Add support for single line format parser

README.md

@@ -62,7 +62,7 @@ Create a solver instance and solve the board:
 ```kotlin
 val solver = Kudoku.defaultSolver()
 val solution = solver.solve(sudoku)
-println(solution.toString())
+println(solution)
 ```
 
 Choose from multiple solver implementations:
@@ -72,11 +72,19 @@ val solver1 = Kudoku.satSolver()
 val solver2 = Kudoku.bruteForceSolver()
 ```
 
+Support for popular text formats:
+
+```kotlin
+val string = "003020600900305001001806400008102900700000008006708200002609500800203009005010300"
+val sudoku = Kudoku.createFromSingleLineString(string)
+val encoded = sudoku.toSingleLineString(emptyFieldIndicator = EmptyFieldIndicator.DOT)
+```
+
 Create a random Sudoku with a given difficulty:
 
 ```kotlin
 val sudoku = Kudoku.create(SudokuType.Classic9x9, Difficulty.VERY_HARD)
-println(sudoku.toString())
+println(sudoku)
 ```
 
 Check how hard is a given sudoku:

src/main/kotlin/io/github/ilikeyourhat/kudoku/Kudoku.kt

@@ -3,7 +3,8 @@ package io.github.ilikeyourhat.kudoku
 import io.github.ilikeyourhat.kudoku.generating.SudokuGenerator
 import io.github.ilikeyourhat.kudoku.model.Sudoku
 import io.github.ilikeyourhat.kudoku.model.SudokuType
-import io.github.ilikeyourhat.kudoku.parsing.text.SudokuTextFormatParser
+import io.github.ilikeyourhat.kudoku.parsing.SingleLineSudokuParser
+import io.github.ilikeyourhat.kudoku.parsing.SudokuTextFormatParser
 import io.github.ilikeyourhat.kudoku.rating.DeductionBasedRater
 import io.github.ilikeyourhat.kudoku.rating.Difficulty
 import io.github.ilikeyourhat.kudoku.solving.SolutionCount
@@ -46,6 +47,10 @@ object Kudoku {
         return SudokuTextFormatParser(supportedTypes).parseOne(string)
     }
 
+    fun createFromSingleLineString(string: String): Sudoku {
+        return SingleLineSudokuParser().fromText(string)
+    }
+
     fun rate(sudoku: Sudoku): Difficulty {
         return DeductionBasedRater().rate(sudoku)
     }

src/main/kotlin/io/github/ilikeyourhat/kudoku/parsing/EmptyFieldIndicator.kt

@@ -0,0 +1,10 @@
+package io.github.ilikeyourhat.kudoku.parsing
+
+enum class EmptyFieldIndicator(val value: Char) {
+    ZERO('0'),
+    DOT('.'),
+    X('X'),
+    ASTERISK('*'),
+    UNDERSCORE('_'),
+    SPACE(' ')
+}

src/main/kotlin/io/github/ilikeyourhat/kudoku/parsing/SingleLineSudokuParser.kt

@@ -0,0 +1,72 @@
+package io.github.ilikeyourhat.kudoku.parsing
+
+import io.github.ilikeyourhat.kudoku.model.Sudoku
+import io.github.ilikeyourhat.kudoku.type.Classic12x12
+import io.github.ilikeyourhat.kudoku.type.Classic16x16
+import io.github.ilikeyourhat.kudoku.type.Classic25x25
+import io.github.ilikeyourhat.kudoku.type.Classic4x4
+import io.github.ilikeyourhat.kudoku.type.Classic6x6
+import io.github.ilikeyourhat.kudoku.type.Classic9x9
+
+@Suppress("MagicNumber")
+class SingleLineSudokuParser {
+
+    private val typeMap = mapOf(
+        16 to Classic4x4,
+        36 to Classic6x6,
+        81 to Classic9x9,
+        144 to Classic12x12,
+        256 to Classic16x16,
+        625 to Classic25x25
+    )
+
+    fun toText(
+        sudoku: Sudoku,
+        emptyFieldIndicator: EmptyFieldIndicator
+    ): String {
+        require(sudoku.isSupported()) { "Unsupported sudoku type: ${sudoku.type.name}" }
+
+        return sudoku.allFields
+            .map { encodeValue(it.value, emptyFieldIndicator) }
+            .joinToString("")
+    }
+
+    fun fromText(text: String): Sudoku {
+        val type = typeMap[text.length]
+            ?: throw IllegalArgumentException("Unsupported sudoku type with input length ${text.length}")
