From ab6bf5f4f75e9aa16e71a5fed7c03f1ac8ce2762 Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Fri, 21 Aug 2020 14:51:42 +0200
Subject: [PATCH] general: Add workaround for Windows bug in various uses of
 isprint()

See #994; there is a regression in certain versions of the Windows CRT that gives the wrong result for isprint().  This adds workarounds to various potentially affected locations where isprint() is being used.
---
 direct/src/dcparser/dcPacker.cxx                     | 2 +-
 direct/src/plugin/p3dStringObject.cxx                | 5 +++++
 dtool/src/interrogate/interfaceMakerPythonNative.cxx | 4 ++++
 dtool/src/prckeys/makePrcKey.cxx                     | 9 ++++++---
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/direct/src/dcparser/dcPacker.cxx b/direct/src/dcparser/dcPacker.cxx
index b6dbd60855..810744c2ab 100644
--- a/direct/src/dcparser/dcPacker.cxx
+++ b/direct/src/dcparser/dcPacker.cxx
@@ -1102,7 +1102,7 @@ enquote_string(ostream &out, char quote_mark, const string &str) {
     if ((*pi) == quote_mark || (*pi) == '\\') {
       out << '\\' << (*pi);
 
-    } else if (!isprint(*pi)) {
+    } else if (!isprint(*pi) || (*pi) == '\t') {
       char buffer[10];
       sprintf(buffer, "%02x", (unsigned char)(*pi));
       out << "\\x" << buffer;
diff --git a/direct/src/plugin/p3dStringObject.cxx b/direct/src/plugin/p3dStringObject.cxx
index 8d87a2dc8c..4cd1d1f513 100644
--- a/direct/src/plugin/p3dStringObject.cxx
+++ b/direct/src/plugin/p3dStringObject.cxx
@@ -83,6 +83,11 @@ output(std::ostream &out) {
         out << "\\\x22";
         break;
 
+      case '\t':
+        // Certain versions of the Windows CRT classify tab as printable.
+        out << "\\t";
+        break;
+
       default:
         out << *si;
       }
diff --git a/dtool/src/interrogate/interfaceMakerPythonNative.cxx b/dtool/src/interrogate/interfaceMakerPythonNative.cxx
index 40572007fc..2a90a4b1db 100644
--- a/dtool/src/interrogate/interfaceMakerPythonNative.cxx
+++ b/dtool/src/interrogate/interfaceMakerPythonNative.cxx
@@ -8019,6 +8019,10 @@ output_quoted(ostream &out, int indent_level, const std::string &str,
         << '"';
       continue;
 
+    case '\t':
+      out << "\\t";
+      break;
+
     default:
       if (!isprint(*si)) {
         out << "\\" << oct << std::setw(3) << std::setfill('0') << (unsigned int)(*si)
diff --git a/dtool/src/prckeys/makePrcKey.cxx b/dtool/src/prckeys/makePrcKey.cxx
index 23bf0914b0..fea188c87c 100644
--- a/dtool/src/prckeys/makePrcKey.cxx
+++ b/dtool/src/prckeys/makePrcKey.cxx
@@ -93,10 +93,13 @@ output_c_string(std::ostream &out, const string &string_name,
         last_nl = false;
       }
 
-      if (isprint(data_ptr[i])) {
+      if (data_ptr[i] == '\t') {
+        out << "\\t";
+      }
+      else if (isprint(data_ptr[i])) {
         out << data_ptr[i];
-
-      } else {
+      }
+      else {
         out << "\\x" << std::hex << std::setw(2) << std::setfill('0')
             << (unsigned int)(unsigned char)data_ptr[i] << std::dec;
       }