From a2bec4b4fa3cdb3586f5f5591873ad566a94204d Mon Sep 17 00:00:00 2001
From: anon <anon>
Date: Fri, 19 Apr 2024 01:20:08 +0200
Subject: [PATCH 1/3] Remove an allocation when decoding base64

---
 email.d | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/email.d b/email.d
index 6c704ca..a665650 100644
--- a/email.d
+++ b/email.d
@@ -9,6 +9,9 @@ pragma(lib, "curl");
 import std.base64;
 import std.string;
 import std.range;
+import std.utf;
+import std.array;
+import std.algorithm.iteration;
 
 import arsd.characterencodings;
 
@@ -866,18 +869,10 @@ class IncomingEmailMessage {
 				break;
 				case "base64":
 					if(textMessageBody.length) {
-						// alas, phobos' base64 decoder cannot accept ranges, so we have to allocate here
-						char[] mmb;
-						mmb.reserve(textMessageBody.length);
-						foreach (char ch; textMessageBody) if (ch > ' ' && ch < 127) mmb ~= ch;
-						textMessageBody = convertToUtf8Lossy(Base64.decode(mmb), charset);
+						textMessageBody = textMessageBody.decodeBase64Mime.convertToUtf8Lossy(charset);
 					}
 					if(htmlMessageBody.length) {
-						// alas, phobos' base64 decoder cannot accept ranges, so we have to allocate here
-						char[] mmb;
-						mmb.reserve(htmlMessageBody.length);
-						foreach (char ch; htmlMessageBody) if (ch > ' ' && ch < 127) mmb ~= ch;
-						htmlMessageBody = convertToUtf8Lossy(Base64.decode(mmb), charset);
+						htmlMessageBody = htmlMessageBody.decodeBase64Mime.convertToUtf8Lossy(charset);
 					}
 
 				break;
@@ -1172,6 +1167,20 @@ string encodeBase64Mime(const(ubyte[]) content, string LINESEP = "\r\n") {
 	return cast(immutable(char[]))content.chunks(SOURCE_CHUNK_LENGTH).base64encode.join(LINESEP);
 }
 
+/// Base64 range decoder UFCS helper.
+alias base64decode = Base64.decoder;
+
+/// Base64 decoder, ignoring linebreaks which are mandated by RFC2045
+immutable(ubyte[]) decodeBase64Mime(string encodedPart) {
+	return cast(immutable(ubyte[])) encodedPart
+		.byChar // prevent Autodecoding, which will break Base64 decoder. Since its base64, it's guarenteed to be 7bit ascii
+		.filter!((c) => c != '\r')
+		.splitter!((c) => c == '\n')
+		.joiner
+		.base64decode
+		.array;
+}
+
 /+
 void main() {
 	import std.file;

From ca4adf991f4287de596bf31e6fa96c668d6bcfaa Mon Sep 17 00:00:00 2001
From: anon <anon>
Date: Fri, 19 Apr 2024 12:46:57 +0200
Subject: [PATCH 2/3] Clean up stupid code

---
 email.d | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/email.d b/email.d
index a665650..a121900 100644
--- a/email.d
+++ b/email.d
@@ -1174,9 +1174,7 @@ alias base64decode = Base64.decoder;
 immutable(ubyte[]) decodeBase64Mime(string encodedPart) {
 	return cast(immutable(ubyte[])) encodedPart
 		.byChar // prevent Autodecoding, which will break Base64 decoder. Since its base64, it's guarenteed to be 7bit ascii
-		.filter!((c) => c != '\r')
-		.splitter!((c) => c == '\n')
-		.joiner
+		.filter!((c) => (c != '\r') & (c != '\n'))
 		.base64decode
 		.array;
 }

From aa0f47caa1e3d4521f9d6f1dbb7b6ef2b104c41d Mon Sep 17 00:00:00 2001
From: anon <anon>
Date: Fri, 19 Apr 2024 12:47:16 +0200
Subject: [PATCH 3/3] Unittest mime base64 decoder encoder

---
 email.d | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/email.d b/email.d
index a121900..79f652a 100644
--- a/email.d
+++ b/email.d
@@ -1179,6 +1179,18 @@ immutable(ubyte[]) decodeBase64Mime(string encodedPart) {
 		.array;
 }
 
+unittest {
+	// Mime base64 roundtrip
+	import std.algorithm.comparison;
+	string source = chain(
+		repeat('n', 1200), //long line
+		"\r\n",
+		"äöü\r\n",
+		"ඞ\rn",
+		).byChar.array;
+	assert( source.representation.encodeBase64Mime.decodeBase64Mime.equal(source));
+}
+
 /+
 void main() {
 	import std.file;