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| 1 | +package io.apimatic.core.security; |
| 2 | + |
| 3 | +import java.util.Base64; |
| 4 | + |
| 5 | +/** |
| 6 | + * Factory class for creating digest codecs based on encoding type. |
| 7 | + */ |
| 8 | +public final class DigestCodecFactory { |
| 9 | + |
| 10 | + private DigestCodecFactory() { } // Prevent instantiation |
| 11 | + |
| 12 | + /** |
| 13 | + * Creates a Hex codec. |
| 14 | + * @return a DigestCodec for Hex encoding/decoding |
| 15 | + */ |
| 16 | + public static DigestCodec hex() { |
| 17 | + return new HexDigestCodec(); |
| 18 | + } |
| 19 | + |
| 20 | + /** |
| 21 | + * Creates a Base64 codec. |
| 22 | + * @return a DigestCodec for Base64 encoding/decoding |
| 23 | + */ |
| 24 | + public static DigestCodec base64() { |
| 25 | + return new Base64DigestCodec(); |
| 26 | + } |
| 27 | + |
| 28 | + /** |
| 29 | + * Creates a Base64Url codec. |
| 30 | + * @return a DigestCodec for Base64Url encoding/decoding |
| 31 | + */ |
| 32 | + public static DigestCodec base64Url() { |
| 33 | + return new Base64UrlDigestCodec(); |
| 34 | + } |
| 35 | + |
| 36 | + private static final int HEX_RADIX = 16; |
| 37 | + private static final int HEX_BYTE_MASK = 0xff; |
| 38 | + private static final int HEX_BYTE_LENGTH = 2; |
| 39 | + private static final int HEX_SHIFT = 4; |
| 40 | + |
| 41 | + /** |
| 42 | + * Codec for Hex encoding/decoding. |
| 43 | + */ |
| 44 | + private static class HexDigestCodec implements DigestCodec { |
| 45 | + @Override |
| 46 | + public String encode(byte[] bytes) { |
| 47 | + StringBuilder sb = new StringBuilder(); |
| 48 | + for (byte b : bytes) { |
| 49 | + sb.append(String.format("%02x", b & HEX_BYTE_MASK)); |
| 50 | + } |
| 51 | + return sb.toString(); |
| 52 | + } |
| 53 | + |
| 54 | + @Override |
| 55 | + public byte[] decode(String encoded) { |
| 56 | + int len = encoded.length(); |
| 57 | + if (len % HEX_BYTE_LENGTH != 0) { |
| 58 | + throw new IllegalArgumentException("Invalid hex string length."); |
| 59 | + } |
| 60 | + byte[] result = new byte[len / HEX_BYTE_LENGTH]; |
| 61 | + for (int i = 0; i < len; i += HEX_BYTE_LENGTH) { |
| 62 | + result[i / HEX_BYTE_LENGTH] = (byte) ( |
| 63 | + (Character.digit(encoded.charAt(i), HEX_RADIX) << HEX_SHIFT) |
| 64 | + + Character.digit(encoded.charAt(i + 1), HEX_RADIX)); |
| 65 | + } |
| 66 | + return result; |
| 67 | + } |
| 68 | + } |
| 69 | + |
| 70 | + /** |
| 71 | + * Codec for Base64 encoding/decoding. |
| 72 | + */ |
| 73 | + private static class Base64DigestCodec implements DigestCodec { |
| 74 | + @Override |
| 75 | + public String encode(byte[] bytes) { |
| 76 | + return Base64.getEncoder().encodeToString(bytes); |
| 77 | + } |
| 78 | + |
| 79 | + @Override |
| 80 | + public byte[] decode(String encoded) { |
| 81 | + return Base64.getDecoder().decode(encoded); |
| 82 | + } |
| 83 | + } |
| 84 | + |
| 85 | + /** |
| 86 | + * Codec for Base64Url encoding/decoding. |
| 87 | + */ |
| 88 | + private static class Base64UrlDigestCodec implements DigestCodec { |
| 89 | + @Override |
| 90 | + public String encode(byte[] bytes) { |
| 91 | + return Base64.getUrlEncoder().withoutPadding().encodeToString(bytes); |
| 92 | + } |
| 93 | + |
| 94 | + @Override |
| 95 | + public byte[] decode(String encoded) { |
| 96 | + return Base64.getUrlDecoder().decode(encoded); |
| 97 | + } |
| 98 | + } |
| 99 | +} |
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