Update README.md

Reviewed-on: Infendro/kotlin-encoding#2

.gitea/workflows/main.yaml

@@ -1,36 +0,0 @@
-on:
-  push:
-    branches:
-      - main
-
-env:
-  GIT__TOKEN: ${{ secrets.TOKEN }}
-
-jobs:
-  publish:
-    runs-on: linux
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: actions/cache/restore@v4
-        with:
-          key: gradle
-          path: |
-            ~/.gradle/caches/
-            ~/.gradle/wrapper/
-            ~/.konan/
-
-      - uses: actions/setup-java@v4
-        with:
-          java-version: '24'
-          distribution: 'temurin'
-
-      - run: ./gradlew publish
-
-      - uses: actions/cache/save@v4
-        with:
-          key: gradle
-          path: |
-            ~/.gradle/caches/
-            ~/.gradle/wrapper/
-            ~/.konan/

.gitea/workflows/publish.yaml

@@ -0,0 +1,47 @@
+on:
+  push:
+    branches: [ main ]
+
+jobs:
+  publish:
+    runs-on: linux
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          java-version: '24'
+          distribution: 'temurin'
+
+      - name: Cache Gradle
+        uses: actions/cache@v4
+        with:
+          key: gradle-${{ hashFiles('**/libs.versions.toml') }}
+          restore-keys: gradle
+          path: |
+            ~/.gradle/caches/
+            ~/.gradle/wrapper/
+
+      - name: Cache Konan
+        uses: actions/cache@v4
+        with:
+          key: konan-${{ hashFiles('**/libs.versions.toml') }}
+          restore-keys: konan
+          path: |
+            ~/.konan/
+
+      - name: Cache Node
+        uses: actions/cache@v4
+        with:
+          key: node-${{ hashFiles('**/libs.versions.toml') }}
+          restore-keys: node
+          path: |
+            ~/.gradle/nodejs
+            ~/.gradle/yarn
+
+      - name: Publish
+        run: ./gradlew publish
+        env:
+          INFENDRO__TOKEN: ${{ secrets.TOKEN }}

.gitea/workflows/test.yaml

@@ -0,0 +1,28 @@
+on:
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    runs-on: linux
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Java
+        uses: actions/setup-java@v4
+        with:
+          java-version: '24'
+          distribution: 'temurin'
+
+      - name: Cache Gradle
+        uses: actions/cache@v4
+        with:
+          key: gradle-${{ hashFiles('**/libs.versions.toml') }}
+          restore-keys: gradle
+          path: |
+            ~/.gradle/caches/
+            ~/.gradle/wrapper/
+
+      - name: Test
+        run: ./gradlew jvmTest

README.md

@@ -1,18 +1,19 @@
-# Kotlin Encoding
+# encoding.kt
 
-This library provides various character encodings in Kotlin Multiplatform.
+`encoding.kt` is a Kotlin Multiplatform library that provides common `ByteArray` encodings.
 
-## Features
+Supported encodings:
-
+- Base2 (binary)
-* Encode and decode ByteArrays using various character encodings.
+- Base8 (octal)
-    * Binary
+- Base10 (decimal)
-    * Hex
+- Base16 (hexadecimal, uppercase/lowercase)
-    * Base32
+- Base32
-    * Base64
+- Base36
-* Multiplatform support
+- Base45
-    * JVM
+- Base56
-    * JavaScript
+- Base58
-    * Linux
+- Base62
+- Base64 (standard/URL)
 
 ## Installation
 
@@ -24,22 +25,20 @@ repositories {
 }
 
 dependencies {
-    implementation("com.infendro:encoding:1.1.0")
+    implementation("com.infendro:encoding:1.3.0")
 }
 ```
 
 ## Usage
 
 ```kotlin
-import com.infendro.encoding.Hex
-
 fun main() {
     // the string to encode
     val test = "Hello World!".encodeToByteArray()
 
     // encode the string with the desired encoding
-    val encoded = Hex.encode(test).decodeToString()
+    val encoded = Base16.encode(test).decodeToString()
 
