Added: NDBUF_RORB flag is a read-only aware flag. Set this to avoid

writes to read-only buffers. E.g. use
ndbuf_setflags (b, NDBUF_RORB);
Fixes: More checks for non-reallocatable buffer are added;

include/ndbuf/ndbuf.h

@@ -30,6 +30,7 @@
 #define NDBUF_BURN  (1 << 1)  /* burn buffer data before free */
 #define NDBUF_NREA  (1 << 2)  /* non reallocatable buffer */
 #define NDBUF_UCMO  (1 << 3)  /* user defined memops functions */
+#define NDBUF_RORB  (1 << 4)  /* read-only buffer */
 
 struct ndbuf_memops {
   void *(*alloc)(size_t);

ndbuf.c

@@ -336,12 +336,25 @@ uint32_t ndbuf_write_u64(ndbuf_t *b, uint64_t uu)
   return sizeof(uint64_t);
 }
 
+static inline int __ndbuf_is_ro(ndbuf_t *b)
+{
+  return (b->flags & NDBUF_RORB) ? 1 : 0;
+}
+
+static inline int __ndbuf_is_nrea(ndbuf_t *b)
+{
+  return (b->flags & NDBUF_NREA) ? 1 : 0;
+}
+
 /* write raw data with the given length */
 uint32_t ndbuf_write_raw(ndbuf_t *b, void *wi, uint32_t len)
 {
   if(!b || !b->raw) return 0;
   if(!wi || !len) return 0;
+  if(__ndbuf_is_ro(b)) return 0; /* read only buffer */
+
   if(b->ulength + len >= b->rlength) {
+    if(__ndbuf_is_nrea(b)) return 0; /* non reallocatable buffer */
     if(__rdb_grow(b, len)) return 0;
   }
 
@@ -361,7 +374,10 @@ uint32_t ndbuf_write_raw_head(ndbuf_t *b, void *wi, uint32_t len)
 
   if(!b || !b->raw) return 0;
   if(!wi || !len) return 0;
+  if(__ndbuf_is_ro(b)) return 0; /* read only buffer */
+
   if(b->ulength + len > b->rlength) {
+    if(__ndbuf_is_nrea(b)) return 0; /* non reallocatable buffer */
     /* allocate a new one and copy it right */
     if(b->rlength + len > NDBUF_MAXLENGTH) return -1;
 
@@ -617,6 +633,8 @@ uint32_t ndbuf_print_va(ndbuf_t *b, const char *fmt, int argc, va_list ap)
   uint32_t len = 0, clen;
   int r, count;
 
+  if(__ndbuf_is_ro(b)) return 0; /* read only buffer */
+
   for(t = fmt, count = 0; *t != '\0'; t++, count++) {
     if(count > argc && argc != -1) return 0;
     switch(*t) {