diff options
Diffstat (limited to 'pdf/pdf.go')
| -rw-r--r-- | pdf/pdf.go | 39 |
1 files changed, 20 insertions, 19 deletions
@@ -141,21 +141,21 @@ const ( // Lexer is a basic lexical analyser for the Portable Document Format, // giving limited error information. type Lexer struct { - p []byte // input buffer + P []byte // input buffer } func (lex *Lexer) read() (byte, bool) { - if len(lex.p) > 0 { - ch := lex.p[0] - lex.p = lex.p[1:] + if len(lex.P) > 0 { + ch := lex.P[0] + lex.P = lex.P[1:] return ch, true } return 0, false } func (lex *Lexer) peek() (byte, bool) { - if len(lex.p) > 0 { - return lex.p[0], true + if len(lex.P) > 0 { + return lex.P[0], true } return 0, false } @@ -671,9 +671,10 @@ func (u *Updater) loadXref(lex *Lexer, loadedEntries map[uint]struct{}) error { var haystackRE = regexp.MustCompile(`(?s:.*)\sstartxref\s+(\d+)\s+%%EOF`) -// Initialize builds the cross-reference table and prepares -// a new trailer dictionary. -func (u *Updater) Initialize() error { +// NewUpdater initializes an Updater, building the cross-reference table and +// preparing a new trailer dictionary. +func NewUpdater(document []byte) (*Updater, error) { + u := &Updater{Document: document} u.updated = make(map[uint]struct{}) // We only need to look for startxref roughly within @@ -685,7 +686,7 @@ func (u *Updater) Initialize() error { m := haystackRE.FindSubmatch(haystack) if m == nil { - return errors.New("cannot find startxref") + return nil, errors.New("cannot find startxref") } xrefOffset, _ := strconv.ParseInt(string(m[1]), 10, 64) @@ -696,20 +697,20 @@ func (u *Updater) Initialize() error { var throwawayStack []Object for { if _, ok := loadedXrefs[xrefOffset]; ok { - return errors.New("circular xref offsets") + return nil, errors.New("circular xref offsets") } if xrefOffset >= int64(len(u.Document)) { - return errors.New("invalid xref offset") + return nil, errors.New("invalid xref offset") } lex := Lexer{u.Document[xrefOffset:]} if err := u.loadXref(&lex, loadedEntries); err != nil { - return err + return nil, err } trailer, _ := u.parse(&lex, &throwawayStack) if trailer.Kind != Dict { - return errors.New("invalid trailer dictionary") + return nil, errors.New("invalid trailer dictionary") } if len(loadedXrefs) == 0 { u.Trailer = trailer.Dict @@ -722,7 +723,7 @@ func (u *Updater) Initialize() error { } // FIXME: We don't check for size_t over or underflow. if !prevOffset.IsInteger() { - return errors.New("invalid Prev offset") + return nil, errors.New("invalid Prev offset") } xrefOffset = int64(prevOffset.Number) } @@ -731,10 +732,10 @@ func (u *Updater) Initialize() error { lastSize, ok := u.Trailer["Size"] if !ok || !lastSize.IsInteger() || lastSize.Number <= 0 { - return errors.New("invalid or missing cross-reference table Size") + return nil, errors.New("invalid or missing cross-reference table Size") } u.xrefSize = uint(lastSize.Number) - return nil + return u, nil } // Get retrieves an object by its number and generation--may return @@ -1097,8 +1098,8 @@ func FillInSignature(document []byte, signOff, signLen int, // PDF 1.6. func Sign(document []byte, key crypto.PrivateKey, certs []*x509.Certificate) ([]byte, error) { - pdf := &Updater{Document: document} - if err := pdf.Initialize(); err != nil { + pdf, err := NewUpdater(document) + if err != nil { return nil, err } |