-    println(encoded) // 48656c6c6f20576f726c6421
+    println(encoded) // 48656C6C6F20576F726C6421
 }
 ```

build.gradle.kts

@@ -1,48 +1,40 @@
-group = "com.infendro"
+@file:OptIn(ExperimentalWasmDsl::class)
-version = "1.1.0"
 
-repositories {
+import com.infendro.plugin.infendro
-    mavenCentral()
+import com.infendro.plugin.token
-}
+import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
+
+group = "com.infendro"
+version = "1.3.0"
 
 plugins {
+    alias(libs.plugins.infendro)
     alias(libs.plugins.multiplatform)
     id("maven-publish")
 }
 
 kotlin {
     jvm()
-    js {
-        nodejs()
-    }
     linuxX64()
-}
+    linuxArm64()
+    mingwX64()
+    macosX64()
+    macosArm64()
+    js { nodejs() }
+    wasmJs { nodejs() }
+    wasmWasi { nodejs() }
 
-publishing {
     repositories {
-        maven {
+        mavenCentral()
-            url = uri("https://git.infendro.com/api/packages/Infendro/maven")
+    }
-            authentication.create("header", HttpHeaderAuthentication::class)
-            credentials(HttpHeaderCredentials::class) {
-                val token = secret("git.token") ?: throw GradleException()
 
-                name = "Authorization"
+    sourceSets {
-                value = "token $token"
+        commonTest.dependencies {
-            }
+            implementation(libs.test)
         }
     }
 }
 
-fun secret(
+publishing.repositories {
-    key: String,
+    infendro(token)
-): String? {
-    val property = key
-    val environment = key
-        .uppercase()
-        .replace(".", "__")
-
-    val prop = properties[property] as String?
-    val env = System.getenv(environment)
-
-    return prop ?: env
 }

gradle/libs.versions.toml

@@ -1,5 +1,10 @@
 [versions]
-kotlin = "2.1.20"
+infendro = "1.1.0"
+kotlin = "2.3.0"
 
 [plugins]
+infendro = { id = "com.infendro.plugin", version.ref = "infendro" }
 multiplatform = { id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin" }
+
+[libraries]
+test = { module = "org.jetbrains.kotlin:kotlin-test", version.ref = "kotlin" }

settings.gradle.kts

@@ -1 +1,6 @@
 rootProject.name = "encoding"
+
+pluginManagement.repositories {
+    maven("https://git.infendro.com/api/packages/Infendro/maven")
+    mavenCentral()
+}

src/commonMain/kotlin/com/infendro/encoding/Base10.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "0123456789".encodeToByteArray()
+
+object Base10 : Encoding by NumericEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base16.kt

@@ -0,0 +1,10 @@
+package com.infendro.encoding
+
+private val uppercase = "0123456789ABCDEF".encodeToByteArray()
+private val lowercase = "0123456789abcdef".encodeToByteArray()
+
+object Base16 : Encoding by StreamEncoding(uppercase) {
+    val UPPERCASE = this
+
+    object LOWERCASE : Encoding by StreamEncoding(lowercase)
+}

src/commonMain/kotlin/com/infendro/encoding/Base2.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "01".encodeToByteArray()
+
+object Base2 : Encoding by StreamEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base32.kt

@@ -1,31 +1,6 @@
 package com.infendro.encoding
 
-object Base32 : Encoding() {
+private val alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567".encodeToByteArray()
-    private val CHARACTERS = arrayOf<Byte>(
+private const val padding = '='.code.toByte()
-        0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
-        0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50,
-        0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
-        0x59, 0x5a, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
-    )
-    private const val PADDING: Byte = 0x3d
 
-    override fun encode(
+object Base32 : Encoding by StreamEncoding(alphabet, padding)
-        bytes: ByteArray,
-    ): ByteArray {
-        return encode(
-            bytes,
-            CHARACTERS,
-            PADDING,
-        )
-    }
-
-    override fun decode(
-        bytes: ByteArray,
-    ): ByteArray {
-        return decode(
-            bytes,
-            CHARACTERS,
-            PADDING,
-        )
-    }
-}

src/commonMain/kotlin/com/infendro/encoding/Base36.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ".encodeToByteArray()
+
+object Base36 : Encoding by NumericEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base45.kt

@@ -0,0 +1,51 @@
+package com.infendro.encoding
+
+import com.infendro.encoding.exception.IllegalByteException
+
+object Base45 : Encoding {
+    private val alphabet: ByteArray = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:".encodeToByteArray()
+    private val base: Int = alphabet.size
+
+    override fun encode(bytes: ByteArray): ByteArray {
+        val result = mutableListOf<Byte>()
