feat(scummtr): Fix text extraction resource for German releases of In…

…dy3 (#58)

This is an original bug in the official German releases, some German Eszett
characters were misencoded as \255 instead of \225, triggering the "special
espace sequence" code.

The following script lines are impacted:

[023:SC#0108]^irgendwo hier im Schlo\255.
[028:SC#0071]Nicht so schnell!  Woher weiß ich, da\255 Sie kein Spion sind?

Just ignore the \255 and replace it with the inteded \225, on the fly.
This unbreaks exporting/importing the text with ScummTR.

See also the related original ScummVM bugs:

    https://bugs.scummvm.org/ticket/1675
    https://bugs.scummvm.org/ticket/2715

Thanks to @gabberhead for reporting the issue.

src/ScummTr/text.cpp

@@ -24,7 +24,9 @@
  */
 
 #include "common/toolbox.hpp"
+#include "common/io.hpp"
 #include "ScummRp/block.hpp" // for tagToStr
+#include "ScummRp/scummrp.hpp"
 
 #include "text.hpp"
 
@@ -362,25 +364,41 @@ void Text::_writeEscMsg(const std::string &s)
 	size = s.size();
 	for (size_t i = 0; i < size; ++i)
 	{
+		byte b = (byte)s[i];
 		if (countdown > 0)
 		{
-			_writeEscChar((byte)s[i]);
+			_writeEscChar(b);
 			--countdown;
 		}
 		else if (func)
 		{
-			_writeEscChar((byte)s[i]);
-			countdown = Text::funcLen((byte)s[i]);
+			_writeEscChar(b);
+			countdown = Text::funcLen(b);
 			func = false;
 		}
-		else if ((byte)s[i] == 0xFF || (byte)s[i] == 0xFE)
+		else if (b == 0xFF || b == 0xFE)
 		{
-			_writeEscChar((byte)s[i]);
+			// Ignore badly-encoded German Eszett (0xFF instead of 0xE1) in Indy3 German.
+			// This is a bug in the original and official German releases of the game.
+			// See issue #58, https://bugs.scummvm.org/ticket/1675, and
+			// https://bugs.scummvm.org/ticket/2715.
+			if (ScummRp::game.id == GID_INDY3 && b == 0xFF && i < size - 1)
+			{
+				byte nextByte = (byte)s[i + 1];
+				if (nextByte == 0x2E || nextByte == 0x20)
+				{
+					ScummIO::warning("Fixing likely misencoded German Eszett character for Indy3");
+					b = 0xE1;
+					_writeChar(b);
+					continue;
+				}
+			}
+			_writeEscChar(b);
 			func = true;
 		}
 		else
 		{
-			_writeChar((byte)s[i]);
+			_writeChar(b);
 		}
 	}
 }
@@ -625,7 +643,7 @@ int Text::getLengthOldMsg(FileHandle &f)
 
 int Text::getLengthMsg(FileHandle &f)
 {
-	byte b;
+	byte b, nextByte;
 	int32 start;
 	int i;
 
@@ -634,7 +652,17 @@ int Text::getLengthMsg(FileHandle &f)
 	{
 		if (b == 0xFF || b == 0xFE)
 		{
-			i = Text::funcLen(f->getByte(b));
+			f->getByte(nextByte);
+
+			// Ignore badly encoded German Eszett characters that would be interpreted
+			// as a \255 escape sequence. See also Text::_writeEscMsg() comment above.
+			if (ScummRp::game.id == GID_INDY3 && b == 0xFF && (nextByte == 0x2E || nextByte == 0x20))
+			{
+				ScummIO::info(INF_DETAIL, xsprintf("Ignoring 0x%.2X%.2X sequence in Indy3 (likely a bogus German Eszett)", b, nextByte));
+				continue;
+			}
+
+			i = Text::funcLen(nextByte);
 			f->seekg(i, std::ios::cur);
 		}
 	}