From 7c370ec87399d2e91654c0c30440eb3e01f7d7cc Mon Sep 17 00:00:00 2001
From: Andrew Martin <andrew.c.martin@saic.com>
Date: Sun, 4 Nov 2012 16:15:26 +0100
Subject: [PATCH] Fixed #4305 (improve check: 'vector.size() < 1' should result
 in 'inefficient checking for '...' emptiness.')

---
 lib/checkstl.cpp |  7 +++++++
 test/teststl.cpp | 28 ++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index 29e5c0e3a..3840812ab 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -954,6 +954,13 @@ void CheckStl::size()
                         sizeError(tok1);
                 }
 
+                // check for comparison to one
+                if ((tok->previous() && !tok->previous()->isArithmeticalOp() && Token::Match(end, ">=|< 1")) ||
+                    (end->next() && !end->next()->isArithmeticalOp() && Token::Match(tok->tokAt(-2), "1 <=|>"))) {
+                    if (isStlContainer(varid))
+                        sizeError(tok1);
+                }
+
                 // check for using as boolean expression
                 else if ((Token::Match(tok->tokAt(-2), "if|while (") && end->str() == ")") ||
                          (tok->previous()->type() == Token::eLogicalOp && Token::Match(end, "&&|)|,|;|%oror%"))) {
diff --git a/test/teststl.cpp b/test/teststl.cpp
index 076093d46..07109f66a 100644
--- a/test/teststl.cpp
+++ b/test/teststl.cpp
@@ -1441,6 +1441,34 @@ private:
               "}\n");
         ASSERT_EQUALS("[test.cpp:4]: (performance) Possible inefficient checking for 'x' emptiness.\n", errout.str());
 
+        check("void f()\n"
+              "{\n"
+              "    std::list<int> x;\n"
+              "    if (x.size() >= 1) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (performance) Possible inefficient checking for 'x' emptiness.\n", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    std::list<int> x;\n"
+              "    if (x.size() < 1) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (performance) Possible inefficient checking for 'x' emptiness.\n", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    std::list<int> x;\n"
+              "    if (1 <= x.size()) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (performance) Possible inefficient checking for 'x' emptiness.\n", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    std::list<int> x;\n"
+              "    if (1 > x.size()) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (performance) Possible inefficient checking for 'x' emptiness.\n", errout.str());
+
         check("void f()\n"
               "{\n"
               "    std::list<int> x;\n"