lib: introduce `NativeArray::native_to_s`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/standard/string.nit b/lib/standard/string.nit
index 63c8226..4892f95 100644 (file)
--- a/lib/standard/string.nit
+++ b/lib/standard/string.nit
@@ -2184,6 +2184,48 @@ redef class Array[E]
        end
 end
 
+redef class NativeArray[E]
+       # Join all the elements using `to_s`
+       #
+       # REQUIRE: `self isa NativeArray[String]`
+       # REQUIRE: all elements are initialized
+       fun native_to_s: String
+       do
+               assert self isa NativeArray[String]
+               var l = length
+               var na = self
+               var i = 0
+               var sl = 0
+               var mypos = 0
+               while i < l do
+                       sl += na[i].length
+                       i += 1
+                       mypos += 1
+               end
+               var ns = new NativeString(sl + 1)
+               ns[sl] = '\0'
+               i = 0
+               var off = 0
+               while i < mypos do
+                       var tmp = na[i]
+                       var tpl = tmp.length
+                       if tmp isa FlatString then
+                               tmp.items.copy_to(ns, tpl, tmp.index_from, off)
+                               off += tpl
+                       else
+                               for j in tmp.substrings do
+                                       var s = j.as(FlatString)
+                                       var slen = s.length
+                                       s.items.copy_to(ns, slen, s.index_from, off)
+                                       off += slen
+                               end
+                       end
+                       i += 1
+               end
+               return ns.to_s_with_length(sl)
+       end
+end
+
 redef class Map[K,V]
        # Concatenate couple of 'key value'.
        # key and value are separated by `couple_sep`.