fix: assert size in remove_prefix/suffix

fix #973

Author: alandefreitas

include/boost/url/decode_view.hpp

@@ -460,7 +460,7 @@ class decode_view
 
         @par Preconditions
         @code
-        not this->empty()
+        n <= this->size()
         @endcode
 
         @par Complexity
@@ -477,13 +477,13 @@ class decode_view
         @par Example
         @code
         decode_view d( "Program%20Files" );
-        d.remove_prefix( 6 );
+        d.remove_suffix( 6 );
         assert( d == "Program" );
         @endcode
 
         @par Preconditions
         @code
-        not this->empty()
+        n <= this->size()
         @endcode
 
         @par Complexity

src/decode_view.cpp

@@ -52,6 +52,7 @@ void
 decode_view::
 remove_prefix( size_type n )
 {
+    BOOST_ASSERT(n <= dn_);
     auto it = begin();
     auto n0 = n;
     while (n)
@@ -68,6 +69,7 @@ void
 decode_view::
 remove_suffix( size_type n )
 {
+    BOOST_ASSERT(n <= dn_);
     auto it = end();
     auto n0 = n;
     while (n)

test/unit/decode_view.cpp

@@ -171,12 +171,42 @@ struct decode_view_test
             BOOST_TEST_EQ(s, "uri test");
         }
 
+        // remove_prefix() with n == size() (issue #973)
+        {
+            decode_view s(str, no_plus_opt);
+            s.remove_prefix(s.size());
+            BOOST_TEST(s.empty());
+            BOOST_TEST_EQ(s.size(), 0u);
+        }
+
+        // remove_prefix() with n == 0
+        {
+            decode_view s(str, no_plus_opt);
+            s.remove_prefix(0);
+            BOOST_TEST_EQ(s, "a uri test");
+        }
+
         // remove_suffix()
         {
             decode_view s(str);
             s.remove_suffix(5);
             BOOST_TEST_EQ(s, "a uri");
         }
+
+        // remove_suffix() with n == size() (issue #973)
+        {
+            decode_view s(str, no_plus_opt);
+            s.remove_suffix(s.size());
+            BOOST_TEST(s.empty());
+            BOOST_TEST_EQ(s.size(), 0u);
+        }
+
+        // remove_suffix() with n == 0
+        {
+            decode_view s(str, no_plus_opt);
+            s.remove_suffix(0);
+            BOOST_TEST_EQ(s, "a uri test");
+        }
     }
 
     void
@@ -372,6 +402,78 @@ struct decode_view_test
 #endif
     }
 
+    void
+    testJavadocs()
+    {
+        // decode_view()
+        {
+            decode_view ds;
+
+            boost::ignore_unused(ds);
+        }
+
+        // decode_view(pct_string_view, encoding_opts)
+        {
+            decode_view ds( "Program%20Files" );
+
+            boost::ignore_unused(ds);
+        }
+
+        // empty()
+        {
+            BOOST_TEST( decode_view( "" ).empty() );
+        }
+
+        // size()
+        {
+            BOOST_TEST_EQ( decode_view( "Program%20Files" ).size(), 13u );
+        }
+
+        // front()
+        {
+            BOOST_TEST_EQ( decode_view( "Program%20Files" ).front(), 'P' );
+        }
+
+        // back()
+        {
+            BOOST_TEST_EQ( decode_view( "Program%20Files" ).back(), 's' );
+        }
+
+        // starts_with(core::string_view)
+        {
+            BOOST_TEST( decode_view( "Program%20Files" ).starts_with("Program") );
+        }
+
+        // ends_with(core::string_view)
+        {
+            BOOST_TEST( decode_view( "Program%20Files" ).ends_with("Files") );
+        }
+
+        // starts_with(char)
+        {
+            BOOST_TEST( decode_view( "Program%20Files" ).starts_with('P') );
+        }
+
+        // ends_with(char)
+        {
+            BOOST_TEST( decode_view( "Program%20Files" ).ends_with('s') );
+        }
+
+        // remove_prefix(size_type)
+        {
+            decode_view d( "Program%20Files" );
+            d.remove_prefix( 8 );
+            BOOST_TEST_EQ( d, "Files" );
+        }
+
+        // remove_suffix(size_type)
+        {
+            decode_view d( "Program%20Files" );
+            d.remove_suffix( 6 );
+            BOOST_TEST_EQ( d, "Program" );
+        }
+    }
+
     void
     run()
     {
@@ -385,6 +487,7 @@ struct decode_view_test
         testStream();
         testPR127Cases();
         testBorrowedRange();
+        testJavadocs();
     }
 };