StringUtil::extractLine (#989)

* Added extractLine line parsing to StringUtil. Use for matching lines instead of calcLines. calcLines uses extractLine to extract lines.
Fixed problems found in output of some tests- due to how a how final line is handled. Now a final line has a \r or \n\r combination, but nothing else after it, it is considered the last line (not the line after it).

* Use StringUtil::extractLine in slang-generate.

* Improved comment on extractLine

* Remove test code from StringUtil::extractLine

* Made StringUtil::extractLine act as if line terminators are 'separators'.
Added unit-test-string.cpp - to check behavior.

* Adding LineParser - not entirely necessary, but slightly easier to use.

* Improved LineParser::Iterator end testing.
Added improved tests for LineParser.

* Move line comparson after termination case - to fix problem with gcc release build.

* Make UnownedStringSlice handle comparison when begin is nullptr - as it uses memcmp and passing nullptr to memcmp is undefined, leading to optimizer being able to do some unfortunate optimizations on gcc.

1 files changed, 14 insertions, 18 deletions

diff --git a/tools/slang-generate/main.cpp b/tools/slang-generate/main.cpp
index 046b2063c..7c0e3672a 100644
--- a/tools/slang-generate/main.cpp
+++ b/tools/slang-generate/main.cpp
@@ -554,30 +554,26 @@ void emitSimpleText(
     FILE*               stream,
     StringSpan const&   span)
 {
-    char const* cursor = span.begin();
-    char const* end = span.end();
-
-    while (cursor != end)
+    UnownedStringSlice content = span;
+    while (true)
     {
-        int c = *cursor++;
-        switch (c)
+        const auto line = StringUtil::extractLine(content);
+        if (line.begin() == nullptr)
         {
-        default:
-            fprintf(stream, "%c", c);
             break;
+        }
 
-        case '\r': case '\n':
-            if (cursor != end)
-            {
-                int d = *cursor;
-                if ((c ^ d) == ('\r' ^ '\n'))
-                {
-                    cursor++;
-                }
-                fprintf(stream, "\n");
-            }
+        // Write the line
+        fwrite(line.begin(), 1, line.size(), stream);
+
+        // Specially handle the 'final line', excluding an empty line after \n.
+        // We can detect, as if input ends with 'cr/lf' combination, content.begin == span.end(), else if content.begin() == nullptr.
+        if (content.begin() == nullptr || content.begin() == span.end())
+        {
             break;
         }
+
+        fprintf(stream, "\n");
     }
 }