refactor: remove unnecessary stack (#17)

Author: nnnkkk7

errors.go

@@ -9,10 +9,9 @@ import (
 
 // Sentinel errors returned by [Reader]. These are compatible with [encoding/csv].
 var (
-	ErrBareQuote     = errors.New("bare \" in non-quoted-field")
-	ErrQuote         = errors.New("extraneous or missing \" in quoted-field")
-	ErrFieldCount    = errors.New("wrong number of fields")
-	ErrTrailingComma = errors.New("extra delimiter at end of line") // Deprecated
+	ErrBareQuote  = errors.New("bare \" in non-quoted-field")
+	ErrQuote      = errors.New("extraneous or missing \" in quoted-field")
+	ErrFieldCount = errors.New("wrong number of fields")
 )
 
 // ParseError represents a parsing error with location information

field_parser_test.go

@@ -89,7 +89,7 @@ func TestParseBuffer(t *testing.T) {
 
 		sr := &scanResult{
 			quoteMasks:     []uint64{0},
-			separatorMasks: []uint64{0b010101010}, // bits 1,3,5,7 (commas)
+			separatorMasks: []uint64{0b010101010},  // bits 1,3,5,7 (commas)
 			newlineMasks:   []uint64{0b1000000000}, // bit 9 (newline)
 			chunkCount:     1,
 			lastChunkBits:  10,
@@ -116,7 +116,7 @@ func TestParseBuffer(t *testing.T) {
 		sr := &scanResult{
 			quoteMasks:     []uint64{0, 0},
 			separatorMasks: []uint64{0b1000010000000, 0b10000000}, // commas in each chunk
-			newlineMasks:   []uint64{1 << 20, 1 << 13},  // newlines
+			newlineMasks:   []uint64{1 << 20, 1 << 13},            // newlines
 			chunkCount:     2,
 			lastChunkBits:  64,
 		}
@@ -378,7 +378,7 @@ func TestRowsInitialization(t *testing.T) {
 		// Positions: 0=a 1=, 2=b 3=, 4=c 5=\n 6=d 7=, 8=e 9=\n 10=f 11=, 12=g 13=, 14=h 15=, 16=i 17=\n
 		sr := &scanResult{
 			quoteMasks:     []uint64{0},
-			separatorMasks: []uint64{0b1010100010001010}, // commas at 1,3,7,11,13,15
+			separatorMasks: []uint64{0b1010100010001010},   // commas at 1,3,7,11,13,15
 			newlineMasks:   []uint64{0b100000001000100000}, // newlines at 5, 9, 17
 			chunkCount:     1,
 			lastChunkBits:  18,
@@ -603,7 +603,7 @@ func TestQuoteHandling(t *testing.T) {
 		// would not include it in separatorMask
 		sr := &scanResult{
 			quoteMasks:     []uint64{(1 << 0) | (1 << 4)}, // quotes at 0,4
-			separatorMasks: []uint64{1 << 5},               // only comma at 5
+			separatorMasks: []uint64{1 << 5},              // only comma at 5
 			newlineMasks:   []uint64{1 << 7},
 			chunkCount:     1,
 			lastChunkBits:  8,
@@ -844,7 +844,7 @@ func TestEdgeCases(t *testing.T) {
 
 		sr := &scanResult{
 			quoteMasks:     []uint64{0},
-			separatorMasks: []uint64{0b010101010}, // commas at 1,3,5,7
+			separatorMasks: []uint64{0b010101010},  // commas at 1,3,5,7
 			newlineMasks:   []uint64{0b1000000000}, // newline at 9
 			chunkCount:     1,
 			lastChunkBits:  10,
@@ -868,7 +868,7 @@ func TestEdgeCases(t *testing.T) {
 		sr := &scanResult{
 			quoteMasks:     []uint64{0},
 			separatorMasks: []uint64{0b00110}, // commas at 1,3
-			newlineMasks:   []uint64{0},        // no newlines
+			newlineMasks:   []uint64{0},       // no newlines
 			chunkCount:     1,
 			lastChunkBits:  5,
 		}

reader.go

@@ -50,13 +50,9 @@ type Reader struct {
 	// By default, each call to Read returns newly allocated memory owned by the caller.
 	ReuseRecord bool
 
-	// Deprecated: TrailingComma is no longer used.
-	TrailingComma bool
-
 	r io.Reader
 
 	// Internal state
-	numLine        int
 	offset         int64
 	rawBuffer      []byte
 	fieldPositions []position
@@ -116,9 +112,6 @@ func (r *Reader) Read() (record []string, err error) {
 		rowInfo := r.parseResult.rows[r.currentRecordIndex]
 		r.currentRecordIndex++
 
