struct iovec_wrapper *a, const struct iovec_wrapper *b) _pure_;
+static inline bool iovw_equal(const struct iovec_wrapper *a, const struct iovec_wrapper *b) {
+        return iovw_compare(a, b) == 0;
+}
+
 int iovw_put(struct iovec_wrapper *iovw, void *data, size_t len);
 int iovw_consume(struct iovec_wrapper *iovw, void *data, size_t len);
 int iovw_append(struct iovec_wrapper *iovw, const void *data, size_t len);