std.Progress: fix suffix printing

Previously, `suffix` was copied to `output_buffer` at position
`max_end`, thereby writing into reserved space after `max_end`.
This only worked because `suffix` was not larger than
`bytes_needed_for_esc_codes_at_end` (otherwise there'd be a potential
buffer overrun) and no escape codes at end are actually written.

Since 2d5b2bf, escape codes are no
longer written to the end of the buffer. They are now written
exclusively to the front of the buffer.
This allows removing `bytes_needed_for_esc_codes_at_end` and
simplifying the suffix printing logic.

This also fixes the bug that the ellipse suffix was not printed in
Windows terminals because `end.* > max_end` was never true.

Author: erikarvstedt

lib/std/Progress.zig

@@ -312,16 +312,10 @@ fn bufWrite(self: *Progress, end: *usize, comptime format: []const u8, args: any
         error.NoSpaceLeft => {
             self.columns_written += self.output_buffer.len - end.*;
             end.* = self.output_buffer.len;
+            const suffix = "... ";
+            std.mem.copy(u8, self.output_buffer[self.output_buffer.len - suffix.len ..], suffix);
         },
     }
-    const bytes_needed_for_esc_codes_at_end: u8 = if (self.is_windows_terminal) 0 else 11;
-    const max_end = self.output_buffer.len - bytes_needed_for_esc_codes_at_end;
-    if (end.* > max_end) {
-        const suffix = "... ";
-        self.columns_written = self.columns_written - (end.* - max_end) + suffix.len;
-        std.mem.copy(u8, self.output_buffer[max_end..], suffix);
-        end.* = max_end + suffix.len;
-    }
 }
 
 test "basic functionality" {
@@ -335,6 +329,8 @@ test "basic functionality" {
     const root_node = progress.start("", 100);
     defer root_node.end();
 
+    const speed_factor = std.time.ns_per_ms;
+
     const sub_task_names = [_][]const u8{
         "reticulating splines",
         "adjusting shoes",
@@ -350,24 +346,24 @@ test "basic functionality" {
         next_sub_task = (next_sub_task + 1) % sub_task_names.len;
 
         node.completeOne();
-        std.time.sleep(5 * std.time.ns_per_ms);
+        std.time.sleep(5 * speed_factor);
         node.completeOne();
         node.completeOne();
-        std.time.sleep(5 * std.time.ns_per_ms);
+        std.time.sleep(5 * speed_factor);
         node.completeOne();
         node.completeOne();
-        std.time.sleep(5 * std.time.ns_per_ms);
+        std.time.sleep(5 * speed_factor);
 
         node.end();
 
-        std.time.sleep(5 * std.time.ns_per_ms);
+        std.time.sleep(5 * speed_factor);
     }
     {
         var node = root_node.start("this is a really long name designed to activate the truncation code. let's find out if it works", 0);
         node.activate();
-        std.time.sleep(10 * std.time.ns_per_ms);
+        std.time.sleep(10 * speed_factor);
         progress.refresh();
-        std.time.sleep(10 * std.time.ns_per_ms);
+        std.time.sleep(10 * speed_factor);
         node.end();
     }
 }