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Diffstat (limited to 'src/pkg/csv/reader.go')
| -rw-r--r-- | src/pkg/csv/reader.go | 373 |
1 files changed, 0 insertions, 373 deletions
diff --git a/src/pkg/csv/reader.go b/src/pkg/csv/reader.go deleted file mode 100644 index 1f4b61cf9..000000000 --- a/src/pkg/csv/reader.go +++ /dev/null @@ -1,373 +0,0 @@ -// Copyright 2011 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// Package csv reads and writes comma-separated values (CSV) files. -// -// A csv file contains zero or more records of one or more fields per record. -// Each record is separated by the newline character. The final record may -// optionally be followed by a newline character. -// -// field1,field2,field3 -// -// White space is considered part of a field. -// -// Carriage returns before newline characters are silently removed. -// -// Blank lines are ignored. A line with only whitespace characters (excluding -// the ending newline character) is not considered a blank line. -// -// Fields which start and stop with the quote character " are called -// quoted-fields. The beginning and ending quote are not part of the -// field. -// -// The source: -// -// normal string,"quoted-field" -// -// results in the fields -// -// {`normal string`, `quoted-field`} -// -// Within a quoted-field a quote character followed by a second quote -// character is considered a single quote. -// -// "the ""word"" is true","a ""quoted-field""" -// -// results in -// -// {`the "word" is true`, `a "quoted-field"`} -// -// Newlines and commas may be included in a quoted-field -// -// "Multi-line -// field","comma is ," -// -// results in -// -// {`Multi-line -// field`, `comma is ,`} -package csv - -import ( - "bufio" - "bytes" - "fmt" - "io" - "os" - "unicode" -) - -// A ParseError is returned for parsing errors. -// The first line is 1. The first column is 0. -type ParseError struct { - Line int // Line where the error occurred - Column int // Column (rune index) where the error occurred - Error os.Error // The actual error -} - -func (e *ParseError) String() string { - return fmt.Sprintf("line %d, column %d: %s", e.Line, e.Column, e.Error) -} - -// These are the errors that can be returned in ParseError.Error -var ( - ErrTrailingComma = os.NewError("extra delimiter at end of line") - ErrBareQuote = os.NewError("bare \" in non-quoted-field") - ErrQuote = os.NewError("extraneous \" in field") - ErrFieldCount = os.NewError("wrong number of fields in line") -) - -// A Reader reads records from a CSV-encoded file. -// -// As returned by NewReader, a Reader expects input conforming to RFC 4180. -// The exported fields can be changed to customize the details before the -// first call to Read or ReadAll. -// -// Comma is the field delimiter. It defaults to ','. -// -// Comment, if not 0, is the comment character. Lines beginning with the -// Comment character is ignored. -// -// If FieldsPerRecord is positive, Read requires each record to -// have the given number of fields. If FieldsPerRecord is 0, Read sets it to -// the number of fields in the first record, so that future records must -// have the same field count. -// -// If LazyQuotes is true, a quote may appear in an unquoted field and a -// non-doubled quote may appear in a quoted field. -// -// If TrailingComma is true, the last field may be a unquoted empty field. -// -// If TrimLeadingSpace is true, leading white space in a field is ignored. -type Reader struct { - Comma int // Field delimiter (set to ',' by NewReader) - Comment int // Comment character for start of line - FieldsPerRecord int // Number of expected fields per record - LazyQuotes bool // Allow lazy quotes - TrailingComma bool // Allow trailing comma - TrimLeadingSpace bool // Trim leading space - line int - column int - r *bufio.Reader - field bytes.Buffer -} - -// NewReader returns a new Reader that reads from r. -func NewReader(r io.Reader) *Reader { - return &Reader{ - Comma: ',', - r: bufio.NewReader(r), - } -} - -// error creates a new ParseError based on err. -func (r *Reader) error(err os.Error) os.Error { - return &ParseError{ - Line: r.line, - Column: r.column, - Error: err, - } -} - -// Read reads one record from r. The record is a slice of strings with each -// string representing one field. -func (r *Reader) Read() (record []string, err os.Error) { - for { - record, err = r.parseRecord() - if record != nil { - break - } - if err != nil { - return nil, err - } - } - - if r.FieldsPerRecord > 0 { - if len(record) != r.FieldsPerRecord { - r.column = 0 // report at start of record - return record, r.error(ErrFieldCount) - } - } else if r.FieldsPerRecord == 0 { - r.FieldsPerRecord = len(record) - } - return