+
+        for (i in bytes.indices step 2) {
+            val remaining = minOf(bytes.size - i, 2)
+
+            var value = 0
+            for (j in 0..<remaining) {
+                val byte = bytes[i + j]
+                value = (value shl 8) or (byte.toInt() and 0xFF)
+            }
+
+            repeat(remaining + 1) {
+                result += alphabet[value % base]
+                value /= base
+            }
+        }
+
+        return result.toByteArray()
+    }
+
+    override fun decode(bytes: ByteArray): ByteArray {
+        val result = mutableListOf<Byte>()
+
+        for (i in bytes.indices step 3) {
+            val remaining = minOf(bytes.size - i, 3)
+
+            var value = 0
+            for (j in (0..<remaining).reversed()) {
+                val byte = bytes[i + j]
+                val index = alphabet.indexOf(byte)
+                if (index == -1) throw IllegalByteException(byte)
+                value = value * base + index
+            }
+
+            for (j in (0..<(remaining - 1)).reversed()) {
+                result += ((value shr (j * 8)) and 0xFF).toByte()
+            }
+        }
+
+        return result.toByteArray()
+    }
+}

src/commonMain/kotlin/com/infendro/encoding/Base56.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz".encodeToByteArray()
+
+object Base56 : Encoding by NumericEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base58.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz".encodeToByteArray()
+
+object Base58 : Encoding by NumericEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base62.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".encodeToByteArray()
+
+object Base62 : Encoding by NumericEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Base64.kt

@@ -1,35 +1,11 @@
 package com.infendro.encoding
 
-object Base64 : Encoding() {
+private val standard = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".encodeToByteArray()
-    private val CHARACTERS = arrayOf<Byte>(
+private val url = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_".encodeToByteArray()
-        0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
+private const val padding = '='.code.toByte()
-        0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50,
-        0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
-        0x59, 0x5a, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
-        0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e,
-        0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
-        0x77, 0x78, 0x79, 0x7a, 0x30, 0x31, 0x32, 0x33,
-        0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2b, 0x2f,
-    )
-    private const val PADDING: Byte = 0x3d
 
-    override fun encode(
+object Base64 : Encoding by StreamEncoding(standard, padding) {
-        bytes: ByteArray,
+    val STANDARD = this
-    ): ByteArray {
-        return encode(
-            bytes,
-            CHARACTERS,
-            PADDING,
-        )
-    }
 
-    override fun decode(
+    object URL : Encoding by StreamEncoding(url)
-        bytes: ByteArray,
-    ): ByteArray {
-        return decode(
-            bytes,
-            CHARACTERS,
-            PADDING,
-        )
-    }
 }

src/commonMain/kotlin/com/infendro/encoding/Base8.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding
+
+private val alphabet = "01234567".encodeToByteArray()
+
+object Base8 : Encoding by StreamEncoding(alphabet)

src/commonMain/kotlin/com/infendro/encoding/Binary.kt

@@ -1,25 +0,0 @@
-package com.infendro.encoding
-
-object Binary : Encoding() {
-    private val CHARACTERS = arrayOf<Byte>(
-        0x30, 0x31,
-    )
-
-    override fun encode(
-        bytes: ByteArray,
-    ): ByteArray {
-        return encode(
-            bytes,
-            CHARACTERS,
-        )
-    }
-
-    override fun decode(
-        bytes: ByteArray,
-    ): ByteArray {
-        return decode(
-            bytes,
-            CHARACTERS,
-        )
-    }
-}

src/commonMain/kotlin/com/infendro/encoding/Encoding.kt

@@ -1,92 +1,6 @@
 package com.infendro.encoding
 
-import com.infendro.encoding.util.lcm
+interface Encoding {
-import com.infendro.encoding.util.log2
+    fun encode(bytes: ByteArray): ByteArray
-import kotlin.math.pow
+    fun decode(bytes: ByteArray): ByteArray
-
-sealed class Encoding {
-    abstract fun encode(
-        bytes: ByteArray,
-    ): ByteArray
-
-    abstract fun decode(
-        bytes: ByteArray,
-    ): ByteArray
-
-    protected fun encode(
-        bytes: ByteArray,
-        characters: Array<Byte>,
-        padding: Byte? = null,
-    ): ByteArray {
-        val length = log2(characters.size).toInt()
