From e429763dea5a64883b9c133346df6bad6c819558 Mon Sep 17 00:00:00 2001
From: Rapptz <rapptz@gmail.com>
Date: Wed, 6 Feb 2019 02:11:44 -0500
Subject: [PATCH] Try to optimize for the common ASCII case.

This is still a slowdown (about 45ns to 300ns) but it's less severe
than the original implementation (about 900 to 1100ns).
---
 discord/utils.py | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/discord/utils.py b/discord/utils.py
index b581607bc..d60ca9954 100644
--- a/discord/utils.py
+++ b/discord/utils.py
@@ -40,7 +40,6 @@ import warnings
 from .errors import InvalidArgument
 
 DISCORD_EPOCH = 1420070400000
-UNICODE_WIDE_CHAR_TYPE = u"WFA"
 
 class cached_property:
     def __init__(self, function):
@@ -327,9 +326,17 @@ class SnowflakeList(array.array):
         i = bisect_left(self, element)
         return i != len(self) and self[i] == element
 
-def _string_width(string):
+_IS_ASCII = re.compile(r'^[\x00-\x7f]+$')
+
+def _string_width(string, *, _IS_ASCII=_IS_ASCII):
     """Returns string's width."""
+    match = _IS_ASCII.match(string)
+    if match:
+        return match.endpos
+
+    UNICODE_WIDE_CHAR_TYPE = 'WFA'
     width = 0
+    func = unicodedata.east_asian_width
     for char in string:
-        width += 2 if unicodedata.east_asian_width(char) in UNICODE_WIDE_CHAR_TYPE else 1
+        width += 2 if func(char) in UNICODE_WIDE_CHAR_TYPE else 1
     return width