MT#17841 ngcp/utils.lua: implement utils.string.explode_values()

utils.string.explode_values("123") => {'1','12','123'}

Change-Id: Ifa2260b6f53714d1fdae70485e3ccff3e0872a31

ngcp/utils.lua

@@ -256,6 +256,22 @@ function utils.explode(delimiter, text)
     return list
 end
 
+-- from string to table with all the values of that string from 1 to len
+-- "123" -> {'1', '12', '123'}
+function us.explode_values(str)
+  local list = {}
+  local len
+
+  if not str then
+    error("string is nil")
+  end
+  len = string.len(str)
+  for i=1,len do
+    table.insert(list, string.sub(str, 1, i))
+  end
+  return list
+end
+
 function us.starts(String,Start)
    return string.sub(String,1,string.len(Start))==Start
 end

tests/utils.lua

@@ -161,6 +161,13 @@ TestUtils = {}
         assertItemsEquals(utils.explode('=>',"1=>2=>3"), {'1','2','3'})
     end
 
+    function TestUtils:test_string_explode_values()
+        assertError(utils.string.explode_values, nil)
+        assertItemsEquals(utils.string.explode_values(''), {})
+        assertItemsEquals(utils.string.explode_values('1'), {'1'})
+        assertItemsEquals(utils.string.explode_values('123'), {'1','12','123'})
+    end
+
     function TestUtils:test_starts()
         assertError(utils.string.stats, nil, "g")
         assertTrue(utils.string.starts("goga", "g"))