-        val mask = (2.0.pow(length) - 1).toUInt()
-
-        val encoded = mutableListOf<Byte>()
-
-        var buffer = 0U
-        var bits = 0
-
-        for (byte in bytes) {
-            buffer = (buffer shl 8) + byte.toUByte()
-            bits += 8
-
-            while (bits >= length) {
-                val offset = bits - length
-                val index = (buffer shr offset).toInt()
-                buffer = buffer and (mask shl offset).inv()
-                bits -= length
-
-                encoded.add(characters[index])
-            }
-        }
-        if (bits > 0) {
-            buffer = buffer shl (length - bits)
-            val index = buffer.toInt()
-            encoded.add(characters[index])
-        }
-
-        if (padding != null) {
-            val block = lcm(length, 8) / length
-            while (encoded.size % block != 0) {
-                encoded.add(padding)
-            }
-        }
-
-        return encoded.toByteArray()
-    }
-
-    protected fun decode(
-        bytes: ByteArray,
-        characters: Array<Byte>,
-        padding: Byte? = null,
-    ): ByteArray {
-        val length = log2(characters.size).toInt()
-        val mask = 0xFFU
-
-        val decoded = mutableListOf<Byte>()
-
-        var buffer = 0U
-        var bits = 0
-
-        for (byte in bytes) {
-            if (byte == padding) break
-
-            val index = characters.indexOf(byte)
-            if (index == -1) throw Exception()
-
-            buffer = (buffer shl length) + index.toUByte()
-            bits += length
-
-            if (bits >= 8) {
-                val offset = bits - 8
-                val character = (buffer shr offset).toByte()
-                buffer = buffer and (mask shl offset).inv()
-                bits -= 8
-
-                decoded.add(character)
-            }
-        }
-
-        return decoded.toByteArray()
-    }
 }

src/commonMain/kotlin/com/infendro/encoding/Hex.kt

@@ -1,26 +0,0 @@
-package com.infendro.encoding
-
-object Hex : Encoding() {
-    private val CHARACTERS = arrayOf<Byte>(
-        0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
-        0x38, 0x39, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
-    )
-
-    override fun encode(
-        bytes: ByteArray,
-    ): ByteArray {
-        return encode(
-            bytes,
-            CHARACTERS,
-        )
-    }
-
-    override fun decode(
-        bytes: ByteArray,
-    ): ByteArray {
-        return decode(
-            bytes,
-            CHARACTERS,
-        )
-    }
-}

src/commonMain/kotlin/com/infendro/encoding/NumericEncoding.kt

@@ -0,0 +1,39 @@
+package com.infendro.encoding
+
+import com.infendro.encoding.exception.IllegalByteException
+import com.infendro.encoding.util.BigInt
+
+class NumericEncoding internal constructor(
+    private val alphabet: ByteArray,
+) : Encoding {
+    private val base: Int = alphabet.size
+
+    override fun encode(bytes: ByteArray): ByteArray {
+        if (bytes.isEmpty()) return byteArrayOf()
+
+        val result = mutableListOf<Byte>()
+
+        var x = BigInt.from(bytes)
+        while (!x.isZero()) {
+            val (quotient, remainder) = x.divRem(base)
+            x = quotient
+            result += alphabet[remainder]
+        }
+
+        return result.asReversed().toByteArray()
+    }
+
+    override fun decode(bytes: ByteArray): ByteArray {
+        if (bytes.isEmpty()) return byteArrayOf()
+
+        var value = BigInt.zero
+        for (i in 0..<bytes.size) {
+            val byte = bytes[i]
+            val index = alphabet.indexOf(byte)
+            if (index == -1) throw IllegalByteException(byte)
+            value = value.timesAdd(base, index)
+        }
+
+        return value.toByteArray()
+    }
+}

src/commonMain/kotlin/com/infendro/encoding/StreamEncoding.kt

@@ -0,0 +1,80 @@
+package com.infendro.encoding
+
+import com.infendro.encoding.exception.IllegalByteException
+import com.infendro.encoding.util.align
+import com.infendro.encoding.util.ceilDiv
+import com.infendro.encoding.util.lcm
+import com.infendro.encoding.util.log2
+
+class StreamEncoding internal constructor(
+    private val alphabet: ByteArray,
+    private val padding: Byte? = null,
+) : Encoding {
+    private val base: Int = alphabet.size
+    private val bits: Int = log2(base).toInt()
+    private val block: Int = lcm(bits, 8) / bits
+    private val mask: Int = (0x01 shl bits) - 1
+
+    override fun encode(bytes: ByteArray): ByteArray {
+        val size = when (padding) {
+            null -> (bytes.size * 8).ceilDiv(bits)
+            else -> (bytes.size * 8).ceilDiv(bits).align(block)
+        }
