From 9920d17342bba6f712965adfa72c143dade39a2c Mon Sep 17 00:00:00 2001
From: Shannon Booth <shannon.ml.booth@gmail.com>
Date: Sat, 15 Feb 2020 13:04:00 +1300
Subject: [PATCH] AK: Add String starts_with(char) & ends_with(char)

This is simply meant to be a more efficient implementation in the
case that we only need to check a single character.
---
 AK/String.cpp           | 13 +++++++++++++
 AK/String.h             |  2 ++
 AK/Tests/TestString.cpp |  4 ++++
 3 files changed, 19 insertions(+)

diff --git a/AK/String.cpp b/AK/String.cpp
index 4149a15467e..980b346867b 100644
--- a/AK/String.cpp
+++ b/AK/String.cpp
@@ -295,6 +295,13 @@ bool String::starts_with(const StringView& str) const
     return !memcmp(characters(), str.characters_without_null_termination(), str.length());
 }
 
+bool String::starts_with(char ch) const
+{
+    if (is_empty())
+        return false;
+    return characters()[0] == ch;
+}
+
 bool String::ends_with(const StringView& str) const
 {
     if (str.is_empty())
@@ -306,6 +313,12 @@ bool String::ends_with(const StringView& str) const
     return !memcmp(characters() + (length() - str.length()), str.characters_without_null_termination(), str.length());
 }
 
+bool String::ends_with(char ch) const
+{
+    if (is_empty())
+        return false;
+    return characters()[length() - 1] == ch;
+}
 String String::repeated(char ch, size_t count)
 {
     if (!count)
diff --git a/AK/String.h b/AK/String.h
index fea82b40b00..c1c381f00f3 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -157,6 +157,8 @@ public:
 
     bool starts_with(const StringView&) const;
     bool ends_with(const StringView&) const;
+    bool starts_with(char) const;
+    bool ends_with(char) const;
 
     bool operator==(const String&) const;
     bool operator!=(const String& other) const { return !(*this == other); }
diff --git a/AK/Tests/TestString.cpp b/AK/Tests/TestString.cpp
index b96531b74bf..0ba1d4233dc 100644
--- a/AK/Tests/TestString.cpp
+++ b/AK/Tests/TestString.cpp
@@ -80,6 +80,8 @@ TEST_CASE(starts_with)
 {
     String test_string = "ABCDEF";
     EXPECT(test_string.starts_with("AB"));
+    EXPECT(test_string.starts_with('A'));
+    EXPECT(!test_string.starts_with('B'));
     EXPECT(test_string.starts_with("ABCDEF"));
     EXPECT(!test_string.starts_with("DEF"));
 }
@@ -88,6 +90,8 @@ TEST_CASE(ends_with)
 {
     String test_string = "ABCDEF";
     EXPECT(test_string.ends_with("EF"));
+    EXPECT(test_string.ends_with('F'));
+    EXPECT(!test_string.ends_with('E'));
     EXPECT(test_string.ends_with("ABCDEF"));
     EXPECT(!test_string.ends_with("ABC"));
 }