From: Stephan Bosch <stephan.bosch@dovecot.fi>
Date: Wed, 15 May 2019 13:36:18 +0000 (+0200)
Subject: lib: base64 - Add support for encoding without padding.
X-Git-Tag: 2.3.8~126
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=84cd2444ba9bfd19e0417cf5ee164337fd4f50ce;p=thirdparty%2Fdovecot%2Fcore.git

lib: base64 - Add support for encoding without padding.
---

diff --git a/src/lib/base64.c b/src/lib/base64.c
index 53a10dc368..fb8eeace98 100644
--- a/src/lib/base64.c
+++ b/src/lib/base64.c
@@ -11,11 +11,25 @@
 off_t base64_get_full_encoded_size(struct base64_encoder *enc, off_t src_size)
 {
 	bool crlf = HAS_ALL_BITS(enc->flags, BASE64_ENCODE_FLAG_CRLF);
+	bool no_padding = HAS_ALL_BITS(enc->flags,
+				       BASE64_ENCODE_FLAG_NO_PADDING);
 	off_t out_size;
 	off_t newlines;
 
 	/* calculate size of encoded data */
 	out_size = MAX_BASE64_ENCODED_SIZE(src_size);
+	if (no_padding) {
+		switch (src_size % 3) {
+		case 0:
+			break;
+		case 1:
+			out_size -= 2;
+			break;
+		case 2:
+			out_size -= 1;
+			break;
+		}
+	}
 
 	/* newline between each full line */
 	newlines = (out_size / enc->max_line_len) - 1;
@@ -337,6 +351,7 @@ bool base64_encode_finish(struct base64_encoder *enc, buffer_t *dest)
 	const struct base64_scheme *b64 = enc->b64;
 	const char *b64enc = b64->encmap;
 	bool crlf = HAS_ALL_BITS(enc->flags, BASE64_ENCODE_FLAG_CRLF);
+	bool padding = HAS_NO_BITS(enc->flags, BASE64_ENCODE_FLAG_NO_PADDING);
 	unsigned char *ptr, *end;
 	size_t dst_avail, line_avail, write;
 	unsigned char w_buf[9];
@@ -364,15 +379,21 @@ bool base64_encode_finish(struct base64_encoder *enc, buffer_t *dest)
 	case 0:
 		break;
 	case 1:
-		w_buf[w_buf_len + 0] = b64enc[enc->buf];
-		w_buf[w_buf_len + 1] =  '=';
-		w_buf[w_buf_len + 2] =  '=';
-		w_buf_len += 3;
+		w_buf[w_buf_len] = b64enc[enc->buf];
+		w_buf_len ++;
+		if (padding) {
+			w_buf[w_buf_len + 0] =  '=';
+			w_buf[w_buf_len + 1] =  '=';
+			w_buf_len += 2;
+		}
 		break;
 	case 2:
-		w_buf[w_buf_len + 0] = b64enc[enc->buf];
-		w_buf[w_buf_len + 1] =  '=';
-		w_buf_len += 2;
+		w_buf[w_buf_len] = b64enc[enc->buf];
+		w_buf_len++;
+		if (padding) {
+			w_buf[w_buf_len + 0] =  '=';
+			w_buf_len++;
+		}
 		break;
 	default:
 		i_unreached();
diff --git a/src/lib/base64.h b/src/lib/base64.h
index e9c2922e2a..751adf10bf 100644
--- a/src/lib/base64.h
+++ b/src/lib/base64.h
@@ -24,6 +24,8 @@ struct base64_scheme {
 enum base64_encode_flags {
 	/* Use CRLF instead of the default LF as line ending. */
 	BASE64_ENCODE_FLAG_CRLF                 = BIT(0),
+	/* Encode no padding at the end of the data. */
+	BASE64_ENCODE_FLAG_NO_PADDING           = BIT(1),
 };
 
 struct base64_encoder {
diff --git a/src/lib/test-base64.c b/src/lib/test-base64.c
index 0bd54a571c..6e944694f3 100644
--- a/src/lib/test-base64.c
+++ b/src/lib/test-base64.c
@@ -263,6 +263,12 @@ tests_base64_encode_lowlevel[] = {
 		.input = "hello world",
 		.output = "aGVsbG8gd29ybGQ=",
 	},
+	{
+		.scheme = &base64_scheme,
+		.flags = BASE64_ENCODE_FLAG_NO_PADDING,
+		.input = "hello world",
+		.output = "aGVsbG8gd29ybGQ",
+	},
 	{
 		.scheme = &base64_scheme,
 		.input = "foo barits",
@@ -273,6 +279,12 @@ tests_base64_encode_lowlevel[] = {
 		.input = "foo barits",
 		.output = "Zm9vIGJhcml0cw==",
 	},
+	{
+		.scheme = &base64_scheme,
+		.flags = BASE64_ENCODE_FLAG_NO_PADDING,
+		.input = "foo barits",
+		.output = "Zm9vIGJhcml0cw",
+	},
 	{
 		.scheme = &base64_scheme,
 		.input = "just niin",
@@ -283,6 +295,12 @@ tests_base64_encode_lowlevel[] = {
 		.input = "just niin",
 		.output = "anVzdCBuaWlu",
 	},
+	{
+		.scheme = &base64_scheme,
+		.flags = BASE64_ENCODE_FLAG_NO_PADDING,
+		.input = "just niin",
+		.output = "anVzdCBuaWlu",
+	},
 	{
 		.scheme = &base64_scheme,
 		.input =