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Base32 Base58 bug fix Math utils extension
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114 changes: 114 additions & 0 deletions
114
src/main/java/com/hijackermax/utils/encoders/Base32.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,114 @@ | ||
| package com.hijackermax.utils.encoders; | ||
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| import com.hijackermax.utils.entities.Tuple; | ||
| import com.hijackermax.utils.lang.ObjectUtils; | ||
| import com.hijackermax.utils.lang.StringUtils; | ||
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| import java.io.ByteArrayOutputStream; | ||
| import java.util.Arrays; | ||
| import java.util.Map; | ||
| import java.util.Objects; | ||
| import java.util.function.Consumer; | ||
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| import static com.hijackermax.utils.lang.MathUtils.add; | ||
| import static com.hijackermax.utils.lang.MathUtils.subtract; | ||
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| /** | ||
| * Binary-to-text encoding based on variant of Douglas Crockford, without check | ||
| * | ||
| * @since 0.0.7 | ||
| */ | ||
| public final class Base32 { | ||
| private static final char[] CHARSET = "0123456789ABCDEFGHJKMNPQRSTVWXYZ".toCharArray(); | ||
| private static final byte[] IGNORED_CHARS = {0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x20, 0x2D}; | ||
| private static final Map<Character, Integer> ALIASES = Map.of('O', 0, 'I', 1, 'L', 1); | ||
| private static final byte STOP_BYTE = (byte) 0x5B; | ||
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| private Base32() { | ||
| } | ||
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| /** | ||
| * Encodes provided byte array to Base32 String {@link String} | ||
| * | ||
| * @param source byte array | ||
| * @return encoded {@link String} | ||
| * @since 0.0.7 | ||
| */ | ||
| public static String encode(byte[] source) { | ||
| int dataLength = Objects.requireNonNull(source).length; | ||
| StringBuilder result = new StringBuilder(calculateEncodeBufferSize(dataLength)); | ||
| Tuple<Integer, Integer> pointers = new Tuple<>(0, 0); | ||
| for (byte partition = nextPartition(source, pointers); STOP_BYTE != partition; partition = nextPartition(source, pointers)) { | ||
| result.append(CHARSET[partition]); | ||
| } | ||
| return result.toString(); | ||
| } | ||
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| /** | ||
| * Decodes provided {@link String} to byte array | ||
| * | ||
| * @param source {@link String} | ||
| * @return decoded byte array | ||
| * @throws IllegalArgumentException if provided string is not base32 encoded | ||
| * @since 0.0.7 | ||
| */ | ||
| public static byte[] decode(String source) { | ||
| if (StringUtils.isBlank(source)) { | ||
| return new byte[0]; | ||
| } | ||
| ByteArrayOutputStream result = new ByteArrayOutputStream(calculateDecodedBufferSize(source.length())); | ||
| Tuple<Integer, Integer> dataHolder = new Tuple<>(0, 0); | ||
| for (char nextChar : source.toCharArray()) { | ||
| if (0 <= Arrays.binarySearch(IGNORED_CHARS, (byte) nextChar)) { | ||
| continue; | ||
| } | ||
| char upperCaseChar = Character.toUpperCase(nextChar); | ||
| int idx = Arrays.binarySearch(CHARSET, upperCaseChar); | ||
| int partition = idx >= 0 ? idx : ObjectUtils.valueOrDefault(ALIASES.get(upperCaseChar), -1); | ||
| if (0 > partition) { | ||
| throw new IllegalArgumentException("Provided source string is not Base32 encoded"); | ||
| } | ||
| pushPartition(partition << 3, dataHolder, result::write); | ||
| } | ||
| return result.toByteArray(); | ||
| } | ||
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| private static byte nextPartition(byte[] data, Tuple<Integer, Integer> pointers) { | ||
| if (pointers.getKey() >= data.length) { | ||
| return STOP_BYTE; | ||
| } | ||
| int firstPart = (((0xFE >>> pointers.getValue()) & (data[pointers.getKey()] & 0xFF)) | ||
| << pointers.getValue()) >>> 3; | ||
| pointers.modifyValue(add(5)); | ||
| if (pointers.getValue() < 8) { | ||
| return (byte) firstPart; | ||
| } | ||
| pointers.modifyValue(subtract(8)); | ||
| pointers.modifyKey(add(1)); | ||
| if (pointers.getKey() >= data.length) { | ||
| return (byte) firstPart; | ||
| } | ||
| int secondPart = (((0xFF00 >>> pointers.getValue()) & (data[pointers.getKey()] & 0xFF)) & 0xFF) | ||
| >>> 8 - pointers.getValue(); | ||
| return (byte) (firstPart | secondPart); | ||
| } | ||
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| private static void pushPartition(int nextValue, Tuple<Integer, Integer> dataHolder, Consumer<Byte> valueConsumer) { | ||
| dataHolder.modifyValue(k -> k | (nextValue >> dataHolder.getKey())); | ||
| dataHolder.modifyKey(add(5)); | ||
| if (dataHolder.getKey() >= 8) { | ||
| valueConsumer.accept((byte) (dataHolder.getValue() & 0xFF)); | ||
| dataHolder.modifyKey(subtract(8)); | ||
| dataHolder.setValue(nextValue << (5 - dataHolder.getKey()) & 0xFF); | ||
| } | ||
| } | ||
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| private static int calculateEncodeBufferSize(int byteArrayLength) { | ||
| return ((byteArrayLength * 8) / 5) + 7; | ||
| } | ||
|
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| private static int calculateDecodedBufferSize(int stringLength) { | ||
| return (stringLength * 5) / 8; | ||
| } | ||
| } |
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