Method encode

src/main/java/com/thealgorithms/conversions/Base64.java:37–82

Encodes the given byte array to a Base64 encoded string. @param input the byte array to encode @return the Base64 encoded string @throws IllegalArgumentException if input is null

(byte[] input)

     * @throws IllegalArgumentException if input is null
     */
    public static String encode(byte[] input) {
        if (input == null) {
            throw new IllegalArgumentException("Input cannot be null");
        }

        if (input.length == 0) {
            return "";
        }

        StringBuilder result = new StringBuilder();
        int padding = 0;

        // Process input in groups of 3 bytes
        for (int i = 0; i < input.length; i += 3) {
            // Get up to 3 bytes
            int byte1 = input[i] & 0xFF;
            int byte2 = (i + 1 < input.length) ? (input[i + 1] & 0xFF) : 0;
            int byte3 = (i + 2 < input.length) ? (input[i + 2] & 0xFF) : 0;

            // Calculate padding needed
            if (i + 1 >= input.length) {
                padding = 2;
            } else if (i + 2 >= input.length) {
                padding = 1;
            }

            // Combine 3 bytes into a 24-bit number
            int combined = (byte1 << 16) | (byte2 << 8) | byte3;

            // Extract four 6-bit groups
            result.append(BASE64_CHARS.charAt((combined >> 18) & 0x3F));
            result.append(BASE64_CHARS.charAt((combined >> 12) & 0x3F));
            result.append(BASE64_CHARS.charAt((combined >> 6) & 0x3F));
            result.append(BASE64_CHARS.charAt(combined & 0x3F));
        }

        // Replace padding characters
        if (padding > 0) {
            result.setLength(result.length() - padding);
            for (int i = 0; i < padding; i++) {
                result.append(PADDING_CHAR);
            }
        }

        return result.toString();
    }

    /**
     * Encodes the given string to a Base64 encoded string using UTF-8 encoding.