+
+        val values = text
+            .map { decodeValue(it) }
+            .toList()
+        return Sudoku(type, values)
+    }
+
+    private fun Sudoku.isSupported(): Boolean {
+        return typeMap.containsValue(type)
+    }
+
+    private fun encodeValue(value: Int, emptyFieldIndicator: EmptyFieldIndicator): Char {
+        return when (value) {
+            0 -> emptyFieldIndicator.value
+            in 1..9 -> value.digitToChar()
+            in 10..25 -> 'A'.plus(value - 10)
+            else -> throw IllegalArgumentException("Value $value is not supported")
+        }
+    }
+
+    private fun decodeValue(value: Char): Int {
+        return when (value) {
+            in '1'..'9' -> value.digitToInt()
+            in 'A'..LAST_SUPPORTED_LETTER_UPPERCASE -> value.code - 'A'.code + 10
+            in 'a'..LAST_SUPPORTED_LETTER_LOWERCASE -> value.code - 'a'.code + 10
+            in EMPTY_FIELD_INDICATORS -> 0
+            else -> throw IllegalArgumentException("Value $value is not supported")
+        }
+    }
+
+    private companion object {
+        const val LAST_SUPPORTED_LETTER_UPPERCASE = 'P'
+        const val LAST_SUPPORTED_LETTER_LOWERCASE = 'p'
+        val EMPTY_FIELD_INDICATORS = EmptyFieldIndicator.entries.map { it.value }
+    }
+}

src/main/kotlin/io/github/ilikeyourhat/kudoku/parsing/SudokuExt.kt

@@ -0,0 +1,7 @@
+package io.github.ilikeyourhat.kudoku.parsing
+
+import io.github.ilikeyourhat.kudoku.model.Sudoku
+
+fun Sudoku.toSingleLineString(emptyFieldIndicator: EmptyFieldIndicator = EmptyFieldIndicator.ZERO): String {
+    return SingleLineSudokuParser().toText(this, emptyFieldIndicator)
+}

src/main/kotlin/io/github/ilikeyourhat/kudoku/parsing/text/SudokuTextFormatParser.kt → src/main/kotlin/io/github/ilikeyourhat/kudoku/parsing/SudokuTextFormatParser.kt

@@ -1,4 +1,4 @@
-package io.github.ilikeyourhat.kudoku.parsing.text
+package io.github.ilikeyourhat.kudoku.parsing
 
 import io.github.ilikeyourhat.kudoku.model.Sudoku
 import io.github.ilikeyourhat.kudoku.model.SudokuType

src/test/kotlin/io/github/ilikeyourhat/kudoku/integration/parsing/SingleLineFormatTest.kt

@@ -0,0 +1,48 @@
+package io.github.ilikeyourhat.kudoku.integration.parsing
+
+import io.github.ilikeyourhat.kudoku.Kudoku
+import io.github.ilikeyourhat.kudoku.model.Sudoku
+import io.github.ilikeyourhat.kudoku.parsing.EmptyFieldIndicator
+import io.github.ilikeyourhat.kudoku.parsing.toSingleLineString
+import io.github.ilikeyourhat.kudoku.type.Classic4x4
+import io.kotest.matchers.equals.shouldBeEqual
+import org.junit.jupiter.api.Test
+
+class SingleLineFormatTest {
+
+    @Test
+    fun `should handle simple encoding`() {
+        val sudoku = Sudoku(
+            Classic4x4,
+            listOf(
+                0, 0, 1, 0,
+                3, 0, 0, 0,
+                0, 4, 0, 0,
+                1, 0, 4, 0
+            )
+        )
+
+        sudoku.toSingleLineString()
+            .shouldBeEqual("0010300004001040")
+        sudoku.toSingleLineString(emptyFieldIndicator = EmptyFieldIndicator.DOT)
+            .shouldBeEqual("..1.3....4..1.4.")
+    }
+
+    @Test
+    fun `should handle simple decoding`() {
+        val expectedSudoku = Sudoku(
+            Classic4x4,
+            listOf(
+                0, 0, 1, 0,
+                3, 0, 0, 0,
+                0, 4, 0, 0,
+                1, 0, 4, 0
+            )
+        )
+
+        Kudoku.createFromSingleLineString("0010300004001040")
+            .shouldBeEqual(expectedSudoku)
+        Kudoku.createFromSingleLineString("..1.3....4..1.4.")