-		// Update line number for error reporting
-		r.numLine = rowInfo.lineNum
-
 		// Check for comment line (line starting with Comment character)
 		if r.Comment != 0 && r.isCommentLine(rowInfo) {
 			// Skip this line and continue to next

simd_scanner_test.go

@@ -83,13 +83,13 @@ func makeAligned64(data []byte) []byte {
 
 func TestGenerateMasks(t *testing.T) {
 	tests := []struct {
-		name           string
-		input          []byte
-		separator      byte
-		wantQuotePos   []int // expected bit positions for quotes
-		wantSepPos     []int // expected bit positions for separators
-		wantCRPos      []int // expected bit positions for CR
-		wantNLPos      []int // expected bit positions for LF
+		name         string
+		input        []byte
+		separator    byte
+		wantQuotePos []int // expected bit positions for quotes
+		wantSepPos   []int // expected bit positions for separators
+		wantCRPos    []int // expected bit positions for CR
+		wantNLPos    []int // expected bit positions for LF
 	}{
 		{
 			name:         "simple_csv_line",
@@ -279,14 +279,14 @@ func TestGenerateMasks(t *testing.T) {
 
 func TestGenerateMasksPadded(t *testing.T) {
 	tests := []struct {
-		name           string
-		input          []byte
-		separator      byte
-		wantQuotePos   []int
-		wantSepPos     []int
-		wantCRPos      []int
-		wantNLPos      []int
-		wantValidBits  int
+		name          string
+		input         []byte
+		separator     byte
+		wantQuotePos  []int
+		wantSepPos    []int
+		wantCRPos     []int
+		wantNLPos     []int
+		wantValidBits int
 	}{
 		{
 			name:          "single_byte",
@@ -485,8 +485,8 @@ func TestCRLFNormalization(t *testing.T) {
 	tests := []struct {
 		name               string
 		input              []byte
-		wantNewlinePos     []int  // positions in final newline mask (after normalization)
-		wantCRLFNormalized bool   // true if CRLF was normalized
+		wantNewlinePos     []int // positions in final newline mask (after normalization)
+		wantCRLFNormalized bool  // true if CRLF was normalized
 		description        string
 	}{
 		{
@@ -586,19 +586,19 @@ func TestCRLFNormalization(t *testing.T) {
 // CR at byte 63 of chunk N, LF at byte 0 of chunk N+1
 func TestCRLFBoundary(t *testing.T) {
 	tests := []struct {
-		name           string
-		chunk1         []byte // first 64-byte chunk (CR at end)
-		chunk2         []byte // second 64-byte chunk (LF at start)
-		wantChunk1NL   []int  // newline positions in chunk 1
-		wantChunk2NL   []int  // newline positions in chunk 2
-		description    string
+		name         string
+		chunk1       []byte // first 64-byte chunk (CR at end)
+		chunk2       []byte // second 64-byte chunk (LF at start)
+		wantChunk1NL []int  // newline positions in chunk 1
+		wantChunk2NL []int  // newline positions in chunk 2
+		description  string
 	}{
 		{
 			name:         "boundary_crlf",
 			chunk1:       append(make([]byte, 63), '\r'),
 			chunk2:       append([]byte{'\n'}, make([]byte, 63)...),
-			wantChunk1NL: nil,                   // CR at 63 is part of CRLF, not counted here
-			wantChunk2NL: []int{0},              // LF at 0 is the actual newline
+			wantChunk1NL: nil,      // CR at 63 is part of CRLF, not counted here
+			wantChunk2NL: []int{0}, // LF at 0 is the actual newline
 			description:  "CRLF split across chunk boundary",
 		},
 		{
@@ -711,8 +711,8 @@ func TestChunkBoundaryQuotes(t *testing.T) {
 			name:                "boundary_escaped_quote_inside_field",
 			chunk1:              append(append([]byte(`"content`), make([]byte, 55)...), '"'),
 			chunk2:              append([]byte{'"', 'm', 'o', 'r', 'e', '"'}, make([]byte, 58)...),
-			chunk1Quoted:        false,                // starts outside
-			wantSkipNextQuote:   true,                 // "" at boundary
+			chunk1Quoted:        false, // starts outside
+			wantSkipNextQuote:   true,  // "" at boundary
 			wantChunk2QuoteSkip: true,
 			description:         `"content..." with "" escape at boundary`,
 		},
@@ -841,8 +841,8 @@ func TestScanBuffer(t *testing.T) {
 		input              []byte
 		separator          byte
 		wantChunkCount     int
-		wantPostProcChunks []int  // chunks that need post-processing (have escaped quotes)
-		wantFinalQuoted    bool   // should we end in quoted state?
+		wantPostProcChunks []int // chunks that need post-processing (have escaped quotes)
+		wantFinalQuoted    bool  // should we end in quoted state?
 		description        string
 	}{
 		{
@@ -959,14 +959,14 @@ func TestScanBuffer(t *testing.T) {
 // TestScanBuffer_MaskContent verifies the actual mask content
 func TestScanBuffer_MaskContent(t *testing.T) {
 	tests := []struct {
-		name          string
-		input         []byte
-		separator     byte
-		chunkIdx      int
-		wantSepPos    []int
-		wantNLPos     []int
-		wantQuotePos  []int
-		description   string
+		name         string
+		input        []byte
+		separator    byte
+		chunkIdx     int
+		wantSepPos   []int
+		wantNLPos    []int
+		wantQuotePos []int
+		description  string
 	}{
 		{
 			name:         "verify_separator_positions",
@@ -1034,8 +1034,8 @@ func TestScanBuffer_MultiChunk(t *testing.T) {
 	// Chunk 1: bytes 64-127
 	// Chunk 2: bytes 128+
 	chunk0 := strings.Repeat("a,", 20) + "field\n" + strings.Repeat("b,", 10) // ~66 bytes
-	chunk1 := strings.Repeat("c,", 25) + "data\n"                              // ~55 bytes
-	chunk2 := "last\n"                                                         // 5 bytes
+	chunk1 := strings.Repeat("c,", 25) + "data\n"                             // ~55 bytes
+	chunk2 := "last\n"                                                        // 5 bytes
 
 	input := []byte(chunk0 + chunk1 + chunk2)