Ticket #7137: Properly detect C++14 digit separators. (#802)

Add an optional extended description…

lib/mathlib.cpp

@@ -1249,6 +1249,42 @@ bool MathLib::isOctalDigit(char c)
     return (c >= '0' && c <= '7');
 }
 
+bool MathLib::isDigitSeparator(const std::string& iCode, std::string::size_type iPos) {
+    if (iPos == 0 || iPos >= iCode.size() || iCode[iPos] != '\'')
+        return false;
+    std::string::size_type i = iPos - 1;
+    while (std::isxdigit(iCode[i])) {
+        if (i == 0)
+            return true; // Only xdigits before '
+        --i;
+    }
+    if (i == iPos - 1) { // No xdigit before '
+        return false;
+    } else {
+        switch(iCode[i]) {
+        case ' ':
+        case '.':
+        case ',':
+        case 'x':
+        case '(':
+        case '{':
+        case '+':
+        case '-':
+        case '*':
+        case '%':
+        case '/':
+        case '&':
+        case '|':
+        case '^':
+        case '~':
+        case '=':
+            return true;
+        default:
+            return false;
+        }
+    }
+}
+
 MathLib::value operator+(const MathLib::value &v1, const MathLib::value &v2)
 {
     return MathLib::value::calc('+',v1,v2);

lib/mathlib.h

@@ -122,6 +122,13 @@ public:
      * */
     static MathLib::bigint characterLiteralToLongNumber(const std::string& str);
 
+    /**
+     * \param iCode Code being considered
+     * \param iPos A posision within iCode
+     * \return Whether iCode[iPos] is a C++14 digit separator
+     */
+    static bool isDigitSeparator(const std::string& iCode, std::string::size_type iPos);
+
 private:
     /*
      * \param iLiteral A character literal

lib/preprocessor.cpp

@@ -697,7 +697,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
             }
 
             // C++14 digit separators
-            if (ch == '\'' && std::isxdigit(previous))
+            if (MathLib::isDigitSeparator(str, i))
                 ; // Just skip it.
 
             // String or char constants..

test/testmathlib.cpp

@@ -59,6 +59,7 @@ private:
         TEST_CASE(abs);
         TEST_CASE(toString);
         TEST_CASE(characterLiteralsNormalization);
+        TEST_CASE(CPP14DigitSeparators);
     }
 
     void isGreater() const {
@@ -1143,6 +1144,23 @@ private:
         // Unsupported single escape sequence
         ASSERT_THROW(MathLib::normalizeCharacterLiteral("\\c"), InternalError);
     }
+
+    void CPP14DigitSeparators() { // Ticket #7137
+        ASSERT(MathLib::isDigitSeparator("'", 0) == false);
+        ASSERT(MathLib::isDigitSeparator("123'0;", 3));
+        ASSERT(MathLib::isDigitSeparator("foo(1'2);", 5));
+        ASSERT(MathLib::isDigitSeparator("foo(1,1'2);", 7));
+        ASSERT(MathLib::isDigitSeparator("int a=1'234-1'2-'0';", 7));
+        ASSERT(MathLib::isDigitSeparator("int a=1'234-1'2-'0';", 13));
+        ASSERT(MathLib::isDigitSeparator("int a=1'234-1'2-'0';", 16) == false);
+        ASSERT(MathLib::isDigitSeparator("int b=1+9'8;", 9));
+        ASSERT(MathLib::isDigitSeparator("if (1'2) { char c = 'c'; }", 5));
+        ASSERT(MathLib::isDigitSeparator("if (120%1'2) { char c = 'c'; }", 9));
+        ASSERT(MathLib::isDigitSeparator("if (120&1'2) { char c = 'c'; }", 9));
+        ASSERT(MathLib::isDigitSeparator("if (120|1'2) { char c = 'c'; }", 9));
+        ASSERT(MathLib::isDigitSeparator("if (120%1'2) { char c = 'c'; }", 24) == false);
+        ASSERT(MathLib::isDigitSeparator("if (120%1'2) { char c = 'c'; }", 26) == false);
+    }
 };
 
 REGISTER_TEST(TestMathLib)

test/testpreprocessor.cpp

@@ -352,6 +352,11 @@ private:
 
         ASSERT_EQUALS("int i = 0x0F0FFFFF;", preprocessorRead("int i = 0x0F0F'FFFF;"));
         ASSERT_EQUALS("", errout.str());
+
+        // Ticket #7137
+        const char code[] = "void t(char c) { switch (c) { case'M': break; } }";
+        ASSERT_EQUALS(code, preprocessorRead(code));
+        ASSERT_EQUALS("", errout.str());
     }