From: Michael Tremer <michael.tremer@ipfire.org>
Date: Sat, 21 Jun 2025 12:59:17 +0000 (+0000)
Subject: base64: Add function to normalize non-standard base64
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d8905a995f4a836a45019083e85c91ba064684ed;p=pakfire.git

base64: Add function to normalize non-standard base64

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/pakfire/base64.c b/src/pakfire/base64.c
index 9c018cd6..c0af7b96 100644
--- a/src/pakfire/base64.c
+++ b/src/pakfire/base64.c
@@ -117,3 +117,47 @@ ERROR:
 
 	return r;
 }
+
+int pakfire_b64normalize(char** output, const char* input, ssize_t length) {
+	char* buffer = NULL;
+
+	// Automatically determine input length
+	if (length < 0)
+		length = strlen(input);
+
+	// Compute length of required padding
+	size_t padding = (4 - (length % 4)) % 4;
+
+	// Allocate a buffer
+	buffer = malloc(length + padding + 1);
+	if (!buffer)
+		return -errno;
+
+	// Copy and translate to standard base64
+	for (ssize_t i = 0; i < length; i++) {
+		switch (input[i]) {
+			case '-':
+				buffer[i] = '+';
+				break;
+
+			case '/':
+				buffer[i] = '/';
+				break;
+
+			default:
+				buffer[i] = input[i];
+				break;
+		}
+	}
+
+	// Add the padding
+	for (size_t i = 0; i < padding; i++)
+		buffer[length + i] = '=';
+
+	// Terminate the buffer
+	buffer[length + padding] = '\0';
+
+	// Return the buffer
+	*output = buffer;
+	return 0;
+}
diff --git a/src/pakfire/base64.h b/src/pakfire/base64.h
index 8e9306ac..21fe7c24 100644
--- a/src/pakfire/base64.h
+++ b/src/pakfire/base64.h
@@ -28,4 +28,6 @@ int pakfire_b64encode(char** output, const unsigned char* input, const size_t le
 
 int pakfire_b64decode(unsigned char** output, size_t* length, const char* input, ssize_t l);
 
+int pakfire_b64normalize(char** output, const char* input, ssize_t length);
+
 #endif /* PAKFIRE_BASE64_H */