From a781a838222d280d308f6eac01e44ba7fe846f43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sun, 1 Sep 2013 07:13:48 +0200
Subject: [PATCH] Preprocessor: Quicker response for --check-config. No
 'normal' code is needed so skip it.

---
 lib/preprocessor.cpp      | 71 +++++++++++++++++++++++++++++++++++++++
 lib/preprocessor.h        |  3 ++
 test/testpreprocessor.cpp |  2 +-
 3 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/lib/preprocessor.cpp b/lib/preprocessor.cpp
index 44b739c3c..00f01647b 100644
--- a/lib/preprocessor.cpp
+++ b/lib/preprocessor.cpp
@@ -174,6 +174,9 @@ std::string Preprocessor::read(std::istream &istr, const std::string &filename)
     if (_settings && _settings->terminated())
         return "";
 
+    if (_settings && _settings->checkConfiguration)
+        return readpreprocessor(istr,bom);
+
     // ------------------------------------------------------------------------------------------
     //
     // handling <backslash><newline>
@@ -262,6 +265,74 @@ std::string Preprocessor::read(std::istream &istr, const std::string &filename)
     return result;
 }
 
+
+/** read preprocessor statements */
+std::string Preprocessor::readpreprocessor(std::istream &istr, const unsigned int bom) const
+{
+    enum { NEWLINE, SPACE, PREPROCESSOR, BACKSLASH, OTHER } state = NEWLINE;
+    std::ostringstream code;
+    unsigned int newlines = 1;
+    char chPrev = ' ';
+    for (unsigned char ch = readChar(istr,bom); istr.good(); ch = readChar(istr,bom)) {
+        // Replace assorted special chars with spaces..
+        if (((ch & 0x80) == 0) && (ch != '\n') && (std::isspace(ch) || std::iscntrl(ch)))
+            ch = ' ';
+
+        if (ch == ' ' && chPrev == ' ')
+            continue;
+        if (state == PREPROCESSOR && chPrev == '/' && (ch == '/' || ch == '*'))
+            state = OTHER;
+        chPrev = ch;
+
+        if (ch == '\n') {
+            if (state != BACKSLASH) {
+                state = NEWLINE;
+                code << std::string(newlines, '\n');
+                newlines = 1;
+            } else {
+                ++newlines;
+                state = PREPROCESSOR;
+            }
+            continue;
+        }
+
+        switch (state) {
+        case NEWLINE:
+            if (ch==' ')
+                state = SPACE;
+            else if (ch == '#') {
+                state = PREPROCESSOR;
+                code << ch;
+            } else
+                state = OTHER;
+            break;
+        case SPACE:
+            if (ch == '#') {
+                state = PREPROCESSOR;
+                code << ch;
+            } else if (ch != ' ')
+                state = OTHER;
+            break;
+        case PREPROCESSOR:
+            code << ch;
+            if (ch == '\\')
+                state = BACKSLASH;
+            break;
+        case BACKSLASH:
+            code << ch;
+            if (ch != ' ')
+                state = PREPROCESSOR;
+            break;
+        case OTHER:
+            break;
+        };
+    }
+
+    std::string result = preprocessCleanupDirectives(code.str());
+    result = removeParentheses(result);
+    return removeIf0(result);
+}
+
 std::string Preprocessor::preprocessCleanupDirectives(const std::string &processedFile)
 {
     std::ostringstream code;
diff --git a/lib/preprocessor.h b/lib/preprocessor.h
index d12405a67..4e30641aa 100644
--- a/lib/preprocessor.h
+++ b/lib/preprocessor.h
@@ -92,6 +92,9 @@ public:
     /** Just read the code into a string. Perform simple cleanup of the code */
     std::string read(std::istream &istr, const std::string &filename);
 
+    /** read preprocessor statements into a string. */
+    std::string readpreprocessor(std::istream &istr, const unsigned int bom) const;
+
     /**
      * Get preprocessed code for a given configuration
      * @param filedata file data including preprocessing 'if', 'define', etc
diff --git a/test/testpreprocessor.cpp b/test/testpreprocessor.cpp
index fa43151c8..443400521 100644
--- a/test/testpreprocessor.cpp
+++ b/test/testpreprocessor.cpp
@@ -3792,7 +3792,7 @@ private:
 
         // Compare results..
         ASSERT_EQUALS("[file.c:2]: (information) Include file: \"config.h\" not found.\n", errout.str());
-        ASSERT_EQUALS("\n\n\n\nvoid foo();\n", actual[""]);
+        ASSERT_EQUALS("\n\n\n\n\n", actual[""]);
     }
 
     void undef9() {