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Fix string splitting double quote handling #12

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Merged
guymers merged 1 commit into from
Oct 3, 2025
Merged

Fix string splitting double quote handling #12

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65 changes: 45 additions & 20 deletions modules/core/src/main/scala/ceesvee/CsvParser.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -139,12 +139,14 @@ object CsvParser {

case class State(
leftover: String,
insideQuote: Boolean,
insideQuoteIndex: Int,
previousCarriageReturn: Boolean,
)
object State {
val initial: State = State(
leftover = "",
insideQuote = false,
insideQuoteIndex = -1,
previousCarriageReturn = false,
)
}

Expand All @@ -158,7 +160,8 @@ object CsvParser {
state: State,
)(implicit f: Factory[String, C[String]]): (State, C[String]) = {
val builder = f.newBuilder
var insideQuote = state.insideQuote
var insideQuoteIndex = state.insideQuoteIndex
var previousCarriageReturn = state.previousCarriageReturn
var leftover = state.leftover

val it = strings.iterator
Expand All @@ -168,52 +171,74 @@ object CsvParser {

val concat = leftover.concat(string)

// assume we have already processed `leftover`,
// reprocess the last character in case it was a '"' or '\r'
var i = (leftover.length - 1).max(0)
var insideQuote = false
var i =
if (insideQuoteIndex >= 0) insideQuoteIndex
else if (previousCarriageReturn) leftover.length - 1
else leftover.length
var sliceStart = 0

while (i < concat.length) {
(concat(i): @switch) match {

case '"' =>
if (insideQuote && (i + 1) < concat.length && concat(i + 1) == '"') { // escaped quote
i += 2
if (insideQuote) {
if ((i + 1) == concat.length) { // last char
i += 1 // not enough information
} else {
if (concat(i + 1) == '"') { // escaped quote
i += 2
} else {
insideQuote = false
insideQuoteIndex = -1
i += 1
}
}
} else {
insideQuote = true
insideQuoteIndex = i
i += 1
if (i < concat.length) {
insideQuote = !insideQuote
}
}

case '\n' =>
if (!insideQuote) {
val _ = builder += concat.substring(sliceStart, i)
if (insideQuote) {
i += 1
sliceStart = i
} else {
val sliceEnd = if (previousCarriageReturn) i - 1 else i
val _ = builder += concat.substring(sliceStart, sliceEnd)
i += 1
sliceStart = i
}

case '\r' =>
if (!insideQuote && (i + 1) < concat.length && concat(i + 1) == '\n') {
val _ = builder += concat.substring(sliceStart, i)
i += 2
sliceStart = i
} else {
if (insideQuote) {
i += 1
} else {
if ((i + 1) == concat.length) { // last char
i += 1 // previousCarriageReturn set later
} else {
if (concat(i + 1) == '\n') {
val _ = builder += concat.substring(sliceStart, i)
i += 2
sliceStart = i
} else {
i += 1
}
}
}

case _ =>
i += 1
}
}

insideQuoteIndex = insideQuoteIndex - sliceStart
previousCarriageReturn = concat(i - 1) == '\r'
leftover = concat.substring(sliceStart, concat.length)
}
}

(State(leftover, insideQuote = insideQuote), builder.result())
(State(leftover, insideQuoteIndex = insideQuoteIndex, previousCarriageReturn = previousCarriageReturn), builder.result())
}

/**
Expand Down
34 changes: 34 additions & 0 deletions modules/core/src/test/scala/ceesvee/CsvParserSpec.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,40 @@ object CsvParserSpec extends ZIOSpecDefault with CsvParserParserSuite {
assertTrue(lines == List("abc\rdef", "ghi", "jkl")) &&
assertTrue(state.leftover == "mno")
},
test("trailing double quotes") {
val strings = List(
"a,\"b\"",
",c,\"d\"\"e\",\"",
"\"",
"\nfg\"",
)
val (state, lines) = CsvParser.splitStrings(strings, CsvParser.State.initial)
val strings2 = List(
"\n\"\"\"",
"\n\"hi\"\"",
)
val (state2, lines2) = CsvParser.splitStrings(strings2, state)
val strings3 = List(
"j\"",
"\nmno",
)
val (state3, lines3) = CsvParser.splitStrings(strings3, state2)
assertTrue(
lines == List("""a,"b",c,"d""e","""""),
state.insideQuoteIndex == 2,
state.leftover == "fg\"",
) &&
assertTrue(
lines2 == List("fg\"\n\"\"\""),
state2.insideQuoteIndex == 0,
state2.leftover == "\"hi\"\"",
) &&
assertTrue(
lines3 == List("\"hi\"\"j\""),
state3.insideQuoteIndex == -9,
state3.leftover == "mno",
)
},
test("quotes and new lines") {
val strings = List(
"a\"b\"c\n",
Expand Down
4 changes: 2 additions & 2 deletions modules/zio/src/main/scala/ceesvee/zio/ZioCsvParser.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -112,12 +112,12 @@ object ZioCsvParser {
Ref.make(state).map { stateRef => (chunk: Option[Chunk[String]]) =>
chunk match {
case None =>
stateRef.getAndSet(State.initial).map { case State(leftover, _) =>
stateRef.getAndSet(State.initial).map { case State(leftover, _, _) =>
if (leftover.isEmpty) Chunk.empty else Chunk(leftover)
}

case Some(strings) =>
stateRef.get.flatMap { case State(leftover, _) =>
stateRef.get.flatMap { case State(leftover, _, _) =>
ZIO.fail(Error.LineTooLong(options.maximumLineLength))
.when(leftover.length > options.maximumLineLength)
} *> stateRef.modify(splitStrings(strings, _).swap)
Expand Down