preprocessor: Handle "<backslash><newline>" better

src/preprocessor.cpp

@@ -44,6 +44,11 @@ std::string Preprocessor::read(std::istream &istr)
     // For the error report
     int lineno = 1;
 
+    // handling <backspace><newline>
+    // when this is encountered the <backspace><newline> will be "skipped".
+    // on the next <newline>, extra newlines will be added
+    unsigned int newlines = 0;
+
     std::ostringstream code;
     for (char ch = (char)istr.get(); istr.good(); ch = (char)istr.get())
     {
@@ -101,7 +106,6 @@ std::string Preprocessor::read(std::istream &istr)
         // String constants..
         else if (ch == '\"')
         {
-            int newlines = 0;
             code << "\"";
             do
             {
@@ -121,9 +125,6 @@ std::string Preprocessor::read(std::istream &istr)
                     code << std::string(1, ch);
             }
             while (istr.good() && ch != '\"');
-
-            // Insert extra newlines after the string in case the string contained \newline sequences
-            code << std::string(newlines, '\n');
         }
 
         // char constants..
@@ -141,10 +142,30 @@ std::string Preprocessor::read(std::istream &istr)
             code << "\'";
         }
 
+        // <backspace><newline>..
+        else if (ch == '\\')
+        {
+            char chNext = (char)istr.peek();
+            if (chNext == '\n')
+            {
+                ++newlines;
+                (void)istr.get();   // Skip the "<backspace><newline>"
+            }
+            else
+                code << "\\";
+        }
+
         // Just some code..
         else
         {
             code << std::string(1, ch);
+
+            // if there has been <backspace><newline> sequences, add extra newlines..
+            if ( ch == '\n' && newlines > 0 )
+            {
+                code << std::string(newlines, '\n');
+                newlines = 0;
+            }
         }
     }
 
@@ -219,17 +240,6 @@ void Preprocessor::preprocess(std::istream &istr, std::string &processedFile, st
     // Remove space characters that are after or before new line character
     processedFile = removeSpaceNearNL(processedFile);
 
-    // Using the backslash at the end of a line..
-    std::string::size_type loc = 0;
-    while ((loc = processedFile.rfind("\\\n")) != std::string::npos)
-    {
-        processedFile.erase(loc, 2);
-        if (loc > 0 && processedFile[loc-1] != ' ')
-            processedFile.insert(loc, " ");
-        if ((loc = processedFile.find("\n", loc)) != std::string::npos)
-            processedFile.insert(loc, "\n");
-    }
-
     processedFile = replaceIfDefined(processedFile);
 
     processedFile = expandMacros(processedFile);
@@ -436,8 +446,6 @@ std::string Preprocessor::expandMacros(std::string code)
 
         // Get macro..
         std::string::size_type endpos = code.find("\n", defpos + 6);
-        while (endpos != std::string::npos && code[endpos-1] == '\\')
-            endpos = code.find("\n", endpos + 1);
         if (endpos == std::string::npos)
         {
             code.erase(defpos);
@@ -448,14 +456,6 @@ std::string Preprocessor::expandMacros(std::string code)
         std::string macro(code.substr(defpos + 8, endpos - defpos - 7));
         code.erase(defpos, endpos - defpos);
 
-        // Remove "\\\n" from the macro
-        while (macro.find("\\\n") != std::string::npos)
-        {
-            macro.erase(macro.find("\\\n"), 2);
-            code.insert(defpos, "\n");
-            ++defpos;
-        }
-
         // Tokenize the macro to make it easier to handle
         Tokenizer tokenizer;
         std::istringstream istr(macro.c_str());

test/testpreprocessor.cpp

@@ -61,7 +61,8 @@ private:
 
         TEST_CASE(if_cond1);
 
-        TEST_CASE(multiline);
+        TEST_CASE(multiline1);
+        TEST_CASE(multiline2);
 
         TEST_CASE(if_defined);      // "#if defined(AAA)" => "#ifdef AAA"
 
@@ -69,7 +70,6 @@ private:
         TEST_CASE(macro_simple1);
         TEST_CASE(macro_simple2);
         TEST_CASE(macro_mismatch);
-        TEST_CASE(macro_multiline);
         TEST_CASE(preprocessor_inside_string);
     }
 
@@ -375,21 +375,29 @@ private:
     }
 
 
-    void multiline()
+    void multiline1()
     {
-        const char filedata[] = "#define str \"abc\"   \\  \n"
+        const char filedata[] = "#define str \"abc\"     \\\n"
                                 "            \"def\"       \n"
                                 "abcdef = str;\n";
 
         // Preprocess => actual result..
         std::istringstream istr(filedata);
-        std::map<std::string, std::string> actual;
         Preprocessor preprocessor;
-        preprocessor.preprocess(istr, actual);
+        ASSERT_EQUALS("#define str \"abc\"  \"def\" \n\nabcdef = str;\n", preprocessor.read(istr));
+    }
 
-        // Compare results..
-        ASSERT_EQUALS("\n\nabcdef = \"abc\"\"def\"\n", actual[""]);
-        ASSERT_EQUALS(1, actual.size());
+
+    void multiline2()
+    {
+        const char filedata[] = "#define sqr(aa) aa * \\\n"
+                                "                aa\n"
+                                "sqr(5);\n";
+
+        // Preprocess => actual result..
+        std::istringstream istr(filedata);
+        Preprocessor preprocessor;
+        ASSERT_EQUALS("#define sqr(aa) aa *  aa\n\nsqr(5);\n", preprocessor.read(istr));
     }
 
 
@@ -398,6 +406,7 @@ private:
         const char filedata[] = "#if defined(AAA)\n"
                                 "#endif\n";
 
+
         // Expected result..
         std::string expected("#ifdef AAA\n#endif\n");
 
@@ -427,14 +436,6 @@ private:
         ASSERT_EQUALS("\nAAA(5);\n", Preprocessor::expandMacros(filedata));
     }
 
-    void macro_multiline()
-    {
-        const char filedata[] = "#define sqr(aa) aa * \\\n"
-                                "                aa\n"
-                                "sqr(5);\n";
-        ASSERT_EQUALS("\n\n5*5;\n", Preprocessor::expandMacros(filedata));
-    }
-
     void preprocessor_inside_string()
     {
         const char filedata[] = "int main()"