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Fix the issue #35 #36

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Merged
sergejsha merged 1 commit into from
Nov 23, 2025
Merged

Fix the issue #35 #36

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8 changes: 6 additions & 2 deletions src/commonMain/kotlin/Csv.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -16,21 +16,25 @@ public abstract class Csv(
*
* @param newLine the line separator to use
* @param escapeWhitespaces whether to escape whitespaces in values
* @param trailingNewLine whether to add a newline character after the last row
* @return the CSV-formatted string representation
*/
public fun toCsvText(
newLine: NewLine = NewLine.LF,
escapeWhitespaces: Boolean = false,
trailingNewLine: Boolean = false,
): String = buildString {
allRows.forEach { row ->
allRows.forEachIndexed { index, row ->
row.forEachIndexed { index, value ->
val escapedValue = value.escapeCsvValue(escapeWhitespaces)
append(escapedValue)
if (index < row.lastIndex) {
append(',')
}
}
append(newLine.value)
if (index != allRows.lastIndex || trailingNewLine) {
append(newLine.value)
}
}
}
}
Expand Down
118 changes: 41 additions & 77 deletions src/commonMain/kotlin/parseCsv.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,14 @@ internal fun parseCsv(
withHeaderRow: Boolean = true,
): Pair<CsvHeaderRow?, List<CsvDataRow>> {
var pos = 0
var lexer: Lexer = BeforeValue
var lexer: Lexer = SimpleValue

fun nextChar(): Char? {
val nextPos = pos + 1
return if (nextPos < csvText.length) csvText[nextPos] else null
}

var valueStarted = false
val value = StringBuilder()
val row = mutableListOf<String>()
var header: CsvHeaderRow? = null
Expand All @@ -23,6 +24,7 @@ internal fun parseCsv(
fun completeValue() {
row.add(value.toString())
value.clear()
valueStarted = false
}

fun completeRow() {
Expand All @@ -37,122 +39,85 @@ internal fun parseCsv(
while (pos < csvText.length) {
val char = csvText[pos]
lexer = when (lexer) {
BeforeValue -> when (char) {
'"' -> InsideEscapedValue
SimpleValue -> when (char) {
'"' -> {
valueStarted = true
QuotedValue
}
',' -> {
completeValue()
BeforeValue
valueStarted = true
SimpleValue
}
'\r' -> {
if (nextChar() == '\n') {
pos++
}
if (valueStarted) {
completeValue()
}
if (row.isNotEmpty()) {
completeRow()
}
BeforeValue
valueStarted = false
SimpleValue
}
'\n' -> {
if (valueStarted) {
completeValue()
}
if (row.isNotEmpty()) {
completeRow()
}
BeforeValue
SimpleValue
}
else -> {
value.append(char)
InsideValue
SimpleValue
}
}
InsideValue -> when (char) {
',' -> {
completeValue()
BeforeValue
}
'\r' -> {
if (nextChar() == '\n') {
pos++
}
completeValue()
completeRow()
BeforeValue
}
'\n' -> {
completeValue()
completeRow()
BeforeValue
}
else -> {
value.append(char)
when (nextChar()) {
',' -> {
pos++
completeValue()
when (nextChar()) {
null -> { // EOF
completeValue()
completeRow()
}
}
BeforeValue
}
'\r' -> {
pos++
when (nextChar()) {
'\n' -> {
pos++
}
}
completeValue()
completeRow()
BeforeValue
}
'\n' -> {
pos++
completeValue()
completeRow()
BeforeValue
}
null -> {
completeValue()
completeRow()
BeforeValue
}
else -> {
InsideValue
}
}
}
}
InsideEscapedValue -> when (char) {
QuotedValue -> when (char) {
'"' -> when (nextChar()) {
'"' -> {
pos++
value.append(char)
InsideEscapedValue
QuotedValue
}
else -> {
else -> { // Quote closed, value complete
completeValue()
when (nextChar()) {
',' -> {
pos++
valueStarted = true
}
'\r' -> {
pos++
if (nextChar() == '\n') {
pos++
}
completeRow()
}
'\n' -> {
pos++
completeRow()
}
null -> {
completeRow()
}
}
BeforeValue
SimpleValue
}
}
else -> {
value.append(char)
InsideEscapedValue
QuotedValue
}
}
}
pos++
}

if (value.isNotEmpty()) {
if (valueStarted) {
completeValue()
}

Expand All @@ -164,7 +129,6 @@ internal fun parseCsv(
}

private enum class Lexer {
BeforeValue,
InsideValue,
InsideEscapedValue,
}
SimpleValue,
QuotedValue,
}
31 changes: 31 additions & 0 deletions src/commonTest/kotlin/Issue35Test.kt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
/** Copyright 2023-2025 Halfbit GmbH, Sergej Shafarenka */
package de.halfbit.csv

import kotlin.test.Test
import kotlin.test.assertEquals

class Issue35Test {

@Test
fun parseTrailingEmptyFields() {

val given =
"""
year,make,model,price
1997,Ford,E350,3000.00
1999,Chevy,Venture,
2001,VW,,
""".trimIndent()

val csv = CsvWithHeader.fromCsvText(given) as CsvWithHeader
val actual = csv.toCsvText()
val expected = """
year,make,model,price
1997,Ford,E350,3000.00
1999,Chevy,Venture,""
2001,VW,"",""
""".trimIndent()

assertEquals(expected, actual)
}
}
4 changes: 2 additions & 2 deletions src/commonTest/kotlin/ReadmeExampleTest.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ class ReadmeExampleTest {

// (2) csv to text
val csvText = csv.toCsvText()
assertEquals("Code,Name\nDE,Deutschland\nBY,Belarus\n", csvText)
assertEquals("Code,Name\nDE,Deutschland\nBY,Belarus", csvText)

// (3) parse csv text
val csv2 = CsvWithHeader.fromCsvText(csvText) as CsvWithHeader
Expand All @@ -53,6 +53,6 @@ class ReadmeExampleTest {
}
}
)
assertEquals("Code,Name\nDE,Deutschland\nBY,Weißrussland\n", csv3.toCsvText())
assertEquals("Code,Name\nDE,Deutschland\nBY,Weißrussland", csv3.toCsvText())
}
}