+        val encoded = ByteArray(size)
+        var i = 0
+
+        var buffer = 0
+        var bufferBits = 0
+        for (byte in bytes) {
+            buffer = (buffer shl 8) or (byte.toInt() and 0xFF)
+            bufferBits += 8
+
+            while (bufferBits >= bits) {
+                val index = (buffer shr (bufferBits - bits)) and mask
+                bufferBits -= bits
+                encoded[i++] = alphabet[index]
+            }
+        }
+        if (bufferBits > 0) {
+            val index = (buffer shl (bits - bufferBits)) and mask
+            encoded[i++] = alphabet[index]
+        }
+
+        while (i < encoded.size) {
+            encoded[i++] = padding!!
+        }
+
+        return encoded
+    }
+
+    override fun decode(bytes: ByteArray): ByteArray {
+        val end = when (padding) {
+            null -> bytes.size
+            else -> when (val index = bytes.indexOf(padding)) {
+                -1 -> bytes.size
+                else -> index
+            }
+        }
+        val size = end * bits / 8
+        val decoded = ByteArray(size)
+        var i = 0
+
+        var buffer = 0
+        var bufferBits = 0
+        for (b in 0..<end) {
+            val byte = bytes[b]
+            val index = alphabet.indexOf(byte)
+            if (index == -1) throw IllegalByteException(byte)
+            buffer = (buffer shl bits) or index
+            bufferBits += bits
+
+            if (bufferBits >= 8) {
+                val byte = (buffer shr (bufferBits - 8)) and 0xFF
+                bufferBits -= 8
+                decoded[i++] = byte.toByte()
+            }
+        }
+
+        return decoded
+    }
+}

src/commonMain/kotlin/com/infendro/encoding/exception/DecodeException.kt

@@ -0,0 +1,5 @@
+package com.infendro.encoding.exception
+
+abstract class DecodeException : Exception() {
+    abstract override val message: String
+}

src/commonMain/kotlin/com/infendro/encoding/exception/IllegalByteException.kt

@@ -0,0 +1,12 @@
+package com.infendro.encoding.exception
+
+class IllegalByteException(
+    val byte: Byte,
+) : DecodeException() {
+    override val message: String
+        get() {
+            val hex = "0x${byte.toHexString().padStart(2, '0')}"
+            val char = "'${byte.toInt().toChar()}'"
+            return "Illegal byte $hex ($char)."
+        }
+}

src/commonMain/kotlin/com/infendro/encoding/util/BigInt.kt

@@ -0,0 +1,73 @@
+package com.infendro.encoding.util
+
+internal class BigInt private constructor(
+    val words: IntArray,
+) {
+    init {
+        require(words.isNotEmpty())
+    }
+
+    fun isZero(): Boolean = words.all { it == 0 }
+
+    fun timesAdd(multiplier: Int, addend: Int): BigInt {
+        val product = IntArray(words.size)
+        var carry = addend
+
+        for (i in words.indices) {
+            val current = (words[i].toLong() and 0xFFFFFFFFL) * multiplier + carry
+            product[i] = current.toInt()
+            carry = (current ushr 32).toInt()
+        }
+
+        when {
+            carry > 0 -> {
+                val expanded = product.copyOf(product.size + 1)
+                expanded[product.size] = carry
+                return BigInt(expanded)
+            }
+            else -> return BigInt(product)
+        }
+    }
+
+    fun divRem(divisor: Int): Pair<BigInt, Int> {
+        val quotient = IntArray(words.size)
+        var remainder = 0
+
+        for (i in words.indices.reversed()) {
+            val current = (remainder.toLong() shl 32) or (words[i].toLong() and 0xFFFFFFFFL)
+            quotient[i] = (current / divisor.toLong()).toInt()
+            remainder = (current % divisor.toLong()).toInt()
+        }
+
+        when {
+            quotient.size > 1 && quotient.last() == 0 -> {
+                val contracted = quotient.copyOfRange(0, quotient.size - 1)
+                return Pair(BigInt(contracted), remainder)
+            }
+            else -> return Pair(BigInt(quotient), remainder)
+        }
+    }
+
+    fun toByteArray(): ByteArray {
+        val bytes = ByteArray((words.size * 4) - words.last().countLeadingZeroBytes())
+        for (i in bytes.indices) {
+            val (wi, bi) = (bytes.lastIndex - i).divRem(4)
+            bytes[i] = (words[wi] ushr (bi * 8)).toByte()
+        }
+        return bytes
+    }
+
+    companion object {
+        val zero: BigInt
+            get() = BigInt(intArrayOf(0))
+
+        fun from(bytes: ByteArray): BigInt {
+            val words = IntArray(bytes.size.ceilDiv(4))
+            for (i in bytes.indices) {
+                val (wi, bi) = (bytes.lastIndex - i).divRem(4)
+                words[wi] = words[wi] or ((bytes[i].toInt() and 0xFF) shl (bi * 8))
