Extend commit a4b33f8 to other uses of function convert_crlf()

Helper function convert_crlf() from file fl_wayland_clipboard_dnd.cxx has been
repaired by commit a4b33f8 (13 jan 2023). But the same function was also in
file Fl_cocoa.mm. This commit moves the repaired code to class Fl_Screen_Driver
and has both fl_wayland_clipboard_dnd.cxx and Fl_cocoa.mm use it.

src/Fl_Screen_Driver.H

@@ -197,6 +197,7 @@ public:
   static void write_image_inside(Fl_RGB_Image *to, Fl_RGB_Image *from, int to_x, int to_y);
   static Fl_RGB_Image *traverse_to_gl_subwindows(Fl_Group *g, int x, int y, int w, int h,
                                                  Fl_RGB_Image *full_img);
+  static size_t convert_crlf(char *s, size_t len);
   // optional platform-specific key handling for Fl_Input widget
   // the default implementation may be enough
   virtual int input_widget_handle_key(int key, unsigned mods, unsigned shift, Fl_Input *input);

src/Fl_Screen_Driver.cxx

@@ -30,6 +30,7 @@
 #include <FL/Fl_Image_Surface.H>
 #include <FL/Fl_Box.H>
 #include <FL/Fl_Tooltip.H>
+#include <string.h> // for memchr
 
 char Fl_Screen_Driver::bg_set = 0;
 char Fl_Screen_Driver::bg2_set = 0;
@@ -709,6 +710,32 @@ int Fl_Screen_Driver::XParseGeometry(const char* string, int* x, int* y,
   return (mask);
 }
 
+
+// turn '\r' characters into '\n' and "\r\n" sequences into '\n'
+// returns new length
+size_t Fl_Screen_Driver::convert_crlf(char *s, size_t len) {
+  char *src = (char *)memchr(s, '\r', len); // find first `\r` in buffer
+  if (src) {
+    char *dst = src;
+    char *end = s + len;
+    while (src < end) {
+      if (*src == '\r') {
+        if (src + 1 < end && *(src + 1) == '\n') {
+          src++; // skip '\r'
+          continue;
+        } else {
+          *dst++ = '\n'; // replace single '\r' with '\n'
+        }
+      } else {
+        *dst++ = *src;
+      }
+      src++;
+    }
+    return (dst - s);
+  }
+  return len;
+}
+
 /**
  \}
  \endcond

src/Fl_cocoa.mm

@@ -67,7 +67,6 @@ extern int fl_send_system_handlers(void *e);
 
 // forward definition of functions in this file
 // converting cr lf converter function
-static size_t convert_crlf(char * string, size_t len);
 static void createAppleMenu(void);
 static void cocoaMouseHandler(NSEvent *theEvent);
 static void clipboard_check(void);
@@ -2547,7 +2546,7 @@ static FLTextInputContext* fltextinputcontext_instance = nil;
     DragData = (char *)malloc([data length] + 1);
     [data getBytes:DragData];
     DragData[[data length]] = 0;
-    convert_crlf(DragData, strlen(DragData));
+    Fl_Screen_Driver::convert_crlf(DragData, strlen(DragData));
   }
   else {
     Fl_Cocoa_Screen_Driver::breakMacEventLoop();
@@ -3451,22 +3450,6 @@ Fl_Quartz_Copy_Surface_Driver::~Fl_Quartz_Copy_Surface_Driver()
 // Copy & Paste fltk implementation.
 ////////////////////////////////////////////////////////////////
 
-static size_t convert_crlf(char * s, size_t len)
-{
-  // turn \r characters into \n and "\r\n" sequences into \n:
-  char *p;
-  size_t l = len;
-  while ((p = strchr(s, '\r'))) {
-    if (*(p+1) == '\n') {
-      memmove(p, p+1, l-(p-s));
-      len--; l--;
-    } else *p = '\n';
-    l -= p-s;
-    s = p + 1;
-  }
-  return len;
-}
-
 // clipboard variables definitions :
 char *fl_selection_buffer[2] = {NULL, NULL};
 int fl_selection_length[2] = {0, 0};
@@ -3547,7 +3530,7 @@ static int get_plain_text_from_clipboard(int clipboard)
         [data getBytes:fl_selection_buffer[clipboard]];
       }
       fl_selection_buffer[clipboard][len - 1] = 0;
-      length = convert_crlf(fl_selection_buffer[clipboard], len - 1); // turn all \r characters into \n:
+      length = Fl_Screen_Driver::convert_crlf(fl_selection_buffer[clipboard], len - 1); // turn all \r characters into \n:
       Fl::e_clipboard_type = Fl::clipboard_plain_text;
     }
   }

src/drivers/Wayland/fl_wayland_clipboard_dnd.cxx

@@ -320,32 +320,6 @@ static void data_device_handle_selection(void *data, struct wl_data_device *data
 }
 
 
-// turn '\r' characters into '\n' and "\r\n" sequences into '\n'
-// returns new length
-static size_t convert_crlf(char *s, size_t len) {
-  char *src = (char *)memchr(s, '\r', len); // find first `\r` in buffer
-  if (src) {
-    char *dst = src;
-    char *end = s + len;
-    while (src < end) {
-      if (*src == '\r') {
-        if (src + 1 < end && *(src + 1) == '\n') {
-          src++; // skip '\r'
-          continue;
-        } else {
-          *dst++ = '\n'; // replace single '\r' with '\n'
-        }
-      } else {
-        *dst++ = *src;
-      }
-      src++;
-    }
-    return (dst - s);
-  }
-  return len;
-}
-
-
 // Gets from the system the clipboard or dnd text and puts it in fl_selection_buffer[1]
 // which is enlarged if necessary.
 static void get_clipboard_or_dragged_text(struct wl_data_offer *offer) {
@@ -365,7 +339,7 @@ static void get_clipboard_or_dragged_text(struct wl_data_offer *offer) {
       fl_selection_buffer[1][ fl_selection_length[1] ] = 0;
       return;
     }
-    n = convert_crlf(to, n);
+    n = Fl_Screen_Driver::convert_crlf(to, n);
     to += n;
     rest -= n;
   }
@@ -398,7 +372,7 @@ static void get_clipboard_or_dragged_text(struct wl_data_offer *offer) {
       close(fds[0]);
       break;
     }
-    n = convert_crlf(from, n);
+    n = Fl_Screen_Driver::convert_crlf(from, n);
     from += n;
   }
   fl_selection_length[1] = from - fl_selection_buffer[1];;