record, nil -} - -// ReadAll reads all the remaining records from r. -// Each record is a slice of fields. -func (r *Reader) ReadAll() (records [][]string, err os.Error) { - for { - record, err := r.Read() - if err == os.EOF { - return records, nil - } - if err != nil { - return nil, err - } - records = append(records, record) - } - panic("unreachable") -} - -// readRune reads one rune from r, folding \r\n to \n and keeping track -// of our far into the line we have read. r.column will point to the start -// of this rune, not the end of this rune. -func (r *Reader) readRune() (int, os.Error) { - rune, _, err := r.r.ReadRune() - - // Handle \r\n here. We make the simplifying assumption that - // anytime \r is followed by \n that it can be folded to \n. - // We will not detect files which contain both \r\n and bare \n. - if rune == '\r' { - rune, _, err = r.r.ReadRune() - if err == nil { - if rune != '\n' { - r.r.UnreadRune() - rune = '\r' - } - } - } - r.column++ - return rune, err -} - -// unreadRune puts the last rune read from r back. -func (r *Reader) unreadRune() { - r.r.UnreadRune() - r.column-- -} - -// skip reads runes up to and including the rune delim or until error. -func (r *Reader) skip(delim int) os.Error { - for { - rune, err := r.readRune() - if err != nil { - return err - } - if rune == delim { - return nil - } - } - panic("unreachable") -} - -// parseRecord reads and parses a single csv record from r. -func (r *Reader) parseRecord() (fields []string, err os.Error) { - // Each record starts on a new line. We increment our line - // number (lines start at 1, not 0) and set column to -1 - // so as we increment in readRune it points to the character we read. - r.line++ - r.column = -1 - - // Peek at the first rune. If it is an error we are done. - // If we are support comments and it is the comment character - // the skip to the end of line. - - rune, _, err := r.r.ReadRune() - if err != nil { - return nil, err - } - - if r.Comment != 0 && rune == r.Comment { - return nil, r.skip('\n') - } - r.r.UnreadRune() - - // At this point we have at least one field. - for { - haveField, delim, err := r.parseField() - if haveField { - fields = append(fields, r.field.String()) - } - if delim == '\n' || err == os.EOF { - return fields, err - } else if err != nil { - return nil, err - } - } - panic("unreachable") -} - - -// parseField parses the next field in the record. The read field is -// located in r.field. Delim is the first character not part of the field -// (r.Comma or '\n'). -func (r *Reader) parseField() (haveField bool, delim int, err os.Error) { - r.field.Reset() - - rune, err := r.readRune() - if err != nil { - // If we have EOF and are not at the start of a line - // then we return the empty field. We have already - // checked for trailing commas if needed. - if err == os.EOF && r.column != 0 { - return true, 0, err - } - return false, 0, err - } - - if r.TrimLeadingSpace { - for unicode.IsSpace(rune) { - rune, err = r.readRune() - if err != nil { - return false, 0, err - } - } - } - - switch rune { - case r.Comma: - // will check below - - case '\n': - // We are a trailing empty field or a blank linke - if r.column == 0 { - return false, rune, nil - } - return true, rune, nil - - case '"': - // quoted field - Quoted: - for { - rune, err = r.readRune() - if err != nil { - if err == os.EOF { - if r.LazyQuotes { - return true, 0, err - } - return false, 0, r.error(ErrQuote) - } - return false, 0, err - } - switch rune { - case '"': - rune, err = r.readRune() - if err != nil || rune == r.Comma { - break Quoted - } - if rune == '\n' { - return true, rune, nil - } - if rune != '"' { - if !r.LazyQuotes { - r.column-- - return false, 0, r.error(ErrQuote) - } - // accept the bare quote - r.field.WriteRune('"') - } - case '\n': - r.line++ - r.column = -1 - } - r.field.WriteRune(rune) - } - - default: - // unquoted field - for { - r.field.WriteRune(rune) - rune, err = r.readRune() - if err != nil || rune == r.Comma { - break - } - if rune == '\n' { - return true, rune, nil - } - if !r.LazyQuotes && rune == '"' { - return false, 0, r.error(ErrBareQuote) - } - } - } - - if err != nil { - if err == os.EOF { - return true, 0, err - } - return false, 0, err - } - - if !r.TrailingComma { - // We don't allow trailing commas. See if we - // are at the end of the line (being mindful - // of triming spaces - c := r.column - rune, err = r.readRune() - if r.TrimLeadingSpace { - for unicode.IsSpace(rune) { - rune, err = r.readRune() - if err != nil { - break - } - } - } - if err == os.EOF || rune == '\n' { - r.column = c // report the comma - return false, 0, r.error(ErrTrailingComma) - } - r.unreadRune() - } - return true, rune, nil -} |