4 files changed, 88 insertions, 3 deletions
diff --git a/src/drivers/Posix/Fl_Posix_System_Driver.H b/src/drivers/Posix/Fl_Posix_System_Driver.H
index df9407c17..5712f6be2 100644
--- a/src/drivers/Posix/Fl_Posix_System_Driver.H
+++ b/src/drivers/Posix/Fl_Posix_System_Driver.H
@@ -82,6 +82,10 @@ public:
   virtual int dot_file_hidden() {return 1;}
   virtual void gettime(time_t *sec, int *usec);
   virtual char* strdup(const char *s) {return ::strdup(s);}
+  virtual int close_fd(int fd);
+  // next 2 for support of Fl_SVG_Image
+  virtual int write_nonblocking_fd(int , const unsigned char *&, size_t &);
+  virtual void pipe_support(int &, int &, const unsigned char *, size_t );
 #if defined(HAVE_PTHREAD)
   virtual void lock_ring();
   virtual void unlock_ring();
diff --git a/src/drivers/Posix/Fl_Posix_System_Driver.cxx b/src/drivers/Posix/Fl_Posix_System_Driver.cxx
index dcf9e8f1a..ec43ea741 100644
--- a/src/drivers/Posix/Fl_Posix_System_Driver.cxx
+++ b/src/drivers/Posix/Fl_Posix_System_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Definition of Posix system driver (used by the X11, Wayland and macOS platforms).
 //
-// Copyright 1998-2021 by Bill Spitzak and others.
+// Copyright 1998-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -308,6 +308,33 @@ bool Fl_Posix_System_Driver::probe_for_GTK(int major, int minor, void **p_ptr_gt
 #endif // HAVE_DLSYM && HAVE_DLFCN_H
 
 
+int Fl_Posix_System_Driver::close_fd(int fd) { return close(fd); }
+
+int Fl_Posix_System_Driver::write_nonblocking_fd(int fdwrite, const unsigned char *&bytes, size_t &rest_bytes) {
+    if (rest_bytes > 0) {
+      ssize_t nw = write(fdwrite, bytes, rest_bytes);
+      if (nw == -1) {
+        close(fdwrite);
+        return 1; // error
+      }
+      bytes += nw;
+      rest_bytes -= nw;
+      if (rest_bytes == 0) close(fdwrite);
+    }
+  return 0; // success
+}
+
+void Fl_Posix_System_Driver::pipe_support(int &fdread, int &fdwrite, const unsigned char *unused, size_t unused_s) {
+  int fds[2];
+  if (pipe(fds)) { // create anonymous pipe
+    Fl_System_Driver::pipe_support(fdread, fdwrite, NULL, 0); // indicates error
+  } else {
+    fdread = fds[0];
+    fdwrite = fds[1];
+    fcntl(fdwrite, F_SETFL, O_NONBLOCK); // make pipe's write end non-blocking
+  }
+}
+
 ////////////////////////////////////////////////////////////////
 // POSIX threading...
 #if defined(HAVE_PTHREAD)
diff --git a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.H b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.H
index 730d9320d..d05b580d6 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.H
+++ b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.H
@@ -1,7 +1,7 @@
 //
 // Windows system driver for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2021 by Bill Spitzak and others.
+// Copyright 2010-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -114,6 +114,8 @@ public:
   virtual void unlock_ring();
   virtual double wait(double time_to_wait);
   virtual int ready();
+  virtual void pipe_support(int &, int &, const unsigned char *, size_t );
+  virtual int close_fd(int fd);
 };
 
 #endif // FL_WINAPI_SYSTEM_DRIVER_H
diff --git a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
index 237243975..cdb0805eb 100644
--- a/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
+++ b/src/drivers/WinAPI/Fl_WinAPI_System_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Definition of Windows system driver for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2021 by Bill Spitzak and others.
+// Copyright 1998-2022 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -1026,3 +1026,55 @@ void Fl_WinAPI_System_Driver::unlock() {
 void Fl_WinAPI_System_Driver::awake(void* msg) {
   PostThreadMessage( main_thread, fl_wake_msg, (WPARAM)msg, 0);
 }
+
+// create anonymous pipe in the form of 2 unix-style file descriptors
+static void pipe_win32(int fds[2]) {
+  HANDLE read_h, write_h;
+  SECURITY_ATTRIBUTES sa;
+  sa.nLength = sizeof(sa);
+  sa.lpSecurityDescriptor = NULL;
+  sa.bInheritHandle = true;
+  if (CreatePipe(&read_h, &write_h, &sa, 0) == 0) {
+    fds[0] = fds[1] = -1; // indicates error
+  } else { // create unix-style file descriptors from handles
+    fds[0] = _open_osfhandle((fl_intptr_t)read_h, _O_RDONLY | _O_BINARY);
+    fds[1] = _open_osfhandle((fl_intptr_t)write_h, _O_WRONLY | _O_BINARY);
+  }
+}
+
+struct gunz_data { // data transmitted to thread
+  const unsigned char *data;
+  unsigned length;
+  int fd;
+};
+
+static void __cdecl write_func(struct gunz_data *pdata) { // will run in child thread
+  //const unsigned char *from = pdata->data;
+  while (pdata->length > 0) {
+    int done = _write(pdata->fd, pdata->data, pdata->length);
+    if (done == -1) break;
+    pdata->length -= done;
+    pdata->data += done;
+  }
+  _close(pdata->fd);
+  free(pdata);
+}
+
+int Fl_WinAPI_System_Driver::close_fd(int fd) {
+  return _close(fd);
+}
+
+void Fl_WinAPI_System_Driver::pipe_support(int &fdread, int &fdwrite, const unsigned char *bytes, size_t length) {
+  int fds[2];
+  pipe_win32(fds); // create anonymous pipe
+  if (fds[0] == -1) return Fl_System_Driver::pipe_support(fdread, fdwrite, NULL, 0);
+  fdread = fds[0];
+  fdwrite = -1;
+  // prepare data transmitted to child thread
+  struct gunz_data *thread_data = (struct gunz_data*)malloc(sizeof(struct gunz_data));
+  thread_data->data = bytes;
+  thread_data->length = (unsigned)length;
+  thread_data->fd = fds[1];
+  // launch child thread that will write byte buffer to pipe's write end
+  _beginthread((void( __cdecl * )( void * ))write_func, 0, thread_data);
+}