+            .shouldBeEqual(expectedSudoku)
+    }
+}

src/test/kotlin/io/github/ilikeyourhat/kudoku/parsing/SingleLineSudokuParserTest.kt

@@ -0,0 +1,158 @@
+package io.github.ilikeyourhat.kudoku.parsing
+
+import io.github.ilikeyourhat.kudoku.model.Sudoku
+import io.github.ilikeyourhat.kudoku.type.BUILD_IN_TYPES
+import io.github.ilikeyourhat.kudoku.type.Classic4x4
+import io.github.ilikeyourhat.kudoku.type.SamuraiClassic21x21
+import io.kotest.assertions.throwables.shouldThrow
+import io.kotest.matchers.booleans.shouldBeTrue
+import io.kotest.matchers.collections.shouldHaveSize
+import io.kotest.matchers.equals.shouldBeEqual
+import io.kotest.matchers.throwable.shouldHaveMessage
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+import org.junit.jupiter.params.provider.ValueSource
+
+class SingleLineSudokuParserTest {
+
+    private val parser = SingleLineSudokuParser()
+
+    @ParameterizedTest
+    @ValueSource(
+        strings = [
+            "0010300004001040",
+            "..1.3....4..1.4.",
+            "XX1X3XXXX4XX1X4X",
+            "**1*3****4**1*4*",
+            "__1_3____4__1_4_",
+            "  1 3    4  1 4 "
+        ]
+    )
+    fun `should handle multiple empty field indicators`(encodedSudoku: String) {
+        val sudoku = Sudoku(
+            Classic4x4,
+            listOf(
+                0, 0, 1, 0,
+                3, 0, 0, 0,
+                0, 4, 0, 0,
+                1, 0, 4, 0
+            )
+        )
+
+        parser.fromText(encodedSudoku)
+            .shouldBeEqual(sudoku)
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        value = [
+            "classic_4x4, 1234",
+            "classic_6x6, 123456",
+            "classic_9x9, 123456789",
+            "classic_12x12, 123456789ABC",
+            "classic_12x12, 123456789abc",
+            "classic_16x16, 123456789ABCDEFG",
+            "classic_16x16, 123456789abcdefg",
+            "classic_25x25, 123456789ABCDEFGHIJKLMNOP",
+            "classic_25x25, 123456789abcdefghijklmnop"
+        ]
+    )
+    fun `should decode different sudoku types`(type: String, possibleValues: String) {
+        val encodedSudoku = possibleValues.repeat(possibleValues.length)
+
+        val sudoku = parser.fromText(encodedSudoku)
+
+        sudoku.type.name
+            .shouldBeEqual(type)
+        sudoku.isCompleted()
+            .shouldBeTrue()
+        sudoku.values()
+            .distinct()
+            .shouldHaveSize(possibleValues.length)
+    }
+
+    @Test
+    fun `should throw exception when decoding wrong length`() {
+        val encodedSudoku = "1234123412"
+
+        shouldThrow<IllegalArgumentException> {
+            parser.fromText(encodedSudoku)
+        }.shouldHaveMessage("Unsupported sudoku type with input length 10")
+    }
+
+    @Test
+    fun `should throw exception when decoding unsupported value`() {
+        val encodedSudoku = "..1.&....4..1.4."
+
+        shouldThrow<IllegalArgumentException> {
+            parser.fromText(encodedSudoku)
+        }.shouldHaveMessage("Value & is not supported")
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        value = [
+            "ZERO|0010300004001040",
+            "DOT|..1.3....4..1.4.",
+            "X|XX1X3XXXX4XX1X4X",
+            "ASTERISK|**1*3****4**1*4*",
+            "UNDERSCORE|__1_3____4__1_4_",
+            "SPACE|  1 3    4  1 4 "
+        ],
+        delimiter = '|',
+        ignoreLeadingAndTrailingWhitespace = false
+    )
+    fun `should handle multiple empty field indicators`(
+        emptyFieldIndicator: EmptyFieldIndicator,
+        expectedString: String
+    ) {
+        val sudoku = Sudoku(
+            Classic4x4,
+            listOf(
+                0, 0, 1, 0,
+                3, 0, 0, 0,
+                0, 4, 0, 0,
+                1, 0, 4, 0
+            )
+        )
+
+        parser.toText(sudoku, emptyFieldIndicator)
+            .shouldBeEqual(expectedString)
+    }
+
+    @ParameterizedTest
+    @ValueSource(
+        strings = [
+            "classic_4x4",
+            "classic_6x6",
+            "classic_9x9",
+            "classic_12x12",
+            "classic_16x16",
+            "classic_25x25"
+        ]
+    )
+    fun `should encode different sudoku types`(typeName: String) {
+        val type = BUILD_IN_TYPES.single { it.name == typeName }
+        val values = (1..type.maxValue)
+            .flatMap { (1..type.maxValue) }
+        val sudoku = Sudoku(type, values)
+
+        val possibleValues = "123456789ABCDEFGHIJKLMNOP"
+            .slice(0 until type.maxValue)
+
+        val encodedSudoku = parser.toText(sudoku, EmptyFieldIndicator.ZERO)
+
+        encodedSudoku
+            .shouldBeEqual(possibleValues.repeat(possibleValues.length))
+    }
+
+    @Test
+    fun `should throw exception when encoding unsupported type`() {
+        val sudoku = Sudoku(SamuraiClassic21x21)
+
+        shouldThrow<IllegalArgumentException> {
+            parser.toText(sudoku, EmptyFieldIndicator.ZERO)
+        }.shouldHaveMessage("Unsupported sudoku type: samurai_classic_21x21")
+    }
+}

src/test/kotlin/io/github/ilikeyourhat/kudoku/parsing/SudokuTextFormatParserTest.kt

@@ -1,7 +1,6 @@
 package io.github.ilikeyourhat.kudoku.parsing
 
 import io.github.ilikeyourhat.kudoku.model.Sudoku
-import io.github.ilikeyourhat.kudoku.parsing.text.SudokuTextFormatParser
 import io.github.ilikeyourhat.kudoku.type.Classic9x9
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test