XPath: evaluate_string now guarantees zero-terminated result (unless the buffer size is zero)

git-svn-id: http://pugixml.googlecode.com/svn/trunk@762 99668b35-9821-0410-8761-19e4c4f06640

2 files changed, 15 insertions, 7 deletions

diff --git a/src/pugixml.cpp b/src/pugixml.cpp
index 903416c..1d049a2 100644
--- a/src/pugixml.cpp
+++ b/src/pugixml.cpp
@@ -9321,12 +9321,18 @@ namespace pugi
 
 		xpath_string r = evaluate_string_impl(_root, n, sd);
 
-		size_t size = r.length() + 1;
+		size_t full_size = r.length() + 1;
 		
-		// $$ zero-terminate?
-		if (capacity > 0) memcpy(buffer, r.c_str(), (size < capacity ? size : capacity) * sizeof(char_t));
+		if (capacity > 0)
+        {
+            size_t size = (full_size < capacity) ? full_size : capacity;
+            assert(size > 0);
+
+            memcpy(buffer, r.c_str(), (size - 1) * sizeof(char_t));
+            buffer[size - 1] = 0;
+        }
 		
-		return size;
+		return full_size;
 	}
 
 	xpath_node_set xpath_query::evaluate_node_set(const xpath_node& n) const
diff --git a/tests/test_xpath_api.cpp b/tests/test_xpath_api.cpp
index 281e357..b735f8c 100644
--- a/tests/test_xpath_api.cpp
+++ b/tests/test_xpath_api.cpp
@@ -220,17 +220,19 @@ TEST(xpath_api_evaluate_string)
 	
 	// test for just not enough space
 	std::basic_string<char_t> s2 = base;
-	CHECK(q.evaluate_string(&s2[0], 10, xml_node()) == 11 && memcmp(&s2[0], STR("0123456789xxxxxx"), 16 * sizeof(char_t)) == 0);
+	CHECK(q.evaluate_string(&s2[0], 10, xml_node()) == 11 && memcmp(&s2[0], STR("012345678\0xxxxxx"), 16 * sizeof(char_t)) == 0);
 
 	// test for not enough space
 	std::basic_string<char_t> s3 = base;
-	CHECK(q.evaluate_string(&s3[0], 5, xml_node()) == 11 && memcmp(&s3[0], STR("01234xxxxxxxxxxx"), 16 * sizeof(char_t)) == 0);
+	CHECK(q.evaluate_string(&s3[0], 5, xml_node()) == 11 && memcmp(&s3[0], STR("0123\0xxxxxxxxxxx"), 16 * sizeof(char_t)) == 0);
 
 	// test for single character buffer
 	std::basic_string<char_t> s4 = base;
-	CHECK(q.evaluate_string(&s4[0], 1, xml_node()) == 11 && memcmp(&s4[0], STR("0xxxxxxxxxxxxxxx"), 16 * sizeof(char_t)) == 0);
+	CHECK(q.evaluate_string(&s4[0], 1, xml_node()) == 11 && memcmp(&s4[0], STR("\0xxxxxxxxxxxxxxx"), 16 * sizeof(char_t)) == 0);
 
 	// test for empty buffer
+	std::basic_string<char_t> s5 = base;
+	CHECK(q.evaluate_string(&s5[0], 0, xml_node()) == 11 && memcmp(&s5[0], STR("xxxxxxxxxxxxxxxx"), 16 * sizeof(char_t)) == 0);
 	CHECK(q.evaluate_string(0, 0, xml_node()) == 11);
 }