+            }
+            return BigInt(words)
+        }
+    }
+}

src/commonMain/kotlin/com/infendro/encoding/util/Int.kt

@@ -0,0 +1,7 @@
+package com.infendro.encoding.util
+
+fun Int.divRem(divisor: Int): Pair<Int, Int> =
+    Pair(this / divisor, this % divisor)
+
+fun Int.countLeadingZeroBytes(): Int =
+    countLeadingZeroBits() / 8

src/commonMain/kotlin/com/infendro/encoding/util/Math.kt

@@ -2,14 +2,16 @@ package com.infendro.encoding.util
 
 import kotlin.math.log2
 
-internal fun log2(
+internal fun Int.ceilDiv(n: Int): Int =
-    value: Int,
+    (this + n - 1) / n
-) = log2(value.toDouble())
 
-internal fun gcd(
+internal fun Int.align(n: Int): Int =
-    a: Int,
+    ceilDiv(n) * n
-    b: Int,
+
-): Int {
+internal fun log2(value: Int): Double =
+    log2(value.toDouble())
+
+internal fun gcd(a: Int, b: Int): Int {
     var x = a
     var y = b
     while (y != 0) {
@@ -20,9 +22,6 @@ internal fun gcd(
     return x
 }
 
-internal fun lcm(
+internal fun lcm(a: Int, b: Int): Int {
-    a: Int,
-    b: Int,
-): Int {
     return (a * b) / gcd(a, b)
 }

src/commonTest/kotlin/com/infendro/encoding/Base10.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base10 Test` {
+    val encoding: Encoding
+        get() = Base10
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "22405534230753928650781647905".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base16.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base16 Test` {
+    val encoding: Encoding
+        get() = Base16
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "48656C6C6F20576F726C6421".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base2.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base2 Test` {
+    val encoding: Encoding
+        get() = Base2
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "010010000110010101101100011011000110111100100000010101110110111101110010011011000110010000100001".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base32.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base32 Test` {
+    val encoding: Encoding
+        get() = Base32
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "JBSWY3DPEBLW64TMMQQQ====".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base36.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base36 Test` {
+    val encoding: Encoding
+        get() = Base36
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "2678LX5GVMSV1DRO9B5".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base45.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base45 Test` {
+    val encoding: Encoding
+        get() = Base45
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "%69 VD82EI2B.KESTC".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base56.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base56 Test` {
+    val encoding: Encoding
+        get() = Base56
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "4Q9SNpVv4JrdwvjKj".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base58.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base58 Test` {
+    val encoding: Encoding
+        get() = Base58
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "2NEpo7TZRRrLZSi2U".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base62.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base62 Test` {
+    val encoding: Encoding
+        get() = Base62
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "T8dgcjRGkZ3aysdN".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base64.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base64 Test` {
+    val encoding: Encoding
+        get() = Base64
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "SGVsbG8gV29ybGQh".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}

src/commonTest/kotlin/com/infendro/encoding/Base8.kt

@@ -0,0 +1,36 @@
+package com.infendro.encoding
+
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class `Base8 Test` {
+    val encoding: Encoding
+        get() = Base8
+
+    val original = "Hello World!".encodeToByteArray()
+    val encoded = "22062554330674402566756233062041".encodeToByteArray()
+
+    @Test
+    fun `encode empty`() {
+        val actual = encoding.encode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun `decode empty`() {
+        val actual = encoding.decode(byteArrayOf())
+        assertContentEquals(byteArrayOf(), actual)
+    }
+
+    @Test
+    fun encode() {
+        val actual = encoding.encode(original)
+        assertContentEquals(encoded, actual)
+    }
+
+    @Test
+    fun decode() {
+        val actual = encoding.decode(encoded)
+        assertContentEquals(original, actual